Air-to-water heat pump woes

Lilium25

Hello, 

I just wanted to share my experience living in a flat with an air-to-water heat pump and ask your thoughts. Since I moved into this flat, my energy bill has been high (it's a newly built one-bedroom flat - loft (EPC C), I live by myself and am not frivolous with the energy I use). Does anyone (perhaps an engineer) know if the water heater must be on 24/7? Isn't there a function in these systems where you can set the hot water to switch on for a certain period (for example an hour or two hours a day)? My last energy bill was £65 (meter readings submitted on 7th August and the 7th September and I was out of the country from 11/8 to 4/9).  My total energy bill from June 2023 to June 2024 was £1,456 and I haven't switched the heating on since the end of March 2024. I'd be grateful if anyone could share their experience and let me know if my energy bill looks normal (because I think it doesn't). Are these systems supposed to operate at such a high cost? Many thanks in advance

Spies

The water heater should be boosted on a schedule once a day or when the temperature drops in the cylinder by a certain amount, this can be set on the heatpump controller.

When you go away I would assume you can put it in to some sort of holiday mode. 

wrf12345

I will be denounced for saying it, but running an electric shower for a couple of minutes a day versus keeping a cylinder of hot water always hot via a heat pump or gas boiler, the former is going to be a lot cheaper despite the unit cost of electricity being more expensive by a factor of three or four. 

DougMLancs

We use about 0.8-1kWh of electricity a day at the moment to heat our hot water with our heat pump. What temperature have you set for your hot water? It’s typically recommended to set at 48-50 C and then the heat pump/immersion boosts it to around 60 C once a week on a schedule for legionella control. 

It cost us £250 for heating and hot water for our 3 bed semi over a year so what you’re experiencing are not normal running costs. Can I also ask what tariff you’re on?

matelodave

Like Doug above, our hot water only uses about 1kwh a day we have it timed for approx one hour before we get up and theres enough hot water for both of us for all day and in fact,  at this time of the year, we only heat it every other day.

I'm guessing that the OPs temp is set too high - 48-50 degrees is usually enough and if it set up wrongly then there a better than even chance that the boost or backup heater is kicking in if the temp is set above 50-55 degrees.

Most ASHP have a sterilising cycle which, if activated, boosts the temp to around 60 degrees once a week or so, If I let our do that then we dont need the water heated the next day but like many I've deactivated mine as I dont believe its necessary with an unvented tank fed directly from the incoming mains. However in the great scheme of things a boost to 60 once a week isn't going to break the bank.

You need to check your settings - perhaps if you told us which ASHP you've got and how the controls have been set up someone could help with advice. Alternatively there's lots of info on t'interweb.

It may also be useful to to an energy audit to make sure that your meter is actually yours and that accurate readings are being used and not random estimates and that others stuff isn't using some of it. Just because you've got a heatpump it doesn't necessarily follow that its solely to blame for high energy consumption or costs. What tariff are you on

Lilium25

DougMLancs said:

We use about 0.8-1kWh of electricity a day at the moment to heat our hot water with our heat pump. What temperature have you set for your hot water? It’s typically recommended to set at 48-50 C and then the heat pump/immersion boosts it to around 60 C once a week on a schedule for legionella control. 

It cost us £250 for heating and hot water for our 3 bed semi over a year so what you’re experiencing are not normal running costs. Can I also ask what tariff you’re on?

Thank you DougMLancs, 

I am not sure at what temperature the how water is set. When I moved, the system was set up, and neither the managing agency nor the installers explained how to use it or check the settings. To be honest, I'm nervous about checking the panel with the settings because it looks so complicated. I want to check whether as a tenant I have the right to call the manufacturer to send an engineer and re-set it. Every time I raised this with the managing agency, they told me that it was supposed to be on all the time. I am on Octopus 12M Fixed and my direct debit is 

Lilium25

matelodave said:

Like Doug above, our hot water only uses about 1kwh a day we have it timed for approx one hour before we get up and theres enough hot water for both of us for all day and in fact,  at this time of the year, we only heat it every other day.

I'm guessing that the OPs temp is set too high - 48-50 degrees is usually enough and if it set up wrongly then there a better than even chance that the boost or backup heater is kicking in if the temp is set above 50-55 degrees.

Most ASHP have a sterilising cycle which, if activated, boosts the temp to around 60 degrees once a week or so, If I let our do that then we dont need the water heated the next day but like many I've deactivated mine as I dont believe its necessary with an unvented tank fed directly from the incoming mains. However in the great scheme of things a boost to 60 once a week isn't going to break the bank.

You need to check your settings - perhaps if you told us which ASHP you've got and how the controls have been set up someone could help with advice. Alternatively there's lots of info on t'interweb.

It may also be useful to to an energy audit to make sure that your meter is actually yours and that accurate readings are being used and not random estimates and that others stuff isn't using some of it. Just because you've got a heatpump it doesn't necessarily follow that its solely to blame for high energy consumption or costs. What tariff are you on

matelodave said:

Like Doug above, our hot water only uses about 1kwh a day we have it timed for approx one hour before we get up and theres enough hot water for both of us for all day and in fact,  at this time of the year, we only heat it every other day.

I'm guessing that the OPs temp is set too high - 48-50 degrees is usually enough and if it set up wrongly then there a better than even chance that the boost or backup heater is kicking in if the temp is set above 50-55 degrees.

Most ASHP have a sterilising cycle which, if activated, boosts the temp to around 60 degrees once a week or so, If I let our do that then we dont need the water heated the next day but like many I've deactivated mine as I dont believe its necessary with an unvented tank fed directly from the incoming mains. However in the great scheme of things a boost to 60 once a week isn't going to break the bank.

You need to check your settings - perhaps if you told us which ASHP you've got and how the controls have been set up someone could help with advice. Alternatively there's lots of info on t'interweb.

It may also be useful to to an energy audit to make sure that your meter is actually yours and that accurate readings are being used and not random estimates and that others stuff isn't using some of it. Just because you've got a heatpump it doesn't necessarily follow that its solely to blame for high energy consumption or costs. What tariff are you on

Thank you Matelodave, 

The ASHP is the Grant Aerona 3. As I mentioned in my reply to Doug, I'm nervous about checking the settings as I find it very confusing and want to find out if I can call the manufacturer to send an engineer to check and reset it. The system was set by the installers - plumbers before I moved in and there wasn't a handover or someone to explain to me how it works.  I'm with Octopus 12M Fixed (Unit rate 22.52p/kWh). 

FreeBear

Lilium25 said: I'm with Octopus 12M Fixed (Unit rate 22.52p/kWh). 

I suspect you might be better off on the Cosy tariff, or possibly even Agile depending on you attitude to risk. If you know what your split is between heating and general consumption, crunching the numbers should be fairly easy.

Nick_Dr1

2 minutes Googling came up with this
Aerona3 Heat Pump Controller - YouTube -  a whole series of videos explaining how the system works.
Getting an "Engineer" out to set it up is just kicking the can down the road very expensively. What if they set it up and its still expensive? Do you keep calling them back? Far better to figure it out yourself!

You will benefit in any case from a different tariff and then setting a sensible schedule to make best use of cheap periods especially for hot water. As suggested, look at the Octopus Cosy tariff - its designed for heatpumps.