Deep Energy Retrofits
Deep energy retrofits are an increasingly important part of our practice. While each project is unique, common to all of them is significant improvement in energy performance as a key driver in all design decisions, resulting in 50-75% reduction in annual heating and cooling costs. With each project our understanding and knowledge of the issues and their solutions evolves, so naturally the more recent projects are also the most aggressive.
Deep energy retrofits involve getting at the very core elements of a house—the exterior envelope that protects it from the elements and the mechanical systems that manage the air and water that the house uses. Because exterior walls, floors and ceilings must often be disturbed for new insulation and mechanical systems, deep energy retrofits can only be undertaken cost-effectively when they are part of a whole house renovation.
Each of the projects shown here represents a phase in the evolution of our knowledge of retrofitting. As our experience has grown, we have come to focus more and more heavily upon improving the building envelope to reduce energy demand, rather than on adding high technology equipment that improves energy supply. Another way to say this is that we look for passive rather than active solutions. This approach has led us to the Passive House program.
All our current deep energy retrofits embody the following elements:
- Significant improvement of the air-tightness of the house.
- Significant improvement of the insulation of walls, roof, and even basement floors.
- Elimination of thermal bridging wherever possible.
- Very small high-efficiency heating and air conditioning systems using variable refrigerant flow technology and variable speed motors, and often integrated with the domestic hot water system.
- Whole house energy recovery ventilation systems to provide continuous fresh air.
- Value engineering using energy modeling software.