Earthship Summary

I wrote up this little article summarizing the earthship concept over at my blog http://www.mypermaculture.net/?p=107 . Check it out and let me know what you think.

I'll post it here for you guys as well.


Let’s have a look at the earthship building design concept and see what it’s all about.

I’ll start off by listing the basic design principles behind the earthship and then go into more detail later.

1. Thermal/Solar Heating and Cooling

2. Solar and Wind Electricity

3. Contained Sewage Treatment

4. Building with Natural and Recycled Materials

5. Water Harvesting

6. Food Production

Just by looking at the main design principles, you can see the idea behind the earthship design is to take our most basic needs and bring them into one building, where the occupants have direct access and control over them. By decentralizing the control over our most basic needs, the earthship design seeks to help the occupants attain a certain level of freedom, as well as reduce the environmental impact of these centralized system.

So let’s have a look at each of these design principles and go into a little more depth about what they mean.

Thermal/Solar Heating and Cooling

I would say this is the fundamental design principle behind the earthship concept. The idea that the building can pretty much (depends on climate, location, and design) heat and cool itself using only the sun and thermal mass is pretty awesome. But how does this work and what is thermal mass you ask?

Well let’s start with thermal mass. Thermal mass can be any dense, heavy stuff like water, rocks, or compacted earth. Dense means no voids or air spaces. The more dense the mass the more temperature it holds. This density acts as a conduit for temperature. Think of the lake where you like to go swimming. If it is early summer and one of the first hot days, the lake is still going to be cold from the winter even though the air temperature is hot. This is because the lake is a very large mass that has stored all the cold energy from the winter and it will take a long time to lose that cold energy and start to gain heat energy from the warm days of summer. This also works the other way, when it has been hot for a long time and then there is a cold day, the lake will still be relatively warm, having stored all that heat energy from the hot days.

The thermal mass in an earthship works on these principles. The outer few feet of the earth’s surface heat up and cool off depending on the weather. But deeper in the earth, about four feet and beyond, the temperature is more constant, being sheltered from the weather above. Here, the earth can be used to both cool and stabilize temperatures.

In the winter when you want to heat the home, you let the low winter sun shine in on the thermal mass walls of the earthship. The sun heats the mass, the mass stores the heat. The more mass, the more storage capacity. When there is no sun, the heat stored in the mass radiates into the living space.


In the summer when you want to cool your home, you open an air duct running underground and a vent in the greenhouse, which brings in the cool, stable temperature (around 55F) of the earth and lets the hot air escape. This coolness is then stored in the mass of the earthship, further helping to regulate the temperature in the living space.

In summery, the mass of the building helps to stabilize the temperature and with a little input from the sun’s warmth, or the earth’ s coolness, the temperature in the living space is kept relatively comfortable. In some cold climates, where the sun doesn’t shine much in the winter, there could be a need for supplementary heat, but this would be used very minimally.



Solar and Wind Electricity

Earthships produce electricity using solar panels and wind mills. This electricity is then stored in batteries to be used when needed. The more electricity one needs, the more panels/wind mills and batteries are required. These are usually the most expensive element when building an earthship, so if you want to keep the cost down, the first thing to do is reduce your energy consumption. Basically you can run any regular home appliances on these systems, it’s just a matter of how much you want to spend on the set up.

Earthships can also be hooked up to the regular power grid, if the occupants decide this is the route they wish to go. This could be a cheaper way to provide all your electricity needs, if you have a lot of appliances to run and the grid is nearby.



Contained Sewage Treatment

The earthship strategy for treating sewage is based on the observation of wetlands, which have been naturally cleaning water for millions of years. The idea is that the dirty water flows slowly past the roots of plants, which take up the nutrients and turn it into greenery. There are also billions of bacteria which interact with the dirty water and plant roots, also helping to break down any pathogens.

The earthship is set up to use water four times before it leaves the system. The first time is when taking a shower, doing laundry, washing dishes, or brushing your teeth. The water that then flows down the drain from these activities is called grey water. It is somewhat dirty, but not that dirty.

This grey water is then routed through indoor, rubber lined botanical cells, which are planted with a variety of different plants. These plants feast on the nutrient rich grey water and clean it in the process. The second use of the water being to grow indoor plants in the greenhouse, which can be both ornamental and edible. Because of the warm conditions of the earthship, plants will be able to grow year round in these planter cells, providing food and a lovely atmosphere.

The third use of the water comes when flushing the toilet. The grey water that has been used by plants and filtered, is then pumped to the toilet tank and used to flush. There is no need for the toilet to use perfectly clean water to flush, so the grey water, which has been used for two different purposes already, is perfect.

For the fourth and final use of the water, the extra dirty black water, from the toilet, is sent out into a septic tank. From the septic it is directed into outdoor, rubber lined botanical cells, planted with wetland plants specifically chosen to treat sewage. These plants help to break down pathogens from the dirty black water and grow to look nice at the same time. There can be a series of these outdoor treatment cells, depending on the sewage load from the house.

Once the black water has passed through all the planted treatment cells, it is then released back into the ground. This water is now much, much cleaner than if it were just let out into a conventional leach field from a septic and it has been used to grow all sorts of non edible plants.



