Heat Pump Running Costs

Every two years according to the lad who commissioned my thermia.

Out of curiosity how much was it directly though Mitsubishi?

I got my first one done recently. It was just over 2 years old. It was 150 +vat from someone local.

I was worried I had left it too late as I had heard it needed to be every year. Service guy said it was fine though, but I should get it done every year from now.

I would have thought once you have the flow temps set you would not have to be touch anything as they should adjust according to the outdoor temp.

Having a brief look at the link and knowing all houses are different, I would be controlling it using the flow temp to see how it works out (pg. 50 in your link). Taking our own temp curve as an example we have it set at 40° @ -10° and 27° @ +10°, the highest flow temp I have seen is about 33°.

We are all rads so I would have thought your ufh would cope at these temps, temp in our house only fluctuates by a few points of a degree. Again, all houses are different so they will be fine tuning in this and best leave it for a few days before changing the settings again.

Some reading if you have not already-

3 Steps to Maximise Your Heat Pump (or Boiler) Efficiency  - HeatGeek

Weather Compensation or Load Compensation? - HeatGeek

Looking at the brochure I don't see a way of seeing what it is producing so not sure how you work out a COP from the unit, it may be worth emailing ideal boilers to see what they say.

I think there is a 10 year guarantee on the indoor tank and a 7 year warranty on the outside unit so its a decent guarantee from them to be fair.

I will PM you my lads contact details, but he is based in Cork and is flat to the mat servicing them and might not travel that much distance. What you need to do is contact your installer (is it Joule?) and they should give you a name of a service engineer in your area. But from discussions on here its very hard sometimes to get anybody!

we have used these guys (they cover south dublin so will travel it seems!)

https://www.smartheating.ie/

Did you check the glycol percentage in the system, change the anode in the tank if you are om well water or have high hardness in your water....there's a bit more to it

No glycol in my system and yes I have a water softener.

Just putting this up for posterity, A3 rated house Samsung Joule Gen 5 ASHP set up, UFH bottom floor and rads upper two. Circa 21.5 downstairs and 19.5 upstairs but set heat higher at night on UFH to utilise night rate.

Dec 2024 497 KWH used, 245 day and 252 Night at a total cost of €93.67

Average daily usage 16 KWH (3 euro per day), Max 27.81 KWH (5.60 cost) and Min 8.3KWH (1.76 cost)

Will add January in a few weeks to compare.

I have been fiddling with this a little, so the settings i have now probably arent what i had for December (but wont be miles off!)

So i have weather comp curve between -2 and 15 degrees

Lowest temp for UFH at 28 (i think) and highest 40 and rads the same .

Downstairs i removed all zones for the UFH and just the stat in the kitchen to call for heat (the rest are all set to 16 degrees so will never call) and its set at 21.5 during the day and 22.5 or 23 (if its really cold) at night (in the night rate window). Upstairs is set at 19.5 (with maybe an hour at 21 to remove any chill in the evening before the kids goto bed)

I am on a d/n rate (as we have an ev) with flogas a little under 25c per KWH for 8am to 11pm and 12.5c per KWH from 11pm to 8am.

Its a 3 story house so im sure i get the benefit of the UFH rising through the house decreasing rad use upstairs.

I think i could use less units but not at a lower cost i dont think as i am trying to utilise the 12.5c rate as much as i can!

Oh and DHW is also set to heat up in the night rate window.

What size is your house, do you mind me asking?

Similar to ours (205m) so good to have a comparison. We used 482kWh in January but temps were set a little lower. Coming in around 20.5 downstairs and 19ish upstairs. Downstairs all on one zone as well.

I am finding that one north facing room is about a degree cooler than the stat in the hallway…not sure what could be done here apart from increase stat temp to 21? I'm guessing that'd mean I'd be increasing everywhere else downstairs to 21 and the north facing room should get up to 20ish?

yeah not much you can do, as you say itll raise the temp for all rooms! do people find it cold?

our usage isnt optimised for units rather for cost, so i push more running at night with a 12.5c electricity rate (temps increased over night), thats why my min is still over 7kwh.

have to say having spent the weekend in my in laws mid 90s built house i appreciate the comfort of an A rated home…

yeah i have no idea why they change all the settings when they service, ill make sure they dont next year.

you need a specific energy monitor from your HP (or reporting from the device itself), impossible to know otherwise (for example i am charging an ev at least one night a week)

i am using a shelly EM