Gas vs electric heating: which actually costs less?

Why can’t I compare gas and electricity on cents per kWh?

Because the raw gap is enormous and almost meaningless. On the cards we verified this week, gas costs 9.14c–12.70c/kWh (Flogas’s discounted and standard rates — see the cheapest gas ranking) while electricity runs from 16.83c on a discounted NightSaver night rate up to 42.65c on Energia’s standard 24-hour rate. Read those numbers naively and gas wins by three or four to one, end of discussion.

But a kWh on your bill is a kWh of fuel, not a kWh of warmth — and the machine between the meter and the radiator changes the exchange rate. A modern condensing gas boiler turns roughly 90% of each unit into heat in your rooms; the rest leaves through the flue. A plug-in electric heater or an immersion converts essentially 1:1. And a heat pump breaks the intuition entirely: it moves heat from the outside air rather than generating it, so one kWh of electricity typically delivers three to four kWh of heat. That multiplier — the COP — is why a fuel costing three times as much per unit can still heat your house for less.

So the only honest comparison is on the effective cost per kWh of useful heat: the unit rate divided by what the system delivers per unit bought. That is the number this page computes, and it is worth understanding before any ranking — if the unit itself is fuzzy, our kWh explainer pins it down.

What does each heating system actually deliver per unit?

Four systems cover almost every Irish home. Here is the conversion factor each one applies to the electricity or gas you buy — and why it is “typical”, not fixed.

Notice that only one of those numbers is a property of physics alone. The boiler’s 90% and the heat pump’s 3–4 are typical figures for well-installed, well-maintained kit in a suitable house — your own may be better or worse, and for the heat pump the house itself is half the machine.

What is the formula for the real cost of heat?

Two things about that formula before we price it. First, the carbon tax belongs inside the gas bracket: it lands on every kWh of gas at 1.25c inc VAT (the Revenue rate in force this August — the carbon tax guide has the schedule) but never on electricity. Second, the standing charges sit outside the per-unit maths — they arrive whether you burn one unit or ten thousand, which matters enormously if you end up paying two of them. More on that below.

What do current rates say per kWh of heat?

Here is the formula applied to rates we verified on supplier sites on 28 August 2026 — Flogas and Yuno for gas, Energia and Electric Ireland for electricity, all VAT inclusive. The division is ours, and we show the working so you can re-run it with your own tariff.

The same numbers as a picture — shorter is cheaper:

Read the table honestly and three bands appear. At the cheap end, a COP-3 heat pump on a discounted rate (~10c) and discounted gas (~11.5c) are effectively level — the fuels swap places on pennies, and year-1 discounts on either side decide it. In the middle, standard-rate gas, a standard-rate heat pump and night-charged storage cluster around 14–17c. And far out on its own, direct electric heating at day rates costs two to four times everything else — that is the one unambiguous loser in the whole comparison. One caveat on the storage and night-rate rows: a heat pump mostly runs in daytime hours when the house needs heat, so the 16.83c night rate belongs to storage heaters and timed immersions, not to heat-pump arithmetic — the NightSaver ranking and time-of-use guide cover who genuinely gets those windows.

Also remember every discounted rate above is a year-1 price with a standard rate waiting at month 13 — the table shows both Flogas rates for exactly that reason, and year 1 vs year 2 shows the cliff in full.

Is a heat pump always cheaper than gas?

No — and the table above already shows the failure mode. The heat pump’s advantage lives entirely in that ÷3 or ÷4, and the divisor is earned, not guaranteed. It is a seasonal average for a system running low-temperature water in a house that holds its heat. Push the same machine into a draughty, poorly insulated house with the original small radiators, and it must run hotter water for longer; the seasonal COP slides towards 2 to 2.5, and at Energia’s 42.65c standard rate that is 17–21c per kWh of heat by our division — dearer than gas at any rate we verified.

Stack the unfavourable case honestly: a leaky house (COP nearer 2.5), a standard electricity rate because nobody re-shopped after year 1, and a bigger heat demand because the insulation was never done. Each factor multiplies the others. That is how a technology that is genuinely cheaper to run in a B-rated house on a fresh discount becomes genuinely dearer in a D-rated house on a drifted tariff — same pump, same brand, opposite verdict.

The corollary is that for heat-pump owners, the tariff is part of the heating system. The pump turns your electricity plan into your heating bill, so an owner drifting on a standard rate is overpaying for every single radiator-hour — re-shopping annually matters more for them than for anyone else on this page, and a smart time-of-use plan that is cheap outside the 17:00–19:00 peak can suit a pump that runs steadily all day. This is also why we will not print “a heat pump saves €___ a year”: without your COP, your heat demand and your tariff, that number would be an invention.