Building with Natural and Recycled Materials

This aspect of the earthship build is probably the second best place to save money, after the electricity part. If you put in a bunch of time and effort, you can come up with all sorts of recycled material to use, instead of buying it new. Like windows, doors, tubs, toilets, insulation, floor tiles, etc. The main recycled materials used in most earthships though, are recycled bottles, cans, and tires.

The bottles and cans are used as filler when building interior walls with cement, so not as much cement is needed, and when packing out the spaces between the tires to create a smooth interior wall. The bottles can also be used to make beautiful stained glass art.


The tires are used as the main structural element, when filled with rammed earth to create the monolithic, thermal mass walls. These walls are incredibly massive and stable. Here is a good shot of one.

As far as natural materials goes, the dirt in the tires, logs for the roof, and mud plaster to pack out the spaces between tires is about it.



Water Harvesting

The earthship concept is designed to catch rain water that falls on the roof and store it in underground cisterns, where it is then pumped into the house, filtered, and used by the occupants. The size of the cistern depends on the annual rainfall in the area where the earthship is to be built. If there are very long stretches of no rain, then the cistern will be considerably larger than places where it rains all the time.

Catching rain water is especially good where the ground water has been polluted, or mostly used up to the point where a well would need to be super deep to access it. It is also good for not contributing to the depletion of aquifers.



Food Production

Earthships create an environment where plants love to grow, not only for aesthetics, but also for food production. The large south facing windows and grey water planter cells make it perfect for growing plants. The plants don’t need to be watered because of the grey water running through the planters, and they have excellent light exposure.

By growing plants in this greenhouse space along the front of the earthship, you are able to have year round access to fresh food. This growing space is kept warm using the thermal/solar heating principle from above, allowing for some exotic plant species to be kept, that would otherwise die out doors. A popular example is banana plants.

Having year round access to fresh, nutrient dense, organic food gives a major boost to over all health and well being. There is nothing like having fresh tomatoes, picked from your planter, in January when the snow is flying outside. This also adds a real sense of security, knowing you can grow food inside your own home year round.

Here are some great shots of the earthships full of wonderful plants.



All in all the earthship building concept is an excellent example of a better way to design homes, by harmonizing with the natural elements and using them to bring control over the essentials for life back to the occupants.

There is something to be said about living in home that heats and cools itself, produces electricity, treats sewage, catches water, and grows food.

I think that's a great summary. It paints earthships in a wonderful light and rightfully so, they take a very holistic approach that address all the ways our dwellings can better interact with the environment.

Now for my contrarian views that I think those building outside of dessert climates should consider.

Thermal/Solar heating and cooling

This design element has had major beneficial impacts on natural building but most earthships dont seem to have the best balance. "Mass and glass" is typically more expensive than "airtight and super insulated" and much harder to control temperatures with. Most earthships have glass to floor ratios well above more typical passive solar designs. They try to use Thermal Mass TM to compensate but the point of diminishing returns seems poorly accounted for. While TM can reduce temp swings it can also hinder performance for those that like to control their interior temperatures.

Glass ratios above around 12% lead to overheating no matter how much mass is included. All that glass loses a lot heat at night and cloudy spells. Passive solar gain quickly disappears without ACH50 proven airtightness and high R-values to contain it. There seems to be a new rule of thumb emerging for high-performance and net-zero energy homes of less than 5% for avoiding excess costs and overheating.

"Earthtubes" are less of a heating and cooling strategy and more of a ventilation strategy. In their most effective conditioning role "passive cooling", they introduce serious risk in more humid climates by introducing mold and mildew through the inner walls of the cool tube.

Solar & other renewable electricity

Off-grid: Maybe the most expensive and probably the most complicated with maintenance, replacement, toxicity concerns. Battery tech is exploding right now and hopefully will change this conversation in the near future. Sites that are far from the grid may have no choice but this probably leads to wilderness fragmentation, an important concept that earthships seem to ignore.
On-Grid: Cut your system costs and complications in half. Practically eliminate maintenance, replacement, environmental impact concerns. Use more conventional appliances by not having to design and size for peak demand. Help your neighbors and community more by offsetting their dirty energy use with your excess renewable generation.

Contained Sewage Treatment

Grey water use offers some nice benefits.
I dont think the black water systems improve enough on a typical septic system to justify the maintenance, risks and costs. Your descripiton is really just a typical system with a wetlands for the drainfield. Ive visited one of these that I would describe as close to failure. "Wetland" seems to not work as well as a more conventional drainfield medium.

Materials
Love the use of tires as earthship's main deviation from conventional choices. Hate the labor costs which does not equate to best place to save money to me.

Water Harvesting
Nothing really unique that earthships offer here and many of the designs seem to miss a lot of opportunity with earth bermed roofs.

Food Production
This is the most dubious of the earthship claims but perhaps its only in its infancy. I see no benefits and only problems by attaching a greenhouse to the human house. Plants have different needs than humans. Greenhouses have extreme temperatures and humidity that pose a lot of problems for those trying to separate and/or regulate it with the main house.

Seeing that passive solar is a strategy for temperate climates, there doesnt seem to be a lot of opportunity here. The space is too valuable and the food production during the off-season is too measly to justify the loss of floor area. Trying to keep wintertime humidity to safe levels is hard enough with my houseplants, but a whole greenhouse? Impossible without having a separating wall and that is a major conflict for harvesting heat from the south side of a home.

