Anyone with experience of a larger air source heat pump (ASHP) and its running costs?

Howdy @krankyd !

You’re in luck actually, as there’s several members on here with a lot of experience now. Please allow me to introduce them to you. @juliamc @hydrosam @M.isterW @nealmurphy being just four of them that I can think of.

Sorry @krankyd mine’s only a small one !

That's quite a setup you've got, and are planning. I can tell you about my experience with a heat pump but it's only a 11kW unit in a 1990s house, so it's very different to yours.

The advice I give to everyone considering a heat pump is... check your insulation first (good advice whatever your heating source) and make sure your system is designed and installed by someone who knows what they're doing. A heat pump is very different to a gas boiler and if you get it wrong it can be very expensive to run.

Hi,
Thanks for this - we’re getting insulation (as much as we can) fitted first. Currently we have night storage heaters so electric bills are significant, even with the wind contribution. We just have no way to store large amounts of power that we generate into a usable format :/

Hi @krankyd 

I have a 16kW high temp ASHP, but I don’t think I’ve really pushed it to its limits yet! It serves a detatched converted bungalow with unfilled cavity walls.

I’d recommend taking a close look at the whole house heat loss calculations and checking these have used the correct sizing / construction for your house as this could make a big difference when it comes to calculating the heat loss from individual rooms and the house as a whole. What heating system do you currently have? Pipe sizes etc...

Current heating is night storage heaters! We have detailed calc’s for the room sizes, heat loss etc just wanted to know if anyone else has an example of their running costs. I think we are liable to spend over 4-5 K a year on electric!

I’ve kept a note of elec use for the last year, had the ASHP since March 2021, the electricity it’s used has cost us about £700 at 16.24p/kWh. Our bungalow is 99 sqm. 

At the moment (end Feb) our 11kW heat pump is using between 15 and 20kWh per day. It doesn't heat all our hot water so you can add a bit to that.

You seem to have loads of self-generated electricity so is spending £££ on a heat pump the best option? Other forms of electric heating are a lot cheaper to install but aren't popular because of the running cost. Your running costs could be really low because you generate so much electricity.

15-20kwh here too for an 11kw system. 

My number 1 tip is to go with an installer who has been installing heat pumps for some time and has a good selection of previous clients you can speak to. Renewable heating hub is a good forum to go for recommendations.

I’d also go with an installer that agrees to put monitoring on electricity usage and heat generated so that you know the system is working well, and if it’s not they will work with you to optimise the setup. 

Just a thought.  On the OVO App if you go to Usage and select Year or Month the cost is shown, but NOT when you select day.   Hope this may help.