Conventional forced-air furnace is dying. What can we replace it with and still sell our house?

Background: my husband and I live in an 1100-square-foot, 3 story (2 + a basement) completely conventional house in a subdivision. We are working towards doing the early retirement thing and plan to sell this house in 9-10 years. We hope to leave the next owners with a producing food forest and a house that is as green as possible without being so "weird" or high-maintenance that they rip it all out and put conventional stuff back. And obviously, everything needs to be up to code before we can sell.

So with that in mind, our furnace has started acting up over the last few weeks. It goes out, the vents blow cold air, we turn it off and on again a few times until it starts up properly, it works for a week or so, and then the whole cycle repeats. Luckily it had the courtesy to start doing this at the start of summer, so we have some time to either find and fix the problem or figure out what we want to replace it with.

As much as I'd love an excuse to try out a rocket mass heater, it doesn't seem like a good fit with our situation. But I'd love to find something less stupid than natural gas/forced air. Any suggestions?

Why not have both? And, you can wait until you are ready to sell to replace that furnace.  During the next few years, keep you eyes open for buying a used one or one at close out, your ductwork and hook ups for it are not going to go bad when you don't use them, they will still be there for when you sell.

Meanwhile set up a nice looking rocket mass heater or if that can't be done at your location put in a real efficient wood stove.  Now next winter you can see how you like heating with wood !  

Having a way to get heat besides the central furnace can be a nice feature and selling point.  Your house will then be equipped to be comfortable even if services are taken out by storms, floods, fires, etc...

Is it a natural gas, propane,  oil or electric furnace?
Natural gas tends to be cheapest to run around here.
It's less polluting than oil,  but it's still pretty bad,  especially if you consider the fracking that makes it so cheap.

There are some arguments for heat pumps furnaces,  they are way more efficient than resistance heaters, and can use photovoltaic,wind,or  hydro generated electric.
Not so good in  colder climates.

Pellet furnaces are probably the most "civilized" form of home scale biomass burner.

My issue with an actual RMH is the home insurance.
Even if you own outright,  you will probably still want fire insurance, and home built heating appliances of any kind are a hard sell.

Are you DIY types?
If so,  installing a commercially available woodburner makes more sense,  as you could easily remove it and take it with you.
Otherwise,  a woodburner might be an albatross.
You might end up paying to install it, and to have it removed.
I've even  read (here)  that professional installers might refuse to install used units.

At least one state (MN) requires wood stoves to be UL approved or insurance companies won't insure the structure.

I was a plumber in San Francisco for 20+ years; my sister and I own two 100+ year old houses in the Chicago area. Have "done houses" in every way all my life and in 2008 replaced the control unit, various sensors, pumps, tanks, valves and stuff in a 40 year old AOSmith copper boiler heating one of our houses (hydronic). I tend to look at fixing things before buying more. That said, I'm as fallible as the next person, I just have more practice... <g>

Your furnace does not sound like it is necessarily dead/unrepairable.

But. We need to work with the resources available and for you that sounds like it means the local contractors of various types and persuasions, so before talking about your furnace I'll run through briefly my standard text on contractors. It's not pretty, but it's the best I've found. Most building contractors find it quicker/easier/more$ to just replace stuff, but there are some that take a more nuanced approach. Usually it's far far better to call for repair and listen to whatever music they play than to call in saying you need to replace your <whatever>. Let _them_ tell you what's the problem and what they can do. Then ask questions, take their info and quotes and move on to the next prospect. TAKE NOTES!!! It will all mush together, I promise. Make a spreadsheet of your prospects including your first impressions and your last comments.

It's a large pain, but with luck it can be educational. I don't know any other way to give yourself a chance of finding people good for you. When I need a new contractor, I have in the past interviewed more than a dozen and then had to pick from two or three that seemed somewhat plausible.  Location of the shop matters somewhat, although contractors do travel 5-20 miles (depending on roads). But provided other things being equal, closer is better because it makes it easier for the contractor and it makes it easier for you to go to personally express yourself if needed. Remember: The relationship will never get any better than it starts out. You need people who SHOW UP ON TIME (or call well before not showing), that you can work with, who can work with you, who you respect and who respect you. Listen to your feelings, talk to some of them again with questions, changes... See how things play out and record it in the spreadsheet. Pick one and go for it.

Ok, about the furnace. It sounds like some kind of electrical problem and those can always be fixed, even if it means replacing the "motherboard". That doesn't automatically make it the best go, but it's an option. There may be more than one problem; important things may be corroding, something else may have _caused_ that electrical problem. Listen to opinions, look at what they (should) show you, talk with the next guy. It could even possibly be the super smart thermostat having a hairball. One thing that would absolutely require a new furnace would be cracks in the firebox that could let combustion products mix with the air sent into the house. If that is found, have them show you the problem area. If they can't they better have a _very_ good explanation of the whole thing and then you get a 2nd opinion (unless you just want a new furnace...).

