30.0% of Stonington’s housing was built before 1940: 2,885 of its 9,615 units. Stonington was a working harbor long before it was a suburb, and much of our work here is old frame houses. The median unit dates from 1968, and 60.8% of the stock predates 1980.
Detached houses are 68.9% of the town, and 71.6% of occupied homes are owner-occupied. Two-unit buildings hold 8.4% of units and three- and four-unit buildings 8.2%, while only 2.1% are in buildings of fifty or more. Fuel oil heats 57.0% of occupied homes, electricity 14.8%, utility gas 14.1% and bottled gas 11.1%. For most Stonington households, a tighter house means fewer oil deliveries.
The houses we insulate in Stonington
By era, 30.0% predates 1940, 13.4% is from the 1940s and 50s, 17.4% from the 1960s and 70s, 22.9% from the 1980s and 90s and 16.2% has been built since 2000. Since 1940 no decade has built more than the 1980s, which added 13.1% of today’s stock.
The old stock follows the town’s maritime history. The first colonists settled at Wequetequock, Quiambaug and Pawcatuck, where Thomas Stanton set up a trading house in 1649, and the town took the name Stonington in 1666. From the 1790s its harbor sent out a sealing fleet, and in 1842 it became a port of entry, which brought Portuguese immigrants from the Azores. Today the town includes Stonington Borough, Pawcatuck, Lords Point, Wequetequock and the eastern halves of Mystic and Old Mystic. Its National Register listings include the Mystic Bridge Historic District, the Rossie Velvet Mill Historic District, the William Clark Company Thread Mill, and the Mechanic Street Historic District, with 413 buildings.
A Stonington house from before 1940 is usually timber- or balloon-framed, with plaster on lath, walls with nothing in them, a steep attic with little on its floor and often a stone cellar. In a balloon-framed wall the stud bays run open from the cellar to the attic and carry cold air up the house. The wiring is assumed to be knob-and-tube until we have looked, and live knob-and-tube is taken out of service before any wall is filled.
A two- or three-family of that age is the same construction, stacked: a shared stair, one roof over the top apartment and a cellar under all of it. We scope it as one building, because the wall bays and the stair run past every unit.
The post-war houses are capes and ranches from the 1950s, raised ranches from the 1960s and 70s, then the 1980s colonials and contemporaries. The contemporaries have cathedral ceilings with batts pressed against the roof deck; the colonials have insulated walls and leaky attics at the hatch and recessed lights; the raised ranches have a bedroom over the garage on an open floor. On the 57.0% of homes that burn oil, the payback for fixing any of these is counted in deliveries.
Borough houses, second homes and the old house kept half-heated
In recent decades Stonington has seen a large influx of new owners using historic Stonington Borough houses as second homes, and a widespread reconditioning of those houses since the mid-1990s. That changes the insulation question. A restored house has finishes worth protecting, and a second home may sit at a low thermostat setting for weeks at a time.
Protecting the finishes means working from the attic and the cellar first. The attic floor and the cellar rim can be sealed and insulated without touching a room. Walls are a separate decision: they can be dense-packed through a course of siding taken off and put back, or from inside where plaster is already being repaired, and in some restored houses the right answer is to leave them alone and do the top and bottom well.
A house kept cool through the winter still loses heat through every gap, just more slowly, and moist air from a bath or kitchen that leaks into a cold attic can condense on the roof boards. Sealing the attic floor before adding insulation keeps that air in the house. If a second home is closed up entirely, tell us how you run it; the scope for a house heated only to protect the pipes is not the same as for one lived in all year.
We seal before we insulate
Insulation slows heat moving through the building’s shell. It cannot stop air moving through the gaps in it, and an old frame house is full of them.
In a pre-1940 Stonington house the order runs from the top and bottom inward. In the attic, seal the top plates and the tops of any open wall bays, the chimney gap with flashing and fire-rated caulk, the plumbing stack and the hatch; then insulate the attic floor. In the cellar, seal the sill where it sits on the stone and the rim above it, and close the bottoms of the wall bays. Only then decide whether the walls get filled.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Stonington
Most of our projects run between $3,500 and $12,500. In an old Stonington house the attic and cellar work sets the base price, and the walls move it most: how many are filled, and whether through siding taken down and rehung or from inside. Knob-and-tube that has to be retired adds to it. A two- or three-family is priced as one building. A 1980s colonial or contemporary is priced on its attic, any cathedral ceilings and the floor over a garage. Spray foam costs are on their own page.
Open cell foam runs R-3.9 to R-4.2 per inch. Closed cell runs R-6.9 to R-7.1 per inch and also acts as a vapor retarder, which is why it costs more and why it is right in some assemblies and unnecessary in others. All products are manufactured in the United States and meet applicable building code and safety standards. ENERGY STAR says sealing air leaks and adding insulation can save up to 10% on annual energy bills.
Insulation rebates in Stonington
Stonington’s electric company is Eversource, and its gas company is Eversource too. Home Energy Solutions is open to customers of Eversource, United Illuminating, Connecticut Natural Gas and Southern Connecticut Gas, whatever fuel heats the house, for homes of one to four units that have not had the program’s services within six years. A renter needs the landlord’s approval.
The visit itself, carried out by an authorized Home Energy Solutions contractor, has cost a $40 copay since 1 April 2026. Health and safety tests come first; then a blower door locates the air leaks, the ducts are tested if the house has forced hot air or central air, and up to seven hours of air sealing is done free, after which a $10 hourly fee applies. Two-family to four-family houses always get two visits, and a house built before 1985 may be advised to take two. The program is subject to available funding, and there may be a waiting list.