Is electric heating always dearer than gas?

Also no — the opposite slogan fails just as quickly, though it takes more care to kill because for one kind of electric heating it is true. Direct electric at a day rate genuinely is the dearest heat in Ireland: 29.9–42.65c per kWh against gas at 11.5–15.5c, by our sums above. If that is what “electric heating” means in your house, gas wins and it is not close.

But “electric” covers three systems, and the other two close or reverse the gap. A COP-3 heat pump on Energia’s discounted 24-hour rate delivers heat at about 10.0c/kWh — cheaper than every gas rate we verified once carbon tax and boiler losses are counted. On a well-installed system hitting COP 4, our division puts it near 7.5c, and even at the full standard rate a COP-3 pump (~14.2c) undercuts standard-rate gas (~15.5c). Meanwhile storage heaters charging at 16.83c overnight sit close enough to standard-rate gas that control and comfort, not cost, should decide — the NightSaver vs smart page untangles which meter shape those homes should hold onto.

So the honest version of the slogan is narrow: resistance heating at day rates is always dearer than gas. Electricity through a multiplier, or bought in the right window — including an EV tariff’s small-hours rate for a timed immersion, see the EV tariff ranking — is a different fuel economically, and treating all three as one “electric heating” is how households talk themselves out of their cheapest option.

What happens to the standing charges if I keep both fuels?

Everything so far was per-unit maths. The standing charges are the fixed toll on top — and they are the hidden line in every “should I go all-electric?” decision, because the question is really how many networks do you want to pay to be connected to. Keep gas and electricity and you pay both tolls every year regardless of usage; our standing charges guide has the full supplier spread.

The case that catches people is keeping gas for the hob after a heat pump takes over the heating. The boiler is gone, the gas usage collapses to a few hundred kWh of cooking a year — but the standing charge does not collapse with it. On plans we verified this week it runs €141.60 (Energia) to €170.84 (Flogas) a year, with Yuno at €150.03 between them. The arithmetic every such household should run:

Going the other way — an all-gas-heating home wondering about dual fuel — the standing charges argue nothing by themselves: you need the electricity connection anyway, so only the gas toll is optional. What dual-fuel bundles do to the two bills is a separate question, covered in the dual fuel guide, and how the gas toll itself is billed is on the gas bill explainer.

How do carbon tax and the PSO levy tilt the maths?

Each fuel carries one levy the other does not, and they point in opposite directions. Gas carries the carbon tax — 1.25c per kWh inc VAT at the Revenue rate in force this August, already included in our gas working above. It is not decorative: on 11,000 kWh of CRU typical gas usage it is a three-figure annual item, and the trajectory is one-way — the next step, to €71 per tonne, was postponed to 14 October 2026 rather than cancelled. Every future increase lands on the gas side of this comparison and nowhere else.

Electricity carries the PSO levy instead — but as a flat monthly amount, not a per-kWh charge, and from 1 October 2026 it falls to €0.56 a month inc VAT (about €6.67 a year). At that level it barely registers against a heating bill. The structural point matters more than this year’s figures: the carbon levy on gas scales with every unit you burn and is legislated to rise, while electricity’s levy is small, flat, and falling this year. Heating is a ten-to-fifteen-year decision, and on current policy the gas side of the table above drifts upward over that horizon. The details of both levies live in the carbon tax and PSO levy guides.

Where to next?

• Cheapest gas in Ireland — the gas side of the formula, ranked on year-1 and year-2 cost.
• Best night-rate electricity — the tariffs that make storage heating and timed immersions defensible.
• Time-of-use tariffs explained — the tariff shape that suits an all-day heat pump.
• Carbon tax on gas and standing charges — the two levies and tolls in this page’s maths.
• Best energy in Ireland — when the answer turns out to be “fix the tariff first”.

About the author

Conor Ryan

Energy Switching Analyst

Conor Ryan has tracked Irish gas and electricity prices, tariffs and switching since 2019. He builds matched.ie’s energy comparison tools and tests how smart meters and time-of-use plans affect household bills.

7+ years analysing Irish energy marketsCertified in Energy Efficiency (SEAI) and Electricity SupplyFocus on SSE Airtricity, Electric Ireland, Energia and Bord GáisBased in Limerick, covers domestic and small-business tariffs