I am in the Navy stationed in Charleston, but my wife and I are hoping to move closer to family in western NY after I get out next year. We would like to build an ICF home with passive solar and some type of back up heat. We have read about masonry heaters and didn't know if anybody had any experience or advice. Thanks.

IMO, you would be better off with a wood boiler and a large water storage tank. Much easier to control and distribute the output.

often cheaper too, those masonry heaters can get pretty pricey, especially with a fancier chimney.

Hey thanks for the advice so far. Keep it coming. I appreciate the different ideas.

Dunno if you found builditsolar.com, but there are many testimonials there from people who combined passive solar and masonry heaters and lived happily -- and cheaply-- ever after. The folks here prefer insulation to thermal mass and active to passive, perhaps because passive doesn't offer much to sell.

Your passive design is key. If the sun gets you close, then a fire a couple of times a week is a pleasant interlude rather than a chore. If you have sufficient mass to buffer extremes of heat and cold, it shouldn't be all that difficult to stay comfortable. ICF isn't the best choice for thermal mass because you want the concrete exposed to the inside and reacting to diurnal temperature swings. You'll find free software here that allows you to test designs based on historical weather data from the nearest NWS station to your construction site: http://www.energy-design-tools.aud.ucla.edu/heed/

HEED says my house, under construction in Pa,  will stay between 55 and 85 with no additional heating or cooling. My plumber says his passive solar house has never been colder than 62. He has no aux heat.  I'll have wood heat assist and plenty of experience a year from now.

The mass is already working. With the ambient temp ranging daily from 40s to 80s, the temp in the house is remarkably constant and comfortable. The overhangs are shading about 80 percent of the windows at this point. You are welcome to stop by. I am about 20 miles E of IH81.

Passive thermal storage always involves temperatures going above and below the optimal temperature. Active systems allow you to keep it just right. Passive also interferes with thermostat setback. PS - I have nothing to sell and no thermal storage system to defend.

TF Systems has a Vertical ICF that will move the majority of the insulation to the exterior. It would be great for passive. Toddm,, what did you use for your walls?

OK, Jonr, even the folks here who have nothing to sell have insufficient understanding or appreciation of thermal mass. For instance, if the heat loss in my house is 0.5 degrees F/hr at the design day temp of 10 degrees, what would be the Tstat set points for your active system? And if the result overnight is a loss of four degrees, how is that different from nighttime setback?

Which isn't to say that there is abundant knowledge of T mass or passive solar. The OP is right to ask for experience rather than opinions. He'll find it at builditsolar.com.

Jmagill, my house is autoclaved aerated concrete, which is either great for passive solar or terrible, depending on which website you believe. Gotta admit it is hard to get your head around the idea that the same concrete block can be effective at insulation AND heat storage. I am staking my hopes on the fact that the AAC's specific heat (storage capacity) is 0.25, or better than conventional concrete at 0.20. I am impressed so far. Stack two blocks in sunlight on a day that warms from 40 to 60, and the delta T between the top and bottom surface of the uppermost block can be 30 degrees.

Dunno about the TF approach. Seems to me that on a bright winter day, with an extra helping of insolation bouncing off fresh snow, you wouldn't want anything over the concrete. But if there has been any research on this, I haven't found it. ORNL has found that some insulation improved the dynamic effect of thermal mass in hot humid climates like Miami.

if the result overnight is a loss of four degrees, how is that different from nighttime setback

In that dropping quickly and then holding it there loses fewer btu that a slow drop (think area under the curve). And jumping back up to the normal temperature in the morning makes the occupants more comfortable than a multi-hour rise from "too cold".

And last but not least, 4 degrees isn't much of a setback.

I will be watching for reports on how your house does over the winter. I am very interested in the results. I have not done enough research on ACC.

My perfect building system is a concrete wall with insulation on the exterior, a concrete floor with insulation below ( no stem walls). As much passive solar as I can get.
I don't need " a perfect temp. at all times" I can put on a sweater or take it off. I would be far happier with no heating or cooling bills.

Jonr, you have written before, and correctly, that the stuff hits the passive solar fan during an unseasonably hot October. For that heat wave, you'd want 100 tons of concrete requiring 50k btu/hr to rise in temperature by one degree. With that amount of mass as a given, so are slow recoveries on cold mornings, whether the aux heat is active storage or masonry heater. With a masonry heater, at least, you can pour yourself a cup of coffee, pull a chair close and start a cold morning the right way.

We'll pass on the question of whether 66, as opposed to 70, is too cold when the source of heat is omnidirectional. I'm with Jmagill. If my energy costs are $50/month to Allegheny Power plus chain saw gas, I'll be a happy man.

Active storage (say a water tank in the basement) means that it can be isolated from the house so that nothing prevents a quick cooldown or warmup - even 10 degrees at night. Active storage can save more than passive (but the system may cost more). Radiant radiators (running off a water tank) can produce omnidirectional heat. Wood boilers can heat the tank while running at an efficient and clean fast burn. So can solar panels - without losing heat all night like a window.

