What Size Stove Do I Need?

Our kW calculator gives you an instant recommendation based on your room dimensions and insulation. Enter your measurements below and find out in seconds.

Free Tool

The Geekculator

Work out the right stove output for your room in seconds

1Room dimensions

2Good insulation?

Double glazing, loft & cavity wall insulation

3Existing open fireplace?

An open fire loses heat up the flue when not in use

Enter your room dimensions above to see your recommendation.

Understanding insulation

Insulation Categories

Your home's insulation level affects how much heat the stove needs to produce. Here is how to assess yours.

Poor Insulation

+ 1.0 kW

Homes built before 1980, single glazing, solid walls, minimal loft insulation, or multiple draughts.

Average Insulation

Standard

A home built in the 1990s with double glazing and basic cavity wall insulation.

Good Insulation

Standard

Modern, airtight homes built after 2008 with full insulation and sealed windows.

At a glance

Quick Reference Guide

Output Typical Room
3 - 4 kW Small bedroom, snug, or study
5 kW Standard living room (~25 m3)
6 - 7 kW Larger sitting room or open-plan
8 - 10 kW Large open-plan space
10 kW+ Consider a boiler stove

Got your number?

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