Your browser isn't supported
It looks like you're using an old web browser. To get the most out of the site and to ensure guides display correctly, we suggest upgrading your browser now. Download the latest:

Welcome to the MSE Forums

We're home to a fantastic community of MoneySavers but anyone can post. Please exercise caution & report spam, illegal, offensive or libellous posts/messages: click "report" or email forumteam@.

Search
  • FIRST POST
    • Hey!teacher!
    • By Hey!teacher! 12th Feb 17, 10:36 AM
    • 18Posts
    • 7Thanks
    Hey!teacher!
    Air source heat pump costing loads in electricity.
    • #1
    • 12th Feb 17, 10:36 AM
    Air source heat pump costing loads in electricity. 12th Feb 17 at 10:36 AM
    I'm hoping someone here might have some ideas for us before we're broke or frozen!
    We moved into a house in June last year, it's a 1930s semi but with a new extension making it a 4 bed. 1700sq ft.
    Its got an air source heat pump and underfloor heating throughout and it's been great all summer with solar panels for the water giving us plenty of hot water.
    But we've just had our bill from September until January and we've used £800 in electricity! It's around 60kwh per day.
    I've turned it down to what we can bear, which is on the chilly side, we had open fires last night to take the edge off but without them it was colder than I'd like. (It's been snowing though so has been cold) Its gone down to 46 units a day now but with two loads of washing, a heated airer and about 2 dishwasher loads in 24 hrs. Only tv on during the day, with the odd phone charger etc. Nothing else that could be using that amount.

    I just wonder if we can get this down further and be a bit more comfortable. We do have thermostats but the previous owners took them off, the heating engineers
    told us most people wouldn't use them with this type of system. I've been told different things about leaving the floor on or off during the day when we're at work for about 10 hours, as it would take a long time to heat up.

    We know the house needs better insulation in places plus we've got three old double glazed windows which need replacing soon which will make a difference but I'm just wondering if anyone has any ideas of anything we can try now and if it's worth setting thermostats/controllers back on the individual pipes for each room?
Page 2
    • matelodave
    • By matelodave 1st Dec 19, 3:03 PM
    • 4,916 Posts
    • 3,211 Thanks
    matelodave
    It can be, it depend how the system has been configured. As the outside temperature reduces the heatpump has to work harder to maintain it's output however it can get to the point when it cant produce enough heat so the booster heater kicks in.

    The temperature at which this happens can be adjusted or turned off altogether. The system design would probably have included a period of boost heater running at very low temperatures. Have a look at the engineering menu to see what yours has been set at.

    Smaller heatpumps which are running close to their maximum output at say 0 degrees, will need to use the booster more than one that still has some headroom. In the end its a bit of a balance between the cost of a bigger heatpump or running the boost heater a bit more.

    Mine was originally set for -3 but I changed it to -5 however I've turned my boost heater off so it doesn't come on at all and we don't really notice if the heatpump isn't quite managing the load.
    Never under estimate the power of stupid people in large numbers
    • Nigelindevon
    • By Nigelindevon 1st Dec 19, 6:19 PM
    • 3 Posts
    • 0 Thanks
    Nigelindevon
    Thanks - I checked the setting and it’s set at 0. I could try -5, say. Are there any risks other than that it might not make the desired temperature?
    • matelodave
    • By matelodave 1st Dec 19, 8:25 PM
    • 4,916 Posts
    • 3,211 Thanks
    matelodave
    not as far as I know
    Never under estimate the power of stupid people in large numbers
    • lovesgshp
    • By lovesgshp 2nd Dec 19, 8:56 AM
    • 1,364 Posts
    • 750 Thanks
    lovesgshp
    What is the size of the ashp? With approx 160 M2, I would expect the minimum to be around 11Kw output, but more like 14kw, depending on insulation level.
    As Manuel says in Fawlty Towers: " I Know Nothing"
    • matelodave
    • By matelodave 2nd Dec 19, 10:35 AM
    • 4,916 Posts
    • 3,211 Thanks
    matelodave
    Mine is an 11kw LT Daikin Split installed in 2010 heating a 140sq.M detached bungalow.

