Andeh

So despite heating off from 4pm through to now... I'm still getting these odd bloody spikes!!! And they always seem to start around 1.30 am it seems...

Thanks Mark, I will do that! In the meantime I had a long chat with Joules (supplying & who spec'd it all) on the performance of the system & struggle we have in actually getting the house to warm up sufficiently & some odd temp drops we see. They have proposed that with us starting the heating across the FULL ''cool'' house at 3am during -3 degree temps, what is probably happening is the ASHP runs at full whack to pump heat into the house....and because -3 degrees it runs into defrost cycle reasonably quickly. However, due to a cool house & very low flow temps when the defrost cycle kicks in & the ASHP pulls the flow back/uses the UFH temps (which are every low) to defrost the defrost takes longer to run, before the system then restarts and heats the house. At this point the zones are now cold (because defrost cycle drawn back out what little heat) so the ASHP goes into full whack mode....and frosts up. It then reveres & what little heat it has put into the house....is pulled right back into a prolonged defrost period. We have a 50-60mm screed over a full 275sqm bungalow so lower retained heat capacity. We therefore end up in a vicious cycle, created by quite a 'cool' house in the first place. They have recommended we turn it off over night & run it for the course of the day tomorrow & weekend during the warmer periods of the day, to see if this is enough to break the cycle and get real warmth into the slab & house. There is a logic in this, however the really short & odd spikes are unusual all the same, and are possibly caused by the above behaviour!?!?!. They only appeared/appear during the really cold spots (and flatten out when the day warms up). Heatmiser possibly being very sensitive (which it is, I can detect when kids open their door in the morning based on the change in their room temp!!) could be picking this all up due to the 50mm screed acting quite quickly to the change in temps from defrost cycles? If a ''turned off'' ASHP freezes up/detects its frozen (or was frozen when the heating turned off)...... would it still kick in a defrost cycle?

For what its worth, the whole system has been performing pretty well & normally up until the temps dropped this week. Some of the kids bedrooms don't heat up as much as I would like, but they are small rooms, with very high ceilings & carpeted so not unexpected -vs- tiled rooms! Big kitchen has always heated up around 1 degree an hour for October/early November without any issue etc Checked out energy usage so far today and it looks to be around 36kWh for the day to sar, which for nearly 9.5 hours of a 12kw ASHP operation seems remarkably low! Also a flow temp of 32 degrees after a few hours of operation also seems too low....!?

No idea at all! i'm struggling to even imagine what it is. We have MVHR going, and do notice in the morning when some bedrooms are opened the temps really jump as the central corridor retains more heat then the rooms with big windows coming off of it. The fact it is shown in both the Master Bedroom & Kitchen...opposite ends of the house & different MVHR is even more perplexing.... Also shows up in kids bedrooms...

Thanks all, ill add some more details here: We have a large bungalow, lot of windows but good insulated. Ait tightness of 2.2, 160mm PIR in floor & ceiling, 150mm dri therm 32 full fill cavities. Every bit of insulation double checked during installation by myself. It isn't great by buildhub standards/passive, but it is well insulated vs your average new build. Samsung Gen6 12kw ASHP, supplying Joules spec UFH throughout with Heatmiser controls. We have c20 zones of UFH (as 6 bedrooms, 3 bathrooms, large kitchen & lounge with multiple loops etc). It is over zoned but it is all controlled together, controlled as all on & all off during cosy periods. This is why 16 degrees during night to keep all zones ''off'' then boosted to 21 degrees during the 2 x Cosy periods/an hour either side of them. Heating periods right now are 3 am to 8am and 11am to 4pm, with 1 hour DHW first thing & last thing within Cosy periods.... all on via 21 degree temp then all off via 16 degree set back. House holds the heat pretty well loosing 2 degrees over night with the -3 deg temps. Flow temperature right now is 32 degrees out of ASHP, supplying two manifolds. No blending valves on the manifolds, flow rates between 1 and 2L/min. All stats are next to sockets in each room, with UFH below carpets in most rooms. MVHR is on & used throughout. After the day today, this si what it looks like...again showing the heating on & hooting off periods....

To add to the above, we have a lot of zones throughout the house, but they are all being operated together....ie all open for 2 x 4-5 hour periods a day.

