Heat Loss

James Day_2

I'm doing a heatloss on an old brick commercial building.  Heat Loss is for 3rd Floor only.  Around 3500 sqft, 2ft thick brick construction.  What would be a good air exchange number to use for infiltration factor.  I am using Uponors heatloss program and not sure what number I should use for that old of a commercial building.  Ceiling is R-19 insulation.  I usually use wrightsoft but am trying out uponors heatloss.

Thanks, James

Jamie Hall

That's one of those questions...

Are there windows?  What kind?  How big?  How new?  Are doors?  Etc. etc. and so on...



In a previous incarnation I did a fair amount of work on building inspection, and we were always fussing about not enough air changes per hour -- a matter of indoor air quality.  But it depended a lot on the usage of the building.

James Day_2

Heatloss

All single pane windows. R-19 ceiling. Heated apartment below. Not a tremendous amount if windows. No doors to outside.

CMadatMe

Factor

use a value of 1.25

James Day_2

Heatloss

thanks chris

TonyS

Plug in a few different numbers

High Med Low and see if its enough of a difference to take you to the next size boiler,if not don't worry about it.. I am not familiar with that program, I use HVAC Calc and it is a simple matter to go back and change any parameter. I just finished a heat load on a home, came out 73000. So on the TT line that put me at a 110 no matter where I set the infiltration. If it would have been 108000 with med infiltration I would have had to make a call.

Mark Eatherton

The OLD code called for 1.5 NACH...

One way to confirm it for sure would be to do a commercial blower door test. Why guess? For less than $300 you will KNOW where the air is coming from, and how much, and might be able to cut back on some of it to save energy.



ME