Fireplaces

Fireplaces and heaters with flues include open masonry fireplaces, enclosed wood heaters (slow combustion stoves), gas log fires and flued gas space heaters. They combine fire, combustion products and a flue, so their risks are fire spreading to the building, carbon monoxide entering living spaces, and smoke and emissions. Chimneys and flues are covered on their own page; this page covers the appliance, hearth, surrounds and the room.

Many older homes have fireplaces that are no longer used but remain open to the flue, while others have been converted to gas or fitted with inserts; the condition of each, and whether the flue still suits the appliance, is often unknown.

For assessment, fireplaces are graded by the risk they pose to occupants as much as by their condition; a sound-looking heater can still spill carbon monoxide.

What shortens life:

• No servicing of gas heaters.
• Burning wet or treated timber.
• Alterations that bring combustible materials close.

Appliance life depends heavily on use and servicing. Gas heaters that are serviced regularly last much longer and stay safer than those left for years; wood heater fireboxes, baffles and bricks wear with heavy use and wet fuel. Hearths and surrounds last as long as the building unless cracked by heat or altered. The useful life of wood heating is also being shortened by emissions rules and by electrification, which make replacement with heat pumps more attractive than like-for-like renewal.

Carbon monoxide

Gas space heaters with cracked heat exchangers or blocked flues, and fires whose flues spill under negative pressure from exhaust fans, put carbon monoxide into homes. Deaths from unserviced gas heaters have led to safety campaigns and servicing advice.

Clearances to combustibles

Wood heaters and fireplaces installed too close to timber framing, linings, furniture or mantels, or on inadequate hearths, ignite nearby materials over time.

Flue fires and blockages

Creosote from slow-burning wet wood builds up and ignites in flues; nests and debris block flues; see the chimney page.

Smoke and emissions

Wood heaters produce fine particle pollution indoors and outdoors; regulations restrict emissions and, in some areas, use.

Unflued appliances

Unflued gas heaters release combustion products and moisture into rooms; they are restricted in schools and some jurisdictions.

Negative pressure and spillage

Kitchen rangehoods, bathroom fans and clothes dryers depressurise tightly sealed homes, pulling combustion products down flues and into rooms. Spillage is worst when several fans run together, which is why testing must be done under worst-case conditions.

Alterations around appliances

Renovations bring new timber mantels, shelving, cabinetry and wall linings close to fireplaces and heaters, often without anyone checking clearances, and new airtightness reduces the combustion air an appliance needs.

Conversions and inserts

Gas log fires and inserts fitted into old masonry fireplaces depend on flues that may be cracked or unsuited, and on correct flue liners and terminations.

On site

• Soot staining above fireplaces or heaters.
• Heaters close to combustible walls or mantels; small hearths.
• Gas heaters without service tags; yellow flames.
• No carbon monoxide alarm.
• Cracked fireboxes and door glass.

In the records

• Gas heater service records.
• Installation certificates.
• Chimney sweeping records.

• Doors and windows sealed tightly in a home with an open fireplace or gas heater, limiting combustion air.
• Exhaust fans near heaters, which can cause spillage.
• Timber mantels and shelving installed close to fireboxes.
• Smoke smell in the house after the fire has burned down.
• Heaters with dated or missing compliance plates.

• Wet or painted timber stored for burning, which builds creosote quickly.

Separate appliance faults (servicing, cracked heat exchangers, worn seals) from installation faults (clearances, flues, combustion air) and from house effects (negative pressure from fans and airtightness), because each needs a different fix.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

Carbon monoxide findings are always graded as safety regardless of how old or new the appliance is, because the consequence is death; clearance and flue defects follow closely because they cause house fires.

A licensed gas fitter for gas appliances and a qualified installer or chimney sweep for solid fuel, with the building surveyor.

• Gas appliance service with carbon monoxide spillage testing under worst-case conditions (exhaust fans running, doors closed).
• Clearance check of wood heaters and fireplaces to combustible materials and hearth size against the installation standard.
• Flue inspection and sweeping.
• Carbon monoxide alarm check.
• Compliance check of installation certificates and emissions ratings.

The report should state whether each appliance is safe to use, and repairs, replacement or decommissioning.

Testing should be repeated after any renovation that changes airtightness or adds exhaust fans.

• Occupant interview: symptoms when appliances run, smoke or smells, and how often appliances are used and serviced.

Record results for each appliance separately.

• Service gas heaters at the recommended interval, commonly every two years.
• Replace cracked or unsafe appliances, including older flued gas heaters that fail testing.
• Correct clearances with heat shields, larger hearths or relocation.
• Sweep flues and fit bird guards.
• Carbon monoxide alarms in rooms with fuel-burning appliances.
• Remove unflued heaters from bedrooms and sensitive buildings.
• Decommission unused fireplaces and seal and ventilate their flues, or convert to electric heating as part of electrification.

• Combustion air: provide dedicated air supply to appliances in airtight homes, or replace with room-sealed appliances.
• Spillage controls: interlock or balance exhaust fans in homes with open-flued appliances.

• Owner guidance on dry firewood, flue cleaning intervals and never running unflued heaters in closed bedrooms.

Servicing and sweeping recur. Appliance replacement is per unit. Clearance corrections are itemised. Decommissioning is a small lump sum per fireplace.

Safety items are immediate; servicing is recurring; replacement is lifecycle.

Carbon monoxide alarms and servicing are inexpensive compared with the risk they control. Replacing an older flued gas heater or wood heater with a heat pump may cost more up front but removes the carbon monoxide and flue risks, and often qualifies for energy incentives.

• Australia. AS/NZS 2918 covers installation of solid fuel heating appliances; AS/NZS 4012 and 4013 set wood heater efficiency and emissions; AS/NZS 5601.1 covers gas appliances; state gas regulators recommend regular servicing of gas heaters.
• United Kingdom. The Gas Safety (Installation and Use) Regulations 1998 require annual gas safety checks in rented homes; Approved Document J covers combustion appliances; smoke control areas and Ecodesign rules restrict wood burning; carbon monoxide alarms are required with fixed combustion appliances in many homes.
• United States. NFPA 211 covers chimneys, fireplaces and vents; the EPA sets new wood heater emissions standards; the International Residential and Fuel Gas Codes cover installation; many states require carbon monoxide alarms.

Rental minimum standards in several places also set heater requirements.

• Gas heater service records.
• Installation certificates.
• Chimney sweeping records.
• Carbon monoxide alarm details.
• Emissions ratings of wood heaters.

• Records of renovations near heaters or fireplaces.
• Electrification or heater replacement plans.
• Any incidents involving smoke, soot or carbon monoxide.

• Wood heater emissions compliance plates and model details.