Anyone with an ICF house and boiler?

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Paul Whipple

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Jan 21, 2013
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Theres got to be someone on here thats got a ICF home and a gaser. I know its a little over kill for a super insulated house but I think if you add in a large outdoor hot tub and hot water needs it makes sense (to me anyways!)

If you do have one lets hear about your setup.

Construction starts when the ground is thawed this Spring. I'm going hydronic in the downstairs slab and staple up for upstairs and a hrv for air quality. Ive got a 500 gallon and 250 LPG tanks for storage and have a Blaze King Princess (currently heating with it) that will go in the basement. (BK rocks! Love this stove). I'm fortunate wood wise as I've got literally thousands of square mile around me to take what wood I see fit (with the occasional abandoned log deck to boot!)
 
I don't have one but the Garn looks like a fine WHS. And it doesn't matter that your house will be super insulated, you'll just have shorter & fewer burns & use less wood. I would still have to have a stove too though as I love the radiant heat at times and watching the fire.
 
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Im in Alberta so we see some cool temperatures in the winter. The Blaze King will provide that "I'm on vacation somewhere hot" feel to the downstairs.
 
Thanks for starting the thread Paul. I am planning an ICF build this fall. My thoughts are that the building will act most efficiently when the outdoor temperatures swing above and below the indoor temperatures (if that makes sense). I feel that if we see -15 to -35 C for a few months, the heat flow will always be outward. So while others may suggest that it is a waste to go wood fired boiler within a structure of this type, I feel that there are still justifiable reasons. An efficient building should lengthen the time which your storage is effective. So does that not artificially increase the size ( and therefore the "convenience factor") of your storage? Domestic hot water through wood/solar year round is another factor. I am short on time (back in a few weeks) so one last reiteration that I've read here many times, I like to use a fuel source which I have more control of the cost. Look forward to catching up when I return.

Dan.
 
I have a very well insulated 1500 Sq.Ft. with basement (3000 sf total) and 1200 Sq.Ft. garage that I heat with my Heatmor 200 outdoor furnace. I wondered the same question, but it is definitely worth it. Keeping the garage at 59° uses more than the house at 67° I think. It is nice to have a warm truck in the morning and a place to work on stuff. I don't have ICF, but I did do T-mass (2" foam sandwich in center of poured concrete wall) in basement and spray foam for the main level. The house keeps a very even heat with no drafts except for the sliding glass door to nothing since I haven't installed a deck yet.

I have in floor wirsbo in basement and garage and forced air for the upstairs (and cooling). I also have plenty of woods to cut and still find some easy clearing sites to pick up nice oak every now and then.

It totally makes sense. You can heat your hot water, house and the hot tub. No worries about propane price spikes.
 
Hey Dan, I'm probably going to get my boiler from down your way, the place in Blind Bay (Advanced Wood Heat) and I've been looking at the NextGen Biomass 25.

Glad to see you folks agree with my assessment!
 
While I will be going slab on grade(sort of icf), I intend to build a very tight home this year. With storage, I'm looking forward to using my gasser and think you'd find the same. Even in my current drafty, poorly designed install, I'm thrilled with this boiler. It'll be even better when it's working as intended.
 
Paul Whipple said:
Theres got to be someone on here thats got a ICF home and a gaser. I know its a little over kill for a super insulated house but I think if you add in a large outdoor hot tub and hot water needs it makes sense (to me anyways!)

If you do have one lets hear about your setup.

Construction starts when the ground is thawed this Spring. I'm going hydronic in the downstairs slab and staple up for upstairs and a hrv for air quality. Ive got a 500 gallon and 250 LPG tanks for storage and have a Blaze King Princess (currently heating with it) that will go in the basement. (BK rocks! Love this stove). I'm fortunate wood wise as I've got literally thousands of square mile around me to take what wood I see fit (with the occasional abandoned log deck to boot!)
Click to expand...


