Cool air and a steaming outdoor unit in winter are often defrost, not a fault
In heating mode the outdoor coil runs colder than the outside air, so moisture freezes on it. Every so often the system reverses itself for a few minutes to melt that frost: the reversing valve shifts, the outdoor fan stops, and the unit gives off steam. During that cycle the indoor vents can feel cool. That is normal, and it ends on its own.
What is not normal is a coil that stays encased in ice, a unit that never seems to finish defrosting, or backup heat running most of the day in mild weather. Those point to a failed defrost control or coil sensor, an outdoor fan motor that has stopped, a low refrigerant charge from a leak, or snow and ice blocking airflow around the base of the unit. Clear snow away from the outdoor unit and check the indoor filter first; if the ice returns, the cause is inside the system.
Common heat pump faults trace to a short list of parts
A heat pump that runs but will not heat or cool properly is most often low on refrigerant, has a reversing valve stuck partway, or has a weak start capacitor that keeps the compressor from starting cleanly. Short cycling usually comes from an oversized unit, a thermostat wired or configured for the wrong system type, or a restricted indoor coil. Water around the indoor unit means a blocked condensate drain or trap. On a hybrid system, the furnace taking over too early or too late is usually the changeover temperature set at the thermostat or control.
Before we give a written price, the technician measures rather than guesses: supply and return air temperatures to get the temperature split, refrigerant pressures with superheat and subcooling to judge the charge, compressor and fan amperage against the nameplate, and static pressure across the ducts. If refrigerant is low, we find the leak before topping it up, because adding refrigerant to a leaking system only delays the next call. Work is performed by 313A refrigeration and air conditioning mechanics.
Grimsby's lake-moderated winters suit a cold-climate heat pump
A heat pump gathers heat from outdoor air, and its output and efficiency fall as the temperature drops. Cold-climate models use variable-speed compressors designed to keep producing useful heat well below freezing. Along this stretch of the Lake Ontario shore, the lake moderates the weather, keeping winters warmer than they would otherwise be, which means more of the heating season falls in the range where a heat pump works well.
There are still cold snaps. We look at the manufacturer's published capacity at low temperatures, compare it with the heat loss of your house, and decide what covers the coldest days: electric backup heat inside the air handler, or an existing gas furnace in a hybrid setup. If you want the running-cost comparison in more depth, our guide to heat pumps, rebates and the cheapest way to heat a Grimsby home works through it.
Sizing starts with the house and its ducts, not the old equipment
A heat pump delivers air at a lower temperature than a gas furnace, so it has to move more air to deliver the same heat. That makes duct and return-air sizing more important than with a furnace. We calculate the heat loss of the house room by room and measure the duct system before choosing a size.
Grimsby's housing changes the answer. In the post-war homes of the Lakemount Terrace Subdivision, ducts were often laid out for an oil or coal furnace and are now undersized with weak returns; adding a return or enlarging trunk runs can matter more than a larger outdoor unit. In the older cottages of Grimsby Beach and the houses along Main Street East and West, ductwork was squeezed in later or never added at all, and ductless wall heads are often the practical route, as covered on our air conditioning installation page. In the west end, around the Winston Road Neighbourhood, newer homes with condensing furnaces and heat-recovery ventilation usually have ducts that can take an add-on heat pump coil with little change.
The outdoor unit and refrigerant lines go on an exterior wall, so for an older home it is worth checking whether the house is on the Town of Grimsby's heritage register before planning where they sit.
Hybrid systems keep the gas furnace for the coldest days
A hybrid system adds a heat pump coil above an existing or new gas furnace. The heat pump carries the load through most of the season, and the furnace takes over below a changeover temperature that we set with you based on equipment capacity and your energy costs. Enbridge Gas supplies natural gas in Grimsby, so most homes here can keep that furnace as backup.
Each half of a hybrid system falls under a different trade. Gas appliances in Ontario are installed and serviced under Ontario Regulation 212/01 and to the CSA B149.1 installation code, and the refrigerant circuit is a separate compulsory trade. Work is performed by TSSA-certified gas technicians. Work is performed by 313A refrigeration and air conditioning mechanics. On a hybrid installation we also check the furnace's venting, condensate trap and control board, since the two pieces of equipment now share a thermostat and a blower. If the furnace side is the problem, see furnace repair.
Rebates are checked when the quote is written
Government and utility programs for heat pumps open, change and close, and eligibility rules can depend on the equipment model, the home and the timing of the work. We do not quote rebate amounts from memory. When we prepare your written price, we check which programs are open at that time and tell you what the equipment would need to qualify, so you can apply with the right paperwork.
The quote itself lists the equipment, any duct or electrical changes, the line set and outdoor pad, and how the system will be commissioned. Once it is running, yearly maintenance keeps coils clean, the condensate drain clear and the defrost cycle working as it should.