Any open flame changes the air in your living room. Wood, gas, bio-ethanol and Tenderfuel behave differently when it comes to fine particles, CO2, formaldehyde and odour. This guide places the main substances side by side, includes figures where they add useful context, and helps you decide what suits your home.
- Funnel stage
- Awareness, informational
- Cluster
- Emissions (pillar)
- Read time
- About 12 minutes
- Sources
- RIVM, WHO air quality guidelines, EU product rules, Tenderflame product information
In short
- Every flame produces CO2 and water vapour. Incomplete combustion adds fine particles and volatile substances
- Wood releases between 40 and 800 milligrams of fine particulate matter per hour, far more than bio-ethanol or Tenderfuel
- Bio-ethanol burns more cleanly than wood, but fuel quality and burner design decide whether traces of formaldehyde appear
- Tenderfuel is designed for complete combustion through the steel wick and offers a cleaner emissions profile than typical bio-ethanol
Indoor fireplace emissions: what is released by a decorative fire?
Any flame produces CO2 and water vapour. Incomplete combustion adds the following:
- Carbon monoxide
- Fine particulate matter (PM2.5 and PM10)
- Formaldehyde
- Acetaldehyde
- Volatile organic compounds
What determines the amount?
The amount depends on three factors:
- The fuel: composition and purity
- The burner: flame temperature, air supply and design
- The room: volume and ventilation rate
Wood, gas, bio-ethanol and Tenderfuel compared
A modern decorative fire sits at the cleaner end of this range, an older wood stove at the other. Wood typically gives off between 40 and 800 milligrams of fine particulate matter per hour, depending on the stove and how it is used. A modern gas fire stays well below that but needs a closed system and a proper connection. Bio-ethanol releases barely any particulate matter, though a low flame temperature or a dirty burner can release traces of formaldehyde and acetaldehyde. Tenderfuel has been developed for complete combustion through the steel wick, keeping the flame temperature high enough to limit the formation of these by-products. On fine particles, Tenderfuel sits roughly level with clean bio-ethanol. On odour and aldehydes, it typically performs better.
Why flame temperature matters so much
Incomplete combustion nearly always comes down to a flame that runs too cool or gets too little oxygen. A flickering, yellow-orange flame that bends easily is burning incompletely and produces relatively more by-products. A steady, clear flame that leaves no soot on the glass is burning completely. The steel wick feeds fuel evenly, so the flame stays at temperature even as the reservoir runs low. That difference is visible to the naked eye towards the end of a burn cycle.
Practical rules for cleaner indoor air
Four habits keep the air in good shape:
- Ventilate before, during and after use. In an average living room, leave at least one window slightly open while the fire burns and for ten minutes after it is out
- Never run several open flames at once, so no decorative fire alongside ten tealights and a hob in the same small space
- Keep burning time in small rooms to a maximum of two hours in one sitting
- Always use the fuel intended for your model: no alternative alcohol fuels in a Tenderflame, and no Tenderfuel in a standard bio-ethanol burner
Which choice makes sense for whom?
Your main reason for lighting a fire decides the type:
- Warmth is the main goal and you have an approved flue: wood or pellet stove
- You want constant comfort: gas fire with professional installation
- You want atmosphere without building work: bio-ethanol or Tenderflame
Why Tenderflame is often chosen in that last group
Within the atmosphere-without-building-work group, households with children or pets, apartment residents and hospitality venues tend to favour Tenderflame, because the flame is controlled through the steel wick and the fuel is not classified as hazardous under EU product rules.
What the WHO says about indoor air
The World Health Organization advises keeping the yearly average of PM2.5 indoors below 5 micrograms per cubic metre. A wood stove can pass that figure within minutes. Decorative fires running on ethanol or Tenderfuel stay well below it in normal use, provided the room is ventilated. The advice is not to avoid fire altogether, but to use it thoughtfully and ventilate. That way, atmosphere and clean indoor air are not in conflict.
Choose consciously and order at Tenderflame
Want a real flame with predictable combustion and no flue? Browse the Tenderflame collection and order the model that suits your room. If you are still weighing up the fuel, read what bio-ethanol releases first.
Frequently asked questions
Is a decorative fireplace bad for my indoor air?
Used correctly with ventilation, the effect is limited. Tenderfuel burns more cleanly than bio-ethanol and considerably more cleanly than wood.
Do I need a CO alarm with a decorative fire in an apartment?
With Tenderflame products this is not strictly required, but a CO alarm at home is always a sensible precaution, especially alongside a gas hob or boiler.
How much fine particulate matter does a Tenderflame release?
In normal use, the amount released is barely measurable and orders of magnitude lower than a wood stove, which produces 40 to 800 mg of particulate matter per hour.
Should I open windows while using it?
A window left slightly open during use, plus ten minutes of ventilation afterwards, is enough for an average living room. WHO guideline for PM2.5 yearly average: below 5 µg/m³.
Can I burn several decorative fires in the same room?
In large, well-ventilated rooms this is possible, but factor in the extra CO2 and heat this produces.
How quickly does CO2 build up in a closed room?
In a small, unventilated room, CO2 from an open flame can climb noticeably within one to two hours. Ventilate through a window left ajar or a mechanical extraction setting.
Enjoy the fire, keep the air cleaner.
Discover how Tenderfuel, through the steel wick, is easier on your indoor air, without giving up any of the atmosphere.