Keep in mind with a radiant slab in a super insulated building you may (will) not always have warm floors. I have put radiant in slabs for a few ICF homes and had the owners complain that the floors were not always warm, as they expected. Once the floor surface gets below around 78-80F it may not feel warm to bare feet, especially the hard surfaces like concrete or tile.

Do a load calc, if the loads are down around 10 BTU/sq. ft. or lower you may experience a home with comfortable ambient temperatures, but cool floors.

Some installers play around with the tube installation, keep it back from the outside walls a foot or more, and load more tube into the space where you will be walking and spending most of the time. The concept is to decrease the radiant surface area and force it to run more often to cover the load. Don't know how well that actually works, concept sounds good :)

The rule of thumb is 2 btu/sq.ft output for every degree difference between the floor surface and ambient.

Good reading here

http://www.pmmag.com/articles/83903-heating-a-thermos-bottle-house-br-john-siegenthaler
 
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I don't have an ICF home but it's very well insulated so I am experiencing this same situation. Although the house is kept at a constant temp of 70 we have found that t radiant has an effect on the body that can't be achieved with warm air. We have an added mud room bump out with three outside walls and cooler basement on it's own zone and is the most comfortable room in the place due to the nearly constant flow. We also feel the positive effects of the radiant in the main living area on days when the outdoor temperatures are well below zero because we get bathed in the radiant warmth from more constant circulation. That being said, we're more than comfortable enough to pass on rectifying it.
 
I have a good sized ICF house, living in it since 2003.
I have in floor radiant every where.
I use NG. My gas bill for the ICF house is around $50/month in Jan
I import and sell high efficiency pellet boilers and hydronic wood stoves.
I would strongly advise to look into other means to heat your house: solar hot water, mini splits, ....
I also advise to look into passive house building concepts.
You can perfectly build a new house with a 4 to 6 BTU/sf heating load
http://www.phaus.org/learn/passive-house-education/what-is-passive-house-
http://www.passivehouse.us/passiveHouse/PassiveHouseInfo.html
http://www.passivehouse.ca/
 
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I forgot one thing:
any money spent on insulation and tightening up the new house is a savings for the life of the house.
You start saving from day one!
Fuel, any fuel, will only get more expensive. That includes wood and wood pellets

I strongly advise to hire a reputable professional to design your house.
The 10 or $20,000 will be the best investment your will ever make!
Believe me, was there, done it.
Don't go cheap on this one.
Live and learn, they say.
 
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Bob Rohr said:
Keep in mind with a radiant slab in a super insulated building you may (will) not always have warm floors. I have put radiant in slabs for a few ICF homes and had the owners complain that the floors were not always warm, as they expected. Once the floor surface gets below around 78-80F it may not feel warm to bare feet, especially the hard surfaces like concrete or tile.

Do a load calc, if the loads are down around 10 BTU/sq. ft. or lower you may experience a home with comfortable ambient temperatures, but cool floors.

Some installers play around with the tube installation, keep it back from the outside walls a foot or more, and load more tube into the space where you will be walking and spending most of the time. The concept is to decrease the radiant surface area and force it to run more often to cover the load. Don't know how well that actually works, concept sounds good :)

The rule of thumb is 2 btu/sq.ft output for every degree difference between the floor surface and ambient.

Good reading here

http://www.pmmag.com/articles/83903-heating-a-thermos-bottle-house-br-john-siegenthaler
Click to expand...
This is exactly what I did! I built super-tight (as tight as possible w/o going ICF). The cost was prohibitive, and I did all the work myself. I'm heating 3,200 square feet with a design load of 14 btu/ft sq. this is at -45F. Radiant slab-on-grade with porcelain tile. I went 12" O.C. and stayed 12" from any outside wall. If I were doing it again I'd go closer tube spacing 6" or so.

Passionforfire&water: Marc, I do see your point, but with no NG, there is an independence that can only be had by burning wood. One of the things I do for a living is install mini-split air source heat pumps (I do not own one) and they are very economical, however wood is king in my household. It's not even work when you only have to put up less than 4 cord/year.

