Frequently Asked Questions (FAQs)

Topics - Residential - building

The term “residential building” includes:detached one-or-two family dwellings having not more than three stories above grade plane; buildings that consist of three or more attached townhouse units and have not more than three stories...

Topics - building

A commercial building is defined as all other buildings that are not considered a residential building.

Topics - building envelope - Commercial

COMcheck computes an envelope index that is a reflection of the difference between a 'design' building energy performance factor (EPF) and a 'code' or budget building EPF.  The total building load (made up of cooling, heating, lighting, and...

Topics - walls - Residential

REScheck uses nominal insulation R-values. The program does not calculate for compression. For example, if R-19 is entered as the cavity insulation R-value, it assumes the full R-19 in REScheck. Walls with insulation R-values equal to or less than R...

Topics - building envelope - Commercial

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...

Topics - windows - Commercial

When entering your fenestration in COMcheck the pop up window has three options to enter your fenestration.  Choose the second option called Product Performance in accordance with NFRC.  If you do not have a pending product number, enter...

Topics - Commercial - Federal - Manufactured Housing - Multi-Family - Municipal - Residential

Copies of the International Energy Conservation Code (IECC) can be purchased from the International Code Council website. Copies of ASHRAE standards can be purchased from the ...

Topics - air leakage - mechanical - ducts - Residential - duct testing - testing

Both the 2009 and 2012 IECC require duct tightness to be verified. Verification can take place via either a post-construction test or a rough-in test.For the post-construction test, leakage measurement must be made across the entire system,...

Topics - building envelope - basement - walls - Residential

After selecting a basement wall type, a basement wall illustration will appear with input boxes for the basement wall height, depth below grade, and depth of insulation. The illustration helps identify the dimensions being requested. You may enter...

Topics - building envelope - windows - windows - fenestration - Commercial - sprandel systems - u-factor

Fenestration is considered anything that transmits light, however, COMcheck cannot calculate fenestration without having a wall associated with it. In this case the wall is entirely fenestration therefore, the square footage would be the same for...

Topics - building envelope - walls - Residential

Walls that do not fit into any of the preset categories in REScheck (preset categories come directly from the applicable code currently selected in the Code menu) may be entered under the "Other" wall type. When "Other" is chosen as the wall type,...

Topics - lighting - Residential

The 2009 IECC requires that a minimum of 50% of the lamps in permanently installed lighting fixtures be high-efficacy lamps (2009 IECC, Section 404.1). The 2012 IECC has increased the minimum percentage from 50% to 75%, along with an exception for...

Topics - Commercial - Residential - status of state energy codes

Code adoption takes place at the state, and in some cases municipal, level. To determine the code in a particular state, visit the Status of State Energy Code Adoption page.

Topics - addition - alteration - building envelope - Residential

REScheck determines compliance for additions in the same manner as new construction. When entering an addition, only the new portions of the building need to be shown in the software. REScheck will perform trade-offs between envelope assemblies when...

Topics - Commercial - warehouse

Any building that contains conditioned space must comply with either the IECC or ASHRAE Standard 90.1.The IECC exempts buildings with a peak design rate of energy use for space conditioning less than 3.4 Btu/h•ft2 from compliance with...

Topics - Commercial - Residential - code

The IECC addresses mixed occupancies by stating that commercial occupancies must comply with the commercial portion of the code and...

Topics - building envelope - Commercial - software

If multiple users are putting information into COMcheck, each may fill out the appropriate section independently. However, all sections of the building must show compliance to the same code or standard (e.g., cannot show envelope compliance to IECC...

Topics - lighting - lighting - exterior - lighting - interior - Commercial

Exemptions and allowances for lighting are an option that must be activated in COMcheck. To activate the exemptions and allowances, take the following steps:Select either the Interior Lighting or Exterior Lighting Tab Go to the Options menu and...

Topics - addition - alteration - Commercial

COMcheck determines compliance for additions in the same manner as new construction. When entering an addition, only the new portions of the building need to be shown in the software. COMcheck will perform trade-offs between envelope assemblies when...

Topics - Commercial - performance approach

A performance approach (also known as a systems performance approach) allows you to compare your proposed design to a baseline or reference design and demonstrate that the proposed design is at least as efficient as the baseline in terms of annual...