Thanks for that Brian. I live in a cold climate and a lot of the things you mentioned are definitely things that need to be considered when building away from a desert type climate.

I agree with you on the point about having the space very well insulated and airtight. A failure on these fronts will lead to leaching out of warmth from the mass and a more difficult time controlling temperature. I think the a rocket mass heater is pretty much a necessity in a cold, cloudy climate where solar gain is minimal during the winter months. With this addition I believe the large amount of mass in the earthship wall will be of a great benefit in reducing the amount of fuel required to heat the home. This must go hand in hand with the super insulation/airtight factor though for maximum performance. The RMH will add great flexibility in temperature control during winter months.

I am not sure I agree on your figure of an over 12% glass facing leading to over heating. If properly designed, there should be no sun actually shining into the building itself during the summer months. The greenhouse part will certainly heat up, but it will also vent out the top and draw in cooler air through the 'earthtubes'. In the current earthship designs, there is a glass partition wall between the actually living area and the greenhouse area giving that extra line of defence between the large temperature fluctuations of the greenhouse and the stabler temperature of the living space. During the winter months, I don't think over heating would be an issue either due to the lack of sunny days, and if it did become uncomfortably warm in the living space, the greenhouse vents could be opened again to vent the excess hot air.

I agree on the mould/mildew issue with the 'earthtubes' in humid climates, and it is something to be thoroughly research before building to come up with a solution.

The off grid battery tech is always a weak spot when homesteading, but like you say things are changing on this front. I am not sure what you mean by "wilderness fragmentation" , maybe you could explain that to me. Thanks.

I am also not sure what you are saying in terms of "eliminating environmental impact concerns" when being on grid. There are many problems with the way grid power is generated and supplied these days. I'm not sure connecting to the grid will reduce environmental impact over being off grid. I guess the best thing here is to reduce total power consumption in general. Something to always consider

I agree with your thoughts on the problems relating to the black water treatment and the maintenance/cost factors. If designed properly, with lots of money on hand, I would say a well designed wetland black water treatment system would certainly be better for the environment than a conventional drain field though. The key is well designed. I would say composting toilets are much more cost effective and better for the environment as a whole though.

As far as growing food in the greenhouse, it must be well designed. Like I said earlier there should be a wall between the greenhouse space and the living space to help mitigate the issues of having a greenhouse space in a home. This way the temperature and humidity can be better controlled in both spaces. Living in a cold, cloudy climate may very well require the greenhouse to be better insulated and/or have supplementary heat to help with growing food and regulating temp/humidity.

In any case, there are certainly issues pertaining to this building style that need to be thoroughly thought out designed extremely well, especially when building in a cold, humid, cloudy climate.

Discussions like these are really great for people to read and get everyone thinking about things before just going ahead and building willy nilly.

Thanks for your input. This is good stuff here.

Thanks for sharing and taking the criticism well! I want to reiterate all that is good about the earthship and the founders concepts. It is indeed good stuff.

Its great that you recognize importance of airsealing and Rvalue and think alot of people are coming around. I think people are getting to net-zero in the bitter, cold north without combustion appliances like RMH but it involves including the grid in the big picture.

This stuff gets philosophical. Grid tied PV is the best answer we have for improving how dirty the grid really is. PV owners that connect to the grid have a very powerful impact by being a generator closer to the demand which exponentially reduces the neighboring user's dirty energy use.

PV owners who ignore the grid, waste their excess generation which can be 2x as much when you have to design for batteries and peak appliance demand compared to grid tied. All that waste, right next to a neighbor who is a distanced, impactful user of carbon, nuclear, or fish killing based grid energy.

Wilderness fragmentation isnt that hard of a concept to get if you think about it. This stuff gets political so we should stay away from it unless earthship promotes it?

Yes, windows are designed to be fully shaded on the summer equinox, but shoulder seasons dont get as much shade. On a hot day with a big Delta T between indoors and out, a big but fully shaded window area would overheat more than an insulated wall with a smaller window area. You cant cool down a house by opening windows if its warmer outside and humidity is always a concern outside of the desert.

One area I would like to explore more in here is that separation between greenhouse and humanhouse. What's the current thinking on the specifics of that wall? Does it have windows, doors, vents? Is it insulated or mass? When you dont want the humidity but want the heat how is this done?

Brian Knight wrote:Thanks for sharing and taking the criticism well!

You are most welcome.

Brian Knight wrote:
Yes, windows are designed to be fully shaded on the summer equinox, but shoulder seasons dont get as much shade. On a hot day with a big Delta T between indoors and out, a big but fully shaded window area would overheat more than an insulated wall with a smaller window area. You cant cool down a house by opening windows if its warmer outside and humidity is always a concern outside of the desert.

Agreed, but...

This involves your question below.

Brian Knight wrote:
One area I would like to explore more in here is that separation between greenhouse and humanhouse. What's the current thinking on the specifics of that wall? Does it have windows, doors, vents? Is it insulated or mass?

The separation between greenhouse and living space.

