Last updated: By HeatPumpIndex Evidence Desk
This starts from published design heat loss for your climate region rather than a rate per square foot, and then does the thing rules of thumb cannot: it holds the capacity on your quote up against that figure and tells you the ratio.
Every floor you heat, basement included if it is finished and heated.
Leave it blank if you are still shopping. One ton is 12,000 BTU/h, so a quote written either way converts here.
Published design heat loss
20,000 to 26,000
BTU/h, which is 1.7 to 2.2 tons at -18 °C.
Your quote: 60,000 BTU/h, 5.0 tons
2.3 times the top of it.
Ontario Heat Loss reports most Ontario systems are oversized by 30 to 50 percent, and puts square-footage sizing at the cause. Ask for the heat loss calculation this capacity came from before you accept it.
Both rows are published Canadian figures and they are answers to different questions. The design load is scaled from Ontario Heat Loss’s figure for a well built 2,000 sq ft house in this region. It is a sanity check, not the CSA F280 calculation the building code requires for a permit.
Nearly every sizing calculator on the web multiplies your floor area by a rate. This one starts from a measured figure instead. Ontario Heat Loss publishes design heat loss for a well built 2,000 square foot house in four Ontario climate regions, each against the outdoor design temperature that region is sized to: minus 18 in the GTA, minus 22 around Collingwood, minus 24 at Barrie, minus 28 in Muskoka. That pair of numbers is what a heat loss calculation actually produces, and scaling it by floor area keeps the method visible.
The rate per square foot is still on the page, in the second panel, because the comparison is the useful part. For the same 2,000 square foot GTA house the published rules give 60,000 to 120,000 BTU per hour against a design load of 20,000 to 26,000. Four and a half times, at the top end, and both figures are published in good faith by Canadian companies.
Neither is a CSA F280 calculation. What separates a real one from both of these is that it measures the building: how much insulation is in the walls, how much glass faces which way, how leaky the envelope is. Two houses of identical floor area in the same postal code can differ by half again on all three.
A furnace makes the same heat at minus 25 as it does at plus 5, so you size it to the coldest hour and you are finished. A heat pump does not. Its output falls as the outdoor temperature falls, which means sizing it to carry the full design load on the coldest night makes it substantially larger than the house needs for the other ninety-odd percent of the heating season, and an oversized heat pump spends that season cycling instead of running.
So the honest answer to what size is often smaller than the design load, with something behind it for the coldest hours. That something is either electric backup heat or an existing gas furnace, and the choice between them changes both the electrical work and the running cost. The number this page prints is the load. What fraction of it the heat pump carries is the design conversation, and a quote that has not had it has skipped the interesting part.
One consequence worth knowing before the conversation: the smaller the heat pump is sized relative to the load, the more hours the backup runs, and if that backup is resistance heat those hours cost roughly what they would have on baseboards. There is a genuine optimum and it is specific to your house and your electricity plan.
The regional design loads and design temperatures, the oversizing figure and the code clause all come from one page, read during this build. The ton is a definition.
A quote that names a capacity can be compared with this page. A quote that shows the heat loss calculation behind that capacity can be compared with another quote, which is worth more. HeatPumpIndex lists 221 heat pump installers across the Greater Toronto Area; the three below rank highest on our HeatPumpIndex score.
In its own words, from its website: Experience top-notch HVAC repair and maintenance services in Milton and Oakville ON with Free Air Heating & Air Conditioning Ltd. Trust our expert team for AC, furnace, ductless mini-split, heat pump services, and more. Schedule your service today!
Carried on this directory for ductless mini split work and heat pump installation from a base in Leaside. Their own website names heat pump work, and the company appears on Ontario's Home Renovation Savings register.
In its own words, from its website: Family-owned for 75+ years. Service, repairs, installations & honest pricing.