REScheck vs COMcheck: The Ultimate 2025–2026 Comparison
- bpatrick247
- Nov 18
- 3 min read
Updated: Dec 3
Choosing between a REScheck vs COMcheck Energy Efficiency Report can make or break your building permit approval. These two DOE energy compliance tools look similar, but using the wrong one will get your project rejected and cost you weeks of delays. REScheck is designed for residential buildings with three stories or fewer, while COMcheck handles commercial projects and taller multifamily structures. With the 2024 IECC now adopted in most jurisdictions, understanding which tool supports your local code edition is critical. This comparison breaks down exactly when to use REScheck vs COMcheck, what each tool calculates, and how to avoid the most common mistakes that lead to permit rejection in 2025.
Understanding REScheck and COMcheck
When it comes to energy compliance, both REScheck and COMcheck serve important roles. But knowing which one to use is essential.
What is REScheck?
REScheck is a tool specifically designed for residential buildings. It’s perfect for single-family homes, duplexes, and triplexes. If your project involves a residential building that is three stories or fewer, REScheck is your go-to option. It focuses on the building envelope, making it simpler and faster to use.
What is COMcheck?
On the other hand, COMcheck is tailored for commercial projects and multifamily buildings that exceed three stories. This tool is more complex because it considers not just the envelope but also lighting and mechanical systems. If your project involves a larger building or commercial space, you’ll need to use COMcheck.
Key Differences Between REScheck and COMcheck
Here’s a quick comparison of the two tools:
| Criteria | REScheck | COMcheck | Winner for Most Projects |
|------------------------------|------------------------------|------------------------------|---------------------------|
| Primary Use | Residential ≤ 3 stories | Commercial + multifamily > 3 stories | — |
| 2024 IECC Supported | Web only | Web + Desktop | COMcheck |
| Scope | Envelope only | Envelope + Lighting + Mechanical | REScheck (simpler) |
| Typical Outsourced Cost | $175 – $450 | $450 – $1,500+ | REScheck |
When You MUST Use REScheck
Single-family homes, duplexes, triplexes
Townhouses (any height)
ADUs, garage apartments
Residential additions & major renovations
When You MUST Use COMcheck
Any commercial occupancy
Multifamily 4 stories or taller
Mixed-use buildings
Commercial alterations involving lighting or HVAC
2025–2026 IECC Support Cheat Sheet
| IECC Edition | REScheck-Web | REScheck-Desktop | COMcheck-Web | COMcheck-Desktop |
|------------------|--------------|-------------------|---------------|-------------------|
| 2024 IECC | Yes | No – frozen Nov 2023 | Yes | Yes |
| 2021 & older | Yes | Yes | Yes | Yes |
Frequently Asked Questions
<details open>
<summary>Can I use REScheck for a 4-story apartment building?</summary>
<p>No. 99% of U.S. jurisdictions require COMcheck once you exceed 3 stories, regardless of whether it's all residential.</p>
</details>
<details>
<summary>Is the old REScheck Desktop version still legal in 2025–2026?</summary>
<p>Only if your jurisdiction is still on the 2021 IECC or older. The desktop version was frozen in November 2023 and does <strong>not</strong> correctly calculate the 2024 IECC.</p>
</details>
<details>
<summary>What about a 3-story multifamily building — REScheck or COMcheck?</summary>
<p>Most states require COMcheck at 4+ stories, but California (Title 24), Washington, Massachusetts, and a few others allow REScheck on 3-story multifamily.</p>
</details>
<details>
<summary>Which tool is easier for homeowners or small builders?</summary>
<p>REScheck wins by a mile. It only looks at the building envelope. COMcheck also requires lighting power densities and mechanical schedules — easily 3–5× more inputs.</p>
</details>
<details>
<summary>Can I submit both REScheck and COMcheck and let the inspector choose?</summary>
<p>No. The incorrect one will be rejected and you'll have to redo the entire report in the proper tool.</p>
</details>
<details>
<summary>Does log homes or SIP homes change which tool I use?</summary>
<p>No — if it's residential and ≤3 stories, you still use REScheck.</p>
</details>
<details>
<summary>My architect used COMcheck for my new house — is that a problem?</summary>
<p>Yes, huge red flag. COMcheck is almost never accepted for single-family or low-rise residential.</p>
</details>
<details>
<summary>Will using REScheck-Web instead of Desktop get me faster approval?</summary>
<p>In our experience, yes — typically 40–60% faster and fewer errors.</p>
</details>
Conclusion
Choosing the right tool is crucial for your project. Using the wrong one can lead to delays and extra costs. So, whether you're working on a cozy single-family home or a sprawling commercial complex, make sure you know which tool to use. For more information, check out REScheck Review.