Heat Loss Test

AleDukes

How is a Heat Loss Test done?

Ironman

I'm not sure if you mean a blower door test or a heat loss calculation.

Gilmorrie

Slant/fin and Taco have freebie PC-based programs for estimating heat loss. Others are available for a price. You enter a bunch of data regarding the room sizes, windows, insulation, etc. Figure about three hours with the help of a tape measure and an assistant.

If you use natural gas, I can suggest a simple quick-and-dirty way using the gas meter and some arithmetic.

nicholas bonham-carter

Let's go over the sizing by usage method again.
I was looking for an old posting about that th other day.--NBC

Gilmorrie

Over several hours during cold weather, clock the gas meter to determine usage, in cubic feet. Convert to Btu/hr. Then divide by boiler efficiency, maybe 80% for an older unit. If you run the test at the design ambient temp, then you have calculated the heat loss.

If you run the test at a higher temp than the design temp, adjust the Btu/hr by multiplying by (72-Td) /(72-Ta), where:

Td = outdoor design temp
Ta = actual outdoor temp

Gilmorrie

Whoops - multiply by boiler eff, not divide, to get heat loss.

Jamie Hall

The same method works for oil, if you have a way of measuring the amount of oil used. 138,000 BTU/gallon.

Gordy

HDD per btu per sqft. Best method once you nail down the boilers performance. All that is needed is logged run times for heat calls. A digital thermostat does this.

Gordy

True then that gets complicated. But if you did the math the mod/con would be right size.