Calling all Woodstove Mathematicians

[SE Iowa]

I built a large ICF home here in Iowa with radiant floor heat in gypcrete with 11 zones. Total sf is about 4600 of which 2850 is everyday living (above ground and finished). I have one large living room on the main floor with carpet on the north side of house and all the upstairs has carpet. We live in a very windy and somewhat cold climate. We usually only have 2 to 3 weeks of sub zero weather but typical temps are in the 20's for highs during the day for the most of the 3-4 month season. All the windows are low-e gas filled double pane DOUBLE HUNG (biggest mistake on windows in windy climate). We have solid brick siding on house. Heating system runs on an instantaneous condensing boiler that burns natural gas. We cook on gas and have an instantaneous NG hot water boiler too.

That said, our AVERAGE daily btu input is 500,000btus. This is for the 3-4 months of main heating season. This does include our cooking and hot water although in the summer our gas consumption is usually lest than $7/month of actual gas usage (REALLY!) so most of that 500,000 btus is used for heating purposes. Please note some important points that I have noticed about our house.
1. Windows are the weakest link which is even magnified in an ICF home.
2. ICF homes heat and cool DIFFERENTLY in that there is so much more mass. Short changes in temps (like going from day to night) has almost no effect on heating and a slight effect on cooling. We notice that the air conditioner comes on in the late afternoon and cycles normally into the night til 10:00pm. This also can be a detriment when we get that 2 to 3 weeks a winter, when the high temp is -5F during the day. Eventually, that concrete does cool down and so it can be hard for the heat to remain caught up. This is specially true in the large living room on the north side of house with thick semi-plush carpet on it. We sometimes "need" to run the gas fireplace there to maintain room temps (70F).
3. Most people feel that in-floor heating has a slow response time. We do NOT find this to be true in our ICF home as all of the heat seems to stay within the walls. In addition we had some learning curve when we first moved in. Often the heat will overshoot during the shoulder months if the wife opens all the window shades and it's a nice sunny day.

By the way, we heat our main floor to 70F and the upstairs at 69F. This seems to be the most optimal temps for us. Any warmer and you literally sweat to death if you do any housework or "activity". radiant floor heat is different and takes getting used to. When my family comes, it drives them nuts.

 

[flyingcow]

steelejones,
The garn is pretty close in price if you figure the gassifier plus storage tank. This is if you bought an off the shelf storage tank, and not DIY. I had my system put in last winter and love it. I've got 3 kids(15/13/11yrs old) + wife. I'm able to do DHW for 5+ days on one firing of my tarm. Sometimes 6 days. I was under the impression(and I'm sure I'll be corrected ) that unpressurized is a better deal if you plan on using it for DHW in the summer. Anyways, you've come to the right place to figure it out, really good bunch on this site.
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DOC is a tarm dealer and you may be able to order direct from them. Also E.C. Knight in P.I. is a dealer for econoburn(these alos are a nice unit).

I live in the southern end of "The County" and there was a definant chill in the air this morning.

If no one has mentioned it yet, these gassifiers need/like seasoned wood. Preferably at least a year. Get splittin' if you haven't started it yet.

 

[steelejones]

Well I was told last night by someone that the Garn WHS 1500 wouldnt and isnt recommended for basements. Even tho my basement is very large with a large 6' width door going into it. They thought that there was a rod or something that needs to come out verticlly from the top????

Does anyone else on here have a Garn in the basement?

Also, if the garn is in your basement how are you getting rid of the smoke, a horizontal flu? Verticle? If horizontal in your basement im assuming your having to go verticle for 5-6ft then horizontal ?

 

[Gooserider]

Well I was told last night by someone that the Garn WHS 1500 wouldnt and isnt recommended for basements. Even tho my basement is very large with a large 6' width door going into it. They thought that there was a rod or something that needs to come out verticlly from the top????

Does anyone else on here have a Garn in the basement?

Also, if the garn is in your basement how are you getting rid of the smoke, a horizontal flu? Verticle? If horizontal in your basement im assuming your having to go verticle for 5-6ft then horizontal ?

I would want to confirm that with Garn, as I hadn't heard anyone mention that restriction before. I don't know about any rods (maybe a sacrificial anode?) but there is a manway hatch on the top of the unit that needs to be accessible for filling and occasional service. I've heard that some folks put a hatch in the floor above the unit to get around this, which obviously has possible issues depending on what is above - a hatch in the middle of the livingroom or kitchen floor is likely to have "WAF" problems.

I'm not a Garn expert, but as I understand it, the horizontal venting is done simply by going straight out the back of the unit and through the wall, with an elbow pointing down on the outside. They usually put a 55 gallon drum or equivalent partially filled w sand under the elbow to act as a trap for any embers or fly-ash that makes it through the plumbing. Again, I would look for answers about length limits, etc. from official Garn sources.

It is worth noting that the Garn is considered a positive pressure flue device, which means that whatever chimney it has MUST be air tight inside the building to prevent CO issues, and there must be adequate attention paid to design on the outside to keep the exhaust gasses from coming back into the building - both issues that are extra important in an inhabited structure... I'm not sure just what the rules are on that however.

Gooserider