The carbon footprint of home heating — and why the heat pump wins
In a cold climate, heating your home with a gas boiler can emit 2 to 4+ tonnes of CO₂ a year — frequently the single largest line in a personal footprint, ahead of even the car. The good news: it’s also one of the most fixable.
Why heating is so big
Keeping a whole building warm through winter takes a lot of energy, and if that energy is burned fossil gas or oil, the CO₂ adds up fast. The exact number swings enormously with climate, home size, and insulation — a draughty old house can use several times the energy of a well-insulated one for the same comfort.
Roughly, per year:
- Gas boiler, average home: ~2–4 tonnes CO₂.
- Oil heating: higher still per unit of heat.
- Electric resistance heating: depends entirely on the grid — dirty grid, high; clean grid, low.
- Heat pump: the game-changer (below).
The heat pump math
A heat pump doesn’t make heat by burning fuel — it moves heat, delivering roughly 3–4 units of heat per unit of electricity. That efficiency means that even on a moderately clean grid it cuts heating emissions sharply versus a gas boiler, and on a clean grid it gets close to zero. It’s the rare upgrade that’s both lower-carbon and, increasingly, cheaper to run.
What moves the number, in order
- Insulate and seal. The cheapest kilowatt-hour is the one you never need. Loft and wall insulation, draught-proofing.
- Turn it down a degree. Each degree lower is a few percent saved, every hour of winter.
- Switch gas → heat pump, ideally on a clean grid — the big structural cut.
- Heat the rooms you use, not the whole house all day.
The honest framing
If you live somewhere cold and your footprint is stubbornly high, heating is probably the reason — more than flights for many people, because it runs all winter, every winter. Insulation plus a heat pump is the heavy-hitting combination. CO2Mate logs home energy against real factors so the size of this lever is visible rather than assumed.
Sources: IEA on heat pumps and building energy; DEFRA emission factors for natural gas and heating oil; national building-energy statistics.