Wood-burning appliance inspections (WETT): what’s checked and how often

What a WETT inspection is

WETT Inc. (Wood Energy Technology Transfer) describes itself as a non-profit training and education association that promotes the safe and effective use of wood-burning systems in Canada and acts as the national registrar of the WETT program. It says hiring a WETT-certified professional ensures wood-burning appliances are inspected, installed and maintained to current safety codes and standards, and helps homeowners meet insurance or regulatory requirements. Its site has a public directory of certified professionals.

We couldn’t verify WETT’s inspection-level names or typical prices, so ask each inspector what the inspection includes and get the scope in writing before you book.

Who needs one

• Every home that burns wood, every year. The fire codes require a chimney, flue and flue pipe inspection at least once every 12 months.
• When you add or replace an appliance, and after any chimney fire: both trigger an inspection under the same fire code article.
• Buying or insuring a home with a wood stove. Ask your insurer what it needs before you close. In Québec, insurers accept the electronic visual inspection attestation issued by APC member chimney sweeps.
• Rebates. NB Power’s rebates for wood and pellet appliances require a US EPA or CSA B415.1 rating and a WETT installation, and Yukon’s heating system rebate needs an approved final inspection report (details below).

What the inspection checks

An inspection looks at what the fire code and the installation code regulate:

• The chimney, flue and flue pipe. The National Fire Code’s notes list structural deficiencies (a missing liner, inadequate supports or ties) and decay (cracking, settling, crumbling mortar, distortion, advanced corrosion, separated sections, loose or broken supports), plus abandoned openings that haven’t been sealed.
• Creosote and soot. Deposits more than 3 mm thick mean the chimney needs cleaning right away, possibly a change in how you burn, and more frequent inspections.
• Clearances. The required space between the appliance, flue pipe or chimney and combustible construction must be maintained, and nothing combustible may be stored in it.
• The installation. CSA B365 is the installation code for solid-fuel-burning appliances: furnaces, boilers, stoves, ranges, space heaters, factory-built fireplaces and water heaters. It doesn’t apply to site-built fireplaces.
• The appliance itself. Whether it’s certified to CSA B415.1 or the US EPA standard, which you can usually tell from its label or certification plate.

How often to inspect and sweep

The National Fire Code 2020 (Division B, Article 2.6.1.4) requires every chimney, flue and flue pipe to be inspected at intervals of no more than 12 months, when any appliance is added and after any chimney fire, and to be cleaned as often as necessary to keep it free of dangerous combustible deposits. Ontario’s Fire Code has the same inspection rule. The US EPA says fire officials recommend having the appliance, chimney and vent professionally inspected every year.

How often to sweep depends on how much you burn. In Québec, the APC suggests once a year for occasional use and at least twice a year for very frequent use. Between visits, dense smoke at the top of the chimney is a warning sign: the fire code’s note links it to improper operation, a wrongly sized chimney or unsuitable fuel.

Finding a certified inspector

Search the WETT directory ↗ for certified professionals near you and confirm they cover your address. In Québec, use the APC’s Trouver un professionnel directory ↗ and filter by inspectors (Inspecteurs) or chimney sweeps (Ramoneurs). APC members hold the relevant RBQ licence, have passed APC training, carry at least $2 million in liability insurance and have been in business at least two years. WETT doesn’t publish prices, so get two or three written quotes.

Certified and uncertified stoves

CSA B415.1 is the Canadian test method for the heat output, efficiency and emissions of stoves, inserts, factory-built fireplaces, furnaces and hydronic heaters that burn cordwood, chips or pellets. The US EPA tested stoves certified to its 2015 standard to a particulate limit of 4.5 grams per hour; its 2020 limit for new room heaters is 2.0 g/h tested with crib wood or 2.5 g/h with cord wood. EPA says certified stoves burn cleaner and are more energy efficient. In Québec, the APC notes that a certified stove carries a certification plate showing its emissions, the certification year and the standards body, fitted only at original manufacture.

B.C.’s Solid Fuel Burning Domestic Appliance Regulation sets standards for wood-burning appliances sold in the province. The province says a modern, emissions-certified appliance reduces smoke but doesn’t eliminate it, and that modern pellet stoves emit 80–90% less fine particulate (PM2.5) than most appliances burning regular firewood.

Rebates for wood and pellet appliances

Keeping it safe between inspections

• Burn dry wood: the US EPA says wood burns best below 20% moisture, and a moisture meter tells you.
• Keep anything combustible out of the clearance space around the stove and flue pipe.
• Have the chimney inspected after any chimney fire, and whenever you add or replace an appliance.
• Put a CO alarm in the room. For new houses, the National Building Code 2020 requires one in any room with a solid-fuel-burning appliance; see the carbon monoxide guide for your province’s rules.
• Tightening the house changes how chimneys draw, so pair air sealing with a combustion safety check.