How much can you save with a heat pump?

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Heat pumps are the most carbon friendly solution out there when it comes to home heating - but how do running costs compare? For the average UK home, it should cost a similar amount to run a heat pump compared to a gas boiler, but if you chose a smart, green heat pump tariff like Cosy Octopus you could save hundreds of pounds.

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How much does the average heat pump cost to run?

Heating costs with a heat pump can vary from home to home depending on a variety of factors, from how insulated the property is, to which tariff you're on, and how you use your heating.

For an average 2-3 bed home, if you prefer to join the standard Flexible Octopus tariff a heat pump can cost around £78 more a year than gas on average.

Whereas if you're on our Cosy Octopus smart tariff you can save around £220 a year compared to gas.

Check out the cost comparison below for these two scenarios (based on the Ofgem average for a medium sized UK home and April 2024 price cap):

Annual heat demand (heating & hot water) Heating Efficiency Annual Heating Energy Usage Annual General Elec Usage Gas price (p/kWh) Elec price (p/kWh) Gas standing charge (p/KWh) Elec Standing charges (p/kWh) Total Annual Energy Bill Total Annual Bill Savings
Gas boiler: Flexible Octopus 9,250 kWh 83% 11,213 kWh 2,700 kWh 6.04 24.50 31.43 60.10 £1,690 -
Heat pump: Flexible Octopus 9,250 kWh 300% 3,083 kWh 2,700 kWh 6.04 24.50 31.43 60.10 £1,768 -£78
Heat pump: Cosy Octopus 9,250 kWh 300% 3,083 kWh 2,700 kWh 6.04 19.45 31.43 58.00 £1,469 £221

How can I save even more with a heat pump?

What's more, if you use your heat pump to help rid your home of gas once and for all (something we can arrange for free), you'll no longer have to pay gas standing charge, which would save an additional £115 a year.

If the environmental levies were removed from electricity (something the government is considering and we’re lobbying hard for) the average heat pump user would save an extra £186 compared to gas boilers.

Get Cosy, make savings

Cosy Octopus works by allowing you to make the most of the cheap, green ‘Cosy’ periods. This might mean pre-heating your hot water or your home a little earlier than usual, and then once the daily peak in energy demand has passed, turning your green-heating back on to remain as cosy as ever.

All you'll need to do is set a schedule and you'll be good to go. Here are our top tips for how to run your heat pump to maximise savings, including some example schedules.

What have our Cosy customers been getting up to?

We crunched the data from all our customers who have been on our Cosy Octopus tariff for a full 12 months and found that, on average, they saved 20% on their electricity bills compared to our standard Flexible Octopus tariff.

Most customers saved between 7% and 27% with those who had other green tech, like a battery, making the greatest savings.

Cosy profile

This graph shows the average daily consumption profile for the two weeks before and after they switched to Cosy Octopus

When you apply these savings to a medium sized UK home that's a £220 a year saving compared to a gas boiler.

How to join Cosy Octopus

If you have a heat pump, or you're planning to have one installed, switching to Cosy is easy. Just follow the guidance on this page.

Alternatively if you have other low carbon tech devices at home, like an EV or solar panels, a different smart tariff could make your energy cheaper. Check out this quiz to find the right tariff for you.

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Assumptions explained

How we calculated the total energy bill for gas boilers on a Flexible tariff

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Ofgem figures state the annual gas usage of a medium property is 11,500kWh.

Gas used for cooking makes up around 2.5% of this, or 288kWh. This means 11,213kWh is used for heating and hot water, or your heat demand.

From April 2024, the average price cap for gas is 6.04 pence per kWh.

A standing charge also applies for properties with a gas supply. From April 2024, this will be an average of 31.43 pence per day or £115 per year.

The annual average electricity usage of a medium UK home is 2,700kWh.

For a flexible tariff, the average price cap from April 2024 for electricity is 24.5 pence per kWh

A standing charge also applies for properties with an electricity supply. From April 2024, this will be an average of 60.1 pence per day, or £219 per year for those on a flexible tariff.

Using this information, we can calculate the total energy bill cost with a gas boiler:

(11,213kWh x £0.0604) + (288kWh x £0.0604) + (£0.3143 x 365) + (2,700kWh x £0.245) + (£0.601 x 365) = £1690

How we calculated the total energy bill for heat pumps on a Flexible tariff

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A typical air source heat pump should generate three or more units of heat for each unit of electricity it uses.

The UK government energy department (DESNZ) did a live study and found that the average heat pump to be around 300% efficient.

While as they found the average gas boiler to be around 82.5% efficient in a similar live study.

This means, of the 11,213kWh of gas usage, the heat demand is only 82.5% of this, or 9,250kWh (11,213kWh x 0.825).

To deliver the same heat demand of 9,250kWh, a heat pump will require 9,250 ÷ 3 = 3,083kWh of electricity.

The annual average electricity usage (not for heating & hot water) of a medium UK home is 2,700kWh.

This means, with a heat pump, your annual electricity consumption for heating, hot water and general usage is 5,783kWh.

From April 2024, the average price cap for electricity is 24.5 pence per kWh

A standing charge also applies for properties with an electricity supply. From April 2024, this will be an average of 60.1 pence per day, or £219 per year for those on a flexible tariff.

If you keep your gas supply, you'll still consume around 288kWh for cooking and pay the gas standing charge. From April 2024, this will be an average of 31.43 pence per day or £115 per year.

Using this information, we can calculate the total energy bill cost for a heat pump on a flexible tariff:

(5,783kWh x £0.245) + (288kWh x £0.0604) + (£0.3143 x 365) + (£0.601 x 365) = £1,768

How we calculated the total energy bill for heat pumps on our Cosy Octopus tariff

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We've used the same heat pump efficiency and consumption as the Flexible tariff calculation. However we've reduced the average energy price by around 20% based on our initial Cosy findings. When you apply this to the April'24 price cap Cosy octopus prices, it results in a weighted average unit rate of 19.45 pence per kWh.

From April 2024, the standing charge for the Cosy tariff will be 58 pence per kWh.

Assuming there is still gas at the property, your total energy bill with a heat pump on the Cosy tariff works out to be:

(5,783kWh x £0.1945) + (288kWh x £0.0604) + (£0.3143 x 365) + (£0.58 x 365) = £1,469

How we calculated the environmental levies saving

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The environmental levies considered are:

RO - Renewable Obligation Certificates

CfD - Contracts for Difference

FiT - Feed in Tariff

ECO - ECO Scheme

Together, these levies make up 6.06 pence (25%) of your electricity unit rate, which is already included in the total bill figures above.

Electricity Levy Cost with Gas Boiler

If you have a gas boiler in your property, following our previous assumptions, your annual electricity usage is 2,700kWh.

Therefore cost of levies works out to be:

2,700kWh x £0.0606 = £164

Electricity Levy Cost with a Heat Pump

If you have a heat pump in your property, following our previous assumptions and calculations, your annual electricity usage is 5,783Wh.

Therefore cost of levies works out to be:

5,783kWh x £0.0606 = £350

Net Levy Savings with a Heat Pump

The net difference between the two calculations above work out to be:

£350 - £164 = £186

That means if these levies were to be removed, you would save £186 more than you would with a gas boiler just by having a heat pump in your property.

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Published on 30th September 2023 by:

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Aimee Clark

Green heating expert

Hey I'm Constantine, welcome to Octopus Energy!

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