JohnMo

I just bought a few flat pack units from Howdens, if you in off street you will pay way more than if you can find someone with an account. We mentioned a joiner and got 57% off the normal price. Both my sisters used DIY kitchens and were both happy with the result.

I have one of these and it's still in use and looks as good today, as when it was delivered 2 years ago. It has a point of delivery bar code that Royal Mail and delivery companies can use to prove delivery, but as with most things delivery people don't know that, so they will still put a sorry you weren't home ticket in the mail box. But a good sized box. https://www.smartparcelbox.co.uk/

Not even certain it would be as good as you think. So good call cancelling order. My DHW cycle works like this - Call for heat, heat pump puts out enough heat to maintain a predetermined delta T between flow and return. As the delta T reduces it ups the flow temp. It continues to do this until it either it looses the call for heat (cylinder hot) or it gets to 60 deg flow temp. If it hits 60 deg stops heating, but continues circulation, it waits until return temp drops then keeps trying to heat. It will keep hitting 60 and keep retrying, that is my best bet for what would occur - would use loads of electric in the process.

Bought some 6mm2 4-core armoured cable have laid that in to place roughly for now. Will run DC for what looks like about 52m from PV DC isolator to the inverter. Ploughs etc have no access as the PV will be located on a very steep hill, with trees to the rear.

Must say, my UFH and heat pump cost about the same or less than that.

I didn't, but I think more restrictions like that, are thing of the future. There are several calculation tools available online, sorry can't offer any links. Play the numbers, get low water use clothes washing, dishwasher etc to make the numbers work. And you only shower every other day etc. You don't water any plants etc. Also think rain water harvesting.

Basically yes, it's just adding system volume, to give the boiler something to work on, when just a zone or two is on.

Or does it just say something about the grant scheme? Plenty of here with or installing ASHP, not part of the scheme including me. So they don't appear on the statistics h shi** in sh**e out

Just tried the link I had on the email and the web page seems to have gone. Maybe stopped trading?

The biggest issue is a passivhaus will have really low flow temps for UFH. Carpets just act as an insulating blanket. Our house isn't passivhaus standard but is well insulated. Our UFH flow temp is low, floor surface temperature is 1 to 2 degrees above the room temperature. We have carpet in the bedrooms and the UFH is just rubbish.

A 4 port can be connected as a 2 port, just flow in the top and out the bottom connection, blank the other two ports off. You would normally have the buffer position so all the flow goes through it for the whole heating system, so after your return tee (UFH and radiators) for a return line two port. Item 12 in the attached drawing If you want to do it across flow and return, install instead of the bypass like this

If you put an additional pump on the DHW return side, powered from the same power supply as the three way valve, that will overcome the high delta T of the coil. Mine pulls an additional 31W for an hour or so while doing DHW only. My issue isn't a small coil, but 22mm Hep2O running from 3 way valve for about 8m each way, plus a long run from the ASHP.

I found the pipes were just getting slightly damp if I went any lower, so settled on 12 also. Running in day is mostly PV powered, our floor will never get very cold as we have 300mm pipe centres in 100mm concrete and I only run in the day time.

@JoeBano what temp are you flowing? I am doing 12 degree flow temp, running from 9am until 5pm. We still get some overheating from about 4 til 7 due to big windows and lots of solar gain. But way better than it used to be.

Same old, same old, rules of thumb, it's a heat pump it's got to be 28mm. I was being optimistic saying guessing. Possibly a standard cost adder.

Really not engineering at all, just guessing at someone's expense. Sounds like the Green party in Scotland, more interested in getting power and independence from England, than anything useful or Green

You need sand to make concrete or make it with ballast, which is mix of gravel down to small fines. Various grades of concrete are mixed with various quantities of sand, cement and gravel. Varying mixes get different properties depending on what you are doing with it.

Trade prices direct, quoted me (Dec) about £2k for a Grant 6kW, delivered to IV30*** postcode. That includes VAT. I haggled on price found the lowest price I could and they beat it.

What size heat pump are you looking for?

If only the size stated, not much chance of heating with a heat pump. No matter what setting you use.

Two ways to plumb a buffer 4 port basically goes between flow and return. Or two port goes in the return only. Any mixing in the 2 port doesn't affect boiler or heat pump efficiency, where in a 4 port it most likely will, unless the buffer is big and well designed.

I just bought from eBay. If new build I suspect you only need a 4 to 6kW Don't appear to be that expensive here https://www.theheatpumpwarehouse.co.uk/product-category/heat-pumps/air-source-heat-pumps/panasonic-air-source-heat-pump/

I see what you mean about being marginal. I saw them on eBay from their outlet store, which is normally about 20% off the retail price. Full warranty etc. They have other sizes there also. I looked at Trianco, and they are not inverter heat pumps, when I asked. CoP wasn't great. Riello are rebadged Midea monobloc ASHP. The specs look ok, but no experience, they come up on eBay for good prices. Grant could be worth a look also.

Or you could get a cool energy heat pumps for about £3.5k, good for 12kW You would need a huge buffer to make use of off peak charging, if your heat demand is 12kW. Can you configure your zones so you don't need a buffer? Then you are down to £2k for general stuff to install - this could be reduced loads with careful shopping and designing. £3.5k for ASHP £250 for destrat pump £2k for your radiators So about £7.5k £6k cheaper than B.

Good question, hopefully someone can answer?