The 2026 Energize CT insulation rebate covers attic floors, floored-over attics, walls, basement and garage ceilings and rim joists at up to $2.00 per square foot or 75% of the total cost, whichever is less, to a $10,000 maximum. Its wall rule, R-4 or less before and R-13 or more after, fits the empty wall of an old frame house. Parts of Stonington are designated environmental justice communities; the state’s map shows whether a specific address qualifies, and an eligible address may get $2.50 per square foot, up to $15,000. The order cannot be skipped: the Home Energy Solutions visit recommends the insulation, the program approves the project, and only then does an approved contractor from the Energize CT Insulation Installers Network install it. Foam sprayed under a roof deck is not a listed area, so confirm with the program before relying on a rebate for it.
On Energize CT’s 2026–2027 figures for a household of three, $78,692 or less is Income Eligible, with no-cost service and up to 100% of insulation costs covered; $78,693 to $104,924 is Enhanced Incentives, a no-cost visit and up to $2.50 per square foot, the actual range set by zip code; $104,925 and above is the standard tier. A household close to one of those lines should confirm its tier before paying anything.
On financing, the second-home question matters. Energize CT’s Micro Loan from Capital for Change names vacation homes and condos among eligible properties: an Eversource customer who owns and occupies a one- to four-unit home can borrow up to $3,000 at no interest over 36 months, on credit approval, for improvements recommended through Home Energy Solutions and put in by an approved contractor. The Connecticut Green Bank’s Smart-E Loan requires an owner-occupied home of one to four units and offers no money down, loans to $50,000, and 6.99% APR for 5, 7 or 10 years, 7.49% for 12 or 7.99% for 15 where the lender offers it. Smart-E runs through participating contractors; ask any contractor whether it is one.
Network installers alone can earn a household the Energize CT rebate, so ask any installer who quotes, including us, whether they are in that network, and compare prices after any rebate. Federal help ended with Section 25C, which excludes anything placed in service after 31 December 2025; insulation installed in 2026 gets no federal tax credit. Our Connecticut rebate guide has the details.
Code and climate in Stonington
60.8% of Stonington’s housing was built before 1980. Stonington, like all of Connecticut, is in climate zone 5A.
Since 1 October 2022, projects filed in Connecticut have come under the 2022 Connecticut State Building Code, whose energy chapter is the 2021 International Energy Conservation Code with state amendments. Its prescriptive minimums for a new house or an addition: ceilings R-60, though R-49 is enough where it keeps full uncompressed depth over the top plate at the eaves; floors R-30; wood-frame walls R-30 in the cavity, or R-20 cavity with R-5 continuous, or R-13 cavity with R-10 continuous; basement walls R-15 continuous, R-19 cavity, or R-13 cavity with R-5 continuous; windows U-0.30. A new home has to test at 3.0 air changes per hour at 50 pascals with a blower door on the prescriptive path, and no path allows worse than 5.0. A successor code based on the 2024 IECC exists in draft; its effective date has been delayed.
Those values are for new work. For an existing attic, the practical target is the Energize CT rebate’s R-49 or more.
Common questions about insulation in Stonington
Do you install insulation in Stonington, CT?
Yes, in the Borough, Pawcatuck, the Stonington side of Mystic and Old Mystic, and the rest of town. Much of our Stonington work is the 30.0% of houses built before 1940, including two- and three-family houses scoped as one building, and second homes being kept up between visits. We also insulate the 1980s colonials and contemporaries and the post-war capes and ranches. In a larger apartment building the roof and the exterior walls belong to the owner or the association, and insulating them is their decision.
How much does insulation cost in Stonington?
Most projects run $3,500 to $12,500. In a pre-1940 house the attic and cellar set the base, and the walls move it most: how many are filled, and whether through a siding course taken down and rehung or from inside. Knob-and-tube to retire adds cost, and a two- or three-family is priced as one building. A 1980s colonial is priced on its attic and any cathedral ceilings. Seeing the house is free, and the scope and price come in writing.
Are there insulation rebates in Stonington?
Yes. With Eversource for both electricity and gas, a Stonington home qualifies for Energize Connecticut’s Home Energy Solutions visit, $40 or free for income-qualified households. For an old house with empty walls the 2026 rebate matters: up to $2.00 per square foot or 75% of cost, to $10,000, rising to $2.50 where an address lies in one of the town’s environmental justice areas. The visit must recommend the work, the program must approve it, and a network installer must do it. No federal credit applies in 2026.
Our Stonington Borough house is a second home. Is it worth insulating?
Usually, but the scope depends on how you run it. A house heated through the winter, even at a low setting, pays for sealing and insulating the attic floor and the cellar rim, which protect the restored rooms and keep damp air out of a cold attic. A house closed up with the heat just high enough for the pipes saves less, and the walls may not be worth opening. Tell us how often you are there and how you set the heat, and we will scope it to match.
Free estimate in Stonington
In an old Stonington house our free estimate starts in the cellar at the stone, the sill and the rim, then goes up to the attic for the top plates, the tops of the wall bays, the chimney and whatever is on the floor. We check a wall bay or two for fill and wiring, with care for the finishes. Afterward we write up the scope and the price. That is our free estimate, which stands apart from Home Energy Solutions and does not qualify a house for the rebate.
The number is 914-825-6824, answered 8am–8pm every day, and the contact form works too. We come from New Rochelle, NY, with a 100-plus in-house crew that never hands work to subcontractors.
Learn more
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- Insulating older homes
- Wall insulation
- Attic insulation