Frequently Asked Questions (FAQs)

Unfortunately, there is not a way to merge files.  The web tool is definitely the way to go when you have multiple contractors involved as you can create a generic log in and each contractor can work on the same project file to enter their information (e.g., building envelope, lighting, mechanical). 

Project sharing will soon be more user friendly. 

The problem most likely relates to the basement walls you have specified. The DOE-2 simulation program used in REScheck for performance alternative calculations sometimes generates this error even though the entries appear valid.

As a workaround, we recommend that you split your basement walls so that for each basement wall you add a new above-grade wall to represent the above-grade area of the basement wall. 

There are a couple of things to try:

1. Completely remove REScheck or COMcheck
   • Use the Windows operating system “Programs and Features” uninstaller
   • Open Windows Explorer and navigate to C:\Users\<your username>\AppData\Roaming\<REScheck or COMcheck>
   • Delete the check.prp and defaults.dat files
   • Navigate to the REScheck or COMcheck application folder:  C:\Users\<your username>\AppData\Local\Check\<REScheck or COMcheck>
   • Delete all of the contents of this folder, including any sub-folders
     (These steps should ensure the application has been fully removed.)
   • Then try reinstalling REScheck or COMcheck
2. If that doesn’t work, use the web tool which requires no download but you will want to register so you can save your projects.   

Choose a city that is the closest with the most similar weather.  Check with the building official where the project is located to confirm the city selected will be acceptable or if choosing “county” as the designation would be more appropriate.  The easiest way to choose county would be to use the web tool which has the option between city and county on the project tab screen.

Exterior walls in REScheck are defined by the assembly type, gross wall area, cavity/continuous R‑value (U-factor for Other walls) and orientation.  All exterior walls are assumed to be of regular rectangular shape with an average wall height of 9 ft., and the wall width is calculated from the gross area as input by the user. 

REScheck wall materials are assumed to be plywood siding, plywood structural sheathing, and foam insulation sheathing on the framing exterior, batt insulation, wood framing, and 1/2-in. gypboard on the interior.  The entire wall is assumed to have structural sheathing. When continuous foam insulation is specified, 100% of the wall is assumed to be covered at the specified R-value.

The U_o‑factor for all frame walls is based on the R‑value of cavity insulation and the continuous insulation R‑value (if used).  If the user does not enter a continuous insulation (sheathing) R‑value (or enters a value of 0.0), the software assumes a sheathing R‑value of 0.83.  This default value gives credit for some minimal type of sheathing material (such as plywood) under the siding. 

Continuous Insulation

Insulation that runs continuously over structural members and is free of significant thermal bridging; such as rigid foam insulation above the ceiling deck. It is installed on the interior, exterior, or is integral to any opaque surface of the building envelope.

Cavity Insulation

Insulation installed between structural members such as wood studs, metal framing, and Z-clips.

Cavity insulation is used within the wood- or metal-framed wall, while rigid continuous insulation (c.i.) is placed on the exterior side of the framing.  Alternative combinations of cavity insulation and sheathings in thicker walls can be used, provided the total wall assembly has a U-factor that is less than or equal to the appropriate climate zone construction requirements.

Cavity Insulation Calculation in REScheck

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-15 are modeled in REScheck as having 2x4 studs at either 16" or 24" O.C. (on center) and cavity wall insulation R-values greater than R-15 are modeled as 2x6 studs at either 16" or 24" O.C. 

Continuous Insulation Calculation/Insulated Sheathing

The assemblies listed in REScheck already have a default value added for standard sheathing (depending on the assembly component). If no sheathing is indicated by the user, the sheathing is assumed to be plywood with an R-value of 0.83. If insulated sheathing is used, only 80% of the net wall is assumed to be covered by the insulated sheathing. The other 20% is assumed to be covered with plywood.

REScheck Quick Tip

Cavity R-Value - Enter the R-value of any insulation to be installed in the cavities between above-grade wall structural members. The insulating values of other parts of the building assembly (e.g., gypsum board and air films) are accounted for by the program and should not be included.

REScheck  wall assemblies assume cavity insulation completely fills the cavity.  Users who have unique wall assemblies where the cavity is not completely filled with insulation must account for the air space within their wall assembly calculation and should use “other” as the wall type and enter their respective overall calculated U-factor.

Continuous R-Value - Enter the R-value of any continuous insulation in the above-grade wall. Continuous insulation is continuous over framing members or furring strips and is free of significant thermal bridging. The R-values of other parts of the building assembly (e.g., gypsum board and air films) are accounted for by the program and should not be entered. Insulated sheathing installed on the exterior of above-grade walls is an example of continuous insulation. For structural insulated panels and insulated concrete forms, enter the manufacturer-reported R-value for the entire assembly.

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-15 are modeled in REScheck as having 2x4 studs at either 16" or 24" O.C. (on center) and cavity wall insulation R-values greater than R-15 are modeled as 2x6 studs at either 16” or 24” O.C. 

For more detailed information on how the walls are calculated please refer to the REScheck Technical Support Document.

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 determining compliance.

REScheck determines compliance for alterations in a similar manner as additions and new construction, however, each component that is being altered will need to be identified as either meeting an “exemption” from the drop down list of exemption choices or choose “no exemptions” apply and the proposed insulation and/or fenestration values must be entered.  REScheck will perform trade-offs between envelope assemblies that have been identified as “no exemptions” apply to the assembly when determining overall compliance for alterations for a specific project.

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 low-voltage lighting (2012 IECC, Section R404.1).

REScheck currently does not have a lighting input function; therefore, the lighting requirement should be confirmed under the Requirements Tab in the program.

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, the software requires an overall U-factor for the assembly. The assembly U-factor is calculated from the spacing of any framing and its R-value, the R-value of installed insulation, and the R-value of the balance of assembly (items such as OSB sheathing, drywall, interior and exterior air films, etc.). Details of how to perform a U-factor calculation can be found in any basic heat transfer text book or handbook.

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 basement wall dimensions directly into this illustration and select the OK button to have them transferred to the corresponding row in the table on the Envelope screen. If you prefer to enter the dimensions directly into the table on the Envelope screen, you can select Cancel to remove the illustration without entering dimensions. To view the basement wall illustration and inputs at a later time, click the right-mouse button anywhere on the basement row and select Edit Basement Inputs from the popup menu.