Your ducts are not a no-brainer. They may be ok, they may be leaking and corroded to hell. They are almost certainly not "good" because most ducts in this country were never installed "good". But if it has worked ok for you until the furnace got your attention, you can probably go with the evil unto the day and leave the ducts well enough alone until you are given more motivation.

Finally, I often refer people to "heatinghelp.com". Its forum, "The Wall", is mostly heating professionals and they mostly do hydronic heating. However, my experience has been that if you do your homework before asking questions, stay on topic and act respectful, they will try to help out regardless of your system type. It would probably be worth some reading time on their site just to get a feel for that type of work, even if you don't message with them. One of their categories on the right of the screen includes heat pumps and you could find some informative posts there. They also have a "find a professional" page and if you don't find any leads, ask under their "Main" topic about furnace contractors in your area.

Regards,
Rufus

I think Rufus' advice is excellent all around.

...completely conventional house in a subdivision...working towards doing the early retirement...plan to sell this house in 9-10 years...everything needs to be up to code before we can sell

Wiley, if I were you, I would take the next 10 years and become an casual expert on your local real estate and build as much sweat equity in your home as you can economically. Maximizing the value of your home can be done without spending a lot of money. Good advice above on your furnace and I wouldn’t cheap out on getting it maintained. There is an inherent economy in keeping an otherwise functional furnace working. I’ve never resided in a house with forced air heating, only cast iron radiators and hot water systems growing up. My knowledge on forced air is that there is an art and science to the ductwork and many ills often reside in leaky joints, badly designed ducts or vents. if you decide to replace it eventually, doing so closer to the date you sell might be a consideration as a selling point. You might consider seeking out an experienced house inspector and have that person go over your house as if you were considering buying it. Document and use that advice s a roadmap towards what you will need to do.

...leave the next owners with a producing food forest and a house that is as green as possible without being so "weird" or high-maintenance that they rip it all out and put conventional stuff back

Keeping in mind your over-arching goals, I would be leery of investing a lot of time and expense into shoe-horning a producing food forest into a terribly conventional suburban neighborhood. Just that in 10 years you will want your property to sell quickly and fetch as good a price as the market will bare. Focusing on maximizing your “curb appeal” .

One last word I will leave here, you mention a timeline of 10 years and that reminded me of a new very green heating technology I have posted about previously that harvests sunlight, stores that energy (up to 18 years) and can deliver heated liquid on demand and is being touted as having commercial application within 10 years. I could totally see it being retrofitted to forced air systems.

Most modern houses not specifically designed to be heated well in another way require forced air. It's the lazy, high-energy, just-throw-money-at-it-until-it-goes-away solution to keeping badly built matchstick and paper houses habitable.

I like Rufus' take on the situation. Your goal is resale, and to keep the house to code for ease of sale. Your options are limited to what is accepted by insurers and, by extension, the future owners. By this logic, and you'd have to check to see if this is true in your specific case, I think that the best you could do as a single step solution is to see what is available to convert your existing system from natural gas (I think you mentioned that's what powers it) to wood pellet power, with at least a two-stage hopper and a worm-gear powered elevator-style feed. You'd need to keep the main hopper topped up, but other than that, pellets would be added at need automatically, and there would be no heat distribution issues that didn't exist before.

I also like the idea of a woodstove as a secondary heating appliance. But I think enthusiasm for permaculture, reuse, and frugality need to take a backseat to the fact that you intend to sell within a decade.

-CK

Picking up on this point someone else said, a NEW furnace is a real good selling point a 10 year old furnace means little to the buyer, so an argument to replace it before you sell to add to the desirability of the property, also there may be furnace advances in 10 years time so the house would have the "latest" and if you're realy lucky maybe a new rebate program between now and then.

If rocket stoves do not meet code in your area, go for a different kind of wood burner ( or pellet but I vote for wood).  10 years is a long time to save money and carbon output heating that way. Yes you can take it with you or resell if the new owners do not want it, but many people do like the ambiance of a wood stove

Let's say it is $3500 for stove and pipe and you install yourself not too hard, we have successfully installed skylights and stove pipes here.  So that is $350 a year and it is still working and has worth in 10 years !  Let's say $400 a year so you can get some nice tile too.  What are you paying for natural gas heat and then the co2 etc...I don't know your climate or area some people buy wood but the other value for you heating with wood now is educational you are practicing as much homesteading as you can while living in the city.  So better would be if you practice wood harvesting and foraging even if that means you go once a year to a national forest.  But, you shouldn't have to, trees are getting trimmed and taken down in the suburbs constantly and you could likely find ones from a tree trimmer that you can practice some chain sawing and splitting.

So,  chart your pros and cons.  Some of the pros are waiting gives a better furnace when you sell, wood heat saves you money and is skill building. Cons are wood heat takes more time now, etc.,,

I have a Lopi Endeaver that I realy like , but there are many fine stoves out there