24Earth home energy tool
Home Energy Emissions Calculator
Turn utility use into a focused operational emissions estimate, then test three practical home-energy scenarios.
Calculator ready with editable example results.
Enter utility usemonthly quantities from bills
Apply emission factorsgrid plus direct combustion
Compare scenariosindependent, not cumulative
Your home
Monthly energy use
Replace the starting values with an average month from your utility or fuel bills. Enter zero where a fuel does not apply.
Private by design. Values are calculated in this browser and are not saved.
Scenario lab
Change one system at a time.
Each card starts from the current household estimate. Scenarios are independent and are not stacked together.
Efficiency scenario
Use less electricity
Reduce existing grid electricity while keeping all fuels unchanged.
3,360 kWh grid electricity remains each year.
Solar scenario
Supply electricity onsite
Replace a share of annual grid imports with onsite solar on an annual energy-balance basis.
2,100 kWh/year supplied onsite; exports are not credited.
Electrification scenario
Replace fossil heat
Replace the selected heating-related share of fuel use and add the electricity required by a heat pump.
Only include the share used for space or water heating. Leave cooking and other fuel uses unreplaced.
Adds 1,778 kWh/year · break-even grid below 684 g/kWh.
Scenario, not forecast: solar coverage is entered rather than predicted; heat-pump performance varies with climate, sizing, controls, defrost, backup heat, and installation.
Method & boundaries
Simple arithmetic, visible assumptions.
The quality of the estimate depends on the billing data and grid factor you enter.
Current footprint
Monthly electricity is annualized and multiplied by your location-based grid factor. Fuel quantities use UK DESNZ direct-combustion COâ‚‚e defaults.
Solar boundary
The selected annual share displaces grid imports at zero onsite operating emissions. The model does not predict yield, hourly matching, exports, batteries, or lifecycle impacts.
Heat-pump balance
Fuel energy × old-system efficiency × replacement share ÷ seasonal COP gives added electricity. Displaced fuel emissions are removed at the same share.
What is excluded
Upstream fuel supply, transmission losses, equipment manufacture, refrigerant leakage, construction, cost, and future grid changes are outside the estimate.
View UK default fuel factors and heat-content assumptions
| Fuel | Direct factor | Gross energy | Used for |
|---|---|---|---|
| Natural gas | 2.02633 kg CO₂e/m³ | 11.1147 kWh/m³ | Baseline + heat-pump scenario |
| LPG | 2.93936 kg COâ‚‚e/kg | 13.7033 kWh/kg | Baseline + heat-pump scenario |
| Heating oil | 2.54016 kg COâ‚‚e/L | 10.2936 kWh/L | Baseline + heat-pump scenario |
These are UK 2026 defaults; fuel composition and official factors can differ by location. Gross energy values are derived from matching per-unit and gross-calorific-value factors so scenario energy and emissions stay internally consistent.
Factor set 2026.1. Direct fuel defaults come from UK DESNZ 2026 and describe UK activities; local factors may differ. The 400 g COâ‚‚e/kWh grid value and all starting consumption values are illustrative, not country averages. Replace the grid value with a factor whose geography, year, and accounting boundary match your electricity supply. This educational estimate is not a formal greenhouse-gas inventory or engineering assessment.
