Heat Pumps - Not Such A Great Deal?
When gas was cheap and electricity not, the case for heat pumps replacing boilers was quite strong - but with the price of all energy rising and the differential between gas and electricity pricing likely to reduce, is that still the case?
What Are The Economics?
People often get confused by the maths involved but it is actually quite simple:
- A gas boiler will be 80-90% efficient if setup and used properly (they rarely are but that is a different story)
- A heat pump will use electricity in the same way a fridge or freezer does, to take heat from one place and put it somewhere else. This is more efficient than 'actually heating' so 1 unit of electricity can produce 3-5 units of heat (the amount of heat produced by an electric heater say, using that amount of electricity)
- So a gas boiler will produce 0.8 units of heat for the price of 1 unit of gas (based on 80% efficiency)
- And a heat pump will produce 4 units of heat for the price of 1 unit of electricity
- So as long as electricity is less than 5x as expensive as gas, the heat pump should be cheaper
The bad news is that heat pumps only work for well insulated houses as they produce less total heat than a boiler and to keep your house warm you may need to change your radiator sizes and/or configuration.
How Can You Tell If It Works For You?
As long as you know your current energy usage (which is always a prerequisite starting point in these discussions), there is a simple tool which will allow you to compare current spend against the use of a heat pump - see it here: https://hp-annual-usage-estimator.streamlit.app/
It is produced by the Green Heat Coop: Home heating | Green Heat Coop