2025 New York Energy Code (ECCCNYS): What Builders and Homeowners Need to Know

2025 New York Energy Code Overview

New York State is rolling out the 2025 Energy Conservation Construction Code of New York State (ECCCNYS), which takes effect on December 31, 2025 with no grace period. Any project submitted or postmarked after that date must comply with the new code. The 2025 ECCCNYS is based on the 2024 International Energy Conservation Code (IECC) with New York specific amendments that significantly increase requirements for energy efficiency, electrification, and overall building performance. For builders and homeowners in Climate Zone 4A, including Long Island, this represents one of the most impactful code updates since 2020. One of the most significant changes is that new residential buildings under seven stories will no longer be permitted to install fossil fuel equipment starting December 31, 2025.

Insulation and Air Sealing Requirements

Increased Insulation Performance

The 2025 ECCCNYS increases minimum R-values across walls, roofs, floors, and foundations as outlined in Table R402.1.3. Wood framed walls must now meet prescriptive options such as R-30 cavity insulation, R-20 cavity plus R-5 continuous insulation, R-13 cavity plus R-10 continuous insulation, or R-20 continuous insulation. Projects that previously met prescriptive minimums will more frequently require continuous insulation, improved fenestration, or both.

Tighter Air Leakage and Testing

Air leakage limits are more stringent and air barrier continuity and testing are more heavily enforced, particularly for commercial and mid- to high-rise residential buildings. Builders should expect increased scrutiny of air sealing details, thermal bridge mitigation, and envelope testing compared to the 2020 code.

HVAC System Changes

All-Electric HVAC Becomes the Default

The 2025 ECCCNYS aligns with New York’s All-Electric Buildings Act, which requires most new low-rise residential buildings to be all-electric starting in 2026 and expands to nearly all new buildings by 2029 with limited exemptions. In practice, heat pumps become the standard HVAC system type for new construction.

Total System Performance Ratio (TSPR)

Appendix CE introduces the Total System Performance Ratio as a new compliance pathway. Unlike the 2020 code, which focused on individual equipment efficiencies, TSPR evaluates the performance of the entire HVAC system including fans, pumps, energy recovery, and controls. Compliance often requires integrated energy modeling, especially for larger or more complex systems.

Energy Recovery and Advanced Controls

Energy recovery and HVAC control requirements have been expanded, particularly for systems with high ventilation rates or 100 percent outdoor air. Advanced controls such as setback scheduling, demand responsive ventilation, and part load optimization play a larger role in compliance.

Water Heating Requirements

Shift Toward Electrified Domestic Hot Water

Efficiency benchmarks for water heating equipment have increased, and the code strongly favors heat pump water heaters for residential and smaller commercial projects. Traditional gas water heaters are no longer the prescriptive default.

Electric Ready Infrastructure

Appendix RK for residential buildings and Appendix CH for commercial buildings require space and electrical infrastructure to support future electrification even when electric water heating systems are not initially installed.

Renewable Energy and Solar Readiness

Expanded Solar Ready Provisions

New detached single-family homes, two-family dwellings, and townhouses must provide a designated solar ready roof area and electrical infrastructure capable of supporting future photovoltaic systems unless an exemption applies. Renewable energy, EV charging, and energy storage are now explicit parts of the energy code rather than optional considerations.

Lighting and Appliance Standards

Lighting requirements now place greater emphasis on high efficacy fixtures and advanced controls. Even projects that already use LED lighting must carefully design daylight responsive controls, auto dimming, zoning, and demand response features. Appliance efficiency requirements also continue to align with ENERGY STAR standards.

Energy Compliance Pathways

Energy Credits System

Appendix CF introduces a new Energy Credits system that requires projects to select from a menu of efficiency measures and achieve a minimum number of credits. Options include enhanced envelope performance, high efficiency HVAC systems, improved domestic hot water, advanced lighting controls, and renewable energy systems.

Performance and Stretch Path Options

Appendix CE provides the TSPR system performance pathway, while additional stretch and glide path appendices outline more aggressive requirements aligned with future climate goals. Dedicated all-electric residential and commercial resources are included to support fully electrified building designs.

Final Deadline and Practical Takeaways

The 2025 Energy Code takes effect on December 31, 2025 with no grace period. Builders should assume all electric systems as the baseline for new projects, allow additional time for envelope coordination and air sealing verification, and select energy credits early in the design process so compliance is integrated from the start rather than addressed late. For New York City projects pursuing ULEB FAR bonuses, energy compliance should be treated as a performance driven strategy coordinated with zoning, energy modeling, and operational carbon requirements from day one.