65.9% of Trumbull was built between 1940 and 1979, and only 1.5% went up in
the 2010s — the lowest recent-construction rate of the 23 towns in
Fairfield County. People here mostly live in the houses the town was built
with.
A lot of those houses are split-levels, and a split-level loses heat in three
specific places that almost nobody insulates.
The houses we insulate in Trumbull
Trumbull has 12,468 housing units, 85.6% detached and 89.0% owner-occupied,
with a median build year of 1965 and 74.6% of the stock predating 1980. Only
8.6% was built before 1940. This is the textbook post-war Fairfield County
suburb: farmland subdivided in one 25-year burst into capes, ranches,
split-levels and center-hall colonials through Nichols, Long Hill and Tashua.
There is almost no antique stock and almost no new construction, so whatever a
Trumbull house was given when it was built is mostly what it still has.
The split-level is the specific opportunity, because it has three assemblies
that a normal attic job never touches. First, the stepped attic plane: the roof
over the low wing steps up to meet the high wing, and at the step there is a
vertical wall between finished rooms and the attic space over the low side.
Nine times out of ten that wall has batts sagging out of it, no air barrier on
the attic face, and open joist bays running underneath it into the floor
cavity.
Second, the bedroom over the garage. The floor deck sits over unconditioned
space, the common wall between garage and house is rarely sealed at the top
plate, and the band joist at the step between levels is open framing. Third, the
cantilever: where the upper floor projects past the foundation, the joist ends
are exposed to outside air and the floor cavity is usually continuous with the
wall cavity, so air moves in under the finished floor.
The rest of the town is the same era in different shapes — 1940s and
50s capes with knee wall triangles and open joist bays out to the eave, and
ranches with loose-fill settled to four or five inches and an open chimney
chase. In every one of them we seal first, then bring the flat attic up to
depth, then deal with the vertical and overhanging surfaces that got skipped.
We seal before we insulate
Insulation slows heat moving through a surface. It does nothing about air
moving through a gap. Pack a leaky attic with cellulose and you have a leaky
attic with cellulose in it — the air still moves, it just moves through
something fluffier.
So the first half of a real job is closing the holes: top plates, the chimney
chase, the framing above a dropped soffit, the recessed lights, the attic hatch.
In a Trumbull split that means putting a real air barrier on the attic face of
the stepped knee wall and blocking the joist bays that run under it, and closing
the cantilever at the joist ends. Blow insulation over an open stepped wall and
the air keeps moving under the floor exactly as it did before. Then we
insulate.
If a quote specifies a depth of insulation and never mentions air sealing, it
is half a job.
What insulation costs in Trumbull
Most of our projects run between $3,500 and $12,500. A
Trumbull ranch with an open attic and a walk-up hatch is a bottom-of-range job.
A split-level costs more than its square footage suggests, because the stepped
knee wall, the floor over the garage and the cantilever are three separate
assemblies in three separate crawl-height spaces, and each one has to be sealed
before it is insulated.
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. After air sealing and insulating, homeowners typically save 20% or
more on heating and cooling.
Insulation rebates in Trumbull
Trumbull is United Illuminating territory, not Eversource,
and incentives run through Energize Connecticut. The order matters and it is not
negotiable: book a Home Energy Solutions visit first (the
homeowner copay has been $40 since April 2026), have insulation
recommended during that visit, get the project approved before anyone installs
anything, and use a contractor on the Energize CT Insulation Installers Network.
Skip a step and the money is gone.
The rebate is $2.00 per square foot or 75% of the job, whichever is
less, up to $10,000, and $2.50 per square foot up to
$15,000 for income-qualified households and homes in designated
environmental justice communities. Households under 60% of state median income
can qualify for HES-Income Eligible, which covers approved insulation up to
100%.
The scope rule lines up well with a split-level. Attic floors, floored-over attics, above- and below-grade walls, basement and garage ceilings and rim joists qualify, so the stepped
knee wall and the garage ceiling under the bedroom are both in scope, and
attic roof decks and rafters do not qualify. Crawl spaces are not on that list either. A crawl space ceiling may or may not be accepted as a floor over unconditioned space depending on how the job is written up, so if the crawl is the work, confirm it with the program before installation rather than after. If someone quotes
you foam on the underside of the roof and tells you the rebate covers it, it
does not. See the full Connecticut
rebate guide for the mechanics.
The federal Section 25C tax credit ended for anything placed in service after
31 December 2025. There is no federal insulation credit on a
2026 job, whatever you may still read online.
Code and climate in Trumbull
Three-quarters of Trumbull predates 1980 and only 1.5% of it was built in the
2010s, so this is a town where the current code has had almost nothing to do
with the houses people actually own. That code is the 2022 Connecticut
State Building Code, in force since 1 October 2022 and based on the
2021 IECC; the next edition was expected in July 2026 and has been delayed.
Fairfield County is climate zone 5A — you will see 4A
quoted in places, but that comes from an ASHRAE addendum Connecticut never
adopted.
For new construction and additions the code sets R-60 in the
ceiling, R-30 in wood-framed walls (or R-20 cavity plus R-5
continuous), R-30 in floors, and R-19 or R-15 continuous in basement and crawl
space walls. None of that applies to a house that is already
standing. The code does not require an existing building to be altered;
it only requires that altering an assembly not leave you with less insulation
than you started with. A benchmark, not an obligation — and the Department
of Energy separately recommends R-60 for a retrofit attic in this zone.
Common questions about insulation in Trumbull
Do you install insulation in Trumbull, CT?
Yes, and most of what we do here is the post-war stock: split-levels, 1940s
and 50s capes, ranches and center-hall colonials through Nichols, Long Hill and
Tashua. Two-thirds of the town went up between 1940 and 1979, so the same
handful of assemblies come up again and again.
How much does insulation cost in Trumbull?
Most projects run $3,500 to $12,500. A ranch attic sits near the bottom of
that range. A split-level sits higher for its size, because the stepped knee
wall, the floor over the garage and the cantilevered overhang are three separate
assemblies, each in an awkward space, and each needs sealing before
insulating.
Are there insulation rebates in Trumbull?
Yes, through Energize Connecticut. Trumbull is United Illuminating territory,
not Eversource. The rebate is $2.00 per square foot or 75% of the job, whichever
is less, capped at $10,000, and $2.50 per square foot up to $15,000 for
income-qualified households. A Home Energy Solutions visit has to come first and
the project approved before installation. Attic roof decks and rafters are
excluded, and there is no federal tax credit any more.
Why is one level of our split-level always cold?
Because the surfaces between levels are the ones that got skipped. Check
three things: the vertical wall where the low roof steps up to the high wing,
the floor over the garage and the common wall beside it, and any part of the
upper floor that overhangs the foundation. All three are open to outside air in
most Trumbull splits, and adding depth to the flat attic does nothing for any of
them.
Free energy audit in Trumbull
We walk the attic, the basement and the spaces between levels, find where the
house is losing air and heat, and give you a written scope and a price. No
charge, no obligation. If your attic is already deep enough and the real problem
is a stepped knee wall with no air barrier on it, we will tell you that —
it is a smaller job and it is the honest one.
Call 914-825-6824 or use the form on this page. Open
8am–8pm, seven days. We work out of New Rochelle, NY with a 100-plus
in-house crew, and we hold manufacturer installer certifications from the spray
foam manufacturers we use.