What Is a Rescheck?
REScheck, standing in architectural construction as Residential Energy Services check or Residential Energy Code Compliance check, is a specialized computer software program developed by the United States Department of Energy (DOE) and Pacific Northwest National Laboratory. Engineered to simplify energy code compliance for single-family residential builders, architects, and building code officials, REScheck calculates whether a proposed home envelope design satisfies the mandatory thermal requirements of the International Energy Conservation Code (IECC) and state-specific energy codes. Submitting an approved REScheck compliance certificate is a mandatory requirement to obtain residential building permits in jurisdictions across the nation.
Purpose and the Trade-Off Compliance Methodology
The primary purpose of REScheck is streamlining building envelope thermal calculations. Historically, residential builders who wanted to prove compliance with local energy codes were forced to follow strict prescriptive path tables. Under prescriptive rules, every individual building component had to meet rigid statutory R-values or U-factors: ceiling insulation had to be R-49, exterior walls had to be R-20, and all windows had to achieve a U-factor of 0.30 or better. If a modern architectural design featured floor-to-ceiling glass walls or cathedral ceilings with limited rafter space, the design automatically failed prescriptive inspection.
REScheck revolutionized building permitting by introducing a computerized UA (overall thermal transmittance times surface area) trade-off methodology. Instead of evaluating each wall or window in isolation, REScheck calculates the total heat loss through the entire building thermal envelope. This trade-off approach allows builders to compensate for a less-insulated architectural feature by upgrading insulation elsewhere. For example, if a homeowner desires large, decorative picture windows with a slightly higher U-factor, the builder can offset that heat loss by installing R-60 attic insulation or continuous exterior foam sheathing, successfully passing the overall energy code balance.
Compare the prescriptive compliance path with the REScheck trade-off methodology:
| Compliance Parameter | Prescriptive Code Path | REScheck Trade-Off Path (Software) | Builder Flexibility Benefit |
|---|---|---|---|
| Component Evaluation | Every element evaluated independently in isolation | Entire building envelope evaluated holistically | Allows underperforming components to be offset |
| Attic / Ceiling Insulation | Strict fixed minimum (e.g., R-49 rigid) | Flexible (R-38 allowed if walls/windows upgraded) | Solves low-pitch roof and cathedral rafter constraints |
| Window Glazing Area | Strict limits on total fenestration percentage | Trade-off allows expansive custom windows | Facilitates modern glass-heavy architectural designs |
| Calculation Method | Manual checklist comparison against code tables | Automated computer software running DOE algorithms | Eliminates mathematical errors and speeds permit review |
| Building Permit Document | Standard manual inspection sheet | Official signed REScheck Compliance Certificate | Universally accepted by municipal building departments |
Data Inputs: Insulation, Fenestration, and Assemblies
Generating a certified REScheck report requires compiling detailed architectural dimensions and thermal specifications from the building construction plans. The software user enters geographic location data, which allows the program to automatically pull local heating degree days (HDD) and cooling degree days (CDD) from national weather databases, along with the specific version of the energy code adopted by that local jurisdiction (such as 2015, 2018, or 2021 IECC).
Next, the user inputs precise surface square footage and thermal ratings for every boundary separating conditioned living space from unconditioned outdoors or unheated basements. This includes gross ceiling and cathedral roof areas (with cavity and continuous R-values), exterior wood or steel frame walls, basement masonry walls, crawlspace foundation walls, insulated concrete floor slabs, exterior entry doors, and all window and skylight assemblies with their corresponding NFRC-certified U-factors and solar heat gain coefficients.
Review typical building envelope data inputs required for a REScheck report:
| Building Envelope Assembly | Required Architectural Inputs | Measurement Unit | Critical Compliance Metric |
|---|---|---|---|
| Attic / Roof Assembly | Flat ceiling area, rafter depth, cathedral pitch | Square Feet (sq ft) | Cavity R-value & Continuous rigid foam R-value |
| Above-Grade Exterior Walls | Framing spacing (16 in or 24 in oc), stud size (2x4 or 2x6) | Gross Wall Area (sq ft) | Cavity insulation R-value + exterior continuous R-value |
| Windows & Glazed Doors | Rough opening dimensions, frame material type | Net Glazing Area (sq ft) | NFRC-certified U-factor and SHGC ratings |
| Basement / Crawlspace Walls | Depth below grade, continuous interior insulation | Wall Area (sq ft) | Continuous exterior or interior board insulation R-value |
| Concrete Slab Floors | Perimeter slab edge length, depth of vertical insulation | Linear Feet (ft) | R-value of edge slab insulation (e.g., R-10, 24 in depth) |
Software Platforms: REScheck Desktop vs REScheck-Web
The Department of Energy provides two distinct platforms for generating energy reports: the legacy REScheck Desktop software and the modern cloud-based REScheck-Web application. While REScheck Desktop was historically downloaded onto local Windows machines, the DOE has phased out desktop updates in favor of REScheck-Web. The web version automatically updates with the latest state-specific amendments, municipal code adoptions, and climate data revisions without requiring manual software patches.