Here are a few photos showing the separation wall.

http://greenlandlady.com/site/wp-content/uploads/2010/03/Photo.MichaelReynolds.CornerCottage2010.jpg

https://stewardsofearth.files.wordpress.com/2012/06/dsc_0462a.jpg


http://media-cache-ec0.pinimg.com/236x/fe/a1/ec/fea1ec815c76ae5e6264d5f72d7db47b.jpg


Basically, my understanding is that, it is just another wall with glass doors and windows and vents (could just be opening windows/doors). So, when it is hot out and the sun angle is such that the sun is low enough in the sky to be shining in through the separation wall's windows and you want to avoid overheating, there should be blinds/curtains installed on the separation wall's windows, which can be pulled to block the sun's penetration into the living space. This would make a significant difference by it self, but the air vent on the greenhouse could also be opened to allow for the escape of hot air, further cooling things down.

Brian Knight wrote:
When you dont want the humidity but want the heat how is this done?

I am not totally sure about this one. I think you would just open the vents in the separation wall to allow the warm air from the greenhouse come in the living space. I am not sure if that humidity would be much of a problem in the living space. Here's what I see; if it has been cold out long enough that your living space is becoming cool and you wish to warm it, than the sun must be low enough in the sky for it's rays to shine through the separation wall. This also probably means the separation wall's vents have been closed for some time, which would be preventing the humidity of the greenhouse from entering the living space. So now it is sunny and you wish to warm the living space. The opening of the vents to allow the warm air from the greenhouse into the living space would only happen for the period of time where the sun is shining, which I don't think would be long enough to make a significant difference in the humidity of the living space. Or, since the sun is low in the sky and shining in the living space, simply opening the curtains, without opening the vents, might be enough to warm the space.

This is also a reason I think the RMH is a key addition to this design concept. There would be very little reason to open the vents between living space and greenhouse. If it gets too cold, fire up the stove for a bit, get the mass of the walls charged back up and it will stay warm for a long time. Couple this with the insulated curtains and you can really hold that warmth in the living space. If your mass, roof, and floor are nicely insulated and you have those curtains up on the separation wall windows, this set up could really sing. Burning the RMH will also help to dehumidify the air in the living space. It would also allow for more ventilation, because you could now do some burning and open up the separation wall vents, plus the greenhouse vent and earthtubes to get a nice circulation of fresh air in the home without worrying too much about all that heat going out the vents. If it gets cold again, just close everything up and start the stove.

Pretty sweet I think, but of course the big thing is the cost of all that glass and insulation. If you have the money to set it up right, I think this system can do a super good job at keeping you cozy all year round.

Some thoughts to consider...

Really examine all aspects of a chosen design and fully consider all feedback...especially from those that have actually built natural and/or fossorial architecture...

Go for "draft proof" and not "air tight" as the later is a contemporary concept that on paper looks great, but in the long term, contributes to building sickness and stagnation of air unless the architecture in turn is heavily dependent on technology and mechanicals to achieve a positive balance in air to air exchange with some form of heat-cooling recover. Yes there are airtight, net zero structures that are being built...they are all less than 30 years (most 10 years) old and we have no real idea how they will last in the long run. If you are game for a full build experiment...go for it. For my clients and projects, we tend to stick with what is vernacular, traditional, and natural while still achieve close, if not the same results. Being a permaculture site, the trend is to have less industrialized materials, less technology dependence and more natural/traditional modalities of architecture...while still achieve a thermally efficient build.

Most (not all) fossorial architecture historically is found in desert regions. Being underground is a great way to escape heat and too much dryness. Move out of those regions, and it is best to look at what are the vernacular forms of architecture for those areas. Some (in or near the arctic circle) also went below ground, yet these structure relied on fire for warmth, and when adapted to more modern builds, really relied on complete separation of the "greenhouse" from the heated living space by more than just mass or a combination of both in the correct balance and type. A note again than airtight does not work with these natural materials like cobb, cordwood walls, straw bale, etc..

Proper location on the building site is absolutely crucial with fossorial architecture...especially here in the cold north like Vermont. Then the choice is going to have to be whether its going to be a modern high tech build or a vernacular natural build...the two don't really play well together for the most part, yet there can be some interplay.

I am not a fan of attached greenhouses for many of the reason Brian has listed. I would much rather have a separate structure attached by a "weather lock" room that can be opened and shut according to primary living space needs. This greenhouse, if to serve a fossorial home or otherwise is best designed as a Walipini or related structure, and with a RMH or related system if built in the colder north, especially if used for food production year round and/or part of the water/sewage treatment system.

Contained Sewage Treatment isn't an issue accept for "officials" and those that are still afraid of their own poop. Having traveled the world and seen many of these systems and eaten food (like in Japan where humanure is normally spread on gardens and has been for millenia) I commend you for going for the system you have chosen. These systems are not that complicated in general, there is very little health risk as so many worry about, and the benefits are wonderful. Typical septic systems are a control modality for municipalities to stop and/or control construction. These systems are also a money maker for the contractors that engineer and build them. The construction industry has a well established foothold in this area and are very reluctant to entertain other systems that step on their "bread and butter." From composting toilets to black/grey water green house systems...all are much easier to work and live with than most in the building industry, and the Code departments behind them really want to face or admit to.


