ProDave

I will be tiling our hall and utility room floor soon with slate tiles of varying size. I intend to model that on CAD so I have a worked out pattern to follow.

The one I bought came from CPC in one of their special offers about 20 years ago. So I doubt it is still a current model. And yes it is noisy. The outlet comes with a semi rigid expanding hose and duct tape forms the temporary seal to the mvhr vent. This is just a temporary fix for now. I had not anticipated the need for cooling here so had made no provision for it. But thankfully our ASHP does cooling mode and there is an easy pipe route from the plant room to the loft to run pipes for 2 fan coil units which will be the eventual solution for bedroom cooling, though maybe not this year.

This shows the difference between an artist and an engineer. Had I been doing it, it would all be dead square, an exact integer number of blocks wide totally avoiding the need to cut all those slithers at an angle and get it looking nice.

There is no obvious ill effect. I have just done some measuring. Exhaust air temperature from the portable aircon 38 degrees, now going up into the en-suite mvhr extract vent. Outside air temperature at the east end of the house where the mvhr vents are, now just about in the shade 24 degrees. mvhr exhaust temperature 27 degrees, mvhr supply temperature measured at room terminal 25 degrees. Bedroom temperature just about staying at 23 degrees, same as first thing this morning. so cooler has stopped the room temperature rising due to thermal gain. But it is cooler outside today, if it drops much more I will be opening the windows.

No it's not a question of downloading. Just scroll down and look at the temperature and wind speed graphs, do they look like they are updating regularly or only every few hours? e.g it is saying for me right now "last observation 11:50" which is nearly 2 hours ago. It should normally update every 20 minutes or so.

It is funny how different councils behave. Ours know we have moved into the unfinished house but are happy for the moment for us to keep paying band A CT for the static caravan.

I have just set up my portable air conditioner in our bedroom. To "solve" the problem of where to put the warm air extract hose, I have removed the cowl from the en-suite mvhr extract and shoved the pipe up there for the MVHR to extract. I wonder if that will cause any unexpected issues?

I understood enough to know the concept of what you are taking about although if implementing it I would have a learning curve / questions to ask first. I would be interested if you could have a look at my Weather HQ link to see if you are only seeing the graph update every few hours. https://www.weatherhq.co.uk/weather-station/inverness-%2F-dalcross

Up here in the Highlands I probably get colder winters than most of you. Our ASHP seems to work fine here. It does not defrost as often as I feared it would, and it defrosts very quickly, taking about 2 or 3 minutes to complete a defrost cycle, so the amount of wasted heat is quite small. And as others have said, the worst time for icing up is when close to 0 degrees. When it's down to -10 outside the air is so dry it rarely needs to defrost. I would not be buying an ASHP just to heat DHW. Ours does heating as well, and in the winter it spends a lot more time heating the house than heating DHW, but because it heats the house with low temperature UFH it rarely needs to defrost while doing space heating, and although it runs for much longer periods doing that, the HP is not working anywhere near as hard as when heating DHW. And very topical out HP can also do cooling.

In my case I could tee into that flow and return for anything. All my flow and return branches run to their destination with the 2 port valve at the destination, so in the case of the DHH tank, the 2 port valve is on the pipe feeding the coil. I could tee off below that if I wanted with another 2 port valve for any other circuit e.g another heating circuit. Just occasionally we could do with a little heat in the bedrooms so I will organise these FCU's in the bedrooms so they can do heating as well as cooling,

I can only seem to find those sold as a packaged system with the heat pump.

A lot suggest the concept of heating the DHW so say 45 degrees with the HP then topping up with the immersion heater. That concept falls over for me as it would work fine on the first tank warm up. But then you draw some water, or the tank cools by losses, and it will drop to the point of the immersion heater coming on but will rarely get low enough for the HP to turn on. As @joe90 says just use the HP to heat water to 47 or 48 degrees, that is all you need and well withing the parameters for a heat pump.

