Bright-Minded Home – May 2012


By Melissa Coleman

Q+A with Richard Renner, principal of Richard Renner Architects, on deep energy retrofits


Known for his expertise in green building, Richard Renner has been busy with two deep energy retrofits in Massachusetts—one full and one phased—both with the goal of increasing the energy efficiency of an existing home. We checked in with him to find out more about these projects.

Q: What’s the main difference between a phased and a full deep energy retrofit?
A: In a full retrofit, all the work is done at once, so the disruption is minimized and benefits accrue as soon as the work is complete. A phased retrofit unfolds over time, so it takes longer and is probably, in the aggregate, more expensive; however, it is more suited to a limited annual budget.

Q: What does each entail?
A: In the full retrofit we’re adding four inches of rigid foam to the roof and above-grade walls and basement and replacing all windows. The result is a complete upgrade of the exterior envelope making the home tight enough to require a heat recovery ventilator. The phased retrofit balances a desire for increased energy efficiency with the need for significant architectural changes, including a new kitchen and a master bedroom suite addition. So whenever we changed an exterior wall, we improved the envelope. Along the way we also added insulation to the roof, replaced all windows, and installed a heat recovery ventilator.

Q: Are deep energy retrofits growing in demand?
A: Without some form of subsidy, it’s hard to see how full deep energy retrofits will be more than a niche market. It’s more likely that we will take the lessons from full retrofits and apply them in a phased way.