City-Data Forum Heat Loss Calculation (house, transfer, construction)
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10-13-2009, 06:28 AM
 Location: NJ 15 posts, read 38,741 times Reputation: 13

I'm located in Central NJ - Ocean County - I need to come up with my own heat loss calculation. HELP!!! I need all the tips that I could get, starting with Design Outdoor Temperature... Will appreciate any suggestions or tips.

10-13-2009, 07:12 AM
 9,124 posts, read 31,677,302 times Reputation: 3514
If you're not even sure of the design temp for the area, I'd say you're going to have a heck of a time getting an accurate calculation.

10-13-2009, 07:23 AM
 Location: NJ 15 posts, read 38,741 times Reputation: 13
I got that
Design outdoor temp 33.6
Heating degree days 5000

But the rest still is a mistery!

10-13-2009, 07:52 AM
 Location: Bergen co. 563 posts, read 1,093,581 times Reputation: 218

10-13-2009, 12:11 PM
 Location: Home 1,483 posts, read 2,645,800 times Reputation: 620
Heating degree days? What is that definition? Number of days (time) times average temperature delta for that day? Is this a delta T duration problem here?

Also, is this real life or theoretical? Are you trying to outfit your house, or do a physics/chemistry problem?

(BTW, i believe the heat loss is dependent on thermal transmissivity. That depends on surface area exposed and insulation/heat transfer rate. THAT depends on the delta T. So you get your Area times Transmisivity (for each area) times your delta T, times time and you get your energy transferred.)

10-13-2009, 01:50 PM
 Location: NJ 15 posts, read 38,741 times Reputation: 13
I'm converting from electric to gas, its old house and need alot of work, and this is the first step. In order to get permits to install the new gas furnace and AC i have to provide township with heat loss calculation, i don't care how it will come out or what it would say, as long as the township will approve and i can move on with furnace install and the rest of construction.

10-13-2009, 02:52 PM
 Location: Home 1,483 posts, read 2,645,800 times Reputation: 620
That's tough then, that seems like code, not science... I wish I could help you there, but I would suggest you Google it and possibly put in some tag lines like "gov" into the search to get the official site and requirements.

You could always call them up and ask them really nicely too you know!

10-14-2009, 04:46 AM
 9,124 posts, read 31,677,302 times Reputation: 3514
Quote:
 Originally Posted by ValBen I'm converting from electric to gas, its old house and need alot of work, and this is the first step. In order to get permits to install the new gas furnace and AC i have to provide township with heat loss calculation, i don't care how it will come out or what it would say, as long as the township will approve and i can move on with furnace install and the rest of construction.
Ummm, the building department isn't going to just accept some half-assed calculation that you come up with- you may not care what the calculation says, but they will. The calcs typically have to be done either by a licensed engineer or by the HVAC/plumbing contractor that's pulling the permit, and have to show that the furnace being installed is properly sized.
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