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BUILT IN 2005 and situated in an open field on a windy ridge in Palermo, Denise and Barbara’s 2,400 sq ft home suffered air leakage that caused significant comfort issues, frozen pipes and near-constant boiler cycling during cold and windy weather. Their primary goal in the energy retrofit was “to make the house warm enough… not to freeze or have to lug wood when we are in our 80s,” says Denise.

To meet their goal, they enlisted the help of Evergreen Home Performance (EHP) to undertake a thorough assessment and help them make improvements. They discovered that improper air sealing and insulation were causing heat loss through the attic and that some areas—the knee walls and where the porch roof met the main roof—were particularly problematic. Further, there was no existing insulation in the basement.

EHP conducted careful air sealing and installed insulation throughout the house, including loose-fill cellulose across the attic floor and dense-pack cellulose and/ or rigid foam in the knee walls. In the basement, the box sill penetrations were air-sealed, cavities were webbed and blown with dense-pack cellulose and the walls were insulated with fire-rated 2” Thermax insulation panels. A heat pump system was installed for primary heating, while maintaining the old oil-fired hydronic system for hot water only.

The improvements have greatly reduced the home’s energy usage and costs, as shown by reductions of 46% in oil usage, 41% in propane and 81% in wood (electricity increased 129% from heat pump usage, which may be offset by solar panels in the future). The burst pipe problem has been eliminated and the homeowners have reported a significant increase in their comfort. Where in the past the wood stove was required, now the fire is an optional cozy feature.

Why we like it: This project shows how important careful preparation and planning are. We are now seeing a lot of homes built in the 1980s and 1990s coming up for their first major renovations since they were completed. Many were built just before we started paying attention to insulation, and long before we started air sealing, but after we started working with engineered lumber, which made more complicated shapes easier to build. As a result, as this project discovered, defining a continuous surface to air seal and insulate can be particularly challenging. Again, Maine is full of these homes, and the possibility of turning them from energy hogs to energy misers is exciting and necessary.

TECHNICAL SPECS

BUILDING ENVELOPE: Foundation—R-13, Walls—R-13 (no work done), Roof—R-60, Windows—R-10, Airtightness—3.23 ACH50.
SYSTEMS: Heating and cooling—mini-split heat pump (3 heads) as primary heat, woodstove and gas log fireplace as back-up, existing oil-fired hydronic system for hot water. RENEWABLES: exploring solar option for future
SIZE: 2,400 sq ft
COST: $23,350 (after rebates)

PROJECT TEAM

AIR SEALING & INSULATION: Evergreen Home Performance
ENERGY/PERFORMANCE CONSULTANT: Evergreen Home Performance
ENERGY SYSTEMS: ReVision Energy (heat pumps)

This article was reprinted from the spring issue of Green & Healthy Maine Homes magazine. Subscribe today!