First we need to calculate the heat demand for hot water and heating.
Based on the average gas consumption observed of Octopus customers, this worked out to be 12,273kWh.
Gas used for cooking makes up around 2.5% of this, or 307kWh. This means 11,966kWh is needed for heating and hot water, or your heat demand.
A live study by the UK government energy department (DESNZ) found the average gas boiler to be around 85.3% efficient.
This means, of the 11,966kWh of heat demand, only 85.3% is converted into heat.
This works out to be 10,207kWh (11,966kWh x 0.853).
From July 2024, the average unit rate price cap for gas is 5.48p/kWh.
A standing charge also applies for a gas supply. From July 2024, this will be an average of 31.41 pence per day, or £115 per year, for those on a flexible / variable tariff.
The annual average electricity usage of a medium UK home is 2,700kWh.
For a flexible tariff, the average unit rate price cap from July 2024 for electricity is 22.36 pence per kWh.
A standing charge also applies for an electricity supply. From April 2024, this will be an average of 60.12 pence per day, or £219 per year, for those on a flexible / variable tariff.
Using this information, we can calculate the total energy bill cost with a gas boiler:
(11,966kWh x £0.0548) + (307kWh x £0.0548) + (£0.3141 x 365) + (2,700kWh x £0.2236) + (£0.6012 x 365) = £1610
