Boiler Heating Multiple Houses

[lukem]

Howdy,

I have 3 families of in-laws that all live right next to each other (share property lines). Picture a triangle with each corner representing a house...about 200' away from each other.

Leaving all the "other stuff" aside (who feeds the boiler, cuts the wood, home sale, maintenance, etc), would it be possible to provide heat to all 3 houses with one boiler? Each house is of average insulation and approx 2k ft2....forced air furnace. Could they do DHW too?

They seem to think they can, but I dunno. Thoughts?

 

[Eric Johnson]

It's been done. I don't see why not, given a big enough boiler. A Garn might be the perfect choice, though any other large-capacity rig should work.

 

[jeff_t]

Should be easy enough. But they are probably envisioning a smoke spewing monster that they can shove green 2' oak rounds into with a tractor. That you cut for them.

 

[lukem]

Thanks guys. Forgot to mention they want to take the chill off a 20x40 inground pool in the spring too.

 

[BoilerMan]

Well anything is possible.......... A nice boiler building situated is the right place with storage (read ALOT of storage). Would be alot of underground line to trench and insulate properly, a significant investment. But it is certainly do-able. PEX, pumps, and water to air heat exchangers x 3. But the cost can be divided three ways too I guess.

TS

 

[jebatty]

So cool to do this. Should not be a problem. Certainly no material difference from heating a large structure with multiple fan coil units. Deep Portage has a Froling FHG-L50 (170,000 btuh) with 1600 gal storage which heats a rather poorly weatherized 6000 sq ft structure via two water to air heat exchangers in a forced air system.

Deep Portage also heats its main 56000 sq ft learning center with a Wood Gun E500 and a Garn WHS 3200. The Garn, when burned continuously, will heat the facility down to about +12F and the Wood Gun, continuous burn, to about -10F. Your units would be smaller in btu output for sure. DP's system is pressurized and the Garn open system interfaces via a water to water heat exchanger while the Wood Gun supplies the system directly. The learning center is heated with multiple fan coil units.

 

[Frozen Canuck]

Should be no problem for one of the larger boilers. Placement to minimize expensive undergound pipe will help keep overall costs down, highly recommend reading the undergound stickie if you have'nt done so. While your at it you may want to consider indirect water heaters for all the homes so the boiler can supply all DHW. This maybe where you get your biggest bang for the buck as I can't imagine you have much in the way of a heating season compared to more northerly locations.

 

[peakbagger]

There are a couple of "cooperative communities" in NH and VT that are sort of a upgraded version of a commune for boomers. They have small individual houses, with a common building that can be used by all and they all have to do a portion of the work keeping the common areas and heating running. I have read articles about a couple of them and they usually have a Garn in a central location and everyone is assigned a shift to feed it. They usually have a large piece of common land, but the owners tend to be "green leaning" so they rarely cut their own trees and let others "butcher" and supply wood. The one scary part is rarely do I hear about the backup boiler whihc should be present.

Of course before you spend the money on a system, make sure all the houses have energy audits and take care of the details on who does what. Its probably going to cost more up front to put in one boiler for three houses than three individual boilers. For redundancy and efficiency you really should consider two boilers so if ones is down for service you have a backup. In the spring and fall run one and then when its real cold run two. If one fails when its real cold the remaining one should be able to keep things above freezing. While you are at it, you will want to plan to have a emergency generator to handle the boilers and the circ pumps.

 

[BoilerMan]

Just keep their existing forced air units as the backup. Use some electric baseboard or wall hung gas heater in the boiler shed if the boiler is down.

TS

 

[Mark Holden]

One thing not yet mentioned; investment vs. increased property value.
If one house is sold from your triangle, things would get very mixed up; especially if say, one of the underground lines went through it to one of the other houses.
The sold house would be without the added value of the money invested in your proposed community heating system, it would have to be disconnected from the boiler.

On the other hand, were all 3 houses to be sold to someone interested in maximum rental return, the landlord could live in one house while selling heat to the others, and keep the difference over the [by that time] huge cost of fossil fuel.

My retirement plan actually...

 

[rkusek]

I agree with the last couple posters. The existing forced air units will be necessary anyway for a/c, more than sufficient for backup and wouldn't justify a second boiler. I would put the boiler on the property of one most likely to not move, get divorced, etc. That way if something changes and new owner can't get along the remaining two would still be able to use by isolating the lines.

 

[heaterman]

Can it be done? Most definitely. Nearly all of the Garn installations we do heat multiple spaces/structures. You'll probably want/need something that has a maximum firing rate of around 300,000btu to carry that load at design conditions and of course a large capacity for storing heat designed into the system someplace. For that kind of load even 2000 gallons would only carry the heat load for about 5-6 hours when the temp is near minimum for your area.