Assuming my air source heat pump has a COP (coefficient of performance) of 3.0, I estimate total electricity usage for the pump to be 5,000 kwh as …….. 3.0 (COP) x 5,000kwh = 15,000kwh. As noted above my total gas usage is 16500kwh and that includes hot water and gas hob, so taking 15,000 kwh for heating alone is probably to high but better being high than low.
A COP of 3 = For every 1kW electricity used you, get 3kW worth of heat out in laymans terms..
But, its not quite as easy as that, as external influencies such as heat loss and outside ambient temperature…
On average electricity is 3-4 times more (£) than gas per kWh, so you need to factor that in at peak hour rates along with whats available from solar and battery storage, because this will not be constant 365 days year.
Age and “average” remaining life expectancy for you and your wife, also plays a crucial role. Not everyone after your days wan’ts a industrial look or equipment nearing EOL.