A Heat loss calculator for a simpleton!

Cyclist77

Is there an "easy to use" calculator that will get me into the ballpark?

hot_rod

Pikes Peak Building Dept has this Excel based load calc for download.

I use the Sigenthaler program Heat Load Pro at www.heatpros.com There is a free trial, windows based.

Both the Heat Load Pro and HDS are worth owning

https://www.pprbd.org/File/ByAlias/HeatLossCalcXL

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Cyclist77

MY wife and I spent the afternoon with a tape measure. All the room's exterior walls and glass area were measured along with square footage of the floor space. 1 thing I have noticed in a few of the calculators I have perused is the insulation factor. I built our home with 11" exterior walls and an abundance od ceiling insulation.

Cyclist77

Bob, I am printing it out and will have a go at it. Thanks

Cyclist77

Heatpros.com does no work. It appears that domain name is for sale

hot_rod

sorry, hydronicpros.com

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Cyclist77

The free download doesn't seem to work. Thanks anyway.

jesmed1

https://forum.heatinghelp.com/discussion/comment/1839633#Comment_1839633

I've used this online calculator for our house and have compared the results to heat loss calculated from our actual fuel usage, and it gives reasonable results.

The format on the upper part of the calculator seems to have been messed up by Google ads. Just be sure to input the correct number of heating degree days for your area, and your design temperature, in the upper fields interrupted by the ads.

https://builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

GroundUp

Builditsolar is all I use anymore. It's a little janky, but always spot-on if you put in the correct data

Cyclist77

So started playing with Builditsolar calculator and have a question or 2. The section "Floors" that are exposed to outside temperature. Is the basement and crawl space to be included? Not rea exposed. But they are insulated because of radiant floor heat. I think I understand the other information to be included.

jesmed1

You have to use your judgment on the floors and fudge it a bit. We have the same situation, and I enter the full floor surface area but use a high R-value since the floor itself is not really exposed to outside air temps. I used R-30 for our floors, and that seemed to give reasonable results.

Our actual floors are 100-year-old hardwood with no insulation, and subfloor exposed in full basement ceiling below. Our full basement is exposed concrete foundation walls, half submerged below grade and half above. The basement is unheated (except for the heat from two cast iron boilers and piping) and stays in the 60-65 degree temp range, partly because of heat gain through the floor above.

So by ignoring the "slab loss" line and leaving that zero, and using R-30 for the entire first floor area exposed to the unheated basement below, that gave us reasonable results.

In your case, your floors are actually insulated for radiant, so you should probably use an even higher R-value, like maybe R-40.

Cyclist77

Thanks !

OldDudesHideout

U.S. BOILERS HAS A FRIENDLY CALCULATOR