Make the right decisions at the beginning, and a sustainable remodel of an existing home can often outperform a typical new home. Those decisions begin with a thorough evaluation of the home, including testing and inspecting existing insulation, air sealing (the building envelope), and mechanical systems (plumbing, HVAC, and electrical); identifying solar orientation; and identifying structural defects.
The Envelope, Please
If you lack the experience to identify building envelope problems, hire a HERS (Home Energy Rating System) rater, a Building Performance Institute-certified building analyst, or a green building consultant to identify problems and prioritize solutions. Good practices include sealing air leaks and thermal bypasses, installing insulation above code minimums, and properly managing bulk moisture (rain) and vapor.
When the program calls for added living space, consider how to reuse existing volumes and finished areas instead of constructing new. When new space must be added, consider building up instead of out to reduce site impact — soil erosion, damage to existing landscape and trees, and adding impervious surfaces that increase stormwater runoff.
Heat & Cool Less
Consider how to incorporate unconditioned areas such as porches, decks, and patios as well as provide natural ventilation through large operable windows and doors to reduce the amount of energy used for HVAC.
Yes, You Do Windows
North facing: bring in diffused light, don’t provide any heat energy. In cold climates with strong winds they can be a big energy penalty.
South facing: Good in all climates, can be shaded to avoid summer overheating with modest-size overhangs. In cold climates, heat gain can make them more efficient than the walls they are in.
East and west facing: Limit their number; they allow early morning and late afternoon sun to heat up rooms.
Do a 360
Pay attention to indigenous architecture and take cues from what was originally built nearby. Often, older buildings were designed for the climate while newer ones were not. In the South, high ceilings, wide porches, and roof overhangs keep buildings cool and protect them from rainfall. In cooler, dryer climates, small or no overhangs allow the sun to heat the house. Before the advent of central heat and air conditioning, homes were designed to naturally control temperature in each specific climate. Those principles hold true today.
When you consider the existing building, evaluate its condition, and take into account the local climate, you can create a truly sustainable renovation with little extra effort that will please your clients and be an asset to the community and the environment.