I had watched the start of that before, thought the customer had been coached somewhat, besides if it's the same radiators just fed from a heatpump, how can it eliminate hotspots? Stopped watching at that point ...
They're not a straight swap for a combi boiler, but when properly installed they work very nicely, even in an average house.
The units are the same size for the same capacity. If you're heating a room or two, the outdoor unit is about the same size. If you're heating the whole house the unit is larger - the size depends on your heat demand, which depends on your insulation.
My unit on the wall outside my kitchen. When I'm making a cup of tea I'm standing less than a metre away from it, with the window open. It's only slightly noisier than the fridge (which is also about metre away). The sound of the kettle boiling drowns most of it out.
The main noise in the house is water flowing through the pipes, which is the same as any central heating system.
Mine has no indoor unit. Hot water comes out of it, just like a boiler.
The cylinder replaced the existing 1970s cylinder, roughly the same size.
They removed our cold header tank (and F&E tank) to make it a mains pressure hot water system. There's a couple of football-sized expansion vessels, as you'd get on any modern unvented boiler system.
The advantage of something going outside is you don't need to waste wall space. We gained an extra cupboard in the kitchen by removing the oil boiler, as well as a big chunk of garden by losing the oil tank.
Our radiators were 1970s and fairly knackered, but there were only a couple of places where holes needed to be filled and paintwork patched up.
No insulation was improved. We're borderline D/E on the EPC. Upstairs is very leaky but the ASHP copes ok.
Nothing, it works just fine with only those. Obviously the more insulation you have the less you spend, both in running costs and for purchasing and installing the unit.
We moved out for a week because it was installed during lockdown. Without COVID it would have been no problem to stay in situ. The radiators took max a day to swap, and the rest was work outside, in the loft and in the airing cupboard.
If you had a house with both gas and heat pump, there would reach a point where it's cheaper to burn the gas than electricity for the heat pump. The exact threshold will depend on the relative costs of gas and elec. But most people don't have houses with both. For a heatpump there are many days where it's not freezing cold and you win on those, and they tend to outweigh the few days over the course of the year where it is freezing cold.
There's plenty of heat - 278 kelvin of it to be precise.
The main thing is the delta T between outside and inside. The greater your delta T is, the harder the heatpump needs to work. This is where you lose efficiency. But that means getting a COP of 2 or 3 not 4 or 5, so it's still useful.
They are usually buried deep and have warning tape. The pipes are usually fairly sturdy - don't think a spade would do much damage. The pipes are usually laid as a continuous run so there's no fittings to leak. There's an inspection chamber for the fittings like any other drainage pipework. If that leaks you fix the leak and top up the glycol.
Yes, part L 2021. Gas boilers are banned from newbuilds from 2025.
We used to turn ours off at night (before I removed the duff boiler controls fitted by the installers). In the morning it would take a bit longer to warm the house up from cold compared to the oil boiler before, but it was manageable. Bills were ok.
Now we just set the temperature back at night and it'll bring it back up in the morning with no problems.
If you got the right unit properly installed, they're absolutely fine on an average house.
Theo
No, it's fine. They have them in Minnesota where it's -40C and they work ok. Obviously in that kind of weather decent insulation is a good idea. I think the Minnesotans do fit an electric backup heater so you can give it some help in the -20C to -40C region.
They are also popular in Scandinavia, a region not unfamiliar with freezing conditions.
Ours has only seen about -9C and we had a warm house.
How cold is cold for you?
Theo
Agreed, but the majority are being advertised/sold as a straight swap for a gas boiler and with a generous grant from the Government (although probably from the green tax on all our bills)
I've also seen adverts suggesting that they are going to save you money which may only be true if ratio between gas and electricity prices change.
Although related to air conditioning systems fitted in the USA I been watching a few Youtube videos from someone who goes around repairing them. One thing of note is how noisy the outside units (fans) have become if not regularly maintained.
Is that true? On warmer days a properly sized gas boiler will throttle back and use less gas.
Although, pre-central heating, there were fireplaces in the bedrooms and not just the living room and lounge. Both my parents 1930's house and my own 1935 house have closed off fireplaces in the bedrooms to this day.
Not everywhere.
My first home was my grandparents' house in Edinburgh, built in the '30s. There was a fireplace in the living room, and a heated towel rail in the bathroom. The kitchen warmed up when the oven was on, or Granny was using the copper boiler for laundry. The only heat in the bedrooms was provided by hot water bottles.
It was still like that when Granny died in 1977, except by then she had an electric washing machine, instead of the boiler.
are any of the main parties listening to the peoplle? Or are they too busy talking nonsense?
Must be or the people wouldn't keep voting for them.