Brian, your critique of tires? How many have you personally built or been part of designing and building? What was it about these builds you had been part of did you find less than to your liking compared to other "natural" foundation systems.

Food production is a big positive (in the correct climates) of fossorial architecture. Brian and I are in complete agreement about attaching the "food producing" greenhouse (or any actual greenhouse) directly onto a structure as so many of these do. Some work...many fail...and many more are just a problem waiting to happen. Detach this system in some fashion with a "air lock" of some type between the two spaces, and/or make the separating wall just as if it was dealing with the greenhouse as if it was the outside natural environment.

Hope my banter is of some use...

Hi Brian......as usually you are great to quibble with...

(P.S. to other readers...Brian and I are friends and I have the utmost respect for him and his designs, they are the "tech" version of green, while mine are the "natural." His points are valid and the details we argue over (for the most part) are academic among professionals in this field.)

Brian wrote
Wilderness fragmentation isnt that hard of a concept to get if you think about it. This stuff gets political so we should stay away from it unless earthship promotes it?

Im not sure what you mean by this. I googled Wilderness fragmentation this is what i got.

-Wilderness Fragmentation is often defined as a decrease in some or all types of natural habitats in a landscape, and the dividing of the landscape into smaller and more isolated pieces.

I'm not really following what your getting at. Should we only be building in towns and cities that have already decreased the natural habitats? Why stay away from it unless the earthship promotes it? Building any kind of house in the bush is going to deminish natural habitats but if propor permiculture techniques are used in the building and surrounding area arn't we going to increase habitats for critters? What does it have to do with earthships?

Hi Rob, its really more of a philosophical outlook on how we develop land. Its a touchy subject that probably doesnt belong in this thread but I do think most earthship projects I see, hurt the environment when viewed through that lens. I mainly brought it up as a major factor in the on-grid vs off-grid comparisons.

Jay, love you as always and its been awhile since weve had some good banter so I will touch on a few points and leave it alone.. in this thread at least.

You still have never provided any details or descriptions of your draftproof vs airtight argument. They are the same thing to me. There is no point in using insulation if you are not accounting for uncontrolled air movement. Proponents of insulation and air sealing use the blower door as a way to measure how airtight a structure is. Would you also use this measurement device to prove something is draftproof vs airtight? I dont think you can dismiss the importance of measuring airtightness when a project includes insulation. Airtightness is arguably more important than insulation.

When its not seasonal for opening windows, outdoor air introduction is best controlled with a fan. If you are powering it with renewable energy, there will not be much harm to nature but the indoor air quality will be measurably better. Outdoor air introduction is one of the best things you can do for indoor air quality whether the house is leaky, tight or draftproof, whatever that means.

I dont think there is anything less-permacultury about using available technology. Most people building homes are going to include plumbing, electrical and some amount of appliances. Why should we ignore the simple technology of a fan, that is orders of magnitude less complicated than well pumps, refrigerators, heating appliances etc?

Your declarations on the appropriateness of airtight and net-zero are a bit absurd. Scientists have been involved with building airtight and super insulated homes since the late 70s and in case you didnt know, scientists are pretty good at measuring stuff. They use all sorts of instruments to monitor and model how these homes are performing. Over 10,000 homes have been built to the r-2000 standard in Canada. At least as many passive house homes in Europe. Are these homes suffering from catastrophic failure? No. They are saving boatloads of carbon based energy compared to the older ways of building.

I dont care how natural, ancient, or fossorial a structure is, if its using a typical amount of un-renewable energy, its not an outcome that I would want to emulate.

No, I havent built ANY tire walls nor would I unless it was what a client wanted. That doesnt mean I cant critique their usefulness. They use a recycled material, and when done right, will produce a long lasting result just like any natural or "un" natural material. Personally, I think the labor factor is too big to overcome for my personal preferences but if all I had was a bunch of tires, some dirt and a tamp, I would have no problem using the available resources to build some walls with.

Which brings us to Simon's plans. Me and Jay seem to agree on a very big detail with the greenhouse thing. Iam not saying dont do it but I encourage those interested, to dig deep into the details. The pictures you provided were interesting. For all but one, I have more houseplants (humidity generators) than what was shown in the pictures. I could be wrong but some of those varieties did not seem suited to their light exposure. NONE of the pictures showed any food being produced and I think you would be very hard pressed to find a successful example of meaningful, production in such a space. Also, all 3 pics featured sloped glass which Iam pretty sure they have gotten away from for very good reasons.

The separating wall is a problem, not solution. They appear to be mostly glass. So not insulation or thermal mass. Why would you want to double the amount of south-facing glass needed? Windows are a huge expense and there is no compelling reasons to double your costs here when you can nix the greenhouse and do a more traditional passive solar design. When the "greenhouse" is hot or cold, the glass will do a poor job insulating the living space. There is no way you can vent the heat without venting the humidity. These spaces are confused. They are not greenhouses. They are not what I consider proper passive solar design. They seem to be the worst of both worlds.

So this banter thing is a lot of fun,
Here's how I see it, No matter what you build if you look through the lens of Wilderness Fragmentation your going to do more harm than good. Like Brian said thats a differnt topic for another day.

