The 1940s built 15.0% of Old Lyme’s housing, 685 of its 4,557 units, more than any decade since, and 20.8% of the town is older still. The median unit dates from 1964 and 70.8% predates 1980.
It is a town of detached houses. 90.2% of units are single-family detached and 88.7% of occupied homes are owner-occupied, with 5.0% of units in two-unit buildings and 1.8% in buildings of three or four. The count also found 1,468 units vacant. The town’s 7,644 residents are joined in summer by several thousand seasonal vacationers who occupy rental homes and cottages, in beach communities such as Point O’ Woods, Hawk’s Nest and Miami Beach.
No gas company serves Old Lyme, and utility gas heats just 0.8% of occupied homes. Fuel oil heats 66.4%, electricity 16.3% and bottled gas 12.8%. For a year-round house, sealing and insulating pays back in fewer oil and propane deliveries; for a cottage used in summer, the return is a cooler upstairs and a drier floor.
The houses we insulate in Old Lyme
By era, 20.8% of Old Lyme predates 1940, 25.5% is from the 1940s and 50s, 24.5% from the 1960s and 70s, 19.5% from the 1980s and 90s and 9.7% has been built since 2000. After the 1940s, the busiest decade was the 1970s, at 14.2%.
Lyme was set off from Saybrook in 1665. South Lyme was incorporated from it in 1855 and renamed Old Lyme in 1857, because it holds the oldest-settled part of the Lymes. Lyme Street is a historic district with several homes once owned by sea captains, the Florence Griswold House that sheltered the Lyme Art Colony’s Impressionist painters and Peck Tavern are on the National Register, and Colonial and Federal houses stand throughout the town. In a house of that age the walls may be timber-framed and the plaster worth protecting, so the work begins at the top and bottom: seal and insulate the attic, then the sill and rim in the cellar, before anyone decides about the walls. The wiring is inspected first, and live knob-and-tube is retired before a wall is touched.
The 1940s and 50s built a quarter of the stock: capes and small ranches. The cape leaks at its knee walls, open to the eave behind the upstairs rooms, and at the small attic over them. The ranch leaks across an attic floor whose fill has settled and around every ceiling fixture. The southern section of town is mostly flat, cut by tidal marsh and swamp, and a house there built over a crawl space has damp air under its floor to deal with before cold.
The 1960s and 70s added raised ranches, splits and contemporaries, the contemporaries often with cathedral ceilings whose batts sit tight against the roof deck. The raised ranch loses heat along its exposed rim joist and through the floor of the room over the garage. The colonials of the 1980s and 90s have insulated walls and leaky attics, at the hatch, the top plates and the recessed lights.
Point O’ Woods, Hawk’s Nest and the cottage rented for summer
Several hundred people rent seasonal cottages and beach front homes in Old Lyme from late May through mid October. A cottage used only in those months does not need to be insulated like a year-round house, and treating it like one wastes money.
In summer the problem is the roof. A low cottage roof with little or nothing in its rafter bays or over its ceiling heats the rooms beneath by afternoon, and the air conditioners run all day against it. Sealing the ceiling and insulating the roof or attic keeps those rooms cooler, and it is usually the first job worth doing. Underneath, close to marsh and water, the concern is moisture: an open crawl space brings damp air against the floor framing, and closed cell foam, which also acts as a vapor retarder, can seal and insulate the floor or crawl space walls where a sagging batt would hold water.
If the plan is to stretch the season into colder months, or to live there year-round, the order changes: floor or crawl space and plumbing first, then roof, then walls. Tell us how the house is used, and the scope follows.
We seal before we insulate
Insulation slows heat moving through a ceiling, wall or floor, in either direction. It does not stop air, and air carries winter heat out and summer heat and shore humidity in.
In a 1940s or 50s Old Lyme cape the sequence starts at the knee walls: block the open joist bays beneath them, give the back of each knee wall an air barrier, seal the top plates and the chimney gap with sheet metal and fire-rated sealant, and set baffles so the slopes stay ventilated. Then insulate the slopes, the knee walls and the small flat attic, and finish in the cellar at the sill and rim.
If a quote specifies a depth of insulation and never mentions air sealing, it is half a job.
What insulation costs in Old Lyme
Most of our projects run between $3,500 and $12,500. In an Old Lyme cape the number follows the knee walls, slopes and small attic; in a ranch or raised ranch, the attic area, the bypasses and the rim joist. A house on Lyme Street or of the same age is priced attic and cellar first, with the walls a separate choice. A shore cottage is priced on how it is used: roof and ceiling for summer comfort, or floor and crawl space first if it is going year-round. Spray foam costs are laid out 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 Old Lyme
Old Lyme’s electricity comes from Eversource, and no gas company serves the town. Home Energy Solutions is open to customers of Eversource, United Illuminating, Connecticut Natural Gas and Southern Connecticut Gas, whatever fuel heats the house, so Old Lyme’s oil- and propane-heated homes join through their Eversource electric accounts. It covers homes of one to four units that have not had its services in the last six years, and a renter needs the landlord’s approval.
An authorized Home Energy Solutions contractor runs the visit for a $40 copay, in effect since 1 April 2026. It starts with health and safety tests, finds drafts and air leaks with a blower-door test, tests the ducts where there is forced hot air or central air, and seals leaks at no cost for up to seven hours, with a $10 hourly fee beyond that. The program depends on available funding, so a wait is possible.
