Andrew Welser

Since I currently (and for the foreseeable future) am living in north Texas, and hope to one day build myself an off-grid wofati/underground house this is something I've been wondering too. The best answer I've come up with so far is John Hait's book "Passive Annual Heat Storage." While I think he is more northern/heating focused, a similar approach should be effective for us down south; and possibly more effective, or less work/construction may be required for the same result, since our unmodified constant ground temperature is much closer to our desired indoor temperature (I seem to recall seeing numbers in the 70-75 deg range for constant underground temperatures in the Dallas area).

A form of de-humidification may likely be required still; some type of moisture absorbent that gets recharged in the sun or with a fire might be possible; but even if not, a dehumidifier would be much more practical to run off-grid then an AC of any decent size.

It sounds to me like the buildings John Hait describes in his book "Passive Annual Heat Storage" are similar, if not exactly what you are trying to do.

His book is currently available on archive.org: https://archive.org/details/passive-annual-heat-storage-improving-the-design-of-earth-shelters-john-hait

Last winter I was in a poorly insulated/air sealed single-wide mobile home heated only with space heaters (in north Texas, it didn't get all that cold compared to some); here's what worked for me to stay warm and keep electric bills down, thanks to this thread and others on permies for inspiration:

-Thermostats set around 45 deg (F)
-Lots of clothing layers
-Heated pad under the top layer of my dogs bed to keep her warm
-Electric blanket to preheat the bed, along with extra blankets/comforter
-Multiple low watt heat sources for the couch/desk:
    -Heating pad between my back and the back of the couch
    -Heated throw blanket
    -Reptile heat "bulb" in reading lamp to warm hands and face
-Hot drinks to wrap my fingers around (hot water sourced from electric kettle)
-Place space heaters appropriately (and turn up only when needed) to blow heat on me when getting out of shower, changing clothes, etc.
-Reptile heat "bulb" in clamp-on reflector fixture above work bench to keep fingers warm

To change subjects:

Chi Monger wrote:
HEATPUMP MINISPLITS:
…
But for refrigerant?…
…Yes, they all (we entertained several contractors giving free estimates) …basically said it WILL leak (must have annual maintenance, incl. check refrigerant levels—of course that is another income-stream to the companies greedy for more profits).  

As an HVAC repair technician, it is not normal for a properly installed AC or heat pump system to leak refrigerant; anyone telling you that is trying to charge you for service calls, etc: income-stream like you said. Over time it is not uncommon for leaks to begin, especially with the higher working pressures of R-410 and the thinner tubing construction to save material cost, but leaks are not inevitable, and certainly not normal!

Nina Surya wrote:

Ellendra Nauriel wrote:Run the plumbing in such a way that hot water going down the drain gives back at least part of its heat before it really leaves the house (not sure I'm phrasing that the right way).

Ellendra, I'm trying to come up with some kind of practical solution to what you said "Run the plumbing in such a way that hot water going down the drain gives back at least part of its heat before it really leaves the house ". I think you're phrasing it right but can you give an example of what, how...?

One way to do what Ellendra is referring to is by using some kind of "Drain Water Heat Recovery System"  (see diagram/picture below)
Basically some kind of heat exchanger to use heat from the (shower) drain line to preheat the incoming cold water.

I saw a youtube recently of how to DIY radiant/infrared cooling paint

that paint could then be used in a north-sky-facing "window solar heater" (similar to pictured below)

to make a cooler.

6 foot down the temperature of the earth will vary seasonally, around 20' down it will stabilize (close) to the average annual air temperature of your area, normally very similar to the ground water temperature:


Notice on the graphs how the temperature stabilizes and lags behind surface temperature as the depth increases and the "wave of heat" slowly travels through the earth:


(all photos found online searching "underground temperature chart")).

Something mentioned I believe by John Hait in his book "Passive Annual Heat Storage" (currently available for download on archive.org) is that rain water soaking through the ground can greatly affect the temperature underground: if you're depending on the thermal mass of the ground, or the ground temperature then he recommends creating a water impermeable layer (usually plastic sheeting/pond liner) near the surface to prevent rain from cooling the earth or moving heat out of the thermal mass.

Edit to add: Also discussed by John in his book, if you put insulation along with the water barrier, and extend that out 20' or so in all directions, you get the temperature equivalent of 20' of covering earth without having to go down that far, since the heat in effect has to go 20' to the side because of the insulation under the water barrier.

Anne Miller wrote:Since we are talking older vehicles, I hope this is not too off-topic.  Has anyone had problems with windshield wiper blades?  The rubber just dies after a few uses.

The windshield wiper on both vehicles are shot though we decided not to replace them just to use them one time.

Has anyone found a trick to replacing them?

I know it's been a while since this thread's been posted in so I hope I'm not guilty of thread necromancy (older vehicles, older thread ), but I saw Anne's question hadn't been answered and wanted to chime in:

Get full silicone wipers. I can't speak to longevity of other brands, but in 2017 I put PIAA Super Silicone blades on my wife's car, and they were still working well when we traded it in earlier this year; and we're in north Texas where we're doing good to get more than a year or 2 out of the rubber ones because of the sun (car was never garaged and only parked under cover for a couple of those years). At the time PIAA were the only full silicone wipers I could find, but it looks like they may be more common now. In addition to the longevity, another benefit is they make the water bead up on your windshield, just like Rain-X.

Beau Davidson wrote:
fri nov 25 - wood box day (half day)

- try to replace plastic bins with wooden crates and boxes
- maybe try to make a box that will almost hold water
- maybe even try to make some dovetail joints
- some boxes will be quick and some will be very nice
- unlike wooden spoon day - wood boxes will remain with the bootcamp

Isn’t Boxing Day usually the day after Christmas? ;)

From my folder of funny fotos downloaded from the four corners of the interwebs.

I was just listening through these podcasts and Ash's mention of wanting towns without cars that feed themselves reminded me of a website and book I'd read in depth a long while back. While the design probably doesn't take permaculture into mind, and I don't recall how close it comes to feeding itself, the ideas and plans at Carfree Cities are probably a lot closer to his goals than almost any current towns or cites, and might be a good rough draft in that direction.