It is a fair question to ask in January, standing in the kitchen with the furnace running for the third time in an hour. Heat pumps have changed a lot, and for many Waterdown houses the honest answer is yes, with conditions. The conditions depend on your house, your ductwork and how you feel about the coldest weeks of the year.
Does a heat pump actually work when it is cold here?
A heat pump moves heat rather than making it. In summer it pulls heat out of the house and works as a central air conditioner. In winter it runs the other way, pulling heat from the outdoor air and bringing it inside. There is still usable heat in air well below freezing, and that is what makes the idea work.
The older heat pumps many people remember struggled once the temperature dropped below freezing. Cold-climate models are built to keep heating at much lower outdoor temperatures. They do lose some output as it gets colder, and they work harder to deliver it, so the useful questions are how cold it gets here, for how long, and what takes over when the heat pump cannot keep up on its own.
What does a Waterdown winter ask of a heat pump?
At the Hamilton RBG climate station near Waterdown, the 1981-2010 normal daily average temperature is -4.7 °C in January and -3.9 °C in February. That is a long heating season, but on an average winter day it is well within what a cold-climate heat pump is designed to handle.
The harder days are the cold snaps, the clear, still nights when the temperature drops well below the average. On those nights a heat pump on its own may need help, either from built-in electric heat strips or from a gas furnace. Snow matters too. The outdoor unit needs to sit up off the ground on a stand or wall bracket, clear of drifts and of water dripping off the roof, because it defrosts itself during the winter and that meltwater has to drain away and not freeze into a block underneath.
What about keeping the gas furnace as backup?
For most Waterdown houses already on natural gas, this is where the decision gets easier. A heat pump can be paired with a gas furnace so that the heat pump handles the mild and moderate days, which is most of the season, and the furnace takes over when it gets very cold. The thermostat or control switches between them at a set outdoor temperature.
This set-up has a few things going for it:
- You keep a heat source that does not care how cold it is outside, which matters on the worst nights of January.
- The heat pump replaces your central air conditioner, so you are not paying for two outdoor units.
- The switch-over point can be adjusted, so you can lean more on electricity or more on gas depending on what each costs you.
- If the heat pump ever needs repair in winter, the house still has heat.
If your furnace is near the end of its life, it can make sense to replace both at once and have them set up to work together. If the furnace is still sound, a heat pump can often be added to the existing system, as long as the furnace blower and the ductwork can handle it.
Does the age of the house change the answer?
It changes it quite a bit. Waterdown has three broad waves of housing, and each one brings its own questions.
In the newer subdivisions of Waterdown South and Waterdown Bay, houses were typically built with high-efficiency gas furnaces, central air and heat-recovery ventilators. They are usually well sealed and the ductwork was sized with air conditioning in mind. These are often the easiest houses for a heat pump, and a common choice is to replace the central air conditioner with a heat pump when it is due, keeping the furnace as backup.
The post-war and later surveys, such as Glenlea, Buchan Court and Renwood Park, mostly have forced-air systems that started on oil and moved to gas. The original ductwork is often on the small side. A heat pump delivers heat at a lower temperature than a gas furnace, so it relies on moving more air. Undersized ducts or too few returns can leave rooms cool and the system noisy. Measuring the house and the ducts first tells you whether a heat pump will be comfortable as is, or whether some duct work should come first.
The older houses around the Griffin Survey and the McMonnies and Stock Survey were often built for coal or wood and many still heat with hot-water radiators. If there are no ducts, a ductless heat pump with wall-mounted indoor heads can heat and cool the main rooms while the boiler stays in place for the coldest days. Insulation and drafts matter more in these houses than anywhere else, and sealing them up often helps a heat pump more than buying a bigger one. If your house is a designated heritage property, check with the City of Hamilton before adding an outdoor unit or new openings in the walls.
How do the running costs compare?
We will not give numbers here, because they depend on your house and on gas and electricity rates that change. In general terms, a heat pump is most economical in mild and moderately cold weather, when it moves several units of heat for each unit of electricity it uses. As it gets colder, that advantage shrinks. Natural gas is often cheaper to burn on the coldest days, which is exactly why the backup arrangement makes sense for many homes on gas.
The picture is different if your house is not on the gas system and heats with propane, oil or electric baseboards. Those homes often see the biggest change in running costs from a heat pump, and the case for one is usually stronger.
The upfront cost depends on the size of the house, whether ductwork changes are needed, whether the electrical panel has room for the new circuit and whether the furnace is being replaced at the same time. Rebate and incentive programs come and go, and their rules change, so check what is currently available before you sign anything, and before work starts, since some programs need an assessment done first. The guide on what goes into the price of a furnace repair or a new furnace covers the same kind of factors.
What should you check before deciding?
A few questions will tell you a lot:
- How old is your furnace and your air conditioner? If either is near replacement, that is the natural time to consider a heat pump.
- Do the rooms upstairs already struggle in summer? That usually points to duct problems a heat pump will also run into.
- Is there a good spot for the outdoor unit, raised above the snow, away from the roof drip line and not right under a bedroom window?
- Does the electrical panel have space and capacity for another circuit?
- Has someone calculated the heat loss of your house, rather than matching the size of the old equipment?
Winter air in a heated house is dry no matter what heats it. If dry air is already a complaint, the guide on humidity in winter and summer is worth reading alongside this one.
The refrigeration side of a heat pump is a compulsory trade in Ontario. Work is performed by 313A refrigeration and air conditioning mechanics. Where the heat pump is tied into a gas furnace, work is performed by TSSA-certified gas technicians.
So is it worth it?
For a house that is reasonably tight, has decent ductwork or room for ductless heads, and either keeps a gas furnace as backup or is moving off propane, oil or electric baseboards, a cold-climate heat pump is usually a sound choice in Waterdown. For an older house with small ducts and lots of drafts, it can still work, but the house usually needs some attention first. Starting with an honest look at your own house is the most useful step.
If you would like someone to look at your house and talk it through, see our heat pump service.