JohnMo

Been asking ChapGPT loads of ASHP related questions. One was related to the use of ball valve strainers (which I use) and proper inline filters (I had a Spirovent Dirt on the boiler, now sitting idle). The main comment was on pressure drop differences. Spirovent being almost zero even sized at 22mm compared to quite high on the ball valve strainer. The other question was heat pump run time, exploring UFH affects and water volumes. Short answer, as expected more water volume is better. System volume is circa 70 to 80L without volumiser. In cooling mode first run of the day was typically 12 to 14 mins, no longer. Have now installed an additional 50L water volume (around 130L total), used a cylinder that was used on the combi boiler as solar preheat for DHW. Not ideal in theory as it only has 22mm ports. The only place I could install due to layout issues was close the the ASHP. It is connected within the return piping as a volumiser. This means without mitigation the volumiser would get filled with DHW heating water - not ideal. So used a previously used ESBE Mixing valve as a diverter driven by the relay, I use on DHW signal filtering. Added the Spirovent filter while I was there. First run I left the strainer in place as well as the Spirovent, flow reduced from the 19.5L/min to 16L/min, which was worrying. However removing just the strainer from the ball valve flow jumped up to 22.5L/min. Ball valve strainers seem to be pretty rubbish and many get installed. So gained an extra 3L min flow while installing a 22mm volumiser and associated piping plus a 22mm 3 port valve. Run time after volumiser install is been dramatic. Normal first run of the day is 10 to 15 mins, today 42 mins. CoP has increased (like for like outside temp) a small amount 0.04, not big put running CoP was already high, so now achieving 6.53 this morning while running. dT has dropped from 4.4 to 3.8, so this allows me to reduce flow target temp a little and get the same heat transfer, which will reduce run time a little but gain CoP. Still need to complete the insulation, need some additional materials.

Sounds similar to ours, but without the split level. I just put in way less UFH pipes in bedrooms, as the design temp of the room was lower, which what we wanted, converse could be true also if you wanted bedrooms hotter, for strange reason. Just less heat added to room at same flow temperature; pretty much the same as you do for radiators.

Foil lined is basically a plastic covering. So use a paint suitable for plastic or a primer suitable and any suitable paint for the primer over it. I just bought some of this for painting some outside plastic, covers really well and great finish. No primer used. https://amzn.eu/d/jcqODve

That's the difference you get paid for it, so you better get it right first time. 😁 I used all the wisdom at the time 2020, when we installed our heating system, thermostats etc, f'ing waste of time and money. Caused more issues than they fixed (boiler short cycling, under and over swing of room temps), worked my way down to one thermostat, now have none, one switch from cool to heat, now we are on a heat pump. Plus a home assistant relay, which is used to soak up excess PV and charge floor at a great CoP - plus zero cost heating 30% of the time in the shoulder season. Sorry against what you think, thermostats are tat, used for high temp heating systems. Just aren't needed running weather compensation and low flow temps.

Doubt it. Your floor output just drops to zero as the it gets solar gain. On a 7 Deg day the floor surface is only going to because degree or so warmer than the room. Switching a loop off is a waste of time. The time frame to have any affect is way longer than than the solar gain lasts. Just run it all open loop on WC and leave the system to look after it's self. Now on year three with proportionally more glass. In late winter I was actually running the heating at a higher flow temp of excess PV, even though the house was warm. Then as it dropped to -3 overnight (back at WC flow temps) the heat pump actually switched itself off. Spread the pipes out further instead of all bunched up.

Images help, if you could add that would be great. Also does this steel post act as a thermal bridge?

So glad I built single storey - one or two levels of thought process deleted.

Not nice with chips, but pretty nice with ice-cream

Are you sure about that with an ASHP? You need to keep the return temp as low as possible for as long as possible to a get a decent CoP. You would kill CoP pretty quick. Can see an argument to push back in the centre the tank but not the bottom.

Had a gate made either ceder or larch. Anyway did yacht varnish. 18 months later lots had peeled off and plenty had gone black. Two days later had it scrapped off and used ceder oil, applied every two years after that and looked as good as new.

Just your local pie shop. We can get macaroni cheese pies here, there great. The chip shop even fries them!

