Energy and insulation

Incentive programs

2023 Plan for weatherization

I plan to utilize both the Electrification Rebate with the tax credit (25C).

The Electrification Rebate (HEEHR) covers the following weatherization projects: insulation, air sealing, and ventilation. For low-income households (under 80 percent of Area Median Income), HEEHR covers 100 percent of your weatherization costs up to $1,600. For moderate-income households (between 80 percent and 150 percent of Area Median Income), HEEHR covers 50 percent of your weatherization costs up to $1,600.

25C covers the following weatherization projects: insulation, air sealing, doors and windows upgrades, and energy audits. 25C provides households a 30 percent tax credit for the projects, capped per year at the following amounts:

The credit resets each tax year, effectively becoming available again for additional projects.

Total 25C tax credits across panel upgrades and all weatherization projects are capped at $1,200 per year. Heat pumps and heat pump water heaters are subject to a separate 25C cap of $2,000 per year.

Insulating a rock foundation basement

Spray Foam Interior Insulation for Existing Foundation Walls

**Figure 1.** Closed-cell spray foam is used to retrofit an existing rubble basement foundation wall. The spray foam also insulates the sill beam, fills the floor joist cavity at the rim joist, and fills the base of the wall cavity because the wall is balloon framed.
**Figure 1.** Closed-cell spray foam is used to retrofit an existing rubble basement foundation wall. The spray foam also insulates the sill beam, fills the floor joist cavity at the rim joist, and fills the base of the wall cavity because the wall is balloon framed.

How to Install Spray Foam Insulation at Foundation Wall

  1. Inspect the existing foundation wall for any deficiencies.  Make any necessary repairs prior to beginning the retrofit work.  For stone or brick walls, take measures to protect the exposed part of the foundation wall from bulk water if necessary, such as grading the soil surface away from the structure, installing gutters and downspouts, and installing a footing drain.
  2. Install closed-cell spray foam insulation at the foundation wall to at least the minimum levels specified in the local building code.  Extend the spray foam over the sill beam. If the house has balloon framing, use spray foam insulation to fill the base of the wall cavity above the top of the foundation to air seal it to the back side of the existing wall sheathing, as shown in Figure 1.
  3. Apply a spray-on thermal/ignition barrier as required by the local code.

ALTERNATELY, build a perimeter stud wall on the interior side of the spray foam. Don’t insulate the stud wall. Cover it with non-paper-faced gypsum board as the thermal/ignition barrier on the interior side.  If metal studs are used for the interior wall, do not insulate it unless the metal studs are placed at least 1 inch to the interior side of the foundation wall insulation.

Past projects

  • Conversion from boiler with steam radiators to air source heat pumps
  • Water pipe insulation
  • Replaced basement single-pane windows with insulated ones
  • Added insulation to basement joist bay
  • Dryer replacement, gas > electric
  • Whole-house window replacement
  • Rooftop solar panel installation
  • Attic insulation

Compiled 2023-1-27