š§Types of Heat Pumps
This is the first part of the Heat Pumps Demystified section. Weāll start adding technical terminology, but it is not meant to scare you! Getting a few terms down before calling a contractor puts you way ahead of homeowners who wing it.Ā
Remember to flip to the šPhrasebook at the end of the Guidebook if you need a definition!
Firstly, you donāt need to drill underground for any of these systems! Heat pumps in Toronto almost always get their heat from the outside air (called šair-source), rather than the ground (šground-source).
There are four main ways a heat pump can provide warm and cool air to your homeāwe will describe each and the home it's best suited for.Ā
A central heat pump is best
if your home has ducts
The heat pump serves the entire house by moving hot and cool air through the ductwork.Ā
A cold climate heat pump can provide all of a homeās heating and cooling. homeās heating and cooling. Many Torontonians decide to add electric coils in their ductwork for backup heating. The coils are pricey to run, but they should only flip on for short bursts on the coldest days. Whether you should add backup coils is a bit technicalāitās a good conversation to have with your contractor or Retrofit Advisor.
A ductless system is best
if your home doesn't have ducts
A ductless system uses āmini-splitā units mounted on walls or ceilings. These āmini-splitā units look like wall-mounted air conditioning units.Ā
The number of indoor units you need will depend on your homeās size and layout.
A hybrid system is bestĀ
if you have a new (~5-year-old) furnace
These systems use the cold climate heat pump until the outside temperature drops below a set temperature.
At this point, the system switches automatically toĀ the fossil fuel heating system. After working with a contractor or Retrofit Advisor, you may learn that your home isnāt right for a cold climate heat pump by itself. Thatās OK! Hybrid systems can still significantly cut your homeās gas use. The point is to start with a cold climate heat pump as the goal and then rule it out.Ā
If your home has radiators...things
are a little trickier!
You have two choices:
Fully Electric (Aka Air-to-Water Systems): A heat pump transfers heat to aĀ water tank that is then piped through your radiators at a lower temperature than your boiler. These are common in Europe, but not so much in Toronto. Air-to-Water heat pumps do notĀ provide cooling.Ā
Hybrid system:Ā A ductless heat pump is paired with your boiler. Your boiler provides heating on the coldest days. The heat pump does the rest andĀ adds summer cooling.
We hosted a whole webinar on pairing heat pumps and radiators! Watch the recording here:
Also, BC HydroĀ has an excellent video on heat pump types.
š§Heat Pump Sizing
Like cars, heat pumps come in different sizes. The size you need depends on your homeās šheat loadāthatās the amount of heat your home needs to stay warm. With the heat pump sizing done right, you can stare down polar vortexes or heat domes without fearāyouāll know that your heat pump will keep you comfortable.
Calculating your actual heat load takes technical training, but you just need to remember two things:Ā Ā Ā
Your contractor or Retrofit Advisor should calculate your heat load.Ā Ā
Your old utility bills are a great way for them to run that calculation.
Sadly, we've seen highly recommended HVAC installers get heat load wrong. If your contractor tells you either of these two things, you have cause for concern:
Ā Ā
They say they only need to know your homeās square footage. This is a very common myth. It doesnāt work because square footage and heat load are not directly correlated! A small house with lots of drafts takes more energy to heat than a larger house thatās well-sealed (weāll cover drafts and air-sealing in the Prep section).
Ā
They only look at the size of your old furnace. Furnaces are almost always oversized in Canada (meaning they always āshort cycleā).
Old utility bills are a great answerāthe bills tell you exactly how much energy it took to heat your home last winter! No guesswork required, especially if you average the cost for the past few winters.Ā Ā
Some contractors havenāt been trained in this highly effective method, but every Retrofit Advisor has been.Ā If a contractor raises their eyebrows when you pull out your old heating bills, it might be time to contact a Retrofit Advisor or another contractor.Ā
Check out the Guidebook Worksheet!
Finally, a heat pumpās size is measured in āštons,āĀ which is a bit confusing. Thatās not referring to the weight of the unit itself! It refers to the amount of cooling it can do as compared to a 1-ton block of ice...if that sounds weird, youāre not wrong. Itās from a time when measuring energy was much less precise (horsepower is like that, too). Heat pumps come in Ā½ ton increments. Most Toronto homes need a 2, 2.5, or 3-ton heat pump.Ā
Thatās the end of the Heat Pumps Demystified section! Your heat pump knowledge has already come a long way.Ā Ā The next section will have you look more in-depth at your existing heating and cooling system. This will set you up to make some game-changing updates to your home! Keep it up!