MarcelHoldinga

That's quite alright - it shows you're eager to help! I've found the replies so far very useful.

Our slab is around 130 sqm (about 120sqm internal), so not too far off yours.... I've had a root through the menus on our ASHP (Daikin Altherma), and it looks like the installer has stopped down the menus so we're not able to select weather compensation - it's there in the manual, but the footnote indicates that some options may be hidden from view... ? Frustrating that I don't appear to be allowed to control my own heating system in my own house... coudl it be to do with the fact we're getting RHI? Do they stipulate specific usage conditions on the units being installed?

Thanks everyone for your responses... too many to keep up with, so I'll do a load of @ replies in this post... ? @Bitpipe The house is a bungalow, and the heating system (afaik) was designed to match the heating requirement of the house. The heating was on when we moved in - not entirely sure why, unless the intention was to dry out the slab/tiles, and we were advised to keep it running for some reason. We're in Orkney, so we're quite far north, so that could be a reason, I suspect - it doesn't tend to get that cold here, but we do get winds that take anything that isn't securely bolted down away @SteamyTea I spoke to the company that installed the system and when I mentioned reducing the UFH water temp, they said "oh, but if you turn your water temp down, your heat pump will hardly be on..." - funny that, because I thought the whole point of an energy efficient building method like ICF is to minimise running time of your heating system! I've turned the temperature down to 36, but I will have a look whether it gets better with 32. @PeterW We have an E7 (or possibly E10) meter, though at the moment we're with Bulb, who all of a sudden can't supply E7 electricity, so it's all the same rate at the moment - oddly, they could supply us E7 in our previous house... probably due a switch to a supplier that can provide 100% green energy on dual rates... @joe90 The temperature on the heat pump was set to 38 (though I turned it down to 36 this morning), the manifold gauge read 32 at one point yesterday, shortly after, I heard the ASHP kick in and made a point of checking again some time after, and it had increased to 38. @ProDave What you said sounds about right, the room temperature is overshooting the set temperature. I suspect it might be the high water temperature and the fact the actuator motors take about 5 minutes to close once they're open. The pipes on the manifold are marked, so I'll have to take a day or so to figure out which stat controls which loop, and see if there's a couple that have been swapped over. They should be fairl straightforward to swap around if needed, shouldn't they? I've also just noticed that the design specification states that the heating system needs to be "fully programmable with intelligent thermostatic control" - I don't think a timer at the manifold and 6 on/off dial stats counts as intelligent (unless that part was intended to be the owner, in which case, fat chance!). I suspect we need to have a word with our builder to see what's going on here. We should really have noticed, but the build took twice as long as it should, and we've been ground down by the whole process and ended up just pleased we had somewhere to move into!

Thank you Bitpipe, for a moment there I was worried I was just getting told off on my first day! ?

Hi there, I'm new here. We've just moved in to our selfbuild (contractor built) ICF house. The house has 3 bedrooms, a lounge, a dining kitchen, a utility room, an en-suite and a main bathroom, as well as an entrance lobby/corridor. We've got an air to water heat pump, powering wet underfloor heating powered, and an Airflow MVHR system with radial air distribution. The water temperature for the heating is set to 38 degrees and we have 6 thermostats (Honeywell T6360 analog dials), most of which are set around at 19-19.5 degrees. We were advised by one of the engineers that the heating system should be left running 24 hours, so it's ready to provide heat when/where needed, so I took him on his word and have been leaving it running 24/7. I've noticed that the room temperatures regularly register at 3-4 degrees higher than the temperatures set at the thermostat (on cloudy days - never mind when we get a few hours of sun through the windows on a morning). In particular, the main bedroom has regularly is around 23 degrees C at the time we go to bed - way too hot for a bedroom. There is an MVHR outlet in the ceiling and the thermostat that's set to 18 degrees C, yet the temperature in the room gets jacked up to 23. At those temperatures and settings, I've noticed the floor being warm underfoot, which I wouldn't expect with the temp set as low as it is. I've tried to program the MVHR to dump some heat by lowering the supply air temperature and hoping that the summer bypass will kick, but unless I can adjust my heating temperatures before the bypass comes on, I will just end up running the heating to just have the energy sucked straight outside... Does anyone have any tips for managing the temperature in the house so we don't end up being slow cooked overnight? Thanks in advance for any wisdom you might be able to impart!