Heat Pumps

[Deleted member 10041]

No