Wall insulation starts with one question: is the wall open or closed? An open wall, in an addition or a gut renovation, takes batts, mineral wool or foam between the studs. A closed wall has three routes: fill it through drilled holes, add board outside when the siding comes off, or open it from inside. Before any of that, somebody has to find out what is in there, because in Burlington County the answer changes by decade and a wrong guess wastes the budget.
Half this county was built when wall insulation was a builder’s choice. 55.7% of its 185,617 housing units predate 1980 and the median unit dates from 1977, but the other half went up under a rule, and 27.5% of the stock is from the 1980s and 90s with 16.8% since 2000. Those newer walls are already full, so drilling them is the wrong sale. The empty and half-empty walls sit in the older towns, and that is where this work belongs.
Where wall insulation pays in Burlington County houses
The pre-war river towns. Moorestown has 23.8% of its housing from before 1940 against 10.7% countywide, and Burlington Township 7.7%. Those walls are usually empty, finished in lath and plaster, and often balloon-framed, with bays open from cellar to attic. Filling them means blocking the bays top and bottom first, drilling without breaking the plaster keys, and getting an electrician to the knob-and-tube wiring beforehand. Where a wall is solid brick or stone with no cavity, there is nothing to fill, and we say so rather than sell a drill-and-fill.
The 1950s walls with an inch or two in them. Cinnaminson is 21.1% 1940s and 50s housing, Pemberton Township 17.5% and Burlington Township 15.4%. These walls hold a thin, slumped batt that has settled away from the top plate, or a couple of inches of loose fill that has dropped. Neither empty nor full, they get scanned before they get drilled, because filling around a partial batt takes a different hole pattern than filling a bare bay.
Levitt-era tract walls. Willingboro is 90.2% pre-1980 with 51.2% built in the 1960s alone, and the same few house plans repeat across the township, so the same wall repeats too. Once we have scanned two or three of one plan we know where the blocking sits in the rest, which shows up as fewer patched holes inside.
Knee walls and garage walls. The county’s splits and capes, thick on the ground in Delran at 46.3% from the 1960s and 70s and Medford at 35.9%, carry short attic knee walls with open joist bays running under them and an unlined back face. A batt leaned against that back face does nothing; the bay under the floor has to be blocked and the wall sealed on both sides. The same goes for the wall and ceiling between a garage and the bedroom above it, where the air on the cold side smells of exhaust.
Walls that are open anyway. Additions and renovations across Mount Laurel and Evesham, the county’s two big 1980s and 90s townships at 54.4% and 48.9% of that era, are the cheapest wall insulation anyone buys, because the framing is already exposed. That is also when the code numbers below apply.
How we do wall insulation in Burlington County
The first visit finds out what is in the wall. The power comes off at an outlet on an exterior wall, the cover plate comes off, and a light and a hook tell us whether that bay is empty, part filled or full — on each floor and in the old and newer parts of the house, since insulation in one wall does not mean insulation in all of them. An infrared scan fills in the rest, and it reads best in cold weather. Two findings stop the job: fill that looks like gray-brown or silver-gold pebbles, which may be vermiculite and stays put until a licensed professional has tested it, and live knob-and-tube wiring, which an electrician replaces first.
For closed walls, dense-pack is the usual route. Holes of an inch or two go into each stud bay, roughly 6 inches below the ceiling, from inside through the plaster or drywall or from outside behind a removed strip of siding. Every bay is packed to the manufacturer’s density — cellulose at 3.5 to 4.5 pounds per cubic foot, fiberglass at 1.8 to 2.6 — which keeps it from settling and slows air moving through it. Bays over headers, under windows and behind cabinets get their own holes, with a second hole below any blocking, and a scan confirms every bay is full before the holes are patched. Injection foam is the other through-the-hole method, and its product, shrinkage and cure time are settled before the first hole is drilled.
For open walls the material follows the bay. A 3 1/2-inch 2×4 bay takes an R-13 or R-15 batt, or about R-24 to R-25 of closed cell filling it; a 5 1/2-inch 2×6 takes R-20, R-21 or R-23 batts, or a full bay of open cell. Mineral wool goes where its density earns its keep, on a bedroom or bathroom wall that also wants to be quiet, and closed cell is the pick for a shallow wall or the wall shared with a garage. Batts are cut around wiring and boxes rather than folded or pinched, the boxes are sealed, and corners, headers and the wall behind a tub get filled before they are closed up.
Re-siding is the one chance an existing wall gets at continuous insulation. With the siding off, empty cavities are filled and R-5 to R-10 of board goes over the sheathing, with the water control layer, window flashing and furring strips set for the thicker wall; the siding contractor hangs the siding and the board is ours. Solid masonry is different: insulating brick or stone from inside leaves it colder and wetter, and freeze-thaw can damage it, so those walls are judged one at a time and sometimes left alone. Wet, settled or rodent-fouled material comes out under containment before new insulation goes in, and mold on the framing or the sheathing is a remediation trade.
What wall insulation costs in Burlington County
Most of our projects run between $3,500 and $12,500. For closed walls the number follows the number of stud bays, not the square footage of the house: a two-story Moorestown colonial has more bays and more blocking than a Willingboro ranch of the same floor area. It moves with drilling from inside through plaster against outside through siding, with patching and paint, with how much blocking the bays hide, and with whether a scan finds half the wall already filled. Open-wall work is priced by cavity and material. Siding, drywall and wiring belong to those trades. Our insulation cost guide breaks it down.
