nod Posted December 10 Share Posted December 10 We are into December So able to make a comparison between our current and previous build All things considered I think the HP will be the same or slightly more to run We didn’t have an option on this build Both builds are traditional Scoring about the same B89 A if we ever got the urge to add PV Which our buyers are in the process of doing While the HP works exactly the same with UFH I wouldn’t like to have to rely on Rads with a HP They are slow to heat and don’t get very hot I wouldn’t like to have to rely on Rads to heat a poorly insulated home The installer came back to check and set everything up for winter He asked if we could leave the Rads on for a few hours All in all we are pleasantly surprised at how straightforward a HP is and hot water on tap 24-7 is a bonus 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted December 10 Share Posted December 10 Any issues with freezing / defrosting over the winter? Link to comment Share on other sites More sharing options...
ProDave Posted December 10 Share Posted December 10 24 minutes ago, nod said: All in all we are pleasantly surprised at how straightforward a HP is and hot water on tap 24-7 is a bonus Why is that a surprise? I set mine up to operate from a standard heating programmer, because that is what people understand. And why are you surprised to have 24/7 hot water? did you not have that with a boiler? 1 Link to comment Share on other sites More sharing options...
sharpener Posted December 11 Share Posted December 11 18 hours ago, nod said: I wouldn’t like to have to rely on Rads with a HP They are slow to heat and don’t get very hot You can't generalise, it all depends on their size and how the system is configured. The rads in our sitting room were already quite big enough and the room heats up in 30 mins using stored energy from cheap electricity. Previous UFH was extremely slow to respond and the carpet didn't help either. We had 6 other rads upgraded and they are now fine too. We do not heat all the house at the same time, bc it is a big house and we move about it in a well-defined pattern so it is easy to programme the system accordingly. 18 hours ago, nod said: if we ever got the urge to add PV With PV as cheap as it is now I would have thought that it would be a no-brainer to cover all available roof space. Link to comment Share on other sites More sharing options...
MrPotts Posted December 11 Share Posted December 11 PV cheap? I have had a quote for 14 panels and a 10kWh battery for a little over £14k, that’s not cheap to me. If I can get this cheaper please point me towards the right direction. 😀 Link to comment Share on other sites More sharing options...
JohnMo Posted December 11 Share Posted December 11 10 minutes ago, MrPotts said: PV cheap? I have had a quote for 14 panels and a 10kWh battery for a little over £14k, that’s not cheap to me. If I can get this cheaper please point me towards the right direction. 😀 PV is cheap, batteries aren't Actually PV including mounts should be around or less than £200 per kW. An inverter to support couple of hundred pounds. 1 Link to comment Share on other sites More sharing options...
sharpener Posted December 11 Share Posted December 11 52 minutes ago, MrPotts said: I have had a quote for 14 panels and a 10kWh battery for a little over £14k, that’s not cheap to me. I think solar installers are pushing batteries hard bc the panels have become a commodity item and there is comparatively little profit in them. Margins on the batteries are better (for now) and you can install them in the warm and dry. The economic case for the customer is harder to establish, though now e.g. Octopus Cosy will allow you to make three full cycles in 24 hours which is a big improvement. And if you can achieve round trip efficiency >80% you can even make a margin selling their own electricity back to them. But I can't quite. Link to comment Share on other sites More sharing options...
S2D2 Posted December 11 Share Posted December 11 18 minutes ago, sharpener said: I think solar installers are pushing batteries hard bc the panels have become a commodity item and there is comparatively little profit in them. Margins on the batteries are better (for now) and you can install them in the warm and dry. The economic case for the customer is harder to establish, though now e.g. Octopus Cosy will allow you to make three full cycles in 24 hours which is a big improvement. And if you can achieve round trip efficiency >80% you can even make a margin selling their own electricity back to them. But I can't quite. Cosy has rapidly accelerated the payback period on my battery, three full cycles a day so saved the purchase of two additional modules. Sure, it's harder on the batteries, but you're getting the same savings just in a condensed time period. ~12p/kWh into a heat pump with a SCoP of around 4, just with a cheapish 2.8kWh battery. Definitely cheaper than the gas boiler. Link to comment Share on other sites More sharing options...
nod Posted December 11 Author Share Posted December 11 3 hours ago, sharpener said: You can't generalise, it all depends on their size and how the system is configured. The rads in our sitting room were already quite big enough and the room heats up in 30 mins using stored energy from cheap electricity. Previous UFH was extremely slow to respond and the carpet didn't help either. We had 6 other rads upgraded and they are now fine too. We do not heat all the house at the same time, bc it is a big house and we move about it in a well-defined pattern so it is easy to programme the system accordingly. With PV as cheap as it is now I would have thought that it would be a no-brainer to cover all available roof space. We didn’t want to cover our beautiful slate roof with horrible solar panels As stated our buyer has decided to put these things up The salesmen has predicted around £700 per year saving 12 k supply and fit If the saving is correct and I’ve no reason to doubt a salesman 15 years to break even is a long time and the batteries will probably need replacing by then Definitely not a no brainer 1 Link to comment Share on other sites More sharing options...