That's all any polly ever does.
Probably because it was running lower flow temperatures for longer periods - so less fluctuations. The hotter bits may still be hotter, but you won't feel the changes so frequently.
Things have changed lots since the 70's though... I remember about the time I was doing my A levels, we still had individual gas fires in some rooms, and no CH. The morning routine was have a kettle setup on a time switch. The kettle would boil, I would leap out of bed to turn the fire on, and pour the water into the cup waiting with coffee and milk already added, and sharply get back into bed for 15 mins to allow the room to warm a little and some of the ice on the inside of the windows start to melt! (9" solid walls, single glazing)
I can't find the reference now (anyone?!) but at a workshop* I was at recently it was found that the effectiveness/workmanship of insulation in new build and retrofit varied massively - even within the same contractor.
It seems it's one of those things that can't be 'just done'.
Agreed.
A problem with it all is knowing the standard and effectiveness of retrofitted insulation/heating,
And trusting whoever's doing the audit. My home was recently EPC surveyed and the roof was rated 'uninsulated' even though it's just been reroofed and insulated to the latest standard. A long term unemployed friend with no technical background is due to take a 5 day EPC course. At the end of it, he tells me, he'll be fully qualified to do the EPC surveys.
It's also likely to be anti-DIY. If you insulate your own home and come to sell, how will the buyer/buyer's surveyor know what you've done and should they trust you? An architect friend suggested the best a DIYer can do is take a meticulous photo diary of works.
IMVHO, it won't work well in the average house - the insulation is likely to be to too poor for the system to work effectively and the home simply won't warm up enough.
Again, not without decent insulation.
Also, I've not seen any mention of the backup electric heaters in ASHP installations - they kick in when the ASHP can't heat to required temps.
Interesting, thanks. I'd be having a word with the son :-)
The problem is that the heat pumps are ALSO equipped with auxilliary direct immersion heaters so it's hard to tell when the heat pump parts are NOT working [well].
was in a brand new one yesterday...it still had a gas powered water heater
In the same way they have to trust Fred the cowboy builder who may just give you a detailed invoice of things they haven't done properly?
Perhaps a surveyor job is not just to believe the documentation but check for himself?
IME even surveyors dont remove plasterboard to check proper insulation installation...
And once you have improved the insulation to a much higher standard you will use much less gas to heat your home. Until they ban gas boilers the payback time for fitting a ASHP and changing radiators may be well beyond the life expectancy of many on this newsgroup? After improving insulation the most cost effective solution would be to keep the still working gas boiler or a new correctly sized gas boiler at 1/4 the price of a ASHP installation.
However, the green solution is not about saving money but saving the planet. I wonder how long before there are mass protests about how big business is destroying the look of the countryside with their ugly wind turbines on EVERY hillside?
I suspect that many advocates of ASHP have done their research and before committing to an install they have done their sums, installed underfloor heating, ensured that insulation is above the general standard etc.
The problem now is that the cowboy installers seem to have entered into this market and are advertising cost savings by simply replacing a gas boiler with a ASHP. Judging by the response on to these adverts on social media it seems that a great number of people believe every word :(
Mine is about breakeven with gas at current rates, which doesn't make it a no brainer to swap from gas at current prices. However we were swapping from oil and that's a much easier sell. Of course prices fluctuate, so any economic case is going to depend on what point in the cycle you're in (gas, oil and electricity went up a lot last year, wood didn't - so a woodburner became more economical for a time). I'm not sure we're going back to a 'steady state' world with a predicatable pricing ratio any time soon.
In a newbuild, the costs of fitting a heat pump and a gas boiler are similar, whereas the costs of retrofit basically boil down to replacing one thing with another thing. If the original system was knackered, it needed replacing anyway. If it was new, it's a harder sell to rip it out and replace with something else.
One thing to be very wary of is companies selling systems to chase grants, because they're highly likely to leave you with a botch job. Unfortunately there are a lot of botch jobs around (including mine, until I DIYed it).
That's mostly fan bearing noise. If that happens you should change the bearings, like on any other spinning thing.
*Any* system is going to throttle back when less heat is desired, that's a given.The point about heatpumps is the COP depends on deltaT. So if it's warmer outside, not only does the house need less energy, but the COP rises. So you need fewer kWh of heat, but also each kWh of heat needs less electricity input. So you get a double benefit.
Meanwhile for a gas boiler each kWh of heat requires almost* the same kWh of gas.
(* weather compensation to lower flow temps can get you a bit back on a condensing boiler, but I don't think it's a lot in percentage terms. Whereas a heatpump can range from COP=2 to COP=5 according to conditions)
Theo
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