If one was going to build with recycled materials then bonus, I don't care if its tires or cans or used windows or steel cutt from the side of a washing machine. Things are being used in a useful manner and thats better than being sent to the dump to rot in a toxic enviroment or a recycling plant that uses a redictulous amounts of energy (usually not very carbon friendly even with onsite energy production but thats another subject for another thread) to transform said recyclables into something new. But do what you please, build from all new materials if you like. If you don't like the tires use concrete pack your backfill and do a sealed thermal wrap what ever its all good.

If one was to build a earthship style (I say this because anything that isn't built from one of mikes plans is a passive solar TM home) and made sure that it was air tight (when all vents are closed) and insulated properly like an r-20+ (from my understanding anymore r value is not worth the buck) it could most certianly get most of its heating from the sun. Windows sloped or not. (most of mikes designs still have sloping windows except the simple survival that does have sloped windows ontop of the vertical windows and the packaged design but the rest all have sloping windows to get the most amount of sun in on the shortest day of the year) I think that one could most certianly build an interior wall with windows and doors (insulated where it can be) that seperates the main house from the greenhouse. And I think that if it has an airtight seal when doors, windows, and vents are closed there really shouldn't be any excessive humidity issues in the main house and same for the greenhouse if sufficient venting is supplied. As for cold season venting and fresh air could not a hrv of erv be used? the hrv should take some of the moisture out of the air, no? I think that the greenhouse can be a huge aid in keeping steady temperature and it can also be a hinderance if used incorrectly. If insulated curtans or shades are used to keep the warm in on those gray days and cold nights in the winter and to keep the heat out in the summer you should be able to see more gain from your greenhouse than loss. By having a greenhouse attached you don't get the wind and snow hitting the inner windows of the interior glass wall, so heat loss from the main house is minimized basicaly a weather lock. (I live in an old house built in the 60's. I heat with wood and here in the winter at night I close my blinds to keep the heat in. and in the summer often durring the day the temp of the house can be kept quite cool by closing the blinds in the morning and leaving them shut all day. there is a substantial differance in temps just by running my blinds at the right time and i have no TM and the house is very poorly insulated)
So what I put forward is
If you build a house with thermal mass, make it as air tight as you can and have proper ventilation why couldn't you use a greenhouse to do most of your heating and use say a rmh to supliment on the crappy days? Should be a lot more effecient than the matchstick house I'm living in now. especially if electricity is produced onsite in a renewable fasion.

Sure Rob, the greenhouse attachment might be better than a typical home but it might not. It depends on the details. Not liking the weatherlock explanation. A home's exterior walls should be airtight and insulated. Building the home's walls right in the first place is cheaper and better performing than building a "greenhouse" on the outside of them. A greenhouse that overheats in summer and shoulder seasons yet doesnt get adequate overhead light during the main growing season.

Yes to HRV, ERV or other fresh air introduction but they are not intended for de-humidification. They can help when its drier outside but hurt when its more humid outside which is more often than not outside of most desserts when its not cold out.

Boy that separating wall gets more confusing and complicated by the post. So it has vents, windows/doors, insulated curtains but its insulated where it can be. Why not eliminate the poor performing greenhouse and not have to mess with that confused wall? Still not understanding how to harvest heat without the humidity.

Typical passive solar with modest glazing works great without all that fuss and expense. Iam not understanding the details of how the attached greehouse with seperating wall is supposed to perform better unless its just the magic of Michael's paid for plans or consultation that solves the concerns?

Sure Rob, the greenhouse attachment might be better than a typical home but it might not. It depends on the details. Not liking the weatherlock explanation.

It has been my experience that greenhouses should be greenhouses and domestic living spaces there own entity...Mixing the two architectural forms is fraught with issues and often the separations barriers between the two forms seldom work as intended.

Breezeways, weather locks, mud rooms, and related "separating architecture" has a well proven history in both zoological and research facilities, as well as, domestic architecture. Seldom would I design a "frontal greenhouse" onto the domestic living space, but if the layout warrants an attached greenhouse with weather lock works very nicely in my experience.

A home's exterior walls should be airtight and insulated. Building the home's walls right in the first place is cheaper and better performing than building...

A home's exterior walls SHOULD NOT BE AIRTIGHT...to state this so factually is neither historically nor realistically accurate, but a highly subjective statement. Particularly in vernacular, historical, and natural architectures the thermal envelope needs to be "draft proof," yet highly permeable...modern concepts in "air tight" architecture can not facilitate these needs.

Yes to HRV, ERV or other fresh air introduction but they are not intended for dehumidification. They can help when its drier outside but hurt when its more humid outside which is more often than not outside of most desserts when its not cold out.

These devices and the technology behind them do not typically work well within the design construct of natural homes, nor...if the natural home is designed well...are they needed.

Typical passive solar with modest glazing works great without all that fuss and expense. I am not understanding the details of how the attached greenhouse with seperating wall is supposed to perform better unless its just the magic of Michael's paid for plans or consultation that solves the concerns?

I agree with the above comments 99.9%

Many of these concepts of attached frontal greenhouses and the like I am sure can be..."made to work,"...

