Blown-in attic insulation in Cambridge typically costs $1,500 to $4,000 for a standard home, depending on attic size and target R-value. Spray foam insulation is more expensive at $1 to $3 per board foot and is best for rim joists, crawl spaces, and areas requiring an air barrier. Batt insulation for walls or basement is usually $1 to $3 per square foot installed. Many projects qualify for federal or provincial rebates.
For homes in Cambridge's climate zone, National Building Code recommendations typically call for R-50 to R-60 in attics, R-20 to R-24 in walls, and R-12 to R-20 in below-grade basement walls. Older homes often fall well short of these targets. An energy audit can identify exactly where your home is losing the most heat and prioritize where insulation upgrades will have the greatest impact.
High heating and cooling bills, rooms that are difficult to keep comfortable, ice dams forming along your roof eaves in winter, cold floors above an unheated space, and drafts around electrical outlets on exterior walls are all signs of inadequate insulation. An energy audit or thermal imaging inspection can confirm where the gaps are.
Adding insulation to an existing home typically does not require a permit in most municipalities. However, if the insulation work is part of a larger renovation that involves opening walls or making structural changes, a permit may be required. Spray foam insulation applied to certain areas may also have specific code requirements. Confirm with your contractor or the local building department.
Blown-in attic insulation installation typically takes half a day to a full day for an average home. Spray foam work in a basement rim joist can be done in a few hours. More extensive whole-home insulation projects including wall cavity filling may take two to three days. Your insulation contractor should provide a clear timeline in the written quote.
