A gas patio heater is one of the most expensive things you can run in the garden, costing roughly £2 to £2.50 an hour at an example bottled-gas price, while an electric one is far cheaper to run per hour but warms a much smaller patch. Neither is cheap, because you are trying to heat open air that never stops carrying the warmth away. That does not mean you should never light one, but it does mean a long evening under a big gas mushroom heater can quietly cost more than heating the whole house would over the same hours. Here is what each type actually costs, why, and how to stay warm outside for a fraction of it.
The short answer. A typical freestanding gas patio heater burns propane at around 11 to 13 kW and gets through roughly 0.9 kg of gas an hour, which at an example bottle price works out at about £2 to £2.50 an hour. An electric halogen or infrared heater rated at 2kW costs about 52p an hour at 26p per kWh, and a smaller tabletop model around 30p. Gas heats a wider circle; electric heats whoever is sitting in front of it. Over a four-hour evening the gas heater can cost close to £10, the electric one around £2.
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Two very different machines
Patio heaters split into two camps that cost quite different amounts to run. Gas models, the tall mushroom-topped ones and the smaller tabletop versions, burn bottled propane, usually from a 13kg patio gas cylinder tucked in the base. They throw out a lot of heat over a wide area, which is why pubs and restaurants use them, but that heat costs real money because propane is not cheap and the burner is powerful. Electric models use a glowing halogen or quartz infrared element that warms objects and people directly rather than heating the air, so the warmth is felt only where the beam points. They are cheaper to run per hour and can be plugged straight into a socket, but they cover a much smaller zone. Knowing which type you have, and how it charges you, is the first step to working out the cost.
What a gas patio heater costs to run
Gas patio heaters are rated by their heat output, usually somewhere between 11 and 13 kW for a full-size freestanding unit. To turn that into money you need the price of the propane, not the mains gas rate, because these run on bottled gas which costs considerably more per unit than piped gas. Propane holds roughly 14 kWh of energy per kilogram, and a 13kg cylinder therefore carries around 180 kWh. A heater running near full output gets through about 0.9 kg an hour, so a single bottle lasts on the order of 14 to 15 hours of use.
Put an example price on the bottle and the per-hour cost falls out. At an illustrative refill price of £35 for a 13kg cylinder, and roughly 14 hours of burn time, that is about £2.50 an hour. Turn the heater down from full and it lasts longer and costs less, but even at a gentle setting you are rarely below £1.50 an hour. The exact figure moves with the price you pay for gas bottles, which varies a good deal, so treat these as a guide and check what a refill costs you locally. What does not change is the order of magnitude: a gas patio heater is a pounds-per-hour appliance, not a pennies-per-hour one.
What an electric patio heater costs to run
Electric patio heaters are far easier to cost, because they run on mains electricity at a rate you already know. The sum is the one that prices any appliance: power in kilowatts, times hours, times your unit rate, explained in full in what is a kWh. A common freestanding electric infrared heater draws 2kW, so at the standard rate of about 26p per kWh it costs 2 times 0.26, or roughly 52p an hour. A smaller wall-mounted or tabletop unit at 1.2kW costs about 31p an hour, and a big commercial-style 3kW patio heater around 78p.
That is a quarter to a fifth of the gas figure per hour, which sounds like a clear win, and on cost per hour it is. The catch is coverage. Infrared warms what it shines on, so it is excellent for the two or three people sitting directly in front of it and does almost nothing for someone round the side. A gas heater's rising column of warm air spreads further. So the honest comparison is not just pounds per hour but pounds per warm person, and for a small group huddled at a table the electric heater usually wins on both.
| Heater | Rating | Cost per hour | 4-hour evening |
|---|---|---|---|
| Gas freestanding (propane) | ~13 kW, ~0.9 kg/hour | ~£2.00 to £2.50 | ~£8 to £10 |
| Gas tabletop (propane) | ~4 kW | ~£0.70 to £0.90 | ~£3 to £3.60 |
| Electric infrared, large | 2 kW | ~52p | ~£2.08 |
| Electric tabletop | 1.2 kW | ~31p | ~£1.24 |
Electric figures at 26p per kWh, the standard rate under the Ofgem cap for July to September 2026. Gas figures at an example refill price of about £35 for a 13kg propane cylinder; your bottle price may differ. To price your own model, put its wattage into the appliance running cost calculator.
