JohnMo

Insulated plasterboard inside the walls? No undoing or redoing work.

What goes up, must come down. Was involved in an offshore wind farm and it had an onshore sub station, the noise at the sub station had been attenuated really well, but the village about 3 miles away had a nice focussed beam of noise coming down on them, apparently way noisier than you would have expected, anyway £1 million pounds later they had it fixed.

A crankcase heater is generally in the 50W so 50W/h or so. But if it's about 5 degs or below then and water temp has cooled within the heat pump, it may be doing antifreeze cycle of the heat pump, it starts the circulation pump and could also start the heat pump to input heat into the system?

The amount of frosting is directly related to the flow temp of the water and outside temperature. The more work you ask the heat pump to do (i.e. hotter flow temperature) for a given outside temperature the more likelihood of frosting up. So as @ReedRichards says perhaps the WC is just set wrong.

Starting to come to the conclusion, I either leave as it is; a wireless on/off switch, or I need to run a external cable.

Outside observation Sounds like a pretty big ASHP you are looking to install, could your efforts be better spent making fabric improvements to the house so you could install a way smaller heat pump and get down to single fan unit? Also without very careful design your proposal could end making the noise worse, rather than better, and end up focussing the noise in a single direction. Choose make or model of heat pump also makes a real difference in noise production and how annoying it is to othes.

Different sheet of paper, with different tick boxes. Can't get away from those tick boxes.

Never really understood why anyone goes block and beam for anything. Cold breeze under the house when ever it's cold outside. Maybe a good reason, but I wouldn't.

1. At any high point where air can accumulate. 2. As long as it becomes a new high point, pipe always slopes upwards to vent point.

Have ASHP and cylinder, currently operating on an on/off signal from thermostat, with a signal being sent wirelessly. Want use the digital input terminals on the heat pump for a different purpose, so need to connect a PT100 probe. Does anyone know how I can transfer a PT100 probe output wirelessly to the heat pump - is it possible. I have home assistant if that's any help

I have two very different spaces to heat, the house and have UFH in the summer house (it is used most days by the wife) the UFH manages the min temp set point (10 deg), a direct electric heater does the rest. If I batch heat the house overnight I end up spending using the electric heater to keep the summer house above 10 deg. My heat pump has minimal inputs similar to @jack. But I do have a double set point input - unfortunately it's a multi purpose input and I use that for cylinder heating thermostat call for heat. Last night, on cheap rate, I used the immersion to heat the cylinder as a trial, cylinder was at 48 degs this morning and heated in 45 mins. So that works ok. I have another option to connect the cylinder via a PT100 probe, but is just about impossible to route the cable, so would need a wireless option (new thread I think). That would leave the dual set point connection open to use. So dual set point - have one set point set high to batch charge the floor, once up to temp use the thermostat to switch to the lower setting and ASHP circulation pump would continue, but as the flow temp would be pretty high the ASHP would be unlikely to start up, summer house borrows heat from the house.

We have a slab below the insulation for structural reasons, so cold pipes are within that, zip tied to the rebar. Used flexible conduit over those pipes. We only have one electric cable in the floor to our island, this is in our top slab with the UFH pipes, that was in solid 21.5mm plastic drain pipe.

The simple answer is, there is no simple answer. Every house is different Nd every owner has different expectations of house temp. Generally good rules are 1. Always flow from the heat pump at the lowest acceptable temperature. Acceptable meaning gives the house internal temp consistent with your expectations. 2. Run heat pump for long periods, this goes with 1. allowing low flow temps. 3.Try to have house at a consistent temperature, don't allow to cool down to much, if you want it cooler at night only set back the temp a couple of degrees, otherwise the heat pump can't catch up with heat demand. Weather comp allows point 1. (Lowest flow temp). Fixed temp maybe not, depends on the house time temperature constant. Normal house with rads or UFH weather comp.