Checking how our UFH and ASHP performed with the recent cold snap, and our heatmiser app is showing some really odd behavior... Per attached pics. The tiled rooms are hit harder then those carpeted, I'd almost suggest closer to the manifold the bigger the drop. What is causing these large drops? Could it be defrost cycles? Anything I can do to soften this happening, as it is really slowing down the warming up of the house.

I did exactly the same, and have exactly the same loss. It still bugs me, massive insulation around the pipe, fastidiously applied... Nigh on bugger all difference! Grrr

Expanding foam around them?

100% insulate the hot circulation pipe at the very least, otherwise it's basically a radiator dumping valuable heat in a non valuable space!! Im also 90% sure it's in the building regs to do it as well....

We're due to submit ours in the next month or two, is this live now?

Our first winter in our new build, big bungalow is showing its down sides with the extra walls and floor drawing out heat. Lots of big windows reminding us of their presence as well. Im octopus cosy period, which was fine for the October to November month, but last couple of weeks and the week ahead I am adding extra time before/after the periods now. What is more efficient at hammering the power during Cosy periods... Starting the ashp 30mins before the cheap rate to enable the system to wake up and ramp up in time for cheap rate.... Or running the system 30mins after cosy period where the system is running at a steady rate?

We had sliding corner doors, and had about 40mm on both sides against the vertical steels. I was annoyed at the size, but quickly forgot about it! Now with plasterboard and external trims and render you'd never know! Accept what you've got, nobody is going to replace them to gain maybe 15mm. Top rule of self builds... Pick your battles, and know when you're not going to win! Move on.

Just a feature heatmiser offer!

Well, after 4 nights of sat next to the meter (nothing happening) then a couple nights where it did happen and I slept through it.....then £40 on appliance monitoring equipment..... FOUND IT!!! Somehow I had 'prehea / optimum start' enabled in our utility room zone, which is a zone which never really comes on due to plant room...with the warm cylinder, drying clothes etc it was also a room that isn't directly connected with external temperatures. Checking the heatmiser app for this room shows the preheating kicking on at 3am...ahead of 4am when all the heating zones really kicked in! On the bright side...at least I know Heatmiser has an optimum heat capability

Just whatever paints cheapest, twice used Leyland 25L with an extra litre or so of water in for the brick to absorb to good effect.

I'm the past I've successfully painted with a 50L builders bucket, large soft Broom, and a good 25% extra water. Always before I've needed to put a floor down mind you.... It's Messy but goes on super fast and super thick.

Very much agree!

I'm also interested to know!

Remind me tomorrow, I'll take pics of our sink! Similar design/setup to yours.

Thanks again! We have our local supplier coming out on Saturday. Are you able to provide a indication of price? We have a few 1.4 x 1.4 windows and some big sliders at 8m x 2.4m so cost is likely to be punchy!!

It can...but only between the hours of 3am and 4am, and content is solely that of a very bleary eyed & frustrated man in his pants counting wattages! 😍 In other news..... Once again....I spent my night staring at the meter, and for a second time....the bloody energy demand did not materialise! House sat merrily at around 250w Two energy tracking plugs arrived this morning, which will target the American fridge freezer & dish washer as starters..... Ill update accordingly.

Yes, but all very young! It's definitely mocking me.. My current process improvement to enable me to monitor from bed....

So on Thursday and Friday night, my phantom drain used nigh on exactly the same amount of power 1.07kWh (& 1.05kWh) from 3 to 3.30 then 0.65kWh (& 0.67kWh) between 3.30 and 4am. It's hard to imagine a scenerio where the power would be so evenly matched between two days, but happen entirely at random on whether it does it or not. ... But nothing last night per my above post.

Well, sat there between 3am and 3.45 this morning, aaaaand.... Nothing! (2 out of 2 morning monitors drawing a blank) Bought a couple of energy monitoring plugs. American fridge freezer (Samsung twin doors and big draw jobbie) did get glared at for a while with a defrost thing in mind.... Interesting to see it suggested above. It has an ice maker, G rated or something for effieincy... So it'll be the first thing to be plugged into a monitor. Legionnaires is turned off. No solar diverter Several AC units but I think if notice if one of them came on with a change in temp. It's occurred even with an outside temp of several degrees. Grrrrrrrr