Passive wins in simplicity and usually in initial cost.

Basements are expensive in a passive solar house because you want sunlight striking concrete or similar mass. The toughest nut in my design was finding room for storage and mechanicals.

Nothing happens quickly in a house made of 100 tons of concrete. Heed says my house would never be colder than 55 even if I turned off the power and walked away.

Who says I have to lose heat unabated through those windows? These folks sell roll up insulated drapes worth R6 over my uncoated double pane windows. http://www.1windowquilts.com/ They can be motorized by these folks http://www.somfysystems.com/en-us/index.html and operated by remote or electric eye.

Simpler and cheaper, yes, but you missed the most important attribute of passive: aesthetics. What I see out those windows is worth it.

Masonry Heaters are not free, or cheap, and they are not, strictly speaking, passive.

If someone is going to put a masonry heater in, I consider the wood boiler route with tank as it offers ALL the benefit of masonry heating, but with excellent controllability and comfort. and no 15 degree room temperature swings. Even with a panel radiator distribution system you're likely to come in at a similar cost to most masonry heaters, with faster reaction time and real comfort in all areas of the home at all times. The only difference between the "passiveness" of the masonry heater and the wood boiler is perhaps a couple of circulators on the wood boiler system, which these days don't usually have to use any more than 50 watts total combined electrical usage, when running, 25 watts once the wood boiler cools down.

so while I do have something to sell, that doesn't mean I'm wrong. I think that largely masonry heaters are a poor choice for heating unless you can build one very cheaply somehow.

Rob is right. We have had central heating and one degree control since the turn of the century. I can't understand people thinking they can tolerate large temperature (comfort) swings to "save" fuel. The answer is insulation and hydronics in cold climates.

There is no room for "old school" with modern fuel costs. By the way my grandad was a stone mason who specialized in wood burning fireplaces. They are a work of art but only about 1% of the energy of the wood is retained in house or fireplace. Not GREEN.

If you want high effiiciency and comfort, you first start by eliminating all chimneys (keeping in mind the Native American tipi IS a chimney).

"We have had central heating and one degree control since the turn of the century. I can't understand people thinking they can tolerate large temperature (comfort) swings to "save" fuel. The answer is insulation and hydronics in cold climates.

There is no room for "old school" with modern fuel costs"

I guess you live in a bubble and don't enter the real world where the temp changes non stop all day long. We tolerate it just fine. I think you have missed the whole point.

Some of don't need or want to live in the perfect bubble of temp with out a one degree change. If I lived at the temp while sitting at my computer it will be too hot as soon as I get up and do some physical work. The temp my husband likes is different than the temp I like ( especially during a hot flash). The temp I am happy with is very different than the temp I want when I am sitting at the computer.

Add that to the fact that I have no problem opening a window to cool down or sliding an insulate panel over my windows to keep in heat on a cold winter night. I am very happy spending less money on heat because I have insulated better or took a few minutes of my time to light a fire. I am very happy to know that my choice of building materials and active participation in my environment saves me and the world some of that fossil fuel that we are fighting about.

Hello Gentlemen,
Nice thread,
on masonry heaters, we have a group out here that builds the massive Russian units, they work great. very complex though they rely on a large system of duct work for the smoke this is how the heat is stored.
Build a very hot fire once a day, thats it. I have laid copper pipe in a sand bed above the fire box and used a Johnson control sensor, any time the sensor was above 120 it would send water from the copper pipe to the pump distribution panel, and have opportunity to be sent the farther corners of the home infloor slabs.
If I was building a stone home I would still want to toss pipe in the walls, floors, and elsewhere to have the possibility of heating off an accumulation tank or ....boiler on cols cloudy weeks. But I suspect that goes against the passive house idea.
but pipe is cheep, can never be placed after a pour, and offers a lot of future options.
Dan

toddm,

Thanks for the link. I design active systems for passive homes (that's confusing) and for just the reasons Jonr suggests, accept the set back thing. This is an incompatible concept. I do set back water temperature in my hydronic designs and in the all important storage water heater (typically the largest fuel load in a well designed house), but the saving in ambient setback are exaggerated in conventional construction and certainly of no consequence or affect in a super-insulated home.

Passive solar does not preclude the addition of backup active systems. They are just not needed very much with the proper design and mass built into the home.

Opening a window; now that will save the planet! But you might have something there, as this just how they control room temperature in Russia, where district (communal heating) is common and of course they are always thinking GREEN.

Modern construction does not tolerate large temperature swings, nor does large thermal mass or massive fireplaces, but a basic understanding of thermal dynamics and human comfort levels will help in making long term construction decisions.

PS Do be careful of peope trying to "sell" something, you know you can't trust any of them!