Is it the most efficient design for the money spent per square meter/foot? I have not seen one yet that I, or someone like Brian could not design just as well, often with less or better spent fiscal resources. Where Brian and I (I think) agree on almost completely is that if you focus on the proper fenestration balance and design...not passive solar at all, and a super insulated and thermally efficient roof and wall diaphragm matrix, the architecture will be much better served, have lower maintenance, and a much longer viable lifespan architecturally.

Neither I, or Brian, are trying to dissuade anyone from fossorial architecture, particularly in the right biome type. However, one must really weigh the actualities of this architectural design type, as it is very easy to get it wrong...and...very few actually get all the different moving parts working well in concert with each other to make it a good choice. Seldom is it as easily done, as some claim, compared to other types of above grade architecture. (note: this is not the case in all biomes, such as arid desert regions where fossorial architecture works really well and has dominated for millenia.)
Regards,

j

I cant let Jay's comments go uncommented on any more than he can mine but glad we agree on some of the big picture stuff.

Thank you Jay for correcting me on the "all walls should be airtight and insulated" comment. Tropical climates probably dont need insulation and some very rare desert climates can perform fine with "mass only" walls. Even in extreme climates where one would prefer to have a thermally efficient structure there are many situations where it makes no sense to go out of your way to air-seal and insulate.

One of our major disagreements surrounds air-sealing. I feel for most situations where one is concerned about controlling heat flow they need insulation. Insulation can be a waste when bypassed by air leakage.

How about a fridge or cooler analogy? Can you imagine the drop in performance if you left the door or lid ajar? When we build structures without paying strict attention to air sealing, we end up with cracks and holes that add up to the size of windows and doors. This is wasteful. If you are burning wood, it means more labor, soot and ash and less soil building. If you are using fossil fuels then its even worse.

Airtightness is easily measured and quantified. "Draft-proofing" seems to be an arbitrary term with no real meaning. How tight is "draftproof" anyway?

Airtight homes are more energy efficient. They are arguably more durable and healthy because they stop humid airflow through hidden, interstitial cavities which can lead to condensation, mold and rot. They also can increase indoor air quality because they eliminate potentially dangerous sources of infiltration like garages, combustion flues and soil gases.

ERVs, HRVs and other fresh air introduction equipment use the simple technology of fans. They are less complicated than well pumps, fridges and windows. There is not a lot of solid science out there on healthy indoor air quality but these fans are what most researchers point to as the best way of making a measurable improvement.

One of our major disagreements surrounds air-sealing. I feel for most situations where one is concerned about controlling heat flow they need insulation. Insulation can be a waste when bypassed by air leakage.

No one will ever find me condoning a "drafty house" or that it is acceptable to have "air leaks." Find one post where I claim this and I will go back and correct it with apologies for the mistake.

How about a fridge or cooler analogy?

I would be glad to use your fridge and cooler analogy...thanks for bringing it up!...

I am one of probably a handful of folks in North America that has a family history of building, owning and running an "ice house." I have sawn lake ice, mule hulled it, gin pole and pick rigged the blocks, and could probably still draw up an historical blue print of one to 70% accuracy without cracking a book open...

So, let us indeed look at and compare...

No plastic, not concrete, and no modern materials of any kind...yet...the ice stays ice from winter till the next fall...imagine that!

So again, please don't suggest I am not speaking from some modicum of understanding when I say...air tight is a horrid thing for healthy architecture and the goal should be "draft proof."

Airtightness is easily measured and quantified. "Draft-proofing" seems to be an arbitrary term with no real meaning. How tight is "draft proof" anyway?

Brian, we can run test up the "wazoo." I think that folks doing this like yourself, are often "spinning wheels" and often trying way to hard to "reinvent wheels."

Why?

I had, on more than one occasion, with a Japanese Diaku and a Amish Carpenter, walk over and ask me why I was using a level...

"If you know what you are doing it is level...if its not...then you clearly do not know what you are doing..."

I think many of these tests run along the same lines. I have had them done on some designs, never asked the clients about the outcome. I asked, are you warm and did you use much less heating or cooling? answer...yes.

Airtight homes are more energy efficient. They are arguably more durable and healthy because they stop humid airflow through hidden, interstitial cavities which can lead to condensation, mold and rot. They also can increase indoor air quality because they eliminate potentially dangerous sources of infiltration like garages, combustion flues and soil gases.

Hmmm...highly subjective in many respects as "Airtight homes" are also:

New and unproven with a track record of less than 30 years in actual duration.

They are already presenting with issues of interstitial moisture accumulation within the thermal matrix of roof and wall (not subjective as I and other design/builders are seeing in renovation work.) Which flys in the face of "more durable and healthy as they stop humid airflow" as they are not inhibiting the mold and rot...not at all...

ERVs, HRVs and other fresh air introduction equipment use the simple technology of fans. They are less complicated than well pumps, fridges and windows. There is not a lot of solid science out there on healthy indoor air quality but these fans are what most researchers point to as the best way of making a measurable improvement.

Again, subjective in perspective from a designer and builder that promotes their use.

Can we build "teched out" structures with airtight, super insulated thermal envelopes that not only need... but absolutely have to have....mechanical and technical" (sorry way more than a window...that's just silly) ventilation systems...yes we can do this. There are some that might even...only time will tell...like Brian, that can with closed cell foams and related materials build a system that mitigates many of the downfalls of moisture build up issues as well as other challenges...I am sure it can be done...just like space ships are now a reality...

