Rescheck Web Efficiency Package Section 408 Options Explained

Welcome to the Reschexpert blog, today we dive into IECC 2021 energy code for Reschecks and specifically section 408.  The Reschexpert blog is your place to detailed information on the fine details involved in Rescheck.  It is written by Jobe Leonard who does his best to study tiny items within Rescheck reporting and help other users free of charge via the Reschexpert blog.

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Under the 2021 IECC (Section R408), residential buildings must now go beyond the standard prescriptive requirements by selecting at least one “Additional Efficiency Package.” This shift ensures that new homes are not just meeting the bare minimum, but are actively incorporating high-performance systems.

Here is a breakdown of what each option in REScheck Web entails:

1. Enhanced Envelope Performance

This option focuses on the “shell” of the home. To satisfy this, the building’s thermal envelope must be significantly better than the standard code requirements.

• The Requirement: Typically, you must achieve a 5% to 10% improvement in the proposed UA (the total heat loss of the building) compared to the code-minimum UA.

• How to achieve it: Increase insulation R-values in the attic or walls, or use high-performance windows with a lower U-factor than what is locally required.

2. Efficient HVAC Performance

This selection moves the burden of efficiency from the insulation to the mechanical equipment.

• The Requirement: You must install heating and cooling equipment that meets higher efficiency ratings (SEER2, HSPF2, or AFUE) than the federal minimums.

• Common Targets: For example, installing a furnace with $\ge 95\%$ AFUE or a heat pump with significantly higher heating/cooling efficiencies than the standard baseline.

3. Efficient Service Water Heating Performance

This package focuses specifically on how you heat water for sinks, showers, and appliances.

• The Requirement: You must install a high-efficiency water heater.

• Common Targets: This is usually met by installing a Heat Pump Water Heater (EF $\ge 2.0$) or a very high-efficiency Gas Tankless Water Heater (EF $\ge 0.82$).

4. Efficient Thermal Distribution Performance

This option addresses the energy lost while moving air or water through the house. It is often one of the more technical paths to document.

• The Requirement: All ducts and air handlers must be located entirely within the conditioned space (inside the thermal envelope).

• Alternative: In some cases, using a ductless system (like mini-splits) or a high-efficiency hydronic (water-based) distribution system can satisfy this requirement.

5. Efficient Air Sealing and Ventilation Performance

This focuses on “building tight and ventilating right.” It combines a very low air leakage rate with high-efficiency air exchange.

• The Requirement: The building must achieve an air leakage rate of 3.0 ACH50 or less (verified by a Blower Door test) AND include an Energy Recovery Ventilator (ERV) or Heat Recovery Ventilator (HRV).

• The Goal: To reduce “leaky” energy loss while ensuring the indoor air quality remains high through mechanical recovery.

Which one should you choose?

Most designers select the HVAC or Water Heating options because they are often the most cost-effective “paperwork” fixes if the equipment was already planned to be high-efficiency. However, if you are building a very tight, well-insulated home, the Envelope or Air Sealing options may be more natural fits.

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