If you are going to build a super energy efficient home, you should have a super energy efficient boiler! True independence of fuel costs for life.

How do you plan on heating your DHW in the summer? A boiler system FF or wood, emits a lot of heat during the summer for heating water.

TS
 
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Shop - 2,115 sq ft, ~30KBTU/hr @ -20F, including 192 sq feet of windows that are 6K BTU/hr of the design load. Not ICF - 8" SIP (structural insulated panel) walls, exterior foam on concrete foundation, and 14+ inches of cellulose in the attic (High-heel truss, so right out to the wall-line.) Not actually complete yet, but calculates to 6 cords a year, or 5 tons of pellets - NG is not ever going to happen here. 500 gallons of oil, 775 of LPG, 21,000 KWH (resistive) or 6300 with a heat pump (cheaper than pellets, actually, but not feasible in the coldest weather without a ground source.) Actual heating will be multi-modal, but it is good to consider all the options, and see how design of the building can affect the overall use, and what size heat source you might need... (house not built yet, but will probably be neopor 6" panels (SIPs) for walls unless something changes drastically...) Multi-modal boiler/solar system will have massive (650+gallons) tankage, and tank should carry the place for several days at normal temps, longer on a "keep from freezing" basis.

3 things I'm not happy with on ICF houses (and I considered that quite a bit before going SIP) - a better mass system puts all the mass inside the envelope, and all the insulation outside - not mass between insulation layers. ICFs (alone, without concrete and a pump truck to fill them) cost more than poured & formed concrete for the same foundation when I was last shopping. And short of living in the tornado belt, where it appears to make lots of sense if you can afford it, concrete is an expensive wall material once aboveground.
 
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Wow, thanks for all the insights and input! Lots to consider.

I'm trying to stay away from anything with a compressors (mini splits and geo-thermal) as I used to work on the ocean and spent a great deal of time and frustration dealing with malfunctioning refers, freezers and air conditioners. The domestic hot water in the summer thing is a big question, I'm thinking the best way to deal with it is to super insulate the mechanical room and add ventilation. Its surprising to me how much design can cost!
 
Bob Rohr said:
Keep in mind with a radiant slab in a super insulated building you may (will) not always have warm floors. I have put radiant in slabs for a few ICF homes and had the owners complain that the floors were not always warm, as they expected. Once the floor surface gets below around 78-80F it may not feel warm to bare feet, especially the hard surfaces like concrete or tile.
Click to expand...

I have noticed that my floors aren't as warm as I thought they would be - likely since my house is super insulated. The weird thing is the garage floor doesn't even feel all too warm even though I have 2x4 walls with fiberglass and overhead doors that are not as efficient and loose all sorts of heat when opened. Seems to heat really well and have a faster recovery time than I thought I would have though.
 
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Shop - 2,115 sq ft, ~30KBTU/hr @ -20F .... Multi-modal boiler/solar system will have massive (650+gallons) tankage, and tank should carry the place for several days at normal temps, longer on a "keep from freezing" basis.
Click to expand...
I like it! Typical MN cold winter takes only 4 cords of pine/aspen to heat my shop at constant floor temp of 62F. Only "cost" is my time to buck, split and stack firewood from dying or storm damaged trees right out the back door. Except for one large open space and a bare concrete floor, the shop looks more like a house: upper 4' of walls is sheetrock; 2' of green painted wood border trim to transition to 8' of solid white pine naturally finished paneling, random 8-12" widths . 4 x 14,000,000 btu/cord for aspen, 56,000,000 btu total, 3733 btu/sq ft/heating season extending from October to May.

The calculated heat loss is 35,000 btuh at -30F: 1500 sq ft, 14' sidewalls: regular pole barn construction, 6" fiberglass + vapor barrier on walls, 2+ feet blown in fiberglass + vapor barrier in ceiling, 2" foam perimeter insulation down 4 feet, 2" foam under the 5" concrete floor, big 12' x 12' insulated overhead door, 1 - 3' and 1 -4' (for bringing in firewood) service doors, 2 slider windows. In floor radiant on 12" centers. Gasification boiler and 1000 gal storage (well insulated) inside the shop.

