How much carbon does your home actually produce?

Most household carbon footprint calculators ask you twelve questions, give you a single number in tonnes, and tell you to plant a tree. We think that's roughly useless. The useful questions are: where is my carbon actually coming from, and what would it take to cut it?

The three sources that matter

For a typical Irish household, almost all energy carbon comes from three places:

• Electricity — roughly 224 gCO₂/kWh on the 2026 Irish grid average. A home using 5,000 kWh/year generates about 1.1 tonnes.
• Heating — gas boilers emit ~205 gCO₂/kWh of gas burned; oil about 257; solid fuel much more. A BER D gas-heated home burns ~15,000 kWh of gas and produces about 3 tonnes/year.
• Transport — an EV at grid-average carbon produces ~250 kg/yr per 1,000 km driven; a petrol car is ~3–4× that.

A typical Irish 3-bed with gas heating and one petrol car is emitting around 6–8 tonnes of CO₂ a year just from energy. About half of that is heating.

The big levers

In order of how much they move the needle:

1. Switch heating to a heat pump. A COP 3.5 heat pump on Irish grid electricity produces ~64 gCO₂/kWh of heat, compared to 205 for gas. You cut heating emissions by about two-thirds overnight.
2. Electrify your car. ~70% reduction in transport emissions on the grid average, ~85% if you smart-charge on overnight wind.
3. Shift when you use electricity. Off-peak Irish grid carbon is routinely 80–120 gCO₂/kWh (wind-dominated nights) versus 380+ gCO₂/kWh at peak. Moving 30% of your usage to off-peak cuts electricity carbon by ~25% with no change in how much you use.
4. Add solar + battery. Most effective when combined with a heat pump and EV, because you can store and self-consume clean generation instead of pulling from grid peaks.

Why carbon is the supporting story

Here's the honest framing: most people don't change their heating system to save carbon. They change it to save money, and ETS2 will soon make that saving enormous. The carbon reduction comes for free. That's how real decarbonisation happens — when the cleanest option is also the cheapest.

The Energy Score breaks out your specific carbon footprint from electricity, heating and charging, shows it in relatable terms (flight equivalents, not kg), and maps it to the financial savings of each change.