Frequently Asked Questions (FAQs)

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...
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...
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 - building envelope - Commercial - 40% WWR glazing limitations
The Scope and Application sections of the 2009 IECC address use of ASHRAE 90.1 (2007) as an alternative.  See below for the text.  It is appropriate to use ASHRAE 90.1 as an alternative when your building exceeds 40% glazing, although it does not...
Topics - building envelope - walls - windows - fenestration - windows - glazing - Commercial - calculating above-grade wall area
COMcheck implements the calculation based on the definition of above and below-grade walls in the applicable code.  The calculation for percentage of glazing in ASHRAE Standard 90.1 and the IECC are different as the IECC only looks at above grade...
Topics - Commercial - warehouse
Warehouses must be considered carefully. The first consideration is whether it is going to be conditioned, cooled and/or heated, or semi heated. Next is the applicable energy code. Older codes did not require the building envelope to meet the...
Topics - Commercial - low-energy - non-conditioned
In the 2015 IECC, Section C402.1.1 Low-energy buildings – low energy buildings or portions separated from the remainder of the building by a building thermal envelope complying with the code, can be exempt from the building thermal envelope...
Topics - Commercial - Residential - historic
Note:  The key point is not the age of the building, but whether it is registered or eligible to be registered and listed.  In the following cases, historic buildings are considered exempt from provisions of the energy code (however, we recommend...