Deep Energy Retrofits

Super-insulated wall assembly

Air sealing and insulating interior walls with spray foam

Latest news: Saving 70 Percent or More of Energy Use In Your Home - Berkeley Lab Scientists Study the Deep Energy Retrofit

Deep Energy Retrofits aim to save at least 50% total energy in homes. This particular project goes a little deeper to 70% savings - the target set out by the Affordable Comfort 1000 home challenge . The objectives of this study are to demonstrate how to get to low energy savings and to document how to identify aspects of each home that are working well and those that are less successful so that others can learn from these pioneering efforts. We are performing detailed end-use monitoring of gas and electricity use in ten deep retrofit homes in northern California. All the retrofits have been paid for by the home owners so this gives insight into what is done without direct incentives. The detailed measurements allow us to identify where the energy is used in a home, where savings are being met (and where they are not) and what aspects of the retrofits are successful (and which are not). Monitoring is currently underway, but we have already been able to identify key issues:

  1. Keep it simple. Simpler approaches are easier for a contractor to understand and get right the first time. They also tend to be more robust and less likely to fail in the long term.
  2. Use existing off the shelf technology. Again - this increases the likelihood that a contractor can get it right. It also reduces the risk for homeowners (and we are very risk-averse when it comes to our homes).
  3. Staging of retrofits over time can be a successful strategy to reduce the one-time financial burden - but it requires good planning.
  4. 70% savings are attainable - but only if all end uses are addressed.
  5. At these low levels of energy use the contributions of occupants are significant - so their behavior can make or break their ability to meet their energy saving targets.
Principal Investigator(s): 
Iain Walker
Team Members: 
Brennan Less