Woodburner Size Calculator
Enter the room's length, width and height and how well it is insulated. The calculator gives the wood burning stove output in kW, the stove size to buy and whether you need an air vent.
- Stove output
- Room volume
- Air vent
Measure the room the stove sits in. Open plan spaces count as one room.
Divide the room volume in cubic metres by 14 for the stove size. A room 5 m by 4 m with a 2.4 m ceiling is 48 m³, so it needs about a 3.4 kW stove. A draughty room needs nearer 5 kW, a modern insulated room about 2.4 kW.
Woodburner size chart
Average insulation. Search for a room.
| Room (m) | Volume (m³) | Average (kW) | Draughty (kW) | Insulated (kW) |
|---|---|---|---|---|
| 3 × 3 × 2.4 | 21.6 | 1.5 | 2.2 | 1.1 |
| 4 × 3 × 2.4 | 28.8 | 2.1 | 2.9 | 1.4 |
| 4 × 4 × 2.4 | 38.4 | 2.7 | 3.8 | 1.9 |
| 5 × 4 × 2.4 | 48 | 3.4 | 4.8 | 2.4 |
| 5 × 5 × 2.4 | 60 | 4.3 | 6 | 3 |
| 6 × 4 × 2.4 | 57.6 | 4.1 | 5.8 | 2.9 |
| 6 × 5 × 2.4 | 72 | 5.1 | 7.2 | 3.6 |
| 7 × 5 × 2.4 | 84 | 6 | 8.4 | 4.2 |
| 8 × 6 × 2.4 | 115.2 | 8.2 | 11.5 | 5.8 |
kW.
Room size and stove
Average insulation. Slide the room volume.
The stove grows with the room.
How to size a woodburner
Room to kW. Step through it.
Measure
Length, width, height.
Ask your installer for a heat loss survey if the room is unusual.
Small, medium or large stove
Stove outputs. Compare them.
Most rooms.
Large rooms.
Open plan.
Running a big stove slowly makes tar. Size it to the room.
Before you buy
Stove checks. Tick each item.
Tick each item as you go.
Burn only dry wood with under 20% moisture.
What you get
Stove sizing. Each tile explains one result.
kW.
m³.
If needed.
Per hour.
A day.
Ecodesign stoves burn cleaner and need less wood for the same heat.
Frequently Asked Questions
No question matches that search.
What size woodburner do I need?
Divide the room volume in cubic metres by fourteen for the output in kilowatts.
What size stove for a room of about fifty cubic metres?
About a three and a half kilowatt stove in an average room.
Do I need an air vent for a woodburner?
In the UK, stoves over five kilowatts usually need a permanent vent.
Is a bigger stove better?
No. An oversized stove is run slowly, which tars the flue and wastes wood.
How much wood does a stove burn?
About a third of a kilogram an hour for each kilowatt.
Does insulation change the stove size?
Yes. A well insulated room needs about a third less.
Can one stove heat a whole house?
Only an open plan home, or with a boiler stove and radiators.
Warm without wasting wood
Choose a stove that matches your room and it burns clean, hot and efficiently all winter.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.