Well I did what I thought was the right thing....1680 square foot bungalow with a full, finished, walkout basement.
ICF basement walls, SIP main floor walls, R50 blown attic insulation, HRV and 98% efficient propane furnace. I topped up the tank after 30 days and to my disappointment 467 litres consumed @ .63 / litre for a total of $337.64 including taxes.  Based on research and testimonials from others who have built this way, I thought that I would be able to heat this place with a candle! Anything that you could contribute to make me feel better and ease my fear of the cold weather to come would be appreciated.

TL
that does not sound right, not even close. standard stick frame houses should be able to be heated for that amount.

question: what sort of SIPs did you do? EPS, urethane? what thickness? Caulked and installed right?

Is there any leaks in your propane tank or lines by chance?

Thanks for the prompt response. I installed 6 1/2" EPS Thermapan SIPs myself being very certain to caulk or foam where specified. I hadn't thought of a leak. I'll call the company tomorrow.

I agree there has to be something wrong there. I have a one story SIP house with R50+ cellulose and all I have had to do this year to date is fire up our masonry heater. Now we haven't had brutally cold weather yet but it keeps the heat in for a long time. The idea of a leak with your propane is a good thought.

Something is definitely strange here. OK, lets get some facts.

1. Did you put any foam board under the basement floor to insulate the concrete from the dirt?
2. Did you seal and insulate the rim board?
3. Good windows with good seals?
4. Do you have large windows or a lot of square feet of windows?
5. What has the average temperature been?
6. Did you do a blower door test to see if you have any leaks? It should be under .3 air changes per
hour
7. How much is the HRV running? It might be running way too much.
8. What temperature did you keep the house at?
9. Did the furnace seem to run a lot?
10. Are you sure the correct jet is in the furnace?
11. How thick (R-Value) of the walls?
12. Were the panel walls triple sealed at every spline, floor and top plate?
13. Was your furnace sized correctly?
14. Is there a possibility that the tank or the line running to the house has a leak?  At the pressure regulator at the   
      house?  You should be able to smell something somewhere if you have a leak.  Most propane tanks have a gauge on
      them, so you might want to check that to get an idea of useage.

I would suggest you find someone with an infrared camera to take pictures of your house to see if you have any leaks. At night is best, or a very cloudy day as the sun warming up a wall will really mess with the pictures. Some of the places to look for air leaks are the rim board area, around doors and windows and all along where the roof meets the walls.

If you have a small structure, no windows, no doors, R-50 walls and roof and it isn’t too cold, you might heat it with a candle, but in the real world we have windows and doors, and it can get right cold. Here, high in the Rockies, the temperature has varied from –10 to around 30 F the last month or so. I have not turned on the main heat yet (propane water heater). I have a 500 gallon propane tank, filled it last March, it’s down to a quarter of a tank (topping it Tuesday for when it gets cold), a 2800 sq/ft home, R-24 walls, R-40 roof and I’m heating it right now with the fireplace. It’s 16 F right now outside, it’s 72 on the main floor and 71 upstairs. The point is, everything needs to be done right, and attention to details is critical. Check your furnace, HRV, do a blower door test and get the pictures from the infrared camera, and see where you stand.

Steve
GrandCountySIPs.com