SteamyTea

That jump you are seeing is about the same as a 2 kW heater. What things do you have in the house that can draw that much energy i.e. kettle, cooker, oven, vacuum cleaner, fan heater (friend of mine left one on in his loft for months). It is also about the same as your HP draws.

Good, that has eliminated that then.

Get the cat to answer it

As @dpmiller says, maybe the meter is the wrong way around. But your solar diversion could also be part responsible for your inconsistent usage. If your tank is in a ready to heat state during the day, solar will probably go into it, if that same state is at night, then the HP will take over. Can you set things up so that the HP will only heat the water when it is dark, easy this time of year, not so easy in summer, but your solar should do most of the work then.

You can tune a system to be very efficient when you have a regular outcome i.e known volume and temperature of water to heat. Somewhere, along the line, a regular setup will only hit that point I frequently. The problem is, for most people, the higher capital costs. But worth thinking about and costing out if your DHW usage is high i.e lots of baths in a day. Worth remembering that a modulating gas boiler is sized, generally, for the DHW load and not the space heating load. And my E7 setup is sized and controlled on a room by room basis. I can totally, and easily, disconnect the space heating and still have DHW, or the other way around. Space heating and DHW do different things, at different times and at different temperatures.

In some ways, it may be better having 2 heat pumps, one to do the house heating, the other just for DHW. A non inverter type for DHW would be a good option. Trouble is, we all want one device to do everything i.e I want my car to have the acceleration of a Tesla S, the economy of a Nissan Leaf, the handling and road holding of a 911, but the comfort of the original DS5. And the ability to do 1000 miles between fuel stops. It must also get me home when I am drunk (though I found the forging handing and 70 profile tyres on my old 309 helped here), and it must not cost any more than a Dacia base model. Needs to tow 2 tonnes as well, and be convertible into a camper, with bog and shower. Can't see even the best gas boiler doing all that.

I think they are rebadged imports. And not inverter type. Good for what they are designed for, dumbly pumping out warm water 24/7.

http://www.dreamheatpumps.co.uk/5kw_heat_pump_SWIM.html It is for a swimming pool.

You are a winner mate, don't let anyone put you down.

Go on then, run away. So no official warnings, what a let down.

So how many warnings have I had? Less than @pocster.

And your point is, apart from running out of original thoughts. I think site moderators should stick to moderation, not shit stirring with a holier than thou attitude.

(expletive deleted) you

Or Father, in your case.

Or a lot more tenacious when it comes to dealing with pettiness. Now you may feel that you can keep this up for a while, trust me, I am an expert at this sort of thing. Had to deal with it loads of times when teaching.

I had to do an emergency repair on a PU moulding machine when I worked in the Derbyshire. Now take into account that this was the 1990's, and the humour of the area. My impersonation of Lenny Henry went down quite well. "Katanga"

If you take a normal kitchen fridge, which is a heat pump and measure the load when it is running, it will draw about 100W. An ASHP often draws about 5A when running, so that is about 1.2 kW. So the compressor can detract quite a bit from the total performance. Now I would hope that a half decent ASHP would stop the compressor (and the fan and associated fluid pumps) when there is no hope of getting any advantage. So if the unit was purely running on resistance heating, the only parasitic load is a contactor or two latched on and the fluid pump (which you need anyway), so the CoP is near enough 1. But if it is close to the operating minimum temperature, then all the gubbins may well still be working, plus maybe some defrosting cycles happens as well, this may reduce the efficiency to 0.5. Does this matter, not really as if the unit is designed correctly, this is only for a very short period of time.

Pumps and parasitic loads.

Or just misunderstood your explanation.

Well less than half the people allowed to vote have done that. Morons.

Is that a euphemism again.

Not this, or is it the brazing googles

WTF has happened to your face

Some of that may be true. Luckily we can self identify as anything now.

Even the spammers are avoiding it.