Last night was probably the first in the 17 years we have been in the Highlands that it never really cooled down enough overnight for the night purge not to work very well. Bedroom was still 22.5 this morning. Downstairs, with the floor cooling been on all night, was down to 21 degrees. The ASHP has used 3KWh in the last 12 hours cooling, so has probably extracted about 9KWh of heat from the house. I did try reducing the water flow temperature to 16 degrees but then noticed a bit of condensation forming in the circulation pump, so put it back up to 18 degrees. This little spell has confirmed we need to fit fan coil units to the bedrooms for cooling, something I never thought we would need up here, though I may not get those done for this year.

Where are you getting that data? I normally use Weather HQ to get live weather data (and historic data) and it normally updates about every 20 minutes, but for the last few days it only seems to be updating about every 6 hours e.g here is Inverness, not updated since 16:50 https://www.weatherhq.co.uk/weather-station/inverness-%2F-dalcross

Yes not cooling down here either. I am going to leave the floor cooling on all night. That won't help upstairs. I will open the windows as we go to bed in the hope it cools down in a bit.

I can't see anyone paying more than the c 5.5p octopus are offering. I think it is a political thing so people can't complain about giving electricity away for free. It is not really financially viable. You are better off aiming for maximum self usage instead.

That I believe is an evaporative cooler? It reminds me of an aircon unit we had in an office years ago. It was an all in one monoblock. It didn't have big ducts through the wall. Instead it took in mains water and put the extracted heat into that, it was in escence an air to water heat pump. When the tank of water got to a certain temperature, it opened a valve and dumped it down the drain and refilled the tank from cold mains water. I suspect some water byelaw has outlawed that type of unit by now.

The day has just kept getting hotter here. It seems to have peaked at 30 degrees which is VERY hot for up here. Still far far too hot to open the windows. 24 inside upstairs now. Pleasant 17 and sunny on Shetland, wish we were still there.

Modern machine with aircon in the cab? Well combine harvesters have it so why not?

I must admit I finished early today. The job I was on has a lot of stuff to do up in the loft, and since the job is not urgent, I thought that could wait for a less hot day (preferably a cloudy and wet day)

The 2 things to beware of, are do the existing (now worm infested) joists perform any structural function helping to tie the front and back walls together? I would want SE input on this. With a typical 1.5 storey croft house build, the roof may be prone to spreading with nothing tying the walls (though often the sheer bulk and thickness will prevent that) Ant the trap that 99% fall into is to build a skinny frame and insulate it with 25mm of kingspan thinking they have done a good job, but they usually leave the cavity between the stone house and the inner frame open to the cold roof space. It makes it damned handy as a sparky for running new cables but not much good for energy efficiency.

Been like that for a few days now here. But I have managed to educate the familly to keep the windows shut in the day. In the evening I check the outside temperature and as soon as it drops lower than inside, the windows are opened to start the purge.

The hassle of running the pipes puts me off And it would have to be under the radar otherwise some busy body would tell me I need an abstraction licence (even though it would all go straight back in) I must measure the water temperature in winter. It never freezes even when -15 overnight.

Surely bypass mode will only work to cool a house when outside temperature is lower than inside? If it is hotter outside you will get that hotter air straight into the house. when it is really hot outside you want the MVHR in "heat recovery" mode. All the heat exchanger does is seeks to equalise incoming and outgoing temperature. so when it is hot outside, the incoming air will be cooled a little by the cooler outgoing air.

Just north of Inverness, 26 outside, 22 inside. At least the nights are cool enough for an all windows open night purge to cool the house down for the next day. And today is one day I am not cursing the trees for presently shading all but one of the south facing windows. When the WM finishes I might turn the ASHP back on in cooling mode for a bit. A bit of house wall that is in the sun, 31 degrees, Solar panel surface temperature 42 degrees. And for a contrast, water flowing in the burn, 9 degrees. (hmmmm, just pipe water from the burn through a fan coil unit for cooling?)