    Decent loft insulation, cavity wall insulation which was fitted when it was built in 1986 and 1999 vintage double glazing. Overlay underfloor heating with programmable stats controlling each room.
    Never under estimate the power of stupid people in large numbers
    • Nigelindevon
    • By Nigelindevon 4th Dec 19, 6:58 PM
    • 3 Posts
    • 0 Thanks
    Nigelindevon
    Our Daikin split low temp 8kw is heating 365 sq m, but it’s a certified Passive House with ufh running at 35 degrees. Still learning about it. Really keen Passivhaus people say you don’t need any form of active heating, but we weren’t going to take that risk on the basis that it’s better to find we don’t use it too much rather than wishing we’d installed it when we hadn’t!
    • jojocrane
    • By jojocrane 12th Dec 19, 9:32 PM
    • 2 Posts
    • 0 Thanks
    jojocrane
    Is anyone able to share a picture of their Samsung unit with all the details. Iíve just moved into a rental property and the landlord is convinced the system is functioning properly but weíre freezing now because last months bill bled us dry. We were told to leave the ASHP running, which we do for the downstairs underfloor heating (set to 21) but our radiators upstairs never feel hot. We ďtriedĒ for 3 weeks leaving them on constantly and the house became hot (radiators only warm) but we were hit with a hugeeeeee bill. So now weíve turned them to twice daily but as they never get HOT(only warm) it never provides enough heat to even try heating upstairs??!! So itís basically money down the drain! Any help will be amazing, Iíve no idea but Iím a paranoid mess checking my smart meter because we canít afford another disaster of a bill. Many thanks all 🤞🙏🤞
    • matelodave
    • By matelodave 13th Dec 19, 9:40 AM
    • 4,916 Posts
    • 3,211 Thanks
    matelodave
    Is anyone able to share a picture of their Samsung unit with all the details. Iíve just moved into a rental property and the landlord is convinced the system is functioning properly but weíre freezing now because last months bill bled us dry. We were told to leave the ASHP running, which we do for the downstairs underfloor heating (set to 21) but our radiators upstairs never feel hot. We ďtriedĒ for 3 weeks leaving them on constantly and the house became hot (radiators only warm) but we were hit with a hugeeeeee bill. So now weíve turned them to twice daily but as they never get HOT(only warm) it never provides enough heat to even try heating upstairs??!! So itís basically money down the drain! Any help will be amazing, Iíve no idea but Iím a paranoid mess checking my smart meter because we canít afford another disaster of a bill. Many thanks all 🤞🙏🤞
    Originally posted by jojocrane
    You are not using the system correctly, radiators should be lukewarm and remain like that most of the time, they should not not hot and should be left on for much longer periods than just a couple of hours a day.

    You cannot use a heatpump like a conventional boiler because it will cost you a lot to run and you'll still be cold - the main thing to check is that your flow and hot water temperatures are not set so high that the boost/back-up heater operates as this will send your bills sky high. You really do need to learn how to use it properly and not keep turning it on and off like a conventional bolier

    If I shut my system off, it can take a couple of days to rewarm the house, so I just turn it down a couple of degrees overnight, rather than off.

    Air Source Heatpumps are much more sensitive to outside temperature changes than say a conventional boiler and people with them tend to focus on their consumption but you do need to be aware that you will use most of your energy in the winter (something like 70% in my case) so it will look high ath this time of the year. Make sure you are on a decent low cost tariff.
    Last edited by matelodave; 13-12-2019 at 9:43 AM.
    Never under estimate the power of stupid people in large numbers
    • Cardew
    • By Cardew 13th Dec 19, 12:19 PM
    • 28,082 Posts
    • 13,924 Thanks
    Cardew
    I’ve just moved into a rental property

    _
    _



    but we were hit with a hugeeeeee bill.
    Originally posted by jojocrane

    How big is hugeeeeee?


    As you have just moved in, are you sure that the consumption is all yours? i.e from meter readings at the start of your tenancy to an actual reading?


    As said above, and by the owner, an ASHP must be left on 24/7, With ufh, correctly, at a low temperature setting, your upstairs radiators will be cool to touch, that's why they should be much larger than a property with conventional CH.
    Last edited by Cardew; 13-12-2019 at 12:53 PM.
    • Andy_WSM
    • By Andy_WSM 13th Dec 19, 2:14 PM
    • 2,179 Posts
    • 4,604 Thanks
    Andy_WSM
    and the house became hot
    Originally posted by jojocrane
    If the house did indeed become "hot" then there's part of your problem. As stated above, leave it on low continually. Use the radiator thermostats to stop rooms becoming "hot" and the heat pump won't need to do as much work and cost you as much to run.

