JohnMo

If it's solar PV you heat via the immersion, using a diverter. Wouldn't bother with solar thermal these days, it's an expensive one trick pony. But if you are getting an MCS solar PV then just export excess and get paid for it. If a self install divert to hot water via immersion. Either way a 2 coil cylinder is for solar thermal. It also takes away a chuck of cylinder volume dedicated to solar thermal.

What would you be doing with the second coil? A normal heat pump cylinder is perfectly adequate with a single coil. Just get one with around 3m² coil. Job done.

To add to the above - didn't bother with MCS. I paid £800 for a heat pump specific 210L cylinder, new from City Plumbing. £1300 for a monobloc 6kW ASHP, billy bargain from eBay. £ a couple of hundred for cable, pipes and fittings. Installed myself, except final electrical hookup - electrician for 1 hour, while doing other work. So all in circa £2500. No heating mods needed, as I have UFH.

Search ASHP MCS Umbrella scheme

Nothing to do with grant. You will still get the grant. But, Buffers and hydraulic separation remove efficiency, so adds to running cost, but also require secondary circulation pump. Both suffer from distortion where the heat pump sees higher flow temperatures than the heating system, this drive efficiency down. Flow temp, the higher it is, the higher the running costs. A single zone system allows heat pump to have the flow regime it requires, without a buffer or hydraulic seperation. The cheapest way to run a heat pump, is generally always on, flowing to a open heating system on weather compensation. No thermostats.

Welcome Look in to MCS self installation schemes. This where the supplier take the design responsibility, looks after the grant aspects, leave you to arrange installation, they then commission. This means you get the grant, without MCS inflation. Things to watch out for Design temp need to be 45 degs or lower. Single zone No buffer No hydraulic separation

Or in an area of inflated house prices, where you throw money at it and still see a profit. Plenty around us pay people to everything, but house prices are not high, not sure why they bother?

As soon as you flow water below dew point (let's say 12 degs) for more than a few minutes you will start to generate condensation. Target flow temps below dew point, you get condensation forming. Our summer house has a fan coil and have never seen a single drip from it. It flows from the same circuit as the house UFH.

Now lost? What is an Aircon exhaust pipe?

To do what? Read the post or pre cooling data sheets and related water temps, air flow rates and then kW output in cooling mode. Yes you can cool, but not very well at normal flue rates, even if you configure to run boost it's still a low kW output. Really doesn't make much difference if you install anywhere in the MVHR circuit. If you install a MVHR that was massive, and min flow rates suited your house design, set up a normal boost and super boost you may have something, but ducts would be oversized, every inside the house fully insulated.

I spoke to a contractor last year, he had been south to hot world called England. Anyway driving down the motorway all windows open in his car, Aircon full cold, couldn't understand why the car was so hot inside. 30+ outside all windows open, 70mph blast of hot air!

We get loads of weeds in our gravel drive. We don't have a weed membrane, but the weed are wind driven seeds that land in the gravel and root in the wind driven soil from the fields around us. So would be there with or without membrane. 20 mins with a spray backpack and weedkiller once a year does the trick.

That's a good suggestion - a pergola doesn't have to cost much. I just built one with 2x PV panels. So solar shade and generation in one assembly. Vertical just do 3x 500W panels to a 1kW inverter. Or as you say horizontal or any angle in between. It's also useful to have PV generation in winter, vertical will give twice the output in Dec/Jan. A 200m² new build to a half decent build spec, should only need a 4kW heat pump. CoP of 5 to 6 doing cooling, will generally be pulling less than 500W (modulated down). If the sun's out and you need cooling, PV is generating. Our two horizontal 500W panels in full sun the other day were generating between 800 and 900W, which is enough to run our 6kW heat pump.

Mine was a zero cost option, replace blinds with curtains if you want. Choose the right ASHP it will come with cooling out the box. Mine switches from heat to cool via a repurposed light switch. So £2 if you don't have one kicking about. Runs WC for cooling and heating so you don't even need a thermostat. PV - buy 2 to 4 500W panels, £68 each, string inverter £250 to £300, DC and AC isolation switch £100 for both. £100 for cable, MC4 plugs and sundry bits. Then you need mounts depending on where you locate. Panels make great fence panels, roof for pergola etc.

So do you use only AC for heating and cooling? How do you do hot water?

The way to operate is to run with a single flow temp for both fan coil and UFH. It means the fan coils are bigger for a given output in kW. But running everything above dew point, means no condensation, so no drains required. A quick look at an online dew point calculation, house kept at 21, RH 60%, dew point is 12.9. I set my target flow temperature at around that. I get no condensation on the UFH manifold. Floor surface temperature is around 19 to 20 depending on floor covering. So a mile away from condensation. The heat pump cycles based on return temp of around 19 degs. This is in the morning no solar gain So short 10 min runs then off for an hour or so. This it when we get solar gain Much longer runs. When we get to heights of summer, the heat pump runs several hours at a time. Our house internal temp almost all driven by solar gains, without internal blinds and UFH cooling our lounge l easily gets to 27 degs. Now it may go up to 24, but it recovers back sensibly levels quickly. But with a floor that is cooler than the air, it always feels cooler than it says on the a temperature gauge. Think old stone church always feels cool even when it's baking hot.

We have a long thin house, so way different from factor yourself, it didn't change our test result much when converted to ACH.

Your answer is pretty much 1.4 ACH

Are you sure, I think it's (1.4 x 479) / volume. So if house is 200m² and ceiling are 2.4m high is 200 X 2.4 = 4800. (1.4 x 479) / (2.4 x 200) = 1.4 ACH

Without knowing your house volume he cannot know that!

External blinds are best, internal blinds ok. UFH run in cooling mode. Fan coils.

The 4G ones apparently have just been issued, in the last week or so. Believe a few have been installed around us - near Elgin. Octopus are still playing about, insisting they attempt the smart meter install 3x, before moving to getting a SIM card meter.

I doubt they would really know, they would have no idea if I did 5 miles a day or 500 miles.

Have you bought these heat pumps?

1.4 is m³/h·m² . You know the m² figure You need to work out the house volume in m³. Now you have house m² and house m³. Multiple 1.4 by your m² area. You now have the air loss per hour atv 50Pa. Divide your answer by your volume. That should be your ACH at 50Pa