Once all structural assemblies and insulation ratings are entered, the software runs its comparative algorithms and generates a percentage score indicating whether the home passes or fails. A score of 0% or higher indicates complete compliance, with positive numbers showing the percentage by which the proposed design exceeds code standards (e.g., 'Passes by 8%'). The software then prints a comprehensive multi-page package featuring the Inspection Checklist and the official Compliance Certificate, which must be signed by the builder or energy rater and submitted to the local building department to obtain construction permits.
Compare REScheck Desktop versus REScheck-Web cloud software:
| Software Feature | Legacy REScheck Desktop | Modern REScheck-Web (Cloud) |
|---|---|---|
| Operating Platform | Local Windows PC software installation | Any web browser on Mac, PC, tablet, or smartphone |
| Code Version Updates | Requires manual downloads of patch files | Automatically updated with latest IECC and state codes |
| Project Collaboration | Files saved locally as .rck files; difficult to share | Cloud storage allows instant team sharing across architects and raters |
| Supported Energy Codes | Older codes up to 2018 IECC (Phased out) | Current codes including 2021 IECC and state custom codes |
| DOE Software Support | Maintenance phased out; no new codes added | Actively supported and continuously updated by DOE/PNNL |
How to Create and Submit a Passing REScheck Report
Follow these five steps to complete an energy code calculation and generate an official REScheck certificate for building permitting.
Gather Architectural Blueprint Specifications
Collect floor plans, exterior elevations, window schedules with NFRC U-factors, and insulation specifications from the architect.
Launch REScheck-Web and Select Jurisdiction
Create a free DOE account at energycodes.gov, start a new residential project, and choose your local city or county and adopted energy code.
Input Building Envelope Component Measurements
Enter accurate square footages, cavity R-values, continuous insulation ratings, and window U-factors for ceilings, walls, and foundations.
Review Compliance Percentage and Adjust Ratings
Verify that the software displays a green 'Passes' badge; if failing, upgrade attic insulation or window ratings until compliance is achieved.
Generate, Sign, and Submit Official Certificate
Download the final PDF package, print the Inspection Checklist, sign the compliance statement, and attach it to your building permit application.
Frequently Asked Questions (8 Questions Answered)
Q1: What does the name REScheck stand for?
REScheck stands for Residential Energy Services check or Residential Energy Code Compliance check, developed by the Department of Energy.
Q2: Why do I need a REScheck report?
Municipal building departments require a passing REScheck report to issue a residential building permit, proving the home meets state energy codes.
Q3: How much does the REScheck software cost?
REScheck is completely free public software provided by the United States Department of Energy and accessible online at energycodes.gov.
Q4: What is the difference between COMcheck and REScheck?
REScheck is designed for detached one- and two-family residences and low-rise townhomes (3 stories or less), while COMcheck is for commercial and high-rise buildings.
Q5: What does a passing score on REScheck look like?
The report must show 'Passes', with a percentage score of 0% or higher, indicating that total building envelope heat loss does not exceed code allowances.
Q6: Can a homeowner do their own REScheck?
Yes, anyone with accurate architectural blueprints and insulation specifications can use the software, though many hire certified energy raters to ensure accuracy.
Q7: Does REScheck calculate HVAC equipment sizing?
No, REScheck only calculates building envelope thermal insulation compliance; HVAC equipment sizing requires a Manual J and Manual S calculation.
Q8: What code versions does REScheck support?
REScheck-Web supports multiple editions of the International Energy Conservation Code (IECC 2009, 2012, 2015, 2018, 2021) and numerous state-specific codes.
Final Thoughts & Key Takeaways
In conclusion, understanding what is a rescheck? provides essential clarity, practical strategies, and actionable advice. By incorporating these foundational insights, adhering to verified safety guidelines, and following structured best practices, you ensure reliable, long-term outcomes while preventing common mistakes. Stay informed, consult certified professionals when needed, and maintain consistent quality care.