construction error

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Equest help,

I am a new Equest user, so I have a fairly simple question. I put in
custom wall and roof constructions, with just R-values for each layer
because I wanted to match exactly an energy model I did with another
program as a comparison. I keep getting an error message saying "Wall
has no heat capacity. U-value used". How do I fix this, but still get
the exact U-value I want?

Thank you,

Kari Krolikowski

Krolikowski, Kari's picture
Joined: 2013-06-15
Reputation: 0

You can simply enter the U-value instead of using the layers. One word of caution: DOE-2 calculates the exterior wall film resistance based on the weather data wind speed. So the U-value you enter should not include that exterior film resistance.

The alternate is to add all but 1 of your layers as materials to get the wall heat capacity then match the overall U-value by specifying the remaining layer resistance.

Either way, the summary table at the bottom of the LV-D report gives you the wall U-value with ext. film resistance.
Brian Fountain

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Joined: 2011-09-30
Reputation: 201