Renovation Projects That Improve Energy Efficiency at Home

Air infiltration — uncontrolled air movement through gaps in a home's envelope — accounts for a substantial share of heating and cooling loss in many older homes. Draught-proofing targets the most common leakage points: door frames, window surrounds, attic hatches, electrical outlets on exterior walls, and penetrations where pipes or cables pass through walls.

Materials such as weatherstripping, door sweeps, foam backer rod, and low-expansion spray foam sealant handle most of these tasks without specialist skills. Focus first on the attic floor and basement ceiling if you have them — these junctions between conditioned and unconditioned space are often the largest combined source of leakage. A candle or incense stick held near suspect areas on a windy day can reveal air movement before you commit to any material.

Heat rises, and in under-insulated homes a significant portion escapes through the ceiling and roof assembly. The US Department of Energy provides recommended insulation R-values by climate zone — most temperate US regions benefit from R-38 to R-60 in the attic, though many existing homes fall well short of that range.

Blown-in cellulose or fibreglass can often be added over existing insulation, making attic upgrades one of the more straightforward professional installations. Air-sealing the attic floor before blowing in additional material is essential — insulation slows heat transfer but doesn't stop airflow on its own. For a quick comparison of insulation types and where each is typically used, see our insulation types overview.

Exterior walls are a significant source of heat loss, particularly in homes built before insulation standards became standard practice. In wood-framed homes with hollow stud cavities, blown-in insulation can be installed by drilling small holes in the exterior or interior wall surface, injecting material, and patching — a much less disruptive process than opening walls entirely.

Homes with masonry or solid wall construction present a more involved challenge: interior or exterior rigid insulation board is typically required, each with trade-offs around interior space loss or exterior appearance. Consult a licensed insulation contractor to assess which approach suits your wall assembly, and check whether local building codes require vapour control layers as part of the assembly.

Single-pane windows are a significant thermal weak point. Full window replacement with double- or triple-pane units improves both insulation and condensation control, but it carries a higher upfront cost and typically requires professional installation. As a more accessible alternative, secondary glazing — a second pane installed on the interior side of an existing window — can meaningfully reduce heat loss and noise without the cost or disruption of full replacement.

DIY secondary glazing kits using acrylic or polycarbonate panels are available for straightforward installations, though custom-fitted systems offer better long-term performance. Regardless of approach, ensure window frames are in good repair and any gaps between frame and wall are sealed before treating the glass itself.

Heating and cooling equipment that is poorly maintained or past its service life uses significantly more energy to achieve the same output. Regular filter changes, annual professional servicing, and keeping vents and returns clear of obstruction are baseline maintenance tasks that preserve efficiency at minimal cost.

When equipment replacement becomes necessary, modern high-efficiency units — including heat pumps, which can serve both heating and cooling functions — can offer substantial efficiency gains over older systems. Federal tax credits under the Inflation Reduction Act currently cover a portion of costs for qualifying high-efficiency HVAC equipment; consult a licensed HVAC contractor and a tax professional to confirm eligibility for your specific situation, as rules and limits can change.

Water heating typically accounts for a meaningful share of a home's total energy use. If your water heater is more than ten to twelve years old, replacement with a high-efficiency model is worth considering — heat pump water heaters, in particular, can use significantly less electricity than conventional resistance models, and may also qualify for federal or utility incentives.

For homeowners not yet ready to replace, pipe insulation on hot-water supply lines reduces standby heat loss, and lowering the tank thermostat to 120°F (where it's safe to do so and hot enough to inhibit bacterial growth) reduces the energy required to maintain stored water temperature. Always confirm safe operating temperatures with the unit's documentation or a licensed plumber.