The 2026 Energize CT insulation rebate, for incentives running 1 January to 31 December 2026, pays up to $2.00 per square foot or 75% of the total cost, whichever is less, with a single maximum of $10,000, on attic floors, floored-over attics, walls, basement and garage ceilings and rim joists. A floored-over attic in an older cape qualifies if it starts at R-4 or less and finishes at R-19 or more. Foam under a roof deck is not a listed area, so ask the program before counting on money for a cathedral ceiling. The steps are fixed: a recommendation at the Home Energy Solutions visit, program approval before installation, and installation by an approved contractor from the Energize CT Insulation Installers Network.
Income sets the tier. Income Eligible is at or below 60% of state median income, with no-cost service and up to 100% of insulation costs covered; Enhanced Incentives is above that and below 80% of area median income, with a no-cost visit and up to $2.50 per square foot. For a household of six, Energize CT’s 2026–2027 figures draw those lines at $123,658 and $164,879, with zip code setting the Enhanced band.
Energize CT’s Micro Loan, from Capital for Change and subject to its credit approval, serves Eversource customers who own and occupy a one- to four-unit home, and its rules include condos and vacation homes: up to $3,000 with no interest over 36 months, for improvements recommended through Home Energy Solutions and installed by an approved contractor. The Connecticut Green Bank’s Smart-E Loan requires an owner-occupied home of one to four units and lends up to $50,000 with no money down, at 6.99% APR for 5, 7 or 10 years, 7.49% for 12 and 7.99% for 15 where a lender offers it. Smart-E goes through participating contractors, so ask whether yours takes part.
Because the rebate depends on a network installer, ask any installer who bids, including us, whether it belongs to the Insulation Installers Network, and set the bids side by side after any rebate. Disregard any pitch built on the federal credit: Section 25C ended for anything placed in service after 31 December 2025, so 2026 insulation earns no federal tax credit. Our Connecticut rebate guide has the details.
Code and climate in Old Lyme
70.8% of Old Lyme’s housing was built before 1980. The shore keeps winter highs in the upper 30s to low 40s, with about 28 inches of snow in an average winter, but Old Lyme is in climate zone 5A like the rest of Connecticut.
Houses and additions filed since 1 October 2022 are built under the 2022 Connecticut State Building Code, whose energy chapter is the 2021 International Energy Conservation Code with state amendments. A new house needs R-60 in the ceiling, satisfied by R-49 where it runs full height and uncompressed over the top plate at the eaves; R-30 in floors; wood-frame walls at R-30 cavity, R-20 cavity with R-5 continuous, or R-13 cavity with R-10 continuous; basement and crawl space walls at R-15 continuous, R-19 cavity, or R-13 cavity with R-5 continuous; and U-0.30 windows. Its blower-door test must show 3.0 air changes per hour at 50 pascals on the prescriptive path, with 5.0 the limit on any path. The next code, based on the 2024 IECC, has been adopted in draft, but its effective date has been delayed.
For existing work the rebate’s numbers are the practical ones: R-49 or more on an attic floor, R-19 or more on a basement or garage ceiling.
Common questions about insulation in Old Lyme
Do you install insulation in Old Lyme, CT?
Yes, from Lyme Street to Black Hall, Laysville, Soundview, South Lyme and the beach communities. Most of our Old Lyme work is capes and ranches from the 1940s and 50s, a quarter of the town, raised ranches and contemporaries from the 1960s and 70s, and older Colonial and Federal houses, where the attic and cellar come first. Seasonal cottages are scoped to how they are used.
How much does insulation cost in Old Lyme?
Most projects run $3,500 to $12,500. A 1940s or 50s cape is priced on its knee walls, slopes and small attic, and a ranch or raised ranch on its attic area, bypasses and rim joist. A historic house is priced attic and cellar first, with the walls a separate decision. A summer cottage may need only its roof and ceiling, or its floor first if it is going year-round. We see the house at no charge and write down the scope and price.
Are there insulation rebates in Old Lyme?
Yes. Old Lyme has Eversource electricity and no gas company, so homes heated by oil or propane enroll in Energize Connecticut’s Home Energy Solutions through their electric account, for a $40 copay or free for income-qualified households. Insulation the visit recommends, approved beforehand and installed by an Insulation Installers Network contractor, can earn up to $2.00 per square foot or 75% of cost, to $10,000, and income-qualified households can receive more. The federal credit is gone for 2026.
We rent out our Old Lyme beach cottage from late May to mid-October. Is insulation worth it?
Often, but not the winter kind. For a summer-only cottage the useful work is overhead: sealing the ceiling and insulating the roof or attic so the upper rooms stop baking by afternoon and the air conditioners run less. Underneath, near marsh and water, keeping damp air off the floor framing matters more than R-value. Wall insulation and a full heated-house scope only pay if the season is getting longer or the cottage is becoming a year-round home, and then the floor and plumbing come first.
Free estimate in Old Lyme
In an Old Lyme cape our free estimate opens the knee-wall doors, checks the slopes and the small attic above, and goes down to the cellar for the sill, the rim and the oil or propane boiler. At a shore cottage we get under the floor and into whatever space there is above the ceiling, and ask how many months of the year it is used. You get a written scope and price. None of that is a Home Energy Solutions visit, and it does not make a house eligible for the rebate.
Call 914-825-6824 any day, 8am to 8pm, or send the contact form. We work from New Rochelle, NY, with our own 100-plus in-house crew, never subcontractors.
Learn more
- Insulation contractors across New London County
- Insulation contractors in East Lyme
- Insulation contractors in Waterford
- Crawl space insulation
- Roof and cathedral ceiling insulation
- Insulating older homes