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Updated January 18, 2023

2023 is bringing some important updates to Connecticut codes and incentive programs that will likely create both opportunities and challenges for residential designers, developers and builders. We wanted to provide a short summary of some of the key changes.

Covered in this Article:


      Rebate Program Changes                             New Energy Code Requirements                            Renewable Energy Tax Credits


Rebate Program Changes


The EnergizeCT Residential New Construction program has announced some major modifications aligned with the state’s goal of electrifying all buildings in Connecticut.

  • Effective July 1, 2023, the RNC program will only accept new rebate applications for homes with electric space and water heating.  Homes using carbon fuels may be submitted up to that date and will have two years to complete from the application date.

  • High performance all-electric homes can qualify for additional incentives up to $10,000 for a single-family home or $2,500 for a multifamily unit. For homes that do not qualify as high performance there are alternative incentives for installing high-efficiency heat pumps.

  • The maximum HERS index that qualifies for rebates has been reduced from 60 to 55 to align with the new energy code requirements.

  • The bonus incentives for high-performance certifications have been continued and enhanced. The $1,500 per unit for multifamily Passive House certification continues while the incentives for Zero Energy Ready Home certification have been increased.

  • Click here to view the updated incentive table

energy code

New Energy Code Requirements


Connecticut adopted the 2021 IECC with amendments on October 1, 2022. Some key changes are:


  • ERI or HERS Index Compliance Path: The ERI or HERS index required to meet code following this path has been reduced from 61 to 55.

  • Insulation: The prescriptive requirements for wall insulation now require at least R-5 continuous exterior insulation while ceiling insulation has been increased to R-60. Slab insulation must now extend a minimum of 4’ below grade.

  • Airtightness: While the airtightness requirement for homes following the prescriptive path is unchanged at 3.0 ACH50, for those using the ERI or HERS compliance path it has been relaxed to 5.0 ACH50. Higher limits continue to apply to attached dwelling units and these higher limits have also now been extended to all homes less than 1,500 sf.

  • Duct Leakage. The Connecticut exemption from leakage testing if all ducts and air handlers are inside the conditioned space has been deleted. All ducts must now meet the leakage standard and the allowed leakage has been cut in half if the air handler and duct system is not completely within the thermal envelope.


Renewable Energy Tax Credits

  • The tax credits for renewable energy resources, primarily solar photovoltaic and geothermal heat pumps, have been retroactively increased to 30% and extended for a further ten years.


This summary is only intended to highlight the major changes that will impact our clients’ planning for 2023. If you have questions, please contact us today!

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