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Ever consider just what an hour of heating your home costs? It’s a matter that’s becoming all too relevant with escalating energy prices. Your central heating warms up your home but burns gas or electricity every single minute it’s on. How much that cost depends on your boiler’s capacity, how efficient it is, and for how many hours you use it each day.
You can use hour-by-hour costing knowledge to make better use of your energy—and save money without giving up comfort. Whether heating a small flat or a big home, it is well worth knowing what you spend on heat by the hour.
Let’s break it down in a super simple way.
What Fuels Your Heating System?
Central heating is the system that warms your entire home. It tends to push hot water through pipes to radiators in each room. Some systems also heat your water for taps.
And what drives it? It all rests upon the fuel that you employ.
In the UK, central heating generally uses gas. It’s less expensive than using electricity, and it heats up quickly. If you have a gas boiler, it burns gas to warm up your system’s water.
Some people use electricity, particularly in flats or houses with no gas supply. Others may use oil, LPG, or biomass, but these are not so prevalent.
Air Source Heat Pump Grants
What is a kWh & Why Does It Matter?
When we talk about energy use at home, we refer to kWh – short for kilowatt hour.
A kilowatt hour is a measurement that tells us about just how much energy an appliance will draw if it runs for an hour. It is not necessarily measured by the hours that you use something, but by how powerful it is and how long it runs.
Let us break it down with an example.
- If you use a 1 kW heater for 1 hour, that makes 1 kWh.
- If you use a 2 kW heater for 2 hours, that is 4 kWh.
- And if your 24 kW gas boiler runs for 1 hour, that is 24 kWh.
So if you are looking at energy costs in pence per kWh, that means charging you based on an appliance’s use of energy. The higher kilowatts, or longer that you keep them on, the greater energy being consumed — and the higher that will cost.
Price of Electricity and Gas in 2025 in the UK
There is a standard energy price cap that gets revised every few months. This is a cap on what energy suppliers are allowed to charge you for each unit of energy if you are on a standard tariff.
Between 1 April 2025 and 30 June 2025, these are the Direct Debit prices:
- Electricity: 27.03p per kWh
- Gas: 6.99p per kWh
Prices are inclusive of VAT and are applicable in England, Scotland, and Wales.
Now let’s discuss how this will impact your heat costs.
If you own a 24 kW gas boiler, which is usual in a typical UK house, and use it for 1 hour, here’s the calculation:
- 24 kW × 1 hour = 24 kWh
- 24 kWh × 6.99p = £1.68 for one hour of heating
If you use that boiler for 4 hours a day, you’ll spend:
- 24 kW × 4 = 96 kWh
- 96 × 6.99p = £6.71 per day for gas heating alone
Then include your standard daily rate (that you pay irrespective of use):
- Gas: 32.67p
- Electricity: 53.80p
- Combined: 86.47p per day
So you’re paying nearly £0.87 a day just for being on the grid, without switching anything on.
Overall, if you use your boiler for 4 hours a day and have standing charges, your energy costs each day might be somewhere around £7.58. Spread over a 30-day month, that’s roughly £227.40 for heating and access charges alone — before you’ve boiled a kettle or switched on a light.
How Much Does It Cost to Run Central Heating for 1 Hour in the UK?
The cost of running your central heating depends on two main things:
- How powerful your boiler is (in kW)
- How much do you spend on gas or electricity (per kWh)?
Now assume that your home is centrally heated with gas – that’s most prevalent in the UK.
Gas costs about 6.99p per kilowatt hour (kWh) in 2025.
So, if your 24 kW boiler operates for 1 hour, the calculation goes like this:
- 24 kW × 6.99p = 167.76p = £1.68 per hour
If it runs for 2 hours?
- £1.68 × 2 = £3.36
It’s just that way. The stronger the boiler or the longer you have it running, the greater the price.
Average Cost Per Unit of Energy (2025 Rates)
Here is the average price for 1 kilowatt hour (kWh) of energy in the UK now:
| Fuel Type | Cost per kWh |
|---|---|
| Mains Gas | 6.99p |
| Electricity | 27.03p |
Want to Work Out Your Own Heating Cost? Here’s How
You can calculate this in easy steps:
- Discover your boiler’s kW rating (you can find this by checking your model online in most cases)
- Multiply it by today’s gas price per kWh (Currently, that’s 6.99p a kilowatt hour in Britain)
It costs that much an hour.
