Simply input your room's measurements and insulation type below and our stove size calculator will tell you what size log burner you need for your home. Our stove calculator even provides links to stoves that are genuinely suited to your space. Try it out below, and follow our concise guide to heat output (kW), size and installation for further information.

KiloWatt Calculator
Calculate the kiloWatt power needed to heat your room
Please enter the room height in Metres
Please enter the room width in Metres
Please enter the room length in Metres
Choose the room's insulation level: Poor, Average or Good


Stove Calculator Explained

Though only a rough estimate, the formula of our stove kilowatt calculator works as follows: we multiply the width, length and height of your space, and divide by a number between 15-25 depending on the insulation of your home:

  • Poorly insulated: mainly refers to homes built before 1950, or a space with multiple draughts present and very little insulation
  • Moderately insulated: usually a home build in the 1990s and fitted with double glazing
  • Well insulated: signifies new, airtight homes built after 2008, after which compulsory heating standards were introduced

What size log burning stove do I need?

If you have a big room, the temptation is to purchase a large, magisterial stove - likewise with cosier living spaces, a more compact stove might appear the best choice. However, this isn't the best approach. If too small you'll have to constantly be topping up the fuel load on those chillier days, which risks overheating and can eventually damage the stove. Similarly, bigger stoves need to follow their manufacturing guidelines: starving them of their expected fuel load or firebox temperature will distort the overall efficiency.

Heat Output (kW) & Efficiency of Stoves

All the stoves sold by Direct Stoves are measured in kilowatts (kW). The higher the kilowatt output, the greater the heat generated. You should also note the terms 'nominal heat output' and 'maximum heat output' - nominal marks the point where fuel supply is efficiently producing a healthy output, and maximum being the highest kW limit a stove should reach.

Another thing to notice is our efficiency ratings, always measured in % terms. This figure compares the amount of heat that's radiating across your room with the amount that inevitably escapes through a chimney or flue e.g. a 75% efficiency simply means 25% of the overall output is lost elsewhere.

Other Factors

As well as using our stove size calculator, there are a host of other factors that will feed into the decision process, such as how well insulated your rooms are, how old your house is, and the spatial layout of your downstairs. For example, if you have an open plan design with an archway connecting two rooms, this should be treated as one room. Or if there's an open staircase, meaning heat will inevitably travel upstairs, this will impact on your kW requirements. Even window size and aspect of your house can affect your choice - so overall, ensure you clearly define the confines of your space beforehand.

Stove Installation

Wood burning stoves warm the room by convection, heating the air around it which rises and fills the room with heat. To work effectively your stove must have a reasonable amount of space around it. If your stove is fitted into an opening just a few millimetres larger than itself its efficiency and the amount of heat put out will be greatly reduced.

You should also take care that there are no combustible materials near your stove, curtains, wallpaper, soft furnishings etc..

We would recommend the following minimum clearances as a guide for safety and best performance:

  • Distance at the back of the stove 50mm – 75mm (as a minimum)
  • Distance at the sides of the stove 100mm – 125mm (as a minimum)
  • Top of the stove 100mm – 150mm (as a minimum)

Of course every situation is unique so please feel free to check any stove related issues with our helpful and friendly staff.

For more information on how to choose the right stove for your home, take a look at our resources section.