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Heat Pumps · Indoor UnitAir Handler Repair & Replacement
Air handler repair and replacement deals with the indoor half of a heat pump system: the cabinet that holds the blower, the refrigerant coil and, in most Ontario installs, an electric heat kit. Repair it when the fault is a motor, a control board, a heat-kit part or a drain; replace it when the coil leaks out of warranty, or when the outdoor unit is being replaced and the two would no longer match. A diagnostic visit is $90–$150.
An air handler does for a heat pump what a furnace does for an air conditioner, minus the flame. In a house with no gas furnace it moves the air, carries the indoor coil and holds the electric resistance elements that back the heat pump up in deep cold and during defrost. That makes it common where gas mains never reached — rural Caledon, Lowville, Kilbride, Campbellville, Carlisle and rural Flamborough — and in all-electric townhouses. The term itself is defined in our air handler glossary entry.
Five parts cause nearly all air handler repairs. The ECM blower motor or its control module fails and the fan stops or surges; the control board loses a relay; a sequencer, limit or element in the electric heat kit burns open, so the house falls behind on the coldest nights while the heat pump itself runs fine; the coil develops a refrigerant leak; or the drain pan cracks or clogs and water shows up under the cabinet. Four of those are straightforward repairs. A leaking coil is where the replacement question starts.
A replacement air handler has to match the outdoor unit in three ways: capacity, refrigerant and metering device. An R-410A coil cannot be paired with a new R-454B or R-32 outdoor unit, and the newer refrigerants call for air handlers built and listed for them. A mismatched pair loses capacity and efficiency and can cost you the manufacturer's warranty, so we check the outdoor model number against the manufacturer's matched-system data before quoting. Refrigerant work is done by a technician holding an ODP card.
Location changes the job. An air handler in an attic or above a finished ceiling needs a secondary drain pan under the whole cabinet and a float switch that stops the system when water reaches it; without them, the first sign of a blocked primary drain is a stained ceiling. Closet units need the same float protection plus enough door or grille area for return air. Faults on the outdoor side of the system are covered under heat pump repair.
Signs the air handler is the problem
- The outdoor unit runs but little or no air moves at the registers — a blower motor or module fault
- Heat keeps up in mild weather and falls behind in a cold snap, pointing at the electric heat kit, not the heat pump
- Water under the cabinet, a full secondary pan, or the system shutting off on its float switch
- Ice on the indoor coil with heating and cooling both weak — a refrigerant leak or an airflow fault
- A heat-strip breaker that trips, or a burning smell that does not clear after the first minutes of the season
How it works
No air, no backup heat, water, or ice. Tell us where the unit sits — basement, closet or attic — and the brand of the outdoor unit, so the likely motor modules and float switches are on the truck.
The technician checks blower amperage and the motor module, the board's outputs, each stage of the heat kit with a clamp meter, refrigerant pressures and the drain. You get the fault and the price in writing.
Repairs with stocked parts are finished that visit. For a replacement we confirm the matched model, recover the refrigerant, set the new cabinet with its pans and float switch, then pressure-test, evacuate and charge. Request a quote with both model numbers if you have them.
Brands: We service air handlers from Lennox, Carrier, Trane, Goodman, Rheem, Daikin, York, Amana and KeepRite, and the ducted indoor units of Mitsubishi, Fujitsu and Daikin heat pumps.
Common questions
Can I replace just the air handler and keep the outdoor unit?
Yes, if a matched air handler is still made for that outdoor model and its refrigerant. It makes sense when the outdoor unit is under about 10 years old and in good shape. When the outdoor unit is older, or runs on a refrigerant the new cabinets are not listed for, replacing one half leaves you with a mismatched system and a second bill soon after.
Is an air handler the same as a furnace?
No. A gas furnace burns fuel and has a heat exchanger and a vent; an air handler has no combustion at all. Its heat comes from the heat pump's coil and from electric elements. An electric furnace is the closer relative: a blower and elements with no refrigerant coil doing the main work.
Why is my hydro bill so high in a cold snap?
The electric heat kit is probably carrying the load. Resistance elements use two to three times the electricity of a working heat pump for the same heat, and they take over if the heat pump is locked out, low on refrigerant or set to hand off too early. We check the staging and the thermostat settings so the strips run only when they are needed.
The coil is leaking. Repair the coil or replace the whole air handler?
In a furnace system the coil is a separate box and is swapped alone — see evaporator coil replacement. In an air handler the coil sits inside the cabinet; on some models it is sold as a part, on others the cabinet is the practical unit of replacement. Under parts warranty, replace the coil. Out of warranty and past 12 years, replace the air handler.