The Ontario Building Code | Equipment Sizing
9.33.2.2. Equipment Sizing
(1) The heating system capacity shall be based on the heating load calculated in accordance with Sentence 6.2.1.1.(1).
(2) Where a cooling system is installed, the cooling system capacity shall be based on the cooling load calculated in accordance with Sentence 6.2.1.1.(1).
(3) The heating and cooling equipment capacities shall be determined in accordance with the requirements of CSA F280, "Determining the Required Capacity of residential Space Heating and Cooling Appliances".
9.33.3. design Temperatures
In Plain Language
Heating equipment must be sized as set out in this article, matching capacity to the building's actual heat loss rather than being arbitrarily oversized or undersized.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.