# Calculating Actual Heat Loss

Posted By jebatty, Jan 4, 2012 at 11:43 PM

1. #1

### jebatty Minister of Fire 2. ```NULL ```

Jan 1, 2008
5,413
728
Loc:
Northern MN
My data on weighed wood burns might have induced some of you to also do this for a sufficient period of time to use that data to calculate actual heat loss. My boiler and storage are inside the heated space. For Nov-Dec I burned 3014 lbs of wood. That works out to 12,455 btuh actual heat loss (3014 x 6050 / 61 / 24). Degree days in my location for these two months were 1993, which also means, fwiw, 6.24 btuh/dd. My shop is kept at 60F, so my heat loss does not represent an equivalent house.

If some have boiler and storage inside the heated space and could do the calculation, and others have the same outside the heated space and do the calculation, we might start to get a better idea of the contrast from a heating perspective of boiler and storage location.

You might want to try weighed wood burns for awhile and see what the result is for actual heat loss for your home or other building.

2. #2

### ihookem Minister of Fire 2. ```NULL ```

Jan 25, 2009
668
43
Loc:
Allenton, Wisconsin
I have weighed my wood a few times. I also figured what my btu needs were. I figure an 80% efficiency with my eko 25. My boiler is 120' away so that makes a difference. I still wonder were I can find a good heat loss calc. on the internet. I use build it solar.com I think it' a good heat calc but want others to compare.

3. #3

### Hunderliggur Minister of Fire 2. ```NULL ```

Dec 23, 2009
602
8
Loc:
Lothian, MD
I used REScheck from the Department of Energy to establish the code compliance for my log house to our local building department. At a UA of 834, I am 6% better than code without taking into account my solar orientation. UA 834 at 50F delta T (70 indoor, 20 outdoor), is about 40KBTUH. At 3 GPM and delta T of 20 in my radiant, I get about 28KBTUH per zone. Today it was more like 10F outside so my loss is 50KBTUH which is consistent with my zone pumps running most of the time.