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Aloha
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September 5, 2025
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New build. Daikin heat pump Altherma 4 advice please.

  • September 5, 2025
  • 15 replies
  • 1034 views

I have recently moved into a new build house with a heat pump system.

 

Its a Daikin Altherma 4 with a 280 litre cylinder.

 

The hot water is currently set to 45c on a reheat setting.

 

I'm trying to make it as energy efficient as possible on the hot water side.

 

I keep hearing so many different reports on which setting is best etc.

 

We are a family of 4. 2 adults and 2 teens.

 

We all normally shower etc in the evening and wash the dishes mainly in the evening, all of which happens roughly around 6pm to 8pm.

 

I'm up at 6am for work and have a quick face wash etc around 6.30.

 

The weekend is similar but sometimes the showers, baths happen during the day.

 

 I have heard that Schedule and reheat is better than just reheat?

 

If so, what kind of times should i be setting on and off, and what temps?

 

Also is it better to have a longer set back temp. like 20 or 25c or just leave it currently at 10c?

 

Also is eco better than comfort?

 

At the moment, we find that 45c on reheat works fine, but i would like to get the hot water schedule as efficient  as i can.

 

Any advice would be greatly appreciated.

 

    Best answer by juliamc

    There are 3 settings you can choose between: Schedule; Schedule and Reheat; Reheat (only). 

    I have mine set to Schedule and Reheat, which I think is the best of both worlds. 

    I think you should try setting yours to Schedule and Reheat. You could have the Comfort temperature at 48 and Eco at 45, then set the schedule to Comfort at 3pm and Eco at 3am. You will want to have the room heating on soon so you need to heat the water when you won’t notice the heating is paused. Lower your reheat temperature to 40 deg so it doesn’t reheat too often.


    Nb. When it’s running the Schedule the hot water heating cycle will start at the set time, and heat the tank until it reaches the target temperature. At that point it won’t heat the water again until the next scheduled time. You don’t actually need to set a Stop time.

    The other thing about timing all this is that 4pm to 7pm is the peak time for electricity usage. If you can avoid heavy use during those hours you will be helping the grid. There are some tariffs that offer a cheaper rate outside of those hours.

    15 replies

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    A
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    AlohaAuthor
    Rank 2
    September 6, 2025

    Thank you so much for your advice.

    So just to clarify.

    I set my reheat to 40c

    Set comfort to 48c

    Set eco to 45c.

    Then program  schedule for hot water on at 3pm on comfort till 8pm then off.

    Then programme eco to come on at 3am and then off at 8am.

    Does that sound right? 

    That way it won’t be one all day then? 

    Or do I leave it on 24/7 and just put the two schedule times in? 

    That’s the bit where I get a bit confused. do I put a stop setting in between those two times? 

    So you’re saying that I don’t need to set a stop time? 

    Just a schedule to come on at comfort setting at 3pm and then and eco setting at 3am? 

    You have been so helpful to me 

     

      juliamc
      Rank 20
      juliamc
      Rank 20
      September 6, 2025

      ...

      I set my reheat to 40c

      Set comfort to 48c

      Set eco to 45c.

      ...

      Just a schedule to come on at comfort setting at 3pm and then and eco setting at 3am? 

       

      I’d say yes to those settings, having selected “Schedule and Reheat”

      Unless there’s something different about Altherma 4 !! Mine’s an Altherma 3 and it doesn’t need the Stop.

      Try those settings and temps, and keep an eye out for it coming on to do a reheat after all the showers. You will find it helpful to see how long it takes to heat the tank during the scheduled times (if you look on your Usage graph from your electricity meter - assuming it’s a smart meter of course, you won’t have to get up at 3 in the morning).

      Please report back and let me know how it goes. 

      Julia

        A
        Rank 2
        AlohaAuthor
        Rank 2
        September 6, 2025

        Thank you so much.

        I’ve  now put a schedule and reheat on.

        3pm comfort 48c

        3am eco 45c

        Reheat 40c 

        I may introduce a further setting Like turning off the hot water at 8 pm and then have it coming back on again at 3 am for the eco-setting. 
        As you say, it’s experimenting to see which works best. At the end of the day, I don’t want it to cycle on and off all day when it’s not being used. I mean, hot water usage is after 6 pm at night and a tiny little bit in the morning the next day

        Ben_OVO
        Community Manager
        Ben_OVO
        Community Manager
        September 8, 2025

        Morning ​@Aloha and a warm welcome to the OVO Forum.

         

        I hope you’re well and had a good weekend. I’ve added the Heat Pump badge to your Forum account so that other members can recognise the kit you have. Thanks for your great post - I’m really happy to see you’ve received some helpful answers here.

         

        ​@BPLightlog / ​@juliamc thanks as always for your valuable insights 🤝.

         

        ​@Aloha you might also find some useful information in this previous research piece:

         

         

        There’s also some handy info on the Daikin page here: https://www.daikin.ie/en_gb/knowledge-center/7-tips-to-make-sure-your-heat-pump-is-running-100--efficiently.html

         

        Keep us updated as to how you get on - we’d appreciate it. Cheers!

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        Chris_OVO
        Community Manager
        Chris_OVO
        Community Manager
        September 18, 2025

        Hey ​@Aloha, 

         

        I just wanted to check in and see how everything is going with the new schedule. Have you seen any improvements? 

         

        I bet Julia and BP would love to hear how their advice has made a difference! 😊

        Renewable energy jokes never get old.
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