# Does the volume of a space matter when solving a heat loss equation

I received a practice question where I was given all the factors to utilize the heat required equation (pg 163 of the handbook, last equation). The BTU/H was already calculated and a given, the temp differential was given, and so were the degree days. But I was also given a diagram with dimensions to the space…

Was I supposed to use the dimensions somehow? the only other equation I could think that needs dimensions is BTU/h=U x A x Temp Diff…but the question already had a BTU/h, and no given U value. And the question was specifically about heat required?

For all the equations in the handbook that involve BTU/h…they all mean the same thing for that variable right, heat energy per hour? It doesn’t magically change meaning per what equation you’re using, right?

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Hi @Shikha,

I’m afraid I don’t have the resource the resource you’re looking at, so I’m not 100% sure, but perhaps the diagram was a read herring? Or otherwise you were meant to use a different equation and the problem was asking for something slightly different than the heat required?

BTU/h will always represent the same thing. A BTU is the amount of energy it takes to raise the temperature of water by 1 degree fahrenheit. BTU/h is a unit of power (remember, power=work/time), which is equal 1 BTU being output in an hour.
I had to visit this website to refresh myself on the best way to describe btu/h:
https://energyeducation.ca/encyclopedia/BTU/hour

I’d definitely check out some of the PDD “OBJECTIVE 1.2: DETERMINE THE SIZE OF MECHANICAL, ELECTRICAL, PLUMBING SYSTEMS AND COMPONENTS TO MEET PROJECT GOALS” lectures on this for more information. I really relied on these lectures to bring me up to speed on HVAC and heat loss calculations.

These are a few good ones:

Hope this helps!
-Darion