Flick a switch changes ASHP from heating to cooling. Just set to run at 11.5 degs, (no condensation seems to form at that temp) run at times likely to have a decent amount of solar. Need to automate it for next year. Have home assistant and solar forecast already built in. So thinking, June to Aug, if solar forecasts X kWh forecast the smart relay switches on heat pump from say 10am to 5pm. It's not fantastically effective, but does knock the excess heat off - solar gain only reason we get hot inside. It's all run on excess PV, so cost is basically zero. But get your point on a fan coil. Our outside temp rarely goes above 25 degs, so EER is circa 6 while cooling.

He is wanting the heat pump to output a higher temperature that it's currently programmed to do. So instead of flow say 30 degs, increasing to 32 during cheap rate. Lexone will manage house temp, not flow temperature.

So have just adjusted stuff, upped WC curve up a couple of degrees and set thermostat to 20.5, so it controls the temperature, have set it at 20.5 from 0:40 to 20:00hrs. Our PV diverter has a built in boost timer, so have set immersion on timer overnight during E7 hours for four hours. Tonight's temps very similar to last 24hrs, i.e. sub zero, so can compare usage day on day tomorrow evening.

Heat pumps even quite basic ones, normally have a dual set point option, that is selected via an open/closed zero volt switch. Dual, or double set point have seen in lots of manuals. Normally need an external switch or relay to operate. If you have a simple time switch or smart relay - done. Like this one also.

I have a thermostat, but could just as easily be a time switch as it does little or no temperature control. That's it a 3 way diverter to the cylinder or UFH, no buffer. Any cooling is done via UFH circuits. All done via WC. ASHP modulates it's output based on return temperature without any interference from me. Are you sure you need 9kW with a 155m2 house?

I got them from a local blind supplier, since I wrote the above, I have charged once. They are used almost every day and go up and down on demand no issues.

Dulux Trade paints for me, water down for mist coats (50% water) and then straight after that. Really good covering power, available at B&Q, Screwfix and Toolstation well below than a Dulux Trade Centre prices. Can be mixed to any colour you want. Would suggest a bland pallet of colours if a new build, because you will be redecorating sooner than later, and everything also looks different to what you expect when you get it furnished etc.

We are the same. But that one wall of glass , triple glazed as it is, looses as much heat as the roof, floor and walls all added together

It certainly can be more scientific, but many would run a mile, instead of doing what you and I, have done. My predicted curve at around zero is about 0.3 degrees out; because I didn't forecast in defrosts cycles. Mainly as I had no idea, when they would occur, how long the defrost cycle was etc. So I gave a simple intuitive means of getting the same result. Even with the spreadsheet there is still some manual adjustments, or you just over compensate (most installers do that so they don't get call backs) run slightly hotter, than you need and use TRV's to keep you right.

Hope they are sensible enough to state whole window U values and not just centre pane values. Good glazing in a bad frame makes for rubbish overall U values. When I was looking for windows for our house, started with double glazed, asking for 1.2 U values, got quotes back at 1.8, when questioned we can't get the frames you need? And no we don't do triple glazed, they do not make financial sense. Most suppliers are in general pretty rubbish. Ended up custom built triple glazed. You have to very careful when you read statements like that, are they comparing apples with apples, or an orange? Having a heat pump instead of a gas boiler gets to almost that CO2 saving on its own, especially if you forecast the grid CO2 intensity to 2025 and use 2022 as your baseline for comparison.

How long is that bit of string question. Obviously you are being quoted higher than you expected, if so ask someone else for a quote. If it's part of a bathroom install, you are also paying for the coordination of subcontractors etc. Asking a 3rd party contractor you employ to do the work, is asking for delays, and - he said, she said arguments, if it turns to a crock of sh....

Not sure why that would be the case. Even at 280m2, with a decent state of insulation and air tightness, your heating loads aren't going to over the requirements a 6kW heat pump. We have a 192m2 Durisol house, a long thin single storey all vaulted ceilings house (the worst configuration for low energy) our current total house draw from the grid is 2.1kW with the a 6kW heat pump running, MVHR , treatment plant and it's -2 outside. Our DHW heated during the night at -3 outside and total house draw during that period was a little over 3kW. A kettle will pull 3kW from the grid, we have a panel heater that can pull 2.5kW also, but it gets used in a garden room (long story)