I've been reading the thread about masonry heaters & it got me thinking about a few things, but I didn't want to hijack that thread...

We will be building (again) in a year or two, and I'd like to learn from my mistakes last time.  Not that we had any glaring issues, but there were things that we weren't able to do, due to budget & time constraints.   This house, like the last, will be a walkout ranch.  Basement probably not finished immediately, but likely within a few years.  Our old house had a GFA furnace in the basement, no basement zones for heating.  Living in WI, winters are cold - but the basement never got below 65ish - it was very comfortable down there.  We did 2 inch foam outside the basement walls, but no under slab insulation.  This time I definitely want to insulate the slab, and had been considering doing a solar slab for heating.  I'm wondering if a pellet furnace, controlled by thermostat would be efficient/effective to heat radiant loops in the slab?  I would anticipate that the basement wouldn't be used daily - likely on weekends/if we have people over, etc.  It seems like this could be a good option to heat on-demand rather than all the time.  My biggest concern (whether accurate or not) with the solar slab, is how do you divert it in the summer, so that you're not fighing against your AC?

People ask us to integrate solar in our designs but in the upper Midwest getting half of your DHW is a challenge with a couple of good flat panels. Space heating without storage is not possible. Pellet boilers do not exist to my knowledge. I suggest a condensing water heater for dual purpose.

Pellet boilers exist in droves in Europe/UK. There were one or two vendors with ASME-H ratings being imported into the US a half-decade back, but I haven't heard much about it since. (An aquaintaince I rarely see installed a pretty big one in his air-leaky McManse around then.)

A quick google turned up the ÖkoFEN:

http://www.maineenergysystems.com/OkoFEN_AutoPellet_Boilers.htm

http://www.oekofen-usa.com/

http://www.oekofen-usa.com/en-us/products/pellematic.html

(A nice range of lower-BTU output units!)

And Made in USA Pellergy:

http://www.pellergy.com/wood-pellet-boilers/

and the Swedish/American hybrid EcoBoiler:

http://www.ecoheatsolutions.com/ecoboiler.html

I have no idea what the unit or installed costs are, but they definitely exist. Whether there is good local support for system design, installation & maintenance near you is something you'd have to figure out. For a better insulated house of moderate size your heat loads are probably well below the bigger models, but some of there's probably an ÖkoFEN that would work for you.

Don't forget "HSTarn" a Baxi boiler company

There is a minimum size to any Pellet or wood boiler and usually it is big enough to do the whole house so finding one small enough for the basement alone might be difficult. An option is one of the British wood fires with a "back boiler" which goes to a tank then to the floor through a mixing valve. They can be much smaller in output.

OK. Practically don't exist in the US. When last specified $8000.00 plus FOB northern Minnesota territory. Still questionable economics in most applications. Outdoor gasification wood is still predominant from Alaska to Maine. No good DHW options save batch feed and indirect storage and of course tank-less coils with full-time hot boiler.

From my very limited (and second-hand) experience I'd agree that unless the load is pretty large the economics of a fancy pellet-boiler won't make sense in most cases (and probably never for someone on the US gas grid.)

With a bit of subsidy the numbers seemed to make sense for the larger facility clients in Greenfield MA:

http://www.boston.com/business/technology/articles/2010/04/27/stimulus_funds_funneled_to_pellet_market/

Maybe NRTRob knows something about the pellet boilers installed in Gardiner, ME Public Works building(?) in '09 (referred to on the second page in the above article).

The article indicates a $10-16K installed price-tag for an automated system sufficient for a 2500-3000' house (and we've probably all seen mod-con systems with installed prices in that range), but with a miniscule load that could be handled with a hot water heater it would be tough to recoup that kind of cost on per BTU fuel prices (any fuel).

Below some information on what's coming for subsidies and funding for BioMass applications in Massachusetts for the remaining of 2012 and 2013.
The Massachusetts Clean Energy Center (MassCEC), http://www.masscec.com/, will have available the following funding/grants:
First: $500,000 for 40 to 50 projects to install residential whole house automated pellet systems. This is roughly $10,000 to $12,500 per project.
Second: $1,000.000 for 50 grants to replace polluting outdoor wood boilers. This is $20,000 per grant/project
Third: $150,000 for commercial size projects. 15 grants or $15,000 each

Other wood pellet heaters available are:
http://www.hydro-to-heat-convertor.com/pelletboilers.html (UL2523)

If you live in New England, PA, NY or MI There will be a pilot program for Windhager BioWIN (UL2523) pellet heater starting in October 2012
I limited amount of units will be avaiallble.
Similar pilot program will kick off in PEI-Canada.

Pellet pricing info for the Northeast

Oil - 1,000,000 BTU = $32-$34
wood pellets - 1,000,000 BTU = $15-$16
cord wood - 1,000,000 BTU = $7-$8

Natural gas is around $15

So if there is natural gas it is difficult ot beat this with wood pellets

Dumping heat in the summer is indeed a major drawback to solar hot water space heating. The most common approach is to switch the heat to a swimming pool or hot tub. While heat storage is also advisable -- because peak heat load occurs at night -- a radiant slab is itself storage if you're willing to accept some variation in temps over 24 hour periods. My experience suggests that the swing won't be much, particularly in an insulated basement. If you were to limit solar heat to the basement, with some modest ducting to move excess heat into the rest of the house , I would wait for a season to see how much aux heat you need. I'm thinking a gas-fired tankless would be plenty. It comes down to average daily cloud cover through the winter. The other major drawback to solar space heating, except in the Southwest, is how little the sun is seen in winter.

There is still an argument for multifuel, Badger. A DHW solar system sized for 90 percent of Dec and Jan requirements will have excess capacity in every other month. Given a two coil solar tank and an existing heat storage tank, as in my case, the cost for shifting those excess btus to space heating is a $100 drainback pump and a $60 controller to operate it when the solar tank exceeds 125 degrees. Granted energy expenditure is modest in the shoulder seasons. But when the fuel of choice is wood, solar assist means extra month or two when the only chore at night is to keep the sofa from floating away.

That sofa is looking better every day!

One of the perks(?) of living in a camper van while building a house is a chance to experience the march of human progress on fast forward. Electricity! Flush toilet! Full kitchen! Air conditioning! Sofa! TV! Given the recent drop off in productivity though, it's more like Sofa? TV?

Cost per kwh is around 8 pence here in sweden atm if u use pellets