May 8, 2025

The Cost of Comfort: Calculating Garden Heater Running Costs

Cosy evenings on the patio are priceless… until the bill lands with a thud. If you're wondering exactly how much it costs to run a garden heater per hour (spoiler: between 60p and £2.80), you're in the right spot. Let’s crunch the numbers, compare heater types, and uncover tips to stay toasty for less with our Outdoor heating and firepits collection.

Understanding the Expenses of Outdoor Heating

There’s nothing quite like settling into a snug outdoor nook, drink in hand, under a gentle glow of warmth.

But what you might not realise is that your choice of heater could mean the difference between a modest extra on your energy bill... or a shock that’ll have you reaching for extra layers instead.

Before you light up the patio, let’s unpack what affects the running costs.

Factors Influencing Running Costs

Type of Heater (Electric, Gas)

When it comes to outdoor heating, it’s a battle of the fuels.

Electric heaters, especially infrared models, are brilliant for small spaces and give almost instant warmth with minimal faff. You plug them in, feel the heat, and you’re good to go.

Gas patio heaters, however, are the heavy lifters — warming larger areas fast but at a price. Think of them as the big bonfire to the electric heater’s candle.

Heat Output (kW or BTU/h)

The bigger the output, the bigger the bill — it’s as simple as that.

Electric heaters list their muscle in kilowatts (kW), while gas heaters flex with BTU/h (British Thermal Units per hour). High-output heaters are perfect for big gatherings, but if you’re just having a quiet cuppa under the stars, a smaller unit will do nicely.

It’s about picking the right tool for the job, not throwing a house party with a blowtorch.

Local Energy Prices (Electricity and Gas)

Energy costs swing up and down more often than a fairground ride.

As of 2025, the UK averages around 30p per kWh for electricity and £9 for a 13kg propane bottle. But it’s worth peeking at your own bill — especially if you're in a rural area where prices might shimmy up a bit.

Knowing your local rates gives you a real edge when it comes to budgeting those cosy nights.

Calculating Electric Heater Running Costs

Time to crunch some numbers — but fear not! It’s easier than assembling that mystery-piece BBQ you bought last summer.

Heater Wattage / 1000 = Kilowatts (kW)

First, find your heater’s wattage. Let’s say you’ve got a 2000W model.

Divide that by 1000, and you’ll get the kilowatts (kW).

2000 ÷ 1000 = 2kW.

Simple, right? You’re halfway there.

kW x Cost per kWh = Hourly Running Cost

Now, multiply your kW by your electricity cost.

Using the average 30p per kWh:

2kW × £0.30 = 60p per hour.

So for every hour you’re basking outside, it’ll cost you roughly the same as a decent packet of crisps.

Calculating Gas Heater Running Costs

Gas heaters need a touch more maths magic, but it’s nothing you can’t handle.

BTU/h Output / Efficiency Factor = Gas Consumption Rate

Grab your heater’s BTU rating (say, 40,000 BTU/h).

Divide that by 21,500 BTU/kg — the energy content of propane gas.

40,000 ÷ 21,500 = about 1.86kg of gas burned per hour.

Allow a little wiggle room for efficiency (most heaters aren’t 100% perfect, sadly).

Gas Consumption Rate x Cost per Unit of Gas = Hourly Running Cost

Next, work out how much that 1.86kg of gas will set you back.

If propane’s roughly £0.69 per kg:

1.86 × £0.69 = £1.28 per hour.

Big gas patio heaters (12kW and above) often land you closer to £2.20–£2.80 per hour, especially if you crank them up on a chilly evening.

Example Calculations and Comparisons

Still with me? Good — let’s paint a few real-world scenes.

Scenario	Heater Type	Output	Approx Cost (2 hrs)
Balcony bubbles & nibbles	2kW electric infrared	2kW	£1.20 – £1.60
Family BBQ on the patio	12kW gas patio heater	40,000 BTU	£4.40 – £5.60
Drinks night around the table	3kW tabletop gas heater	10,200 BTU	£1.80 – £3.00

Real-life tip: A Bristol couple saved £££ by popping up some clear café-style windbreaks around their patio. Less heat escaped, meaning they halved their heater usage — and still stayed snug under the stars.

Smart move, right?

Final Thoughts

Keeping cosy outdoors doesn’t have to mean burning through your budget.

Electric heaters are brilliant for smaller, more intimate spaces, while gas heaters are your go-to for big bash nights. Either way, with a little planning — and maybe a few fluffy throws — you can enjoy a warm, wallet-friendly evening under the open sky.

Want to keep your garden glowing without the price shock? Take a peek at our Outdoor heating and firepits collection — packed with smart, stylish options for every kind of outdoor gathering.

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