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COMcheck - Louvers in Envelope Screen

M

Mech

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Oct 30, 2009
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Eastern PA
I am curious how people account for louvers when completing the envelope screen in COMcheck. Do you include them somehow or just ignore them? One of my current projects is a manufacturing facility with adjustable louvers in the walls and exhaust fans on the roof. The louvers account for 3.5% of the wall area, so I thought they should be included somehow. One idea is to enter the area of the louvers as a wall type with really poor thermal characteristic - an indoor air film and an outside air film resulting in a U-value of 1.176.

Thanks
 
my thought on this would be to not include the area of the louver in the building envelope as long as the louver has a damper/connected to a duct. That way the duct is typically insulated and that will limit the flow of heat.
 
here is info from FAQ from energycodes.gov

"Louvers are best treated as un-insulated portions of the wall. You can add them as a separate wall type (for example, if they are metal, metal building would probably be most appropriate) with no insulation but a wall area. COMcheck will do the area-weighted averaging for the opaque wall to calculate the overall U of the opaque wall. The impact of having an uninsulated wall area is that you will be required to “make up for that” in some other portion of the building envelope. This may mean more insulation on the rest of the wall, better windows, or more roof insulation.

Note: There is an allowance for up to 1% of wall area in “recessed equipment” in walls in Standard 90.1 if 90.1 is the code in which you are complying with."
 
Thanks mp25! I looked at a FAQ section, but apparently either it was not the correct one or a skimmed right passed the louver FAQ.
 
This does not make any sense to me. A louver is a portion of the HVAC system, not the building envelope. There is no conductive heat transfer across an operational louver.
 
MMcKenna said:
This does not make any sense to me. A louver is a portion of the HVAC system, not the building envelope. There is no conductive heat transfer across an operational louver.
Click to expand...
What about when the HVAC system is turned off?
 
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