Stove vs open fire: which heats a room better?
The open fire has been at the centre of Irish sitting rooms for generations, and many people are reluctant to lose it. A stove, though, gets a great deal more heat from the same fuel. Here is how the two compare.
Why open fires are inefficient
An open fire draws a large volume of warm room air up the chimney to keep burning, far more than the fire actually needs. Much of the heat produced goes straight up the flue with it, and cold air is drawn in through gaps around doors and windows to replace what has gone. You get radiant heat on the side facing the fire, while the rest of the room and the rest of the house can end up cooler.
The EU Ecodesign regulation for solid fuel heaters gives a sense of the difference: the minimum seasonal efficiency for a new open-fronted appliance is 30%, compared with 65% for a closed-fronted stove burning logs. A traditional open grate with no controls will typically do no better than that minimum, and often worse.
How a stove does better
- Controlled air: a closed firebox lets the stove take in only the air it needs, through adjustable primary and secondary inlets.
- Higher combustion temperature: more of the fuel burns completely, including the gases that would otherwise go up the chimney as smoke.
- Heat transfer: the stove body and glass radiate and convect heat into the room long after the flames die down.
- Less heated air lost: because far less room air is drawn up the flue, draughts are reduced.
The practical result is that a stove usually needs considerably less fuel to keep the same room warm, and it holds heat for longer once the fire burns down.
Smoke and air quality
Open fires produce more smoke per kilogram of fuel because combustion is cooler and less complete. Smoke means fine particles (PM2.5), the pollutant targeted by Ireland's solid fuel regulations. Smoke inside the house is a concern too: when an open fire is lit or refuelled, or a door opens, smoke can spill into the room. A closed stove with its door shut keeps combustion gases inside the appliance and flue.
Safety
- Open fires throw sparks and embers, so a fireguard is essential, especially with children or pets.
- Both open fires and stoves can produce carbon monoxide if the chimney is blocked or the draw is poor. Fit and test a carbon monoxide alarm, and keep the flue swept (chimney sweeping guide).
- A stove's outer surfaces get very hot. Keep a hearth clearance as specified by the manufacturer and use a stove guard where needed.
Cost
An open fire is already there in many houses, so it costs nothing to keep. A stove is an upfront expense: the appliance itself, a suitable flue liner in many cases, hearth work and installation. Fuel savings pay some of that back over time, and how quickly depends on how often the fire is lit and what fuel is used. SEAI does not currently offer an individual grant for stoves; see home heating grants and stoves.
Options if you want to keep the look of an open fire
- Inset or cassette stoves sit inside an existing fireplace opening and keep the surround, with the fire visible behind glass. The archive has an old page on inset stoves.
- Freestanding stoves can stand on the existing hearth in front of or within a chimney breast.
- Gas fires, including high-efficiency glass-fronted models, are an option where there is a gas supply; the archive's gas fires and flueless gas fires pages show older ranges.
- Room-sealed stoves draw combustion air directly from outside, which suits airtight, well-insulated houses. See the archived note on room-sealed stoves.
Airtight houses and ventilation
Modern, well-sealed houses need careful thought. Both open fires and stoves need a supply of combustion air, and Technical Guidance Document J of the Building Regulations sets out the ventilation requirements. A stove's requirement is usually much smaller than an open fire's, and room-sealed designs remove the need for a permanent wall vent in the room. A competent installer will assess this.
So which should you choose?
If the fire is lit only now and then for the atmosphere, keeping an open fire may be reasonable, provided you use compliant fuel and keep the chimney swept. If you rely on it to heat the room through the winter, a properly sized Ecodesign stove burning dry wood or approved smokeless fuel will give more heat, less smoke and fewer draughts for the same fuel.
Frequently asked questions
Is a stove more efficient than an open fire?
Yes. EU Ecodesign rules set a minimum seasonal efficiency of 65% for new closed-fronted log stoves, compared with 30% for open-fronted appliances, and traditional open grates often fall below that.
Can I fit a stove in my existing fireplace?
Often, yes. Inset or cassette stoves fit within the opening and freestanding stoves can stand on the hearth. The flue usually needs checking, and many installations need a flue liner.
Does a stove need a wall vent?
It depends on the stove's output, the house's airtightness and the appliance type. Technical Guidance Document J sets out the requirements; room-sealed stoves take their air from outside.
Are open fires banned in Ireland?
No. The solid fuel regulations control which fuels can be sold. There is no ban on using an open fire with compliant fuel.