I generally keep the floor at a constant 62F. The highest heat loss from the tank I have measured is about 20,000 btuh, normal MN winter heat loss is around 10-15,000 btuh, or 10-15 btu/sq ft. The tank alone when heated with stored btu's will maintain the shop at temp for 48 hours. This winter with temps into the -20F range I was gone for 9 days. Heat from storage and thermal mass kept the shop above 45F for just about 6 days. At 45F I have supplemental electric heat from a 5000w space heater to maintain 45F air temp.

All of this was done at a total cost of about $30,000, or $20/sq ft. I did all the interior finish work (white pine paneling from our trees) and boiler/storage tank install, contractors put up the building, insulation, ceiling, concrete floor and pex.

High energy efficiency and low heating cost does not have to be super-expensive. Obviously plumbing and finishing for a house would be more expensive, but high building envelope energy efficiency can be very moderate.
 
my icf foundation is two inches either side of 8" poured concrete, the basement is supper insulated. I built a timberframe on top and if i didn't have 22' sidewalls than i would have done all icf, but it was cost prohibitive so i went with sip panels. On the coldest windy days we have had i still feel some air infiltrion thru the sips must be in the corners.
 

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Got a 4500sqft full ICF house to the second floor with high velocity air handler w/ heat coil, in floor heat in the 2 stall garage and basement. Also heats the 105 gallon electric water heater faster than the elements. My stove is a portage and main optimizer 250 and kicked butt in January/February when we had -26 temps. Kept the house 72 no sweat. Also adding an external three stall garage with a 100k fan coil later on.

Made a little video of the elaborate maze!
 
I don't have a SIP or ICP house. I did build a 2200 sq. ft house with 8' ceilings in the basement and 9' on the living space. I went with Anderson windows and storms on the double hungs. I have 2x6 walls with 4" closed cell foam. Basement has 2" foam on th eoutside and studed walls inside and R13 batts . I have about 20" cellulose in the attic. I used 4 1/2 cords of wood this year. 1/2 cord was basswood and 1/2 cord was aspen. We keep it @ 67 degrees or so. I have forced air but also 1,000 ft. of 1/2" staple up pex under the kitchen, family rm and some in the master bath ( tile) I can run my EKO 25 @ 160 degree water temp and if it's not windy the house stays 67 in the rooms with pex. The forced air is never used unless it gets below zero and is windy. I don't know if this helps. I will say, if you build, insulate the living heck out of it. I wish I would have insulated even more but don't know what else i would have done. I think i am @ 20k BTU per hr @ about 0 F or even -10 if it's calm. Does anyone else notice a bit of a draft when it's windy?? We do and think it migh tbe the firplce.
 
My only draft is my sliding patio door. They always seem to leak some air.
 
lindnova said:
My only draft is my sliding patio door. They always seem to leak some air.
Click to expand...


I have one on the north side of my house facing a 60 acre field. Bad set up with the winter winds. If they can't build them to stop air, I wish the makers would have a decent storm set up for them.

I have considered getting a European rolling shutter, But we like the light and view it provides.

gg
 
I put in foam backer rod in the gaps, but don't open this door to the porch during the winter.
 
Bob Rohr said:
Keep in mind with a radiant slab in a super insulated building you may (will) not always have warm floors. I have put radiant in slabs for a few ICF homes and had the owners complain that the floors were not always warm, as they expected. Once the floor surface gets below around 78-80F it may not feel warm to bare feet, especially the hard surfaces like concrete or tile.


Yep. that's what my floors are like.. 2" concrete and a slate tile finish.. floor only feels warm if your feet are cold. so I go outside in my bare feet and walk in the snow for a minute or two,walk back in and the floor is toasty warm.:p
Click to expand...
 
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