Primary energy & CO2 calculator

Turn an annual final energy figure — the kWh/yr a tool like the Heating Load or Cooling Load calculator already gives you — into primary energy and CO2 emissions, for gas, oil, coal, biomass, district heating, or grid electricity by country.

Primary = Final × PEF Real per-country grid CO2 data Free, no sign-up

Energy data

Inputs only — every result is on the right.

Final energy kWh/yr — the delivered energy from a heating/cooling/other calculation

Energy carrier

Waiting for input

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Primary energy and CO2 emissions per year.

Primary energy factor (PEF): —
CO2 factor: —
Primary energy: —
CO2 emissions: —

Link copied — it reopens with these exact inputs.

How to use this calculator

Enter the final (delivered) energy — from the Heating Load, Cooling Load or another calculator.
Pick the energy carrier.
For electricity, pick the country to pull its real grid CO2 factor.
Read the primary energy and CO2 emissions.

What this calculates

Final energy is what a building or system actually uses at the point of consumption — the kWh of gas burned, or electricity drawn. Primary energy accounts for everything upstream of that: extraction, processing, generation and transmission losses before the energy ever reaches the building. CO2 emissions follow the same "per kWh of final energy" logic, using the carrier's own carbon intensity:

Primary energy [kWh/yr] = Final energy × PEF
CO2 emissions  [kg/yr]  = Final energy × CO2 factor [g/kWh] / 1000

PEF = primary energy factor, dimensionless

Why electricity is different

Direct fuels — gas, oil, coal — have reasonably universal published PEF and CO2 factors wherever you are, because burning a cubic metre of gas releases the same CO2 anywhere. Electricity does not work that way: its carbon intensity is entirely a function of how that country generates power. A grid running mostly on coal and one running mostly on nuclear or hydro can differ by more than 15× in CO2 per kWh for electricity that looks identical at the socket — which is exactly why there is no single EU-wide electricity CO2 factor. Selecting "Electricity (grid)" here pulls the CO2 factor from the same real, sourced country dataset (Ember Yearly Electricity Data via Our World in Data) that powers this site's own Electricity Carbon Footprint Calculator, rather than guessing at one.

Primary energy factor for electricity does not have an equivalent verified per-country table here, so it stays a single editable field defaulted to a commonly cited EU-typical value (2.3) — replace it with your national figure if you have one published for your country.

Direct-fuel PEF and CO2 factors (gas, oil, coal) and the generic district-heating figure are typical/representative published values, not a certified national factor — regulations like the EU's EPBD set a common framework but leave the exact methodology and factors to each member state, so there is no single number that is correct everywhere. Biomass (pellets, firewood) uses the common "low non-renewable PEF, net-zero biogenic CO2" convention, which some national schemes apply differently — check your governing methodology for a compliance calculation. Electricity's CO2 factor is real, sourced grid data (see the Electricity Carbon Footprint calculator for the full source note and transmission-loss detail this tool does not apply); its PEF is a single EU-typical default, not country-specific. Provided for engineering guidance — verify against your project's governing national methodology for a real design or compliance submission.