It is important to choose a product whose heating power suits the space you want to heat. You will actually probably choose the fire that works with a hot flame, in other words, so that it is as economical and environmentally friendly as possible.
The power of a fire is expressed in kW; this indicates the amount of useful heat produced by the fire at any time, which really heats your home.
The power needed to heat a room must suit the space you want to heat. It varies according to the outdoor temperature, the size of the room, its exposure, the geographical location, the building’s insulation, its inertia etc.
You will also need to take into account the overall heating system and how the building is occupied: in a house fitted with central heating, you would install a less powerful fire that will operate regularly at its optimum setting, and which will be enough for times between seasons, backed up by central heating only in cold weather. However, you will need a more powerful fire in a second home, which needs to be heated up quickly at the beginning of the weekend.
If the fire is too small, it won’t heat (let alone heat up) the room in cold weather. If the fire is too powerful, it will often work slowly, so in not very favourable conditions. Sometimes – even when working slowly – it will overheat the room. In any case, choosing a 20kW fire when a 10kW one would suffice would be a very bad calculation (and investment)!
To choose the right Stûv solution for you, talk to your fitter; they will come to assess your home – guaranteeing the safety of people and the building – and you can explain how you would like to use your fire. They will then be able to recommend the right product for you.
The efficiency of the fire indicates the percentage of heat produced by burning the wood, which actually heats your home: a fire with 80% efficiency gives you 80% of the energy from the wood to heat your home. You should be aware that an open fire (or hearth) is rarely more than 10% efficient, which means that 90% of the energy consumed escapes into the atmosphere!
Efficiency is reduced when the fire is functioning slowly, and combustion is less complete. This is why the public authorities (who have promised to combat climate change) encourage the replacement of older, less efficient stoves with more efficient stoves, fires or inserts.
Smoke takes away heat and different gases, including CO2, CO and fine particles that can damage our airways. With efficient fires that are used correctly, this pollution is minimal; it increases when combustion is less complete.
To sum up: a fire that is well suited to the room it needs to heat usually operates at its optimum rate, with good combustion and efficient results; consumption of wood is minimal, and waste that escapes into the atmosphere is significantly reduced.
Stûv products are officially tested according to European standards: EN 13229 (for wood-burning inserts), EN 13240 (for wood-burning stoves), EN 14785 (for pellet-burning appliances).
As well as monitoring safety, the laboratories also measure power and efficiency and analyse the smoke, which gives consumers and professionals the information they need to compare products with each other. To see the results for Stûv products, click here.