Rebates for wall insulation in Burlington County
Which program applies is decided by the names on your bills. PSE&G bills both gas and electricity in Burlington Township, Cinnaminson, Delran, Moorestown, Mount Laurel and Willingboro. Pemberton Township is JCP&L for electricity, with PSE&G gas reaching only a corner. Evesham and Medford are split on both: PSE&G or Atlantic City Electric for electricity, South Jersey Gas or PSE&G for gas. When the two bills carry different names either program can run the job, and since the gas programs require gas heat, start with whoever bills the heating fuel.
Wall insulation sits squarely inside Whole Home Energy Solutions, which pays on a project of air sealing plus the insulation an assessment calls for. PSE&G pays up to $7,500 in rebates with 0% on-bill repayment of up to $25,000, beginning with an assessment by a BPI-certified contractor participating in its program, whose fee that contractor sets. JCP&L and South Jersey Gas both publish the arithmetic: $2,000 for a modeled 5% energy saving plus $200 for each point above it, capped at $7,500 and at half the project cost, with 0% financing of $2,500 to $25,000 alongside. Atlantic City Electric pays up to $7,500, takes single-family residences only, and finances through the program’s lender rather than the bill. PSE&G, JCP&L and South Jersey Gas each give their own residential customers a free Whole Home Energy Assessment, a short walk-through that installs small items. Ask any installer, us included, whether they participate in the program you plan to use.
Income-qualified households can have the work done outright through PSE&G Home Weatherization, or the $14,000 programs at JCP&L, South Jersey Gas and Atlantic City Electric, whose measures include insulation in walls, ceilings and attics. New Jersey Comfort Partners covers households at or below 250% of the federal poverty guidelines, $82,500 for a family of four in 2026, and refers oil, propane and kerosene homes to the state’s weatherization office. New Jersey’s IRA Home Energy Rebates are not open and the state still describes them as in development. The federal 25C tax credit ended for anything placed in service after 31 December 2025. Our New Jersey rebate guide covers the rest.
Code and climate in Burlington County
Burlington County is climate zone 4A. New Jersey adopted the 2024 IECC on 17 August 2026, and for a wood-framed wall in new work it gives four ways to comply: R-30 in the cavity, R-20 in the cavity plus R-5 continuous, R-13 plus R-10 continuous, or R-20 continuous on its own. A 2×4 bay cannot reach any of those alone, which is why a new 2×4 wall here carries board outside it and a 2×6 wall gets R-5 over R-20 batts. The code counts cavity and continuous insulation separately, gives no credit for sheathing or drywall, and counts a compressed batt only at the R-value it delivers.
The vapor retarder rule is the one most often got wrong in this zone. In zone 4 an unfaced batt behind painted drywall is accepted and so is kraft facing, while polyethylene sheeting is not permitted — the sheet of plastic that northern-zone habits put on the warm side traps moisture in a Burlington wall. Existing houses fall under New Jersey’s Rehabilitation Subcode: blown-in or batt insulation installed against the interior finish is ordinary maintenance with no permit, foam plastic needs a permit, and we pull that permit as part of the job. With 55.7% of this county standing before New Jersey’s first statewide energy subcode of 1 January 1978, most of these walls were built under no insulation requirement whatever.
Towns we serve in Burlington County
Wall work runs across all 40 municipalities in the county. These nine have pages of their own.
Common questions about wall insulation in Burlington County
Can you insulate my walls without opening them?
Yes, that is most of this work. Cellulose or fiberglass is blown through inch-and-a-half holes into each stud bay, packed to the density the manufacturer specifies, and the holes are patched; injection foam goes in the same way. The limits are honest ones: live knob-and-tube wiring has to be replaced first, plaster needs care, blocking and bracing mean extra holes, and a solid masonry wall with no cavity cannot be filled at all.
How do I know whether my Burlington County walls are already insulated?
Shut off the power to an outlet on an outside wall, take the plate off and look into the gap beside the box with a flashlight. Do it on each floor and in both the old and newer parts of the house. An infrared scan finds what the outlets miss, and it reads best on a cold day. It matters here because 27.5% of county housing went up in the 1980s and 90s with full walls already, while Moorestown’s pre-1940 quarter mostly has nothing in them.
How much does blown-in wall insulation cost in Burlington County?
Most of our projects run between $3,500 and $12,500, and for walls the count of stud bays drives it rather than the floor area. Drilling from inside adds patching and paint; drilling from outside means pulling and replacing a course of siding. Hidden blocking, bays half full of old batt, and an electrician replacing knob-and-tube all add to the day. We scan before we quote so the number is based on what is actually in the wall.
Should the knee walls in my split or cape be insulated too?
Yes, and they need more than a batt leaned against them. A knee wall has attic air on its back face and open joist bays running underneath it into the room below, so the bays get blocked, the back face gets an air barrier, and only then does insulation go in. It is one of the most common cold-bedroom causes in the county’s 1960s and 70s splits, which is 46.3% of Delran’s housing and 47.6% of Pemberton Township’s.
Free energy audit in Burlington County
The wall part of an audit is a few small openings and a camera. We check bays on every floor and each elevation, look for blocking and bracing, find the wiring, check the cladding and flashing, and take a reading on any wall already filled. Above and below we look at the attic floor and the rim joist, since a wall leaking at both ends is not really a wall problem.
You get a written scope and a price, with no charge and nothing owed. Call 914-554-2289, 8am–8pm, seven days. The Home Insulators is family-owned, has worked from New Rochelle, NY since 2015, and puts its own 100-plus-person in-house crew on the job; we never subcontract.
Get my free estimateor call 914-554-2289, 8am–8pm every day