Massachusetts insulation map, region by region: where homes get insulated and what they need
4,543 insulation quotes in 221 towns, from Greater Boston and the North Shore to Cape Cod. What each region pays and which insulation fits its homes.
Mateus MagnoLicensed Construction Supervisor · October 22, 2026 · 3 min read
On my map of 4,543 insulation quotes (2021–2026), Middlesex County, which includes Somerville and Cambridge, had the most installed jobs (833, median about $5,000). It was followed by Essex (422, about $4,040), Norfolk (307, about $4,985) and Suffolk/Boston (226, about $5,500). Cape Cod jobs were fewer but larger, with a median around $8,750.
Massachusetts homes are not all the same, so their insulation needs aren't either. A 1910 triple-decker in Somerville, a 1960s ranch on the South Shore and a Cape Cod summer house each need something different.
To show this, I used the job map I built for the insulation crews I work with: 4,543 quotes and 2,089 installed jobs in 221 cities and towns, 2021–2026, with no names or addresses. I added public Census data on when each town's homes were built. Here's what it shows, region by region.
The regions at a glance
| County / region | Quotes | Installed | Quotes that became jobs | Median job |
|---|---|---|---|---|
| Middlesex (Somerville, Cambridge, Newton, MetroWest, Lowell area) | 1,739 | 833 | 48% | $4,995 |
| Essex (North Shore, Merrimack Valley) | 771 | 422 | 55% | $4,040 |
| Norfolk (Brookline, Needham, Quincy, Milton) | 744 | 307 | 41% | $4,985 |
| Suffolk (Boston, Chelsea, Revere, Winthrop) | 510 | 226 | 44% | $5,500 |
| Plymouth (South Shore) | 319 | 123 | 39% | $4,900 |
| Worcester (Central MA) | 247 | 94 | 38% | $4,650 |
| Bristol (Southeast) | 96 | 28 | 29% | $6,450 |
| Barnstable (Cape Cod) | 92 | 45 | 49% | $8,750 |
"Quotes that became jobs" is the share of quotes the homeowner or builder said yes to. Western Massachusetts and the islands had only a handful of jobs, so I left them out of the table.
How old are the homes? That decides the insulation
The darkest part of the state is the inner core around Boston. In Somerville about 80% of homes were built before 1980, in Boston 72% and in Cambridge 68%. Older homes usually mean empty or slumped wall insulation, attics with a few inches of old fiberglass, and lots of air leaks. That's why the jobs cluster there.
Region by region: what homes usually need
The map gives the counts and prices. The advice below comes from what crews typically find in each area's housing.
Somerville, Cambridge and the inner core
Two- and three-family houses and triple-deckers from 1880–1930, often balloon-framed. The big wins are air sealing the top floor, dense-pack cellulose in empty walls and low-slope roofs, and closed-cell foam at the rim joists in the basement. Read my Somerville and Cambridge guide and how dense-pack works in old walls.
Newton, Arlington, Lexington and inner suburbs
Larger single-family colonials and capes, many with finished third floors. Expect knee walls, sloped ceilings and attic hatches. This is where spray foam on the roof line or careful blown-in plus air sealing makes the biggest difference. It also explains Newton's higher $8,025 median.
North Shore and Merrimack Valley
Essex County had the highest share of quotes becoming jobs (55%) and a lower median ($4,040). Many of these are straightforward attic top-ups and air sealing on capes, colonials and older coastal homes. Coastal wind makes air sealing even more important.
South Shore and Southeast
More ranches and split-levels from the 1950s–1970s. Typical work is blown-in attic insulation, basement and crawl space work, and garage ceilings under bedrooms.
Cape Cod
Fewer jobs but the biggest median ($8,750). Cathedral ceilings, crawl spaces and seasonal homes being converted to year-round use often call for spray foam, and that raises the price.
Central Massachusetts
Worcester County jobs were mostly mid-size attic and wall projects, with a median of about $4,650.
About the data
This map is one set of crews' quotes from 2021–2026, not every insulation job in the state. Prices include homeowner and builder jobs and all insulation types, and 2026 is a partial year. I don't publish names, addresses or company details. The housing-age layer comes from public Census data by town.
Want the price view? Read what insulation really costs in Greater Boston.
Insulating a home in Greater Boston?
Magno & Co installs blown-in, fiberglass and spray foam insulation in Somerville, Cambridge and across Greater Boston. Book a free walkthrough and I'll tell you what your house actually needs, and what it doesn't.
Frequently asked questions
Which part of Massachusetts gets the most insulation work?
On my map of 4,543 quotes from 2021 to 2026, Middlesex County, which includes Somerville, Cambridge and Newton, had the most installed jobs (833). Essex, Norfolk and Suffolk counties followed.
Why does Cape Cod insulation cost more?
On my map, Cape Cod jobs had a median of about $8,750, higher than the inner suburbs. Cathedral ceilings, crawl spaces and seasonal homes converted to year-round use often call for spray foam, which costs more per square foot.
What insulation is best for old homes in Somerville and Cambridge?
Most older Somerville and Cambridge homes benefit most from air sealing the top floor, dense-pack cellulose in empty wall cavities and low-slope roofs, and closed-cell spray foam at the basement rim joists.
How old are the homes in Somerville, Cambridge and Boston?
According to Census housing data by town, the median Somerville home was built in 1938, Boston's in 1947 and Cambridge's in 1950. About 80% of Somerville homes were built before 1980.
Mateus Magno is the founder of Magno & Co — a licensed Massachusetts Construction Supervisor (CS-123658), registered Home Improvement Contractor (HIC #220484) and certified Lead-Safe Renovator Supervisor who has renovated and managed over $3 million in projects across Greater Boston.
More about Mateus →
