Costs of Running an Air-source Heat Pump

Here are my stats for electricity usage, compared to the same period a year ago (when heating and hot water were oil-fuelled):

Month	Expected units	Expected cost (£)	Actual units	Actual cost (£)	Actual cost per unit (p)
Nov '24	250	48	290	37	12.8
Dec '24	450	86	340	59	17.4
Jan '25	625	120	440	77	17.5
Feb '25	625	120	320	53	16.6
Mar '25	450	86	162	21	13.0
Apr '25	250	48	74	12	16.2
May '25	125	24	23	6	0.26
Jun '25	25	5	-18	-3	0
Jul '25	25	5	-10	-1	0
Aug '25	25	5	7	3	0.42
Sep '25	25	5	-6	0	0

Note - The expected usage is based on my rough estimates of how much oil I might have been using each month - and that's very rough as I've never kept a close measure of how much oil was in my tank.

So it's early days in monitoring ASHP electricity usage, but I'm pleasantly surprised to see it using (in terms of units of electricity) around 70% of what I was anticipating. And costing under £80 per month during Winter does seem quite reasonable!

How come the per-unit price of the extra electricity used is so low? Well, I'm on a special heat pump tariff which has cheap times of the day. So I prioritise heating/hot water during the cheap periods, but not by a lot. I literally run a schedule that bumps the desired temperature up by a couple of degrees during the cheap periods, and also have a hot water schedule that runs in the middle of the night. I started off on the Octopus Cosy tariff, but this included an increasingly expensive peak-rate slot between 4pm and 7pm - so I decided to move to the Good Energy Heat Pump tariff that has similar low-rate periods and no peak-rate period.

Comments

It's quiet in here...Add your comment

Recent Updates

21 Oct : Costs of Running an Air-source Heat Pump
19 Oct : VC Revolution Cross
21 Oct : Air-Source Heat Pumps
19 Oct : Cyclocross
07 Jul : Do It Yourself!
27 Oct : My Car Costs
13 Feb : Great Days Out
02 Sep : Nature
25 Nov : Piano for the Amateur
14 Nov : Measure
12 Oct : Simple Programming Exercises
11 Oct : Model Railways