Continuous exterior insulation

continuous exterior insulation project test site


Continuous exterior insulation (CEI) is not an established retrofit efficiency measure in Minnesota due to assumed high project costs and a lack of awareness among residing contractors. However, recent CARD-funded modeling work suggests that cost barriers are overstated and that there is significant cost-effective potential within the building stock. Importantly, CEI us a fuel-agnostic decarbonization method with large energy savings that mitigate the added costs of space heating through electrification or renewable gas.

The project team will deploy CEI measures on up to ten homes to evaluate natural gas savings, carbon reduction, and cost-effectiveness. The team will evaluate the efficacy of CEI to lower heating and cooling loads, document projects to identify logistical and other barriers, and model the impact of CEI on decarbonization and electrification efforts. 

Project Summary


  • Demonstrate that CEI applied at the time of building residing can provide deep carbon and natural gas savings.
  • Examine CEI in the context of current decarbonization goals by developing resources and framing CEI outcomes from a contractor perspective.


  • Target project barriers such as the lack of contractor awareness and high perceived costs of CEI.
  • Execute 8–10 CEI projects.
  • Support the development of case studies to be used to engage additional contractors in CEI projects.

Non-energy Benefits

  • Improved occupant comfort
  • Building resiliency
  • Support for future electrification
  • Improved demand response efficacy