Arkansas HVACR NewsMagazine November 2025

HVACR NewsMagazine November 2025

State National Chapter News

As the industry continues to prioritize sustainable and high-performance building practices, the partnership between HVAC and insulation professionals becomes increasingly vital. By working together, they can deliver buildings that not only meet energy codes but also exceed expectations for comfort, durability, and environmental responsibility. Air Tightness, SPF Insulation, and the Importance of Balanced Ventilation Recent updates to residential energy codes now mandate blower door testing,to measure air leakage, with defined maximum thresholds. In cold climates, homes must achieve an air leakage rate below 2.5 ACH 50 , moderate climates must be below 3.0 ACH 50 , and warmer climates allow up to 5.0 ACH 50 Meeting these standards can be challenging with air-permeable insulation materials like fiberglass and cellulose, which often require additional air sealing. In contrast, spray polyurethane foam (SPF) insulation naturally delivers a tighter building envelope, with typical air leakage rates between 1.0 and 1.5 ACH 50 — well below code limits. Since the spray foam, not the interior drywall, forms the air pressure boundary, a blower door test can be conducted before the drywall is installed. Homes sprayed with either low-density or medium-density SPF usually far exceed the air sealing requirements, but if additional sealing is necessary, it’s much easier to touch-up before drywall.

This high level of airtightness significantly improves energy efficiency and indoor comfort, but it also impacts HVAC system design: Lower air leakage achieved with SPF must be accounted for. A tighter envelope means HVAC systems must be properly sized to avoid over-conditioning and ensure optimal performance. Moreover, SPF-insulated homes often fall below the minimum air exchange rates required for maintaining healthy indoor air quality. The guiding principle “Build tight – ventilate right” is especially relevant. Most homes insulated with SPF will require supplemental mechanical ventilation to maintain fresh air exchange. While there are multiple approaches to ventilation, unbalanced systems — such as introducing fresh air directly into the HVAC return — can compromise energy savings and indoor comfort. The HVAC contractor is the ventilation expert and selling and installing a properly engineered ventilation system can add to job revenue and profit. The most effective and energy-efficient solution is a balanced ventilation system using an Energy Recovery Ventilator (ERV) or Heat Recovery Ventilator (HRV). These systems provide continuous fresh air while recovering energy from exhaust air, helping builders meet code

requirements performance.

without

sacrificing

Fire Protection

SPF is a combustible material, and building codes reflect this reality. To