Below are the exemptions for boilers and water heaters based on the information we were able to find in the provincial regulations as of May 2020. Depending on the design conditions, a boiler/water heater may require registration in one province while being exempt in another. While some provinces may have similar guidelines for exemptions in most cases the requirements differ. The exemptions vary based on a combination of heat input, heating surface area, design conditions and diameters.
Always review your design to the newest provincial regulations as they are updated on an ongoing basis.

CRN Boiler Exemption Chart
Province
Exempt (Yes/No)
Reason
British Columbia Reg. 104/2004, B.C. Reg. 184/2019, July 2019    
3 (1) This regulation applies in respect of every boiler and boiler plant, every pressure plant, every pressure vessel, every pressure piping system, every fitting, every plant and all refrigeration equipment and refrigeration plants.
(2) Despite subsection (1), this regulation does not apply to any of the following:
(o) a water heater with a heat input of 120 kW or less [120kW/hr = 409,457 BTU]		    
Alberta Regulation 56 / 2006 (January 1, 2020) section 2(b)(i)    
56/2006: (2) The Pressure Equipment Safety Regulation, the Pressure Welders Regulation and the Power Engineers Regulation do not apply to the following:
(b) a boiler that forms the whole or part of a heating plant and
(i) has a heating surface not exceeding 2 square metres, or
(ii) has an electric power rating not exceeding 20 kilowatts;
49/2006: (o) “heating plant” means:
(i) a boiler in which steam or other vapour can be generated at a pressure not exceeding 103 kilopascals and a temperature not exceeding 121 degrees Celsius.
(ii) a boiler in which liquid can be heated to a pressure not exceeding 1100 kilopascals and a temperature not exceeding 121 degrees Celsius at or near the outlet of the boiler		    
Chapter B-5.1 The Statutes of Saskatchewan (2019) Reg. Part I section 2 and 3    
2 In this Act: (l) “low pressure boiler” means: (ii) a hot water or fluid heating boiler that is operated at a pressure of 1100 kilopascals or less or produces a temperature that is 121°C or less at or near the outlet; 3(1) Subject to subsections (2) and (3), this Act applies to all boilers, pressure vessels, plants, pressure piping systems and fittings except: (g) a low pressure boiler that has a heating surface with an area of three square metres or less    
Manitoba C.C.S.M. c. S210 The Steam and Pressure Plants Act, January 1, 2020    
1. Definitions, “steam plant” means an installation designed or used for generating, utilizing, confining, or storing, under pressure, steam or hot water, including the boiler thereof and all appurtenances and appliances connected therewith, but does not include (a) those that develop less than three horse power, (b) those that are used for heating a building designed and constructed as a private residence intended to house not more than one family, and (c) those that are used for heating a building used solely for residential purposes and containing not more than two separate apartments or suites.    
Ontario Regulation 220/01 Boilers and Pressure Vessels section 2(b), 420/17    
1. (1) In this Regulation, “low pressure boiler” means, (a) a boiler that is intended to generate steam or other vapour at a pressure of 15 psi (103 kPa) or less, or (b) a boiler that is intended to be operated at a pressure of 160 psi (1,100 kPa) or less where the water temperature at any boiler outlet is 250ºF (121ºC) or less; 2. Application (1) This Regulation applies to the design, construction, maintenance, use, operation, repair and service of boilers, pressure vessels and piping. (2) This Regulation does not apply to, (b) a low pressure boiler that has either a wetted heating surface of 30 square feet (2.79 square metres) or less, or a power rating of 30 kW or less;    
Quebec – An Act respecting pressure vessels chapter A-20.01, r. 1 section 2(1), March 8 2018    
Division 2 Scope 2. The following pressure vessels are excluded from the Act and its regulations: 1) steam, hot water or thermal fluid low-pressure boilers whose wet heating surface in less than 2.8 m2 or whose power does not exceed 30 kW;    
New Brunswich Regulation 84-175 under the Boiler and Pressure Vessel Act (O.C. 84-607), Oct 8, 2014    
2 “low pressure heating plant” means a boiler or two or more boilers on the same premises having a safety valve setting of not more than fifteen pounds per square inch (one hundred and three kilopascals) when the boiler is used for producing steam, or a safety valve setting of not more than one hundred and sixty pounds per square inch (one thousand one hundred kilopascals) when the boiler is used for producing hot water at a temperature of not more than two hundred and fifty degrees Fahrenheit (one hundred and twenty degrees Celsius);(installation de chauffage à basse pression) EXEMPTIONS    
Nova Scotia Boiler and Pressure Equipment Regulations N.S. Reg. 10/2011, April 1, 2011    
4 Products exempted from Act and regulations (c) a boiler that has a maximum output capacity of 150 kW (507 104 BTU/hr) or less and has (i) a steam service with a system safety or relief valve set at a pressure of 103 kPag (15 psig) or lower, or (ii) a hot water service with a system safety or relief valve set at a pressure of 206.7 kPag (30 psig) or lower;    
Prince Edward Island Boiler and Pressure Vessel Act, Chapter B-5, June 28, 2019    
1. Definitions; (i) “heating plant” means (ii) any one or more boilers in which water or other liquid may be heated to a pressure not exceeding 1100 kilopascals and a temperature not exceeding 121 degrees Celsius at or near the outlet of the boiler, or 2. (1) Except as provided in subsection (2) this Act and the regulations apply to all boilers, pressure vessels, power plants, heating plants and pressure plants and fuel-burning equipment. (2) This Act and the regulations do not apply to (b) a boiler having a boiler rating of 20 kilowatts or less in capacity, installed in a heating plant; (g) a pressure vessel intended to be installed in a closed hot water heating system having a working pressure of 207 kilopascals or less and having an internal diameter of 610 millimetres or less;    
Yukon Boiler and Pressure Vessels Act RSY 2002, c 16, 2010    
1. In this Act; “heating plant” means (b) any one or more boilers in which water or other liquid may be heated to a pressure not exceeding 1100 kilopascals and a temperature not exceeding 121 degrees Celsius at or near the outlet of the boiler. 2) This Act or any regulation made under this Act does not apply to (b) a boiler having a boiler rating of 20 kilowatts or less in capacity, installed in a heating plant; (g) a pressure vessel intended to be installed in a closed hot water heating system having a working pressure of 207 kilopascals or less and having an internal diameter of 610 millimetres or less;    
NWT Boiler and Pressure Vessel Regulations R-006-93 & Act B-2    
Regulation 1. In these regulations; “high pressure plant” means the complete installation of one or more boilers, engines, turbines, piping, machinery and accessories carrying (a) steam pressure greater than 103 kPa, or (b) water pressure greater than 1,103 kPa where the water temperature is greater than 121°C; (installation à haute pression) “low pressure plant” means a plant of one or more boilers carrying (a) steam pressure not greater than 103 kPa, or (b) water pressure not greater than 1,103 kPa 5. (3) A design and specifications for the following plants need not be submitted for approval unless required by the chief inspector, but such plants must otherwise comply with these regulations: (a) a high pressure plant that does not exceed 929 kW; (b) a steam plant carrying a pressure not exceeding 103 kPa; (c) a hot water plant carrying a pressure not exceeding 1,103 kPa; Act 2. (1) This Act does not apply to; (a) a boiler (i) that develops less than 30 kW of power, or (ii) that is used for heating private residences that house less than three families.    

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