Why heating the garden costs so much
The reason patio heaters are dear is not the appliance, it is the job. Indoors, a heater warms air that is trapped by walls and a roof, so the warmth builds up and stays. Outdoors there is nothing to hold it. The air you heat drifts up and away at once, and a breeze carries it off faster still, so a patio heater is forever warming fresh cold air that immediately leaves. You are, in effect, trying to heat the sky. That is why even a modest-looking flame or element burns through so much energy for so little lasting warmth, and why the running cost per hour is closer to a tumble dryer than to a lamp. It is also why infrared, which heats you rather than the air, is the more sensible outdoor approach: it does not waste energy on air that is about to blow away.
Cheaper ways to stay warm outside
Before you commit to pounds an hour, several near-free options do most of the job. Warm clothing is the obvious one and the most effective by far: a proper coat, hat and blanket keep a person warm for nothing, whereas a patio heater spends real money fighting the same chill from the outside in. A firepit or chiminea burning logs gives focused radiant heat and a bit of theatre, and if you already have a log supply it can be cheaper than propane, though it needs tending and is not allowed everywhere. Heated blankets and battery-powered heated gilets warm the person directly for pennies. And positioning matters: a spot sheltered from the wind, against a wall that has held the day's warmth, is far more comfortable than an exposed one, whatever heater you use. The same directional, heat-the-person logic that makes indoor portable heaters cheapest when aimed at one person applies outside too.
If you want a patio heater, running it cheaply
Say you have decided the warmth is worth it. A few habits keep the cost sane. Pick electric infrared over gas if your seating is fixed and small, since it is a quarter of the per-hour cost and plugs into a socket. Aim the heat at the people, not the empty middle of the patio, and sit close to it. Use it in short bursts to take the edge off rather than running it all evening as background warmth. Shelter the area from wind, which otherwise strips the heat away and makes you turn the heater up. And on a gas model, run it lower than full, since the top setting rarely feels twice as warm as a middling one but burns through the bottle far faster. Treated as an occasional top-up rather than an all-night fixture, a patio heater need not be an expensive habit. For a sense of where it sits against everything else you plug in, the appliance running cost calculator lets you compare it directly.
The bottom line
A gas patio heater is a genuine luxury on the running cost, at roughly £2 to £2.50 an hour, because bottled propane is dear and open air refuses to stay warm. An electric infrared heater costs far less per hour, around 30p to 50p, but only warms the patch it points at, which for a small group at a table is usually all you need. Warm clothes, a sheltered spot and short bursts do more per pound than either. If the garden matters to you, run electric where you can, aim it at people, and use it to take the chill off rather than to heat the whole outdoors, which no heater can afford to do for long.
Common questions
How much does a gas patio heater cost to run per hour?
Roughly £2 to £2.50 an hour at full output for a typical freestanding propane heater, which burns about 0.9 kg of gas an hour. That is based on an example refill price of around £35 for a 13kg cylinder lasting about 14 hours. Your figure depends on what you pay for gas bottles and how high you run it.
Is an electric or gas patio heater cheaper to run?
Electric is much cheaper per hour. A 2kW electric infrared heater costs about 52p an hour at 26p per kWh, against £2 or more for a full-size gas heater. The trade-off is coverage: electric infrared warms only who it points at, while gas spreads heat over a wider area.
Why are patio heaters so expensive to run?
Because you are heating open air that never stays put. Outdoors there is no roof or walls to trap the warmth, so the air you heat drifts away at once and a breeze carries it off faster. The heater keeps warming fresh cold air, which takes a lot of energy for little lasting warmth.
What is the cheapest way to stay warm outside?
Warm clothing, a blanket and a wind-sheltered spot cost almost nothing and do most of the work. A firepit can be cheap if you already have logs. If you use a heater, electric infrared aimed at the people, in short bursts, costs the least.