We can invent and reinvent all kinds of wheels...there is no doubt about this....

But why?

and

At what cost, when there are alternatives...countless alternatives...that folks are sharing with each other now and through our ancestral ages that are all natural and just as good...with millenia long track records...not just a few decades.

I believe, and feel deeply, that just because we can do something a certain way (like all modern materials) does not mean it is what we should do, and if there is a less (over all) impacting system...like permaculture in general...we should adopt those systems.

Allow me to include some links to help strengthen my arguements. One of my main points: Air-Leaks Rot Homes

I think its a huge mistake to not measure things, especially airtightness. By ignoring this important performance variable, its possible that two identical designs could be dramatically different in energy use and related durability.

Improving indoor air quality IAQ with mechanical ventilation is not subjective. Researchers find that measured levels of CO2, radon, VOCs etc are lower with outdoor air introduction. Improving IAQ with mechanical ventilation is fairly established science. Many of us have moved on to not "if" but "how much", an irrelevant consideration for those who dont see the value in measured levels of air pollutants.

Air-tight homes history stretch back closer to 40 years. There are over 10,000 R-2000 canadian homes built to air-tight standards and Passive House Wiki page reports 15,000-20,000 passive house homes as of 2008. One of the many nice things about these programs is that they feature a lot of measurements and monitoring. These homes are performing up to expectations with better IAQ, moisture management, and energy performance. Passive house in particular has amazing performance characteristics (90% energy reductions) and achieving a strict level of measured airtightness is one of their main requirements.

Thanks Brian for the links...

I have, in the past read much of the information shared...overall...I agree parts of it.

So again, not one here is suggesting promoting leaks...we are promoting a "draft proof" structure. VOC's can be a real issue in much of modern architecture...not so much in natural builds. I would also point out that each of your shared postings are aimed at "mainstream" and probably "air tight" architecture. We just don't have those issues in most natural builds...not even many of the older Walipini that have just sat empty for months on end. Go in and the air smells...well...regular. These natural homes are not bombarded with the VOC found in most modern builds, not do they trap these toxins inside because of being "air tight" and they don't rely on a mechanical ventilation system either. There is nothing wrong with opening a window, or going in and out of your house, nor having plants and aquariums/vivariums and a myriad of other things that can general natural air exchanges. Yes...again...we could design "space ships" or perhaps a better analogy is "submarines" to live in...but why?

I do suggest that anyone thinking of building, read the shared links, the information is worth consideration and understanding...Do not take it as complete and utter gospel, as there is a great deal to understand well beyond what is in much of the research that is out there.

I have never told a client not to measure, and if they want to, by all means go for it. Yet it is a very new tool, with a system of learning and interpretation that can also be quite varied. I can appreciate, from a scientific perspective perhaps being curious, and if that interest is there for this data stream, by all means pursue it. Yet, again, I must point out, I don't need a test to tell if a design is working well. If a home that is 40' x 40' with 28' cathedral ceiling in the great room, and 3 floors with 5 bedrooms and only two zones of heat can be maintained at almost 80 degrees fahrenheit for many long winter days in Pennsylvania and only use 2 cords of wood, and less than $800 in propane for an entire winter for a family of 2 adults, 4 grand parents regularly coming and going, and 7 daughters....then...I really don't need a test much beyond what the client reflects in there observation of how warm the house stays. Actually, it is often too warm, as being a Mennonite family the Mother cooks a great deal both in the huge fire place and ovens. Just body heat alone and there activity can raise the daughters bedroom to over 70 degrees on some days.

So, yes we can test, and study, and examine and cross examine, yet in the long run a system works or it doesn't...I have facilitated, as have many others, super insulated virtually all natural homes that are incredibly thermally efficient without the augmentations (or testing.)

Air tight construction is a way...that I agree on...it is not by a long shot the only way...and many of us see evidence that in the long run it isn't very healthy either...but that is just my view. I do understand that it is becoming more and more recommended, just like many things in our past have...only to find out in the long run...oops...maybe we should have done that after all...

I am betting on "draft proof" natural builds, and taking my lead on building methods from the past...with a skeptical...very skeptical eye on the future and modern augmentations....

Thanks for the thoughtful reply, its been a busy permies day!

I disagree that natural builds will not have measurable VOCs for the most part. I think its safe to say most "all natural" builds still have VOC laden computers, appliances, wiring, modern plumbing, and even good old wood has measurable amounts of formaldehyde.

VOCs are only one form of indoor air pollution. Radon is perhaps the greatest concern being the second leading cause of lung cancer. CO2 is also going to be pretty tough to avoid and its a great indicator for overall indoor air quality.

Most natural builds seem to require burning stuff indoors (combustion appliances) to stay comfortable in cold or mixed climates. Talk about indoor air pollution! Smoke particulate, soot, ash, combustion gases..

Surprised that you are satisfied with burning 4800$ worth of propane that was potentially obtained through fracking. This is exactly why we should be reducing air leakage. I still dont understand how one can be so opposed to "airtight" yet so heavily promote "draftproof" but have never offered any explanation to the difference.