Heat Pump - Two Extractor Fans? Help!

[ChrisP99]

Hi,

I have recently moved into a two-bed apartment that has a Dimplex Edel (EDL200UK-630RF) Hot Water Heat Pump.

I have never lived anywhere that has this sort of appliance before, and I want to ensure that I have set it up correctly and understand what it's doing, as my electricity bill from February - March was £225.25 which seems like a lot, and I am averaging £10 a day on electricity and some days I am using 21 KW/h! I know some people spend a lot more, but this is a two-bedroom flat that is extremely well insulated (Built in November 2023).
I have absolutely no clue when it comes to any of these things (Hence me posting here), and the manual is surprisingly poor, so I am hoping some Heat Pump experts here would very kindly assist me.

The target water temperature is only set to be 45 Degrees C. This is actually less than what I'd prefer it to be, and it's further confusing me as to why my bill is so high. I really want to turn it up but I am worried this will cause the immersion to kick in and make everything worse, however...

...I was reading the manual and noticed there is a Counters page in the Installer Settings. It says the following:

1 - 269
2 - 1
3 - 0
4 - 459
5 - 3

The manual only says what 1, 2 and 3 are for, so the heat pump has activated 269 times, and the immersion only once. I have no idea what the other counters even mean.

There is also a setting called Fan Mode that is on setting 1. I have no idea what the Fan Mode is for as the manual says "Standard mode, automatic ventilation." for setting 1 and "Manual mode, forced ventilation." for setting 2.

My apartment has an isolator for all the extractor fans (one in each bathroom and one in the kitchen that is separate from the extractor hood) next to the heat pump. When this is on, every time you turn on a light in one of the two bathrooms, the extractor fan will activate everywhere (both bathrooms plus the kitchen). I usually turn this on and off and it only makes sense to use it when the shower is running. For some reason, the extractor fan in the living room only turns on when one of the bathroom lights is on.

I don't know why I have a separate extractor fan to the heat pump, as the heat pump's own extractor fan comes on when it decides to heat the water up (Usually after a shower). Again, my knowledge of all this is terrible and this is probably me being simple.

There is also an option to set a schedule, which allows the heat pump to be the only way to heat the water (Eco), compared to it using a mixture of both if needed (Comfort), but I don't see a point in this if the immersion heater has only activated once in the month I have lived here.

I want to make sure that these settings are all optimal, and also clear up how all this actually works.

If anyone needs me to clarify anything, feel free to ask.

Thanks!

 

[stem]

Can't say I've had experience of this particular product. However the heat pump design is such that it should reduce the heating cost for heating your hot water compared with a standard hot water cylinder and immersion heater. The Edel does have an immersion as a back up when the heat pump needs some help to heat the water, and looking at your post it appears to have only operated just the once. Heat pumps can struggle to reach high temperatures, so the immersion can take over to finish off the heating at higher temperatures. However, as you have it set low that is why the immersion isn't operating much. However. The water should be heated to 60 C or above weekly to kill legionella. The Edel has a setting to allow this to take place automatically.

You don't say, but I'm assuming here that the property is also heated electrically. In which case even with more expensive methods of heating hot water, (eg standard hot water cylinder and immersion heater) for most people, it makes up a relatively small portion of the overall heating cost. Unless of course you run multiple baths everyday. If you do have standard electric heaters for the property, they would likely be the likely culprit for most of the electricity consumption, and heating with electricity costs about 3 times that of gas. (Heat pumps excluded, as they can be 300% efficient so tend to be a similar cost to gas to run)

If you do have electric heating, you could try switching the Edel heat pump and any accessories such as the immersion heater off for a whole day and see what difference it makes to the electricity consumption.

The heat pump works by using a fan to pull air in from outside via one duct, extracting the heat from it, transferring the heat to the water and then returning the air outside via the other duct. It does not provide room ventilation as the Edel is completely room sealed. Also, it is not connected in anyway with the bathroom extractor fans and cooker hood.

The Edel fan speed 1 is the most economical and the quietest but it can only be used with ducts that are short and don't have many bends. If the ductwork has a high resistance then a higher fan setting may be required.

 

[ChrisP99]

Thank you for the advice. You make a good point that there is a chance that the electric radiators are the cause of the heating bill as I work from home full-time and usually heat my office all day.

I have noticed that the Domestic Hot Water Request light is always on even when I’m not using any water, but I assume there is a reason for that.

 

[Murdochcat]

Moving into an electric only property during the winter is always going to be unsettling.!

Get past Easter and take weekly readings of the kWh usage and then you’ll get an idea of the costs / consumption when you’re not using heating. Then till you’ll get an idea of how much the heating costs b you.

Bear in mind this winter hasn’t been that cold

 

[ChrisP99]

Thanks both for your advice and insight, it makes much more sense to me now!

I have decided to also set a schedule for the heat pump as I (perhaps stupidly) never set one when we moved in, and it is set to be on all the time 24 hours a day (When needed), so it will always try to get to the target temperature, which perhaps is contributing to my electricity bill as well (I used 16 kWh yesterday according to the Octopus app and it just seems like far too much).

I decided to set the following schedule

22:00 - 11:00 - Frost Protection Mode
11:00 - 22:00 - Eco Mode (Heat Pump only)

My thinking is that from 11 AM, it will likely be warmer outside which would then be the best time to heat the water. I am hoping that overnight the temperature in the tank does not drop too much. I'm not sure if 11 hours is correct though for the heat pump to be active. Is that too long?

I have raised the target temperature to be 50 degrees C and have also set a Legionella schedule, thanks for that advice.

I also looked and it seems Octopus has a specific tariff that I could be using for heat pumps that will also be far more economical for me, so I will look into that, but it also has a peak rate that I don't have right now, so I am not sure if it is the most effective.

In the meantime, I'm curious if that schedule is correct for someone who is at home all day most days of the week.

 

[stem]

The hot water cylinder looks to be well insulated, so it shouldn't lose much heat, which means that once the water has heated up even if the heat pump is programmed to be 'on' it should shut down anyway, and won't kick back in until you use some of the hot water, and then it will just top it back up and shut down again. If you didn't use any hot water I would imagine that the water would stay hot for a couple of days, so being off overnight should be fine, provided that no one has a bath after 22:00

'Peak rate' normally refers to the normal daytime electricity, so shouldn't be more than what you are paying now. 'Off peak' used to be about half the cost, but tariffs are always on the move and vary from supplier to supplier so the investigation you refer to is a good idea.

Running the heat pump when the outside temperature is higher is a good idea though. Unless it's using peak rate power and the off peak (often during the night) is much cheaper, even though it won't be getting quite so much heat out of the air during the night. Be interesting to see how you get on.

 

[Why Not Indeed]

I work from home full-time and usually heat my office all day.

Get an electric blanket and shut your office door.