Here is the formula:
Boiler size (kW) × Time (hours) × Energy price (pence per kWh) ÷ 100 = Cost in pounds
Example 1: Gas Boiler
You have a 30 kW gas boiler, and your gas costs 6.99p per kWh. You use your boiler for 1 hour.
- 30 × 6.99 ÷ 100 = £2.10 per hour
If you operate it for 5 hours:
- £2.10 × 5 = £10.50 a day
Example 2: Electric heating
An electric heater uses 2 kW, and your electricity costs 27.03p per kWh. You run it for 3 hours.
- 2 × 3 × 27.03 ÷ 100 = £1.62
Factors that Impact Your Central Heating Costs
Some things can impact your central heating costs. Even if you and your neighbour both have identical boilers, your bills may not be identical. It’s because:
- Size of Your Home: Larger houses require more energy to heat. More rooms, additional radiators, and a greater amount of space to heat up.
- How Hot You Prefer It: How hot you prefer your home determines how much energy your heating system uses. It costs less to keep your home at 18°C than it does at 22°C.
- How Many People Live There: More people generally translates to more rooms being occupied. Which translates to additional heating, particularly if you are all home for the day.
- Where You Live: Houses in cold regions require additional heating. Depending on where you reside, such as Scotland, you will tend to use more heating than an individual living in London.
- Energy Efficiency: Your home is less energy-efficient if you have an outdated boiler or inferior insulation. Your bills could be reduced by an energy-efficient boiler or an intelligent thermostat.
- Heating Duration Per Day: It costs less to run your heating for 3 hours than it does to run it for 8 hours. It’s that straightforward.
- Insulation: When your home retains heat easily, you will not have to run the heating so often. But if heat escapes freely, you will be switching it on frequently.
How Much Does It Cost to Run Gas Central Heating Per Hour?
Let’s take it step by step.
If your 24 kW boiler costs 6.99p per kWh (according to the April 2025 price cap), running it per hour would cost:
If you have a:
- 24 kW boiler → 24 x 6.99 ÷ 100 = £1.68 per hour
- 30 kW boiler → 30 x 6.99 ÷ 100 = £2.10 per hour
- 35 kW boiler → 35 x 6.99 ÷ 100 = £2.45 per hour
- 40 kW boiler → 40 x 6.99 ÷ 100 = £2.80 per hour
Heating On for 2 Hours a Day – Cost Calculator
If you operate your heater for 2 hours a day:
- With a 24 kW boiler → £1.68 x 2 = £3.36 per day
- With a 30 kW boiler → £2.10 x 2 = £4.20 per day
- And with a 35 kW boiler → £2.45 x 2 = £4.90 per day
Multiply that by 30 to find your monthly expenses.
Gas Central Heating Cost Per Month
Let us do an annual calculation of gas central heating.
Here’s the average cost of heating per month UK, based on 2 hours of daily use:
| Boiler Size | Cost per Hour | Cost for 2 Hours/Day | Monthly Cost (30 Days) |
|---|---|---|---|
| 24 kW | £1.68 | £3.36 | £100.80 |
| 30 kW | £2.10 | £4.20 | £126.00 |
| 35 kW | £2.45 | £4.90 | £147.00 |
This is only an approximate estimate. Your own cost could be more or less based on:
- Your tariff
- Thermostat settings
- How long your boiler is actually on
Running Cost of an Electric Central Heating System per Hour
Heating with electricity is prevalent in flats and small houses. Electric boilers are straightforward to fit, have no need for a tank, and are highly efficient. Electricity is, however, costly in Britain.
It costs roughly 38.94p per kWh, so:
- A 24 kW boiler costs around £9.35/hour
- A 30 kW boiler costs about £11.68/hour.
- A 40 kW boiler costs up to £15.58/hour.
So despite being efficient and straightforward, electric boilers are most costly to operate. They are suited for smaller properties or with minimal heating demands.
The Running Cost of Your Central Heating System Per Year
When it comes to central heating’s annual running costs, a number of factors enter the equation, including your heating system’s efficiency, your energy rates, and your type of fuel. Here’s an approximate annual cost breakdown that you might anticipate for various types of fuels:
| Fuel Type | Energy Price (pence per kWh) | Estimated Annual Consumption (kWh) | Adjusted Consumption (kWh) | Total Cost Per Year (£) |
|---|---|---|---|---|
| Gas | 6.99 | 13,500 | 12,150 (90% efficient) | £84,928 |
| Oil | 10 | 13,500 | 12,150 (90% efficient) | £121,500 |
| LPG | 14 | 13,500 | 11,787.5 (87.5% efficient) | £165,025 |
| Electricity | 27.03 | 13,500 | 13,230 (98% efficient) | £357,606 |
Please keep in mind: These are estimated costs. They may vary depending on your home’s size, insulation, and frequency of use for heating.