Sorry once I finished building I was more interested in real pies of any description.

PHE work well due to the turbulent flow at the plates inside the exchanger. Using the change in density as the fluid heats may not/will not give the turbulent flow needed on the cylinder side especially at heat pump temperatures. So may be as good as useless. I would add a DHW suitable pump, and pump from bottom connector through PHE and into top outlet connection. The equivalent area of a PHE when compared to a 3m² cylinder coil is about 1 to 1.2m².

Are you sure, if you have a dMEV fan you don't need any other ventilation, you move from intermittent to continuous section in building regs.

Why? Ours has been there 3 years and looks as good as the day it went in. Will be pretty pissed if it only lasts 10 years.

Just seen this bit, sounds like an easy way to get a rotten deck - warm humid air pumped in

Why bother pushing the air outside? Carbon filter and one with decent grease filter, and do it as recirculating? No idea what your ventilation strategy is, if not MVHR, add a dMEV fan to kitchen and let it slowly tick away and auto boost on rising humidity.

To be frank if you don't know your airtightness and it's better than 3m³/m² at 50Pa I really wouldn't bother. I would do keep it simple dMEV in every wet room. No trickle vents in this rooms. I would choose Greenwood CV2 or CV3 only as these are silent in use and automatically boost intelligently -raising humidity. Either wall or window trickle vents in all dry rooms, but they should be humidity activated. This will sweep humidity from rooms in use only via ventilated only, minimising heat loss. Pennies a year to run no filters, no ducts to run etc.

Ultimately the floor output has to be considered when compared to the whole house demand, so for example. House 200m² and heat demand of 3kW would require the floor output to be 3000W / 200, or 15W per m², if the whole house had UFH, but as you are on 3 storeys of equal floor area (assumed) on each floor you now need 3x the output from ground floor UFH. So 45W per m². If on 200mm centres for the UFH loops that would be approx 40 degs flow temp on the coldest day and the UFH would provide heating for the whole house. 150mm centres would drip that be a couple of degrees.

Not sure who is leading you down that path? But it's nonsense. Your UFH system should be manifold, floor loops and that is pretty much it. All run in weather compensation on a fully open system, certainly no buffer. A volumiser may add running time when warm outside. No actuators or thermostats are needed. All heat pump will flow at 25 some at 20 in heating mode. The way UFH works is via dispersion of heat within the screed. The further it has the travel the more the temperature drops via radial conduction.

Do you need 21 in bedrooms - no, is it comfortable sleeping in 21 degs bedrooms - for me no. Trouble is when you start adding radiators with a different design temperature you also need to add mixers etc to UFH. If going MCS route they design bedrooms at 20 I believe. Do you actually need radiators at all - maybe not? Many on here haven't bothered when they have an upstairs and maybe added an electric point in bedrooms for a panel heater as insurance. Having lived in multiple properties from old and drafty to modern and airtight we have never had heating in bedrooms. Slight lie currently have UFH in bedrooms but buried below high tog carpet, so it rubbish anyway. Are you expecting any overheating in summer. If so why not fan coils. Then flow at UFH flow temps and have decent cooling when it's hot. Make sure the heat pump you are getting does cooling out the box.

I did the same also, so I could build the walls. It's very cost effective route, especially DIY.

General cost adders are 1. not planning well enough, there should be no surprises once out the ground. 2. Deviations from drawings once drawn. 3. Getting carried away with expensive kitchens and bathrooms. My advise Plan everything at the drawing stage. Map out you sockets and lights Map out all your plumbing and heating - how are you heating? Map out a ventilation scheme Massive savings are possible by keeping things simple - one zone heating fully open system. Fully understand how and what you are doing about insulation airtightness etc - if planned well, need not cost you anything additional. All the above allows you to spot bargains but ahead of time and save loads. Things on your plan that look expensive already are 1. the corner with the glazing in the lounge - looks like and expensive structural detail you could eliminate. 2. Do you need french doors in the dining area?

Welcome - not a lot of budget, but on the plus side it's a modest house. But I assume you will be doing a lot of the actual work yourself - if not the money will soon disappear.

You can legally already install balcony solar. But it cannot be plugged straight into a socket, as it is in most parts of the world, it needs to go a consumer unit.