Building America Case Study: Retrofitting a 1960s Split-Level, Cold-Climate Home, Westport, Connecticut

Timothy Merrigan, S. Puttagunta

Research output: NRELFact Sheet


National programs such as Home Performance with ENERGY STAR(R) and numerous other utility air sealing programs have brought awareness to homeowners of the benefits of energy efficiency retrofits. Yet, these programs tend to focus on the low-hanging fruit: air-sealing the thermal envelope and ductwork where accessible, switch to efficient lighting, and low-flow fixtures. At the other end of the spectrum, deep-energy retrofit programs are also being encouraged by various utilities across the country. While deep energy retrofits typically seek 50 percent energy savings, they are often quite costly and most applicable to gut-rehab projects. A significant potential for lowering energy usage in existing homes lies between the low hanging fruit and deep energy retrofit approaches - retrofits that save approximately 30% in energy over the existing conditions. A key is to be non-intrusive with the efficiency measures so the retrofit projects can be accomplished in occupied homes. This cold climate retrofit project involved the design and optimization of a home in Connecticut that sought to improve energy savings by at least 30% (excluding solar PV) over the existing home's performance. This report documents the successful implementation of a cost-effective solution package that achieved performance greater than 30 percent over the pre-retrofit - what worked, what did not, and what improvements could be made. Confirmation of successfully achieving 30 percent source energy savings over the pre-existing conditions was confirmed through energy modeling and comparison of the utility bills pre- and post- retrofit.
Original languageAmerican English
Number of pages2
StatePublished - 2015

Bibliographical note

Work performed by Consortium for Advanced Residential Buildings (CARB), Norwalk, Connecticut

NREL Publication Number

  • NREL/FS-5500-64354

Other Report Number

  • DOE/GO-102015-4692


  • 1960 split level
  • 30 percent energy savings
  • air barrier
  • Building America
  • closed cell polyurethane spray foam insulation (CCSPF)
  • cold climate
  • consortium for advanced residential buildings
  • dense-packed cellulose wall insulation
  • insulating from exterior
  • moisture
  • non-intrusive
  • residential
  • residential buildings
  • retrofit
  • Steven Winter Associates, Inc.
  • SWA
  • utility bill validation


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