sharpener Posted December 11 Share Posted December 11 3 hours ago, nod said: We didn’t want to cover our beautiful slate roof with horrible solar panels Fair enough. My first ones have silver frames but the later ones are all black, not too bad on dark grey slates. And I realised this week that a house near us has black panels on black slates, so inconspicuous I had no idea they had been fitted. 3 hours ago, nod said: 15 years to break even is a long time and the batteries will probably need replacing by then Yes its the batteries that tilt the economics a good deal, the PV on its own would have a lot quicker payback. Link to comment Share on other sites More sharing options...
ReedRichards Posted December 12 Share Posted December 12 On 10/12/2024 at 19:28, nod said: I wouldn’t like to have to rely on Rads with a HP They are slow to heat and don’t get very hot I wouldn’t like to have to rely on Rads to heat a poorly insulated home This is entirely dependent on the size (I.e. surface area) of the radiators. Make that surface area big enough and they will be fast to heat a room, even though they don't get very hot. Make that surface area big enough and they will heat a poorly insulated house perfectly well. Or if you haven't got room for a radiator with a suitably large surface area, get one that is fan-assisted. Link to comment Share on other sites More sharing options...
nod Posted December 12 Author Share Posted December 12 34 minutes ago, ReedRichards said: This is entirely dependent on the size (I.e. surface area) of the radiators. Make that surface area big enough and they will be fast to heat a room, even though they don't get very hot. Make that surface area big enough and they will heat a poorly insulated house perfectly well. Or if you haven't got room for a radiator with a suitably large surface area, get one that is fan-assisted. I was referring to the temperature of the Rads Warm more than hot 1 Link to comment Share on other sites More sharing options...
ReedRichards Posted December 12 Share Posted December 12 (edited) 1 hour ago, nod said: I was referring to the temperature of the Rads Warm more than hot A fact which I acknowledged in my reply. I've had a heat pump for 4 years now and warm radiators can provide all the heat you need. Edited December 12 by ReedRichards Link to comment Share on other sites More sharing options...
marshian Posted Monday at 19:55 Share Posted Monday at 19:55 On 10/12/2024 at 20:28, nod said: We are into December So able to make a comparison between our current and previous build All things considered I think the HP will be the same or slightly more to run We didn’t have an option on this build Both builds are traditional Scoring about the same B89 A if we ever got the urge to add PV Which our buyers are in the process of doing While the HP works exactly the same with UFH I wouldn’t like to have to rely on Rads with a HP They are slow to heat and don’t get very hot I wouldn’t like to have to rely on Rads to heat a poorly insulated home The installer came back to check and set everything up for winter He asked if we could leave the Rads on for a few hours All in all we are pleasantly surprised at how straightforward a HP is and hot water on tap 24-7 is a bonus I don’t get the heat pump and rads comments I could run a heat pump instead of a boiler with the same flow temps I’m running a gas boiler 13 rads with a flow temp of 30 - to 40 deg depending on outside temp - it’s an early 1980’s with some insulation improvements (loft insulation is mainly 70mm so sub standard) and I’m running it 24/7 with setbacks at night and during the day when there is no one home - rad delta is around 6 to 9 deg (depending on flow temp) none of the rads are in the traditional sense hot but room temps are comfortable. 1 Link to comment Share on other sites More sharing options...
ReedRichards Posted 22 hours ago Share Posted 22 hours ago 23 hours ago, marshian said: I’m running a gas boiler 13 rads with a flow temp of 30 - to 40 deg depending on outside temp Either you have a new installation with a low-temperature gas boiler. Or you replaced your rads with larger ones at some time in the past. Or the rads were massively over-specified when they were installed to work with a much higher flow temperature than the 30-40 C you now use Link to comment Share on other sites More sharing options...
marshian Posted 10 hours ago Share Posted 10 hours ago 11 hours ago, ReedRichards said: Either you have a new installation with a low-temperature gas boiler. Or you replaced your rads with larger ones at some time in the past. Or the rads were massively over-specified when they were installed to work with a much higher flow temperature than the 30-40 C you now use All of the above Viessmann 100 W heat only (16 kW) Not a single rad remains from the original house set up 95% of the rads were changed a couple of years ago when I was running a 24kW glow worm boiler the point I was is that rads correctly sized for flow temps and room demand will work perfectly well whatever the heat source is Link to comment Share on other sites More sharing options...
ReedRichards Posted 9 hours ago Share Posted 9 hours ago 1 hour ago, marshian said: the point I was is that rads correctly sized for flow temps and room demand will work perfectly well whatever the heat source is Hopefully no one is disputing this. Except possibly @nodwhose earlier comment displayed a lack of understanding. 1 Link to comment Share on other sites More sharing options...
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