Midea Heat Pump expensive to run

SAC2334

QrizB said:

Paging @SAC2334 who used to be a professional leter reader

I think the first is 52090.16 and the second is 53289.82

That's a difference of 1199.66 kWh, which is rather a lot for six weeks. 200kWh a week.

On the national average Ofgem-capped single-rate tariff of 27.69p/kWh and 54.75p/day, that would be £59.21 a week, £254 a month.

This is however somewhat less than the £350 that your first month cost.

yes 200 kwhs  a week is a horrendous weekly usage .28 kwh s a day is really high  . I average 5 kwh  a day and would find it hard to use that ammount unless i was running a heat pump .
 Your dIal meter readings are almost correct .First reading is 52090, second is 10 kwhs less at 53279 . ( have to look at the tenth dial to see what the single kwhs is reading )

benson1980

SAC2334 said:

QrizB said:

Paging @SAC2334 who used to be a professional leter reader

I think the first is 52090.16 and the second is 53289.82

That's a difference of 1199.66 kWh, which is rather a lot for six weeks. 200kWh a week.

On the national average Ofgem-capped single-rate tariff of 27.69p/kWh and 54.75p/day, that would be £59.21 a week, £254 a month.

This is however somewhat less than the £350 that your first month cost.

yes 200 kwhs  a week is a horrendous weekly usage .28 kwh s a day is really high  . I average 5 kwh  a day and would find it hard to use that ammount unless i was running a heat pump .
 Your dIal meter readings are almost correct .First reading is 52090, second is 10 kwhs less at 53279 . ( have to look at the tenth dial to see what the single kwhs is reading )

Yes, but they are running an ashp. That sort of usage is within the ballpark, as has previously been mentioned- but some scope for efficiency savings.

Ours is using around 25-30kwh a day at the moment. It can use up to 80kwh a day on the coldest days.

@Painter23 You are right that the custom curve would appear to have already been selected as that is the right outlet flow temp at 7C outside with my settings. Even more odd then as it looks like the installers had just set it as a flat line essentially, at 55C. 

Painter23

Thanks guys.
I took a meter reading before I administered the changes and I'll be back at the property tomorrow so can see what 36 hours of new settings has done to the consumption.

As I'm not living there yet so can't tell if it's warm enough in practice but remote readings of the room temp over the last 12 hours or do has shown a fairly consistent temperature of between 15.9-16.9 degrees (not getting too close to the 19 degrees Hive set point). I imagine that if this is a comfortable temp then I leave it alone. Will report back.

I'm also imagining that my hot water is set to Auto so that it only heats up as called for? This would fit the fact that it takes a minute or so for hot water to reach the taps when I first call for it - and I imagine explains why there's never any 'scheduled timer' for the hot water tank?

QrizB

Generally, you won't get "on demand" got water heating with a heat pump. This makes me wonder whether your Hive is even connected to your HW system; it could be alway-on, or you might even have an immersion heater running?

matelodave

Generally the hot water is activated by the heat pump, both in time and temperature so you need to check what the Midea controller is set to. I doubt the Hive has any effect whatsoever, it probably wont control an immersion either.

If you are not there, then make sure that the hot water timer is set to off rather than continuous or timed. When you do actually want hot water you'll have to use the heatpump controller to activated it. May I suggest that you reduce your hot water temp to below 50 degrees as most heat pumps struggle to get above 50-55 degrees and will then kick in an immersion heater which ramps up your consumption.

Likewise check your sterilisation function. TBH once a week is a bit excessive especially if you have a non-vented cylinder and you dont need it set to 65 either

Painter23

There is a hot water immersion controller but it's not set to a timer or switched on, but I still get hot water from the taps, which makes me think it's being heated by the heat pump. Interestingly the previous owner said she did use the Immersion timer for hot water but the installer told me she shouldn't have been.

matelodave

Perhaps a photo or two of your set up (where the cables go and what sort of immersion heater controller). Are there cables between the heatpump controller and the immersion heater

Different manufacturers have different ways of controlling stuff but if you have a hot water tank and the immersion is switched off then it can only be the heat pump that heats it. If you get hot water within a minute or so of turning on the hot tap then you are keeping the tank hot all the time, even when you aren't there.

Most people who complain about high running costs and not being warm enough dont have the system configured correctly and use them like a boiler rather than like a heatpump.. Just minor adjustments to the settings can have quite dramatic effects on the cost and comfort. Setting temperatures too high and turning them on an off with external controls (like Hive) can cause them to cycle on and off which reduces efficiency.

You dont control your car speed with the ignition switch, but thats what a thermostat does to central heating.

My Daikin heatpump can control the tank immersion as well as a 6kw booster/back-up heater. Both of which I have disabled (both with the heatpump controller and via isolating switches). When mine decides to do a sterilisation/disinfect cycle it does it with the heatpump and is set to just 55 degrees which is more than enough for a unvented cylinder, fed with mains water and in use every day.

My weather compensation slope is 25 degrees when it 15 outside up to 40 degrees when its -5 outside you might need it a bit higher than that for radiators (although not if they've been sized correctly) which means that it runs at around 32-34 degrees most of the time

Painter23

Here's the set up in the airing cupboard. The controller on lower far right is the immersion timer which is permanently off. Upper 2 boxes on right are the Hive controller and the Midea controller.

The DHW screen on my Midea controller looks like this:

benson1980

Personally I wouldn't bother with a disinfect cycle at all but that is down to personal preference. Looks like you have this turned off anyway I think on the controller as well.

The one reasonably intuitive part of the midea controls is the schedule. This is where you can see what has been set up in terms of scheduled reheat times and set temp for the tank. 

Schedules set up in 'timer' will just run daily. There are options to then set up schedules for different days of the week if you want.

As already mentioned, cylinder temp of between 45 and 48C is usually adequate for most people and your showers will be plenty warm enough, and is more efficient than heating it to 50+C.

There's another setting in the DHW menu to set the temp drop that will trigger a tank reheat within the scheduled times- Dt5_on. Yours is set to 5C so what this means is that if the tank temperature drops by 5C the tank will start reheating- if it is scheduled to do so. 5C is the default but you can change it if you want.

Painter23

Thank you @benson1980. Is the disinfect cycle the same as the anti-legionella cycle? If so this is a must for me.

If you're able to I'd be grateful for any instructions on how to decipher my current hot water settings and how to customise them. I don't need much hot water - only enough for a couple of showers and hand washing all day.

I've taken meter readings today and compared to 28 hours previous when I made the changes to the heat pump curve. The only other electric usage has been 3 hours of a dehumidifier and some ceiling lights. It seems quite high for one day which makes me wonder if the water is always on?

18/01/2026 - 53281

19/01/2026 - 53318