JohnMo

Cool energy have various sizes on eBay also, seem well priced.

If the mixer will run on a combi it will work from a cylinder. Assume if you are having a hat pump you will have an unvented cylinder? They like a balanced hot cold water water pressure and that's about it. I went combi to heat pump, just had to adjust the mid point mixing temperature.

Flow rate is set per loop length, there is no need to have the same or similar loop lengths. Salus self balancing a actuators will balance the system for you, on a fixed dT, just add one per loop. I have used both mechanical and electronic mixers and prefer the electronic ones. By electronic I mean 3 way valve and actuator controlled to a set or varying temperature. The reason I like, is that they always provide a good recycle flow back to the boiler and only mix when required not all the time. Is UFH right for you? Home all the time and happy with heating nearly all the time it's great. Away all day and heating off don't expect to warm before you go to bed. UFH in bedrooms is rubbish, either not warm enough or too warm. Avoid. Can you existing boiler do weather compensation? If so S and Y plan should be avoided, consider X plan or priory hot water. Low temp radiators or fan coils, would be my vote doing it all again.

I found when I was comuting from Elgin to Aberdeen I would just go with the flow of the traffic. But the loony tunes, would fly past at inappropriate dangerous areas in such a rush to get past everyone. 50 miles later you were one or two cars behind them.

Brand new in box.

eBay for heat pump, City Plumbing for cylinder, existing UFH, some pipe and insulation. Existing thermostat controls the ESBE mixer on UFH. All self installed including UVC (did the training). Heat pump does its thing, without any outside controls. System is super simple.

Plenty of people spend way more on an electric vehicle or diesel etc, with zero returns, just money lost every day and every mile. So no big deal, it's how I want to spend my money. Spent about £3k buying and installing the heat pump and cylinder. Reason is I want small bills, for when I retire. Read the thread title - I am just pointing out heat pumps can be cheap to run. When comparing to indirect electric heating as the MOD is proposing, would be on a similar time of use tariff, but the energy input, would equate in my case, to 3.7 amount. So cost way more to the end user.

Really depend on what you buy, how you buy and how you install. On a new build it's a no brainer. Some old houses (not all) you must be mad or very rich, unless it's a hybrid install.

As I said you need to compare apples with apples. MCS spreadsheet just take the ACH and uses it in the ventilation heat loss calculation. 1.5 ACH assumes you have a vent fan in that room nothing more or less. The calculation shown is for the ventilation heat loss - cell G05

Basics of the maths Heating season SCoP so far is 3.7 for heating including DHW. So around 4p per kWh, compared to 7p to 8p for gas when you factor in efficiency. We batch charge the floor overnight (about 6 hrs) down to an average day temp of about 3 degs and let it run longer on colder days. We generated 9kWh the other day, so that would have been free running for the heat pump - can't get that with gas or oil.

The only advantage I see is it will flow high temperatures so suitable for normal sized radiators. But charged on E7 or similar. May as well install storage heaters. I will dispute. If you have a battery and UFH it's loads cheaper and you can also cool. I'm just using standard E7. Heating season this year has had a warmer house and a lower bill. Heat pump output much better match for the house heating demand than the gas boiler was.

All the info you need https://www.heatgeek.com/do-i-need-to-upgrade-my-radiators-for-a-heat-pump/#google_vignette

MCS seem to make up the numbers and are are populated on their spreadsheet - one of the reasons they always oversize, on well built and well insulated houses. But you have to careful that you are comparing apples with apples. There is a difference between building regs air tests, passivhaus air tests (done pressurised to 50Pa) and natural ventilation rate used for heat loss calculations.

Good weather down south, not so nice up here. This years Dec average is up a couple of degrees (current average is +4), compared to +2 in 2022, but we still managed -9 at the beginning of the month. More rain, so less solar gain. Currently 1 deg with a high of 3 today.

Beware some are coated carbon steel and have an anode to be replaced. Think the Edel is stainless so ok. Some thoughts - A 200L direct UVC was less than £500, so you are paying £1500 for the heat pump part to save upto £1.30 a day, if you get a a CoP of 3, based on 7kWh of hot water a day. So about 4 years to get payback, without the additional installation costs.

Just compared last years December billing with this (used today's rates (pence) at last year's kWh. Last year gas and electric was £70 more expensive than this December is likely to be. This year we have a battery, more solar and ASHP. That reduction includes some high usage days where I was not using the ASHP optimally, plus we always heating the garden room (which we didn't have last year) to above 10 degs and some days up to 21 degs. Taking into account the additional heating going to the summer house, we are closer to £90-100 cheaper than last December. So overall about 23% cheaper running the heat pump compared to gas.

Argo, with EMIX cylinder. Does what you want out the box. https://argoclima.com/en/prodotti/im/ There are others, you are looking for the words "de-superheater"

Could be - if red is hotter than blue, if not then the other way round

There is an Italian heat pump, that when in cooling mode sends the refrigerant into a cylinder coil for heating DHW. But I cannot remember the company name. Did try to buy, but UK seller is plain rubbish, never returned calls etc.

Pretty good write up here on condensation theory https://www.heatgeek.com/condensing-boilers-efficiency/

To be in condensing mode it the return temp that is important not flow temp. You are well inside condensation mode.

If you want Aircon anyway, use the same unit for heating also - everywhere. For DHW either direct immersion heating, during off peak or get one that heats via its own heat pump. Couple of holes in the wall for air in out. Or just get an ASHP, fan coils in the bedrooms and living space, they will do heating and cooling. Unvented cylinder. Simple.

You have to careful when you compare, it's actually on an apples with apples basis. As there are several ways to calculate efficiency, for example passivhaus institute use a different method to most. The energy required to raise one cubic metre of air through one kelvin is 0.33 watt-hours, i.e. its heat capacity per cubic metre is 0.33 Wh m–3 K−1. Thus the total ventilation heat loss, Qv , will be: Qv = 0.33 × n × V × ΔT watts So using a 100m3, and a change rate via mechanical ventilation of 0.3, -3 outside and 20 inside 0.33 x 0.3 x 100 x 23 = 228W heat loss Same calc for 90% eff 0.33 x 0.3 x 100 x (1-0.9) x 23 = 23W heat loss Same calc for 80% eff 0.33 x 0.3 x 100 x (1-0.8) x 23 = 45W heat loss So we are taking quite small numbers an additional 0.5kWh a day at worst (when comparing 80 to 90%) in a boat that possibly leaks heat like seize anyway. If your boat isn't air tight and leaks enough to ventilate itself, without additional mechanical ventilation, then MVHR actually adds to the heat losses, as its ventilation is over and above normal air leakage.

Make sure you allow for wind lift. Not quite the same, but we had a wooden structure with a roof, pinned down to lawn, one very windy night, it took off and parts of it went over a 6 foot wall. Luckily no one injured or cars damaged on the road where they landed.

This what we found - We did it, sold them now. Costs You have to pay extra duties on purchase, as it classed as second home (Scotland). If you register as a business you may be able to get small business relief instead of council tax, which when we did was zero rated. But if you don't register as business, you may be hit with double council tax (a new thing the Scottish government is implementing). But you may also get clobbered with commercial water and sewage rates. You also have to pay for utility charges, and decent broadband is expected etc. General stuff People leave their rubbish, don't recycle, put used plates back into cupboards, without cleaning. You have to find someone who is reliable and good at cleaning (which isn't easy). Overall everyone made money, except us, we got all the grief and running about. Over 4 years and two houses, we made very little, made money on the houses when we sold, but both had lots of work done to them after we purchased. Buy premium bonds, zero risk. Stay in a decent hotel or someone else's holiday home.