How Much Gas Does a Boiler Use Per Hour In the UK?

Last updated: May 14, 2024

Knowing how much gas your boiler uses is essential to reduce energy expenses or compare alternatives. If you’re wondering ‘how much gas does a boiler use per hour,’ read on to find out.

According to Ofgem, Great Britain’s independent energy regulator, a typical household uses 11,500 kWh of gas annually, which is around 960 kWh per month.

Ofgem caps the price of gas and electricity, meaning the supplier can’t charge you more than the cap on its standard variable tariff.

With rising living costs in the UK, the last thing you want is to pay more than you need to for energy.

Having a rough idea of how much energy you should use and average costs may help you estimate your bills and compare prices with other energy providers.

But how much gas does a boiler use per hour in the UK?

This guide explores everything you need to know about your boiler’s gas usage, the average unit rate of gas, and factors that affect your energy bills.

Homeowner asking how much gas does a boiler use?

Key Takeaways:

  • The amount of gas your boiler uses will depend on its size, how long you use it, and its efficiency.
  • The costs included in your gas bill include the unit price rate, standing charges, and VAT.
  • From 1 April to 30 June 2024, Ofgem set the price cap per gas unit to 6.04p (pence) per kWh, including VAT.
  • The standing charge is 31.43 pence daily for gas until 30 June 2024.
  • Your boiler may use too much gas due to a faulty thermostat or programmer, part failures, a pilot light, or an aging boiler.
  • Keeping your boiler serviced and well-maintained can help reduce the gas it uses.

How Much Gas Does A Boiler Use?

Each household has different energy needs, so it’s difficult to give a precise figure for how much gas your boiler should be using.

Your boiler’s exact gas consumption will depend on various factors, such as the amount of time you use it (hours per day), its size (measured in kWh), its efficiency rating, and the boiler temperature settings you use.

However, you can use your boiler size to work out an estimate.

Boiler sizes in the UK are measured in kilowatts (kW) and range from 24 kW to around 40 kW.

An average 35 kWh gas boiler in the UK will consume 35 kilowatt-hours worth of gas.

Therefore, if your gas boiler runs for around 8 hours daily, it will use around 280 kWh of gas.

The above example is based on the UK average boiler size of 35 kW, however, if your boiler is a different size, you can easily work it out by using the following formula:

Your boiler size (in kW) x the hours used per day = daily gas consumption (measured in kWh).

For example, if your boiler has a size (in power output) of 30 kW and you use it for 5 hours each day, you will use 150 kWh of gas daily.

What Is A Kilowatt Hour (kWh)?

A kilowatt hour (kWh) refers to the amount of energy used per hour, with one kW equalling one thousand watts.

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All the appliances you run use watts of energy, including lights and heating.

Remember, if it’s on, it’s using energy, even on standby, and it will affect your energy bills.

Every electrical appliance has a power rating, usually shown in watts (W) or kilowatts (kW) (1,000 W = 1kW). This is the amount of electricity the appliance needs to work.

If you look at the energy bills from your supplier, you’ll see that the unit rate for gas and electricity is shown in kWh.

Your provider charges you by how much gas and electricity you use per kilowatt hour (kWh), depending on the unit price.

What Costs Are Included In Your Energy Bill?

The different costs included your gas and electric bill include:

  • Unit rates
  • Standing charges
  • Taxes like VAT

What Is The Unit Rate for Gas in the UK?

The unit rate is the price your supplier charges you for every unit of gas or electricity you use.

It’s the cost you agreed with your energy suppliers for each kilowatt (kWh) of gas you use, which can be variable or fixed.

If you’re on your supplier’s standard variable tariff, Ofgem’s energy price cap protects you from paying more than the price cap.

The price cap limits the overall amount you pay. However, it doesn’t limit the unit rate or the standing charge a supplier can charge you. For example, you can be on a tariff with a higher unit rate but a lower standing charge.

From 1 April to 30 June 2024, Ofgem set the price cap per gas unit to 6.04p (pence) per kWh, including VAT.

Therefore, it will cost you around £1.8 to run a 30 kW boiler for an hour ((30×6.04) ÷ 100).

Please note that your exact figure will depend on other factors like your supplier, where you live, how you pay, and the age of your boiler.

What Is the Standing Charge for Gas in the UK?

The standing charge is the maximum cost a supplier can charge you if you’ve not used any energy.

The supplier sets it to cover the costs of maintaining the energy supply network, taking meter readings, and supporting government social and environmental schemes.

The standing charge is included in every gas and electricity bill. The supplier will charge you this cost every day even when you don’t use energy on that day.

The energy price cap currently sets the standing charge to 31.43 pence daily for gas until 30 June 2024.

How Is Your Energy Bill Calculated?

Suppliers calculate your gas bill based on various criteria. These include:

  • Your energy consumption: The more energy you use, the higher your bill.
  • The tariff you’re on: This determines the price you pay for your daily standing charges and the cost of each unit of energy you use.
  • Your bill payment method: Customers paying monthly by Direct Debit pay less than those using other payment methods.
  • Where you live: Some areas of the UK pay more for their energy than others. This is because the cost of delivering energy to your home varies by region.
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How Much Gas Does The Average Home Use?

