Heat Pumps: anyone have one/thought about it?

It isn't looking good for our heat pump install. We had the electrician from Octopus around today and the house fuse (80A) just isn't enough for what we want to do. We have 2x ovens, 2x 8kW electric showers, air con and 5kW hybrid inverter. We also have the EV charger, but that can kick down if the load is too great - which a heat pump can't. Basically it's off to Northern power to see if they'll allow it, but its probably going to be a firm no or insistence on 3 phase, which opens up other issues (cost mainly!). The only other solution is to rip out the electric showers, but I don't fancy having to redecorate two shower rooms! The electrics themselves are a dogs dinner aswell. The consumer unit is full, tricky to access and to compound it all, they can't just go from outside as all the solar electrics are indoors. It would also limit our ability to get an induction hob too unless it was a 13A variant.

Ironically none of this was picked up in the survey, so its a good job I pushed for a visit before signing anything!

We'll see what Northern power say I guess. They don't install 100A fuses normally now, but I'm hoping they will and then it might be okay.
 
My electrics are getting a bit tight, apparently UK Power Networks are still fitting 100A fuses but that depends how I fill out their online questionnaire, otherwise it says I need 3 phase. No electric showers here, but we do have an induction hob and EV charge point. We do get 8kW from the Victron system so that does reduce our grid draw, unless it's charging overnight. But then it would just be the car, Victron and a heat pump. Car and house batteries can limit grid draw.

Had a phone call from Octopus, he implied cost would likely be reduced with a full survey, and they could fit the tank in a 600 x 600 x 2100mm space, and put the buffer tank on the loft. They told me I'd be better off buying from them as they'd still be around in 20 years, I said so will a Valiant installer network even if my installer wasn't!
 
Yes, its pretty annoying as we barely draw anything most of the time. The only heavy draw would be overnight, with 5kW to charge the batteries, the EV charger (which throttles anyway) and perhaps the dishwasher. We've never seen much above 10kW as we try to avoid grid use as you'd expect. The problem is they do a max load test, which for us is quite ridiculous. 2x 8kW showers, 2x 3kW ovens, 5kW inverter = 27kW or 117amps! It would never happen in a million years, but its the regs so there we go. :rolleyes:

Honestly its very silly. We're in a 6 year old house yet even that is a nightmare for a heat pump. Just how do they expect everyone to get heat pumps, solar and EV chargers when the infrastructure isn't able.
 
The max load test was recently revised to take into account no one turns on everything at the same time.

The chance of two electric showers going and two ovens and your heat pump going full tilt all at the same time is laughable really.

You are not going to charging batteries from peak time electricity so that can be canned and you aren’t going to be cooking in the middle of the night on 2 ovens (or showering X2) when the car and batteries are charging.

The hybrid inverter should be reducing peak grid load, not adding to it.

The issue with these tests is that they often lack common sense.

Edit: that said, canning the electric showers isn’t a bad thing, mains pressure hot water through a mixer shower is far far superior.
 
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They should be taking into account the diversity factor, which is what's described above.
 
Yes, we only use one of the showers and one of the ovens. They are never used when the battery or EV are charging as that is overnight. We also never use the showers and ovens at the same time.

It's utterly ridiculous.
 
This is one of those areas where the octopus approach falls a bit short as the surveyors are not experienced installers.

I’d suggest speaking to them once you get the quote back as you’ll likely get more sense from the technical team.
 
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