Cost of running my new Air source surprising me - please help on most efficient way to run it!

Peter · 2021-12-23T10:43:30Z

I finished building my house this year and moved in back in June. I’ve been using my air source heat pump for heating and water and not really thought anything about it until I noticed my electricity bills. I’m spending about £13 a day on electricity and decided I need to learn how to most efficiently run my airsource and heating schedule. There really isn’t much information online about this. So I’m really hope someone here will be able to help me please. Thank you My set up is as follows: Mitsubishi Electric Ecodan PUHZ-HW140VHA2 14kW air-source heat pump Mitsubishi Electric EHPT25X-UKHCW 250 litre water tank Mitsubishi Electric FTC5 Ecodan Controller PAC-IF062B-E Heatmiser Streamline thermostat/controllers in each room House: New build house. Largely open plan downstairs. Does have some large window walls in the entrance hall which we would lose a bit of heat through. Floor coverings: upstairs is carpet and low tog underlay. Carpet is thick, but we kept the total tog below the recommended amount (my memory is hazy, possibly 2.5 tog?) Downstairs we have 12mm thick laminate. Underfloor heating upstairs and down Current schedules: Ecodan controller currently set to run at 18degrees continuously. 3 main living rooms (open plan kitchen, dining and lounge) set to 21 degrees between 5am-8.30am and then 16 degrees, then on again at 4pm for a couple of hours at 21, then back to 16 All other rooms in the house: Heatmiser contollers set to Frost protection mode (set to between 10degrees and 15 degrees) Hot water is heated from 6-7am and then half an hour in the afternoon 3-3:30pm. Hot water seems to heat to 41degrees now – although it used to be higher (could it be the compensation curve? Not sure if that changes DHW temp) I think my hot water only heats when scheduled to heat on the Ecodan controller – I though it might be using the immersion heater. From what I can work out, i don’t think the underfloor heating results in the water heating at all unless the immersion heater turns on. Hot water use/costs: October 158 kWh £34.74November 228 kWh £50.13December (<19th) 164 kWh £36.06 Heating use/costs: October 164 kWh £36.06November 621 kWh £136.54December (<19th) 491 kWh £107.96 Temperatures The room temp on the thermometers seems to average around between 15 and 17 degrees. Which feels freezing. We do have a wood burning stove which we have been using to heat the downstairs rooms to a more reasonable temp (gets up to 21-23 when this is running) COP values According to my MSC certificate we should get 3.48 COP. I reckon we’re getting the following: December 2021 <19th 2.348November 2021 2.377October to December 19th 2.179 If anyone can help with any advice that would be very much appreciated. Thank you very much

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Air Source Heat Pumps (ASHPs)

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 4 years ago

Posts: 4427

27/12/2021 3:52 pm

Hi @peter

Thanks for the update. It may be that you do not need to adjust the weather compensation, since auto adaptation should compensate for any differences that may occur. You can download all the installation and operation manuals should you require more detailed information.

I am pleased to see that your energy consumption is now only 25% to 30% of the previous day. Well worth a little time and effort.

👍

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mjr

(@mjr)

Prominent Member Member

Joined: 3 years ago

Posts: 301

23/02/2022 2:45 pm

To edit the compensation curve on the FTC, enter the menu by holding down the menu button instead of pressing it. The menu will look the same at first, but when you go into the options such as Heating, you will see extra options, including an Edit option for the compensation curve.

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George

(@george)

Reputable Member Contributor

Joined: 4 years ago

Posts: 85

23/02/2022 3:12 pm

Posted by: @derek-m

Hi @kev-m

Without me having to go through the manual again, is there a monitoring section within the controller menu, where it is possible to see what the flow and return temperatures are actually reading?

Much easier to do this via the melcoud app or web browser. It can show hourly temperatures for flow/return/tank temp etc.