    If the rooms upstairs have thermostatic radiator valves then set them at 3 or 4, not full on and leave the controls to do their job. Likewise when downstairs has reached 21C the controls will stop the floor needing heat and you will find the heat pump cycles on & off rather than runs continually.

    Mine is set to maintain 21/22C in the whole (detached bungalow) house and I don't spend more than a few £ a day on electricity and notably the heat pump only really runs for 10 mins at a time then a pause of at least as long if not longer.

    • jojocrane
    • By jojocrane 13th Dec 19, 2:35 PM
    • 2 Posts
    • 0 Thanks
    jojocrane
    Thanks all
    Firstly thank you for all the replies!! Iím banging my head and hoping to get to the bottom of it all without hitting another bill. Iím also nervous to start switching the radiators on full time ďincaseĒ we get stung but guess I should bite the bullet.
    So Iíve just been billed for £366 in about 3 and half weeks worth of electric. Our meter went from 468 up to 2853 in 3 weeks!!! Iíve now got the smart meter up and running so Iím trying to monitor it all but itís a minefield. The landlord hasnít really explained( or knows fully) about the system or he does but heís happy to pay £234 A MONTH and of course Iím not!
    Again if anyone with a Samsung could send me a screen shot of the numbers I can adjust on my digital thing on the cylinder Iíd be really grateful or anyone who could message me directly and chat offline.
    But if not, should I be brave and switch it on 24/7 making sure all the radiators are turned down to 3/4??? Obviously the smart meter chews up electric the colder it gets outside, does that mean the radiators are going up and down themselves because thereís no thermostat controlling the upstairs, only downstairs which weíve mastered!! Thank you once again for helping a damsel in distress, really appreciate it 😍
    • matelodave
    • By matelodave 13th Dec 19, 3:24 PM
    • 4,916 Posts
    • 3,211 Thanks
    matelodave
    I dont have a Samsung (mines a Daikin), so I can't comment on how it operates or how your system configured or controlled.

    However as Andy says, you need to try and leave the unit controls to control the unit and just use the room stat and TRVs to adjust for the temperatures that you require in each room. have a shufti here https://www.freedomhp.co.uk/wp-content/uploads/downloads/Installation%20Manual%202019%20for%20email%2019-07-19.pdf and read page 7

    Also because heatpump systems are much slower to respond, you should only make small adjustments to one thing at a time and give it a couple of days to stabilise - keep tweaking just means that you don't know what is going on - if necessary write down the settings, together with meter readings and what the weather is doing so you can correlate what is happening

    It probably took me a couple of months before I'd got my system set up properly and by shutting it down to a low level during the coldest part of the year we ended up doubling our electricity consumption whilst it struggled to reheat the house using the boost heater. We just let it get on with it nowadays and if it's everso cold it runs all night at a low level rather than trying to get it to go flat out to reheat the place

    If the heatpump has weather compensation enabled then it will adjust the flow temperature depending on the external temperature and so will turn the heat pump down when it's warmer and up a bit when it gets colder so mucking about with it will actually reduce the efficiency and cost you more. What temperature have you got your hot water set to, we get away with 45 degrees with a boost to 60 once a week.
    Last edited by matelodave; 13-12-2019 at 3:30 PM.
    Never under estimate the power of stupid people in large numbers
    • Andy_WSM
    • By Andy_WSM 13th Dec 19, 3:35 PM
    • 2,179 Posts
    • 4,604 Thanks
    Andy_WSM
    What temperature have you got your hot water set to, we get away with 45 degrees with a boost to 60 once a week.
    Originally posted by matelodave
    Looks like we have both settled out at similar numbers. Mine is set to 44C and I don't use a boost, I let the solar immersun boost the tank up to 60+ whenever there is enough sun to do so - today was one of those days. I've not had to intervene yet, the sun shines enough at least once a week / 10 days even in the gloomiest of weathers I find.

Welcome to our new Forum!

Our aim is to save you money quickly and easily. We hope you like it!

Forum Team Contact us

Live Stats

2,910Posts Today

6,641Users online

Martin's Twitter