Does an Old Boiler Use More Gas?
Yes, it does. Older boilers are not efficient. What that means is that they take more gas to produce an equivalent amount of heat. If your boiler is 15–20 or more years old, it may be wasting a significant amount of energy.
New boilers, particularly A-rated combi boilers, are up to 95% efficient. What that means is that nearly all of the gas consumed by them goes to heat your home. But older boilers fall beneath 65% efficiency. It’s a lot of wasted gas—and consequently money.
What’s So Great About New Boilers?
- They heat up quicker.
- They consume less gas.
- Smart controls are included with them.
- They are quieter and safer too.
Boiler Efficiency Ratings
Boilers get an efficiency rating to indicate their performance. The UK’s latest system is named ErP, with a rating of between A and G.
- A-rated = 90% or better
- G-rated = less than 70
If your boiler is an older model, it could have a SEDBUK rating, which provides an efficiency percentage but is no longer current.
What Can You Do?
You may also be eligible for a free replacement boiler if you are on a low income or in receipt of certain benefits. Under the ECO4 scheme, you can have a modern, efficient boiler installed at no cost.
How Much Gas Should My Boiler Use?
It’s not easy to estimate exactly how much gas your boiler will use because it varies according to the size of your boiler. Take a 24 kW boiler for instance. It will use 24 kW of energy every hour. It will then use approximately 120 kWh every day if it operates for 5 hours a day.
If your gas bill is rising, it may be due to your boiler consuming gas in excess of what it should.
Here is what you can review:
- Supplier costs: Check that your supplier is not increasing prices.
- Daily standing charge: Some tariffs involve a charge that you pay regardless of how much gas you use.
You’ll be using gas more in wintertime than in summer.
If your bill is too high, also take a look at the amount of kWh you’re using. New smart meters can show you exactly how much gas you’re using. If you suspect that everything’s not quite right, it’s perhaps time to have your boiler serviced!
Ways to Reduce Your Running Costs & Energy Bill
- Replace with a new boiler: Older boilers use energy inefficiently. An updated model is far more efficient and can save you hundreds of pounds a year. If yours is 15-20 years or so old, it may be time to consider a new one.
- Improve your insulation: Heat just escapes from poorly insulated houses. Loft, wall, and floor insulation will keep your home warm and keep your heating system from working too hard.
- Use smart heating controls: Timers and smart thermostats assist you in heating only when you need them. Schedule heating for morning and evening, rather than heating all day.
- Turn the thermostat slightly lower: Reducing it by 1°C can save your heating costs by about £100, but you may not notice any difference in temperature.
- Bleed your radiators: Radiators that are cold at the top but warm at the bottom might have air trapped in them. It causes your system to function less efficiently. Bleeding them sorts that out.
- Seal draughts: Close gaps under windows, around doors, and letterboxes. Smaller gaps can push your heating system to work harder and end up costing you money.
- Make use of free schemes: If you qualify, you can have a free new insulation, boiler, or heating upgrade through the ECO4 scheme. It’s an excellent way to reduce your bills over time.
The Bottom Line
Your home heating costs will depend a lot on the type of fuel you use, the size of your home, and how efficient your boiler is. Electric systems tend to be the most expensive to use, with gas being generally the cheapest. Older boilers don’t make efficient use of heat energy, resulting in higher bills.
But by making a few smart changes—you could improve your boiler, insulate better, and use your heating system more wisely—you can save. Under the ECO4 scheme, if you qualify, you can get a new boiler installed for free. Small changes now can make a significant difference later.
Frequently Asked Questions
Yes, it is wise to use an on/off timer or a smart thermostat to regulate whether the heating is turned on or off so that it operates only when required.
Your home should be 18-21°C. 21°C is comfortable for most individuals if they are engaging in activities, and 18°C is good for sleeping. To save on heating, go for 18-20°C.
Larger properties take more energy to heat, so running costs are going to be greater. More floors, bigger rooms, and additional radiators require additional gas or electricity to heat your home.
Heating with gas is far less expensive than electrical heating. It remains the preferred heating choice in most UK houses. Why? Well, there are over 21 million houses that are mains-gas connected. It’s available everywhere and less expensive than electricity.
