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Cooling & Heating · ReplacePTAC & Through-the-Wall Unit Replacement
PTAC and through-the-wall unit replacement is a chassis swap: the old unit slides out of its wall sleeve and the new one slides in, typically one to two hours per unit once the right model is on site. The job is decided before ordering. A standard PTAC sleeve is 42 inches wide by 16 inches high, through-the-wall sleeves are narrower and differ by brand, and the new unit has to match the sleeve, the voltage and the plug on the wall. Replace instead of repairing when the sealed refrigerant system has failed on a unit past 10 years.
A PTAC (packaged terminal air conditioner) is a self-contained heating and cooling unit that sits in a metal sleeve through an exterior wall, with the controls on the room side and a grille outside. Around Burlington, Oakville, Hamilton and Mississauga they turn up in older apartment and condo buildings, hotels, retirement residences, sunrooms and additions with no ductwork. A through-the-wall air conditioner is the smaller cousin: a narrower sleeve, usually cooling only or cooling with a small electric heater. Both are built to be replaced as a chassis without opening the wall, provided the new unit matches what is already there.
Measure the sleeve, not the front cover of the old unit. PTACs settled on the 42-by-16-inch sleeve decades ago, so a new chassis from most manufacturers fits an existing standard sleeve and reuses its outdoor grille; older odd-sized sleeves need an adapter kit or a new sleeve. Through-the-wall sleeves never standardized: they run roughly 24 to 27 inches wide and differ in depth, so we match the brand's sleeve or quote a replacement. A through-the-wall unit must also breathe out the back only, because a window-type unit with side louvres suffocates inside a wall sleeve and cooks its compressor.
Voltage and plug come next. Most PTACs run on 208/230 volts and are sold with 15, 20 or 30 amp cords, each with a different blade pattern on the plug, and the cord rating sets how much electric heat the unit can make. Some commercial buildings use 265-volt units, which are not interchangeable with the others. We read the old nameplate and the receptacle before ordering so the new unit plugs into the circuit that exists; if the receptacle or breaker has to change, that is electrical work under ESA rules, quoted separately by a licensed electrician.
Then choose how it heats. An electric-heat PTAC warms the room with a resistance element, which is simple and costly to run; a heat pump PTAC heats with its compressor in mild weather and switches to a backup element in the cold, which lowers the bill in a suite where the unit is the main heat. Buildings with a hot-water coil in the sleeve need a hydronic model. In a condo, check first who owns the unit and whether the corporation specifies a model: it is the same ownership question we cover for condo fan coil units, and both are part of our condo HVAC service.
Replace the unit instead of repairing it when
- The compressor hums and trips, or runs with no cooling: a sealed-system failure, and a PTAC has no service ports to recharge through
- Oil stains or ice on the indoor coil point to a refrigerant leak on a unit past 10 years
- The nameplate says R-22, a refrigerant that has been phased out, which makes any sealed-system repair uneconomic
- Rust has eaten the base pan and condensate runs down the inside wall instead of draining outdoors
- The repair quote passes half the price of a new chassis
How it works
A photo of the nameplate (model, volts, amps, BTU), a photo of the plug, and the inside width and height of the sleeve usually settle the replacement model before anyone drives out. Send them through the contact form or call.
On site we check that the sleeve is sound, slopes slightly to the outside so condensate drains away from the room, and that the outdoor grille and the receptacle suit the new unit. The price is written down before the chassis is ordered.
The old unit slides out, the sleeve is cleaned and its seals renewed, and the new chassis goes in, is levelled and tested in cooling and heating. The old unit leaves with us, and its refrigerant is recovered by an ODP-certified technician before disposal.
Common questions
Will a new PTAC fit my existing wall sleeve?
Usually, if the sleeve is the standard 42 inches wide by 16 inches high: most current chassis are built for that opening and reuse the outdoor grille. Take the measurement inside the sleeve, not across the room-side cover. Odd sizes from older product lines need an adapter or a new sleeve, and a rusted or back-sloping sleeve should be replaced along with the unit.
Can I put a window air conditioner in a through-the-wall sleeve?
No. A window unit pulls outdoor air through louvres on its sides, and a wall sleeve blocks them, so the condenser overheats and the compressor fails early. A through-the-wall model vents only through the back. Look for the words through-the-wall or sleeve installation in the manual before buying, and match the sleeve width, which differs between brands.
Should I buy a heat pump PTAC or an electric-heat one?
If the unit is the room's main heat, a heat pump model usually costs less to run, because in mild weather the compressor delivers more heat per kilowatt-hour than a resistance element; it still carries an element for cold days. If the building has central heat and the PTAC mostly cools, the plain electric-heat or cooling-only model is the cheaper purchase.
Is an old PTAC worth repairing?
Fan motors, capacitors, control boards, temperature sensors and blocked drains are worth fixing on a sound unit, and the $90–$150 diagnostic tells you which fault you have. A failed compressor or a refrigerant leak is different: the circuit is factory-sealed, so the repair means cutting in, brazing and recharging. On a unit past 10 years that money belongs in a new chassis.
Do I need condo board approval to replace a PTAC?
Often, yes. Many corporations specify the model, the look of the outdoor grille and who may do the work, because the sleeve passes through the exterior wall. Ask the property manager for the unit specification before ordering; we supply the model data sheet and proof of insurance. The process mirrors condo board approval for an AC or heat pump.