The amount of gas you use will vary depending on your home type and the number of residents in your household.

A larger home means more rooms or space to heat, and more people means more hot water and higher gas usage.

The table below shows Ofgem’s estimates of average energy usage by house size. Ofgem uses these figures to calculate the energy price cap.

Energy UsageHome TypeNumber of ResidentsAnnual Gas Use (kWh)
LowFlat or 1-bedroom house1 to 2 people7,500
Medium2-3 bedroom house2 to 3 people11,500
High4+ bedroom house4 to 5 people17,000

Is Your Boiler Using Too Much Gas?

If you believe your boiler may be using too much gas, the first thing to do is verify your usage and compare it against your gas bill.

Checking your gas usage against your bill will tell you if your energy supplier has under- or overcharged you.

Even if there are no irregularities in your energy bill, it’s still a good idea to regularly check your energy usage so that you can keep tabs on it and moderate your behaviour as much as possible.

This can help you reduce energy use and save money on your heating bills.

Check out our video on how to vet boiler brands/models in the UK:

Why Is My Boiler Using Too Much Gas?

Have you noticed an increase in your recent gas bill, yet the unit cost has not increased? Your boiler may be using more gas than it should and the following factors may be at play:

A Faulty/Broken Thermostat or Programmer

Thermostats and programmers control your boiler automatically so you don’t have to oversee it manually.

You can set the thermostat or programmer to turn the boiler on or off at specific times or when your home reaches the set temperature.

However, if these controls malfunction, your boiler can stay on for 24 hours a day or come on when you don’t need heating or hot water.

As a result, it wastes energy and leads to expensive energy bills. To prevent such scenarios, do a few checks to ensure the controls are working and set to the correct times.

If they’re not working correctly, call a Gas Safe registered heating engineer to investigate further and replace them if necessary.

Part Failures

Some parts in your boiler can fail and affect the operations of your boiler and heating system. For example, a diverter valve, which opens and closes to control where hot water is sent, can get stuck or fail.

Consequently, it can lead to unwanted hot water flow or heating, resulting in wasted energy and higher energy bills.

Scheduling a boiler service can help you identify and prevent such issues from affecting how much gas your boiler uses.

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A qualified heating engineer can monitor the condition of the internal boiler parts and make recommendations when you need to replace them.

Pilot Light

Older boiler models use a pilot light to start the main burner.

The pilot light is a small flame that burns constantly and remains lit to ignite the main burner when you need to turn on the boiler.

Therefore, it will use up more gas than a newer boiler using an electronic ignition that isn’t continuous.

If you’re using an older boiler with a pilot light, consider upgrading to a modern, more energy-efficient boiler.

An Ageing Boiler

A boiler’s efficiency decreases with time, affecting how much gas it uses to heat your home and water.

Boiler efficiency refers to how well your boiler converts fuel into heat. Manufacturers generally calculate it as a percentage of how much fuel the boiler converts into usable energy and how much it loses in the process. 

For example, if your boiler is 90% efficient, only 10% of the energy is lost. However, if your boiler’s efficiency is 70%, you’ll lose 30%.

Therefore, replacing your old, inefficient boiler with a modern, A-rated boiler will ensure you use less gas and reduce energy bills while lowering carbon emissions.

Have you heard about the gas boiler ban and are wondering what the alternatives to gas boilers are? Read our complete guide to replacing your gas boiler with a heat pump.

How Can You Reduce the Amount of Gas Your Boiler Uses?

Some simple actions and changes can make a big difference and help you lower the amount of gas your boiler uses and your energy bill. These can include:

  • Turning your heating thermostat down by a few degrees
  • Ensuring you don’t leave appliances on standby
  • Switching to LED light bulbs
  • Ensuring you don’t overfill the kettle and only heating what you need
  • Taking shorter showers
  • Drying clothes naturally instead of using the dryer
  • Using smart devices to help manage energy use. They can help you understand when and how you use energy and make changes to reduce usage.
  • Improving your home insulation to reduce the amount of gas your boiler needs to burn to heat it.
  • Get your boiler services annually to keep it in the best condition and reduce gas consumption.

How Much Gas Does A Boiler Use Conclusion

Keeping an eye on how much gas your boiler uses can help you keep energy costs to a minimum while reducing your carbon footprint. An efficient boiler ensures you don’t use more gas than needed and keeps your energy bills reasonable.

Always stay informed about price changes and look for lower tariffs from different suppliers. Ensure you have your boiler serviced by a qualified heating engineer to identify and prevent any issues that can cause it to use more gas than necessary.

Most importantly, if you’re using an old, inefficient boiler, consider replacing it with a modern, A-rated model that will waste less gas when providing your home with heating or hot water.

How old is your boiler? Should you consider repairing your boiler or start looking at the latest boiler prices? It’s no secret that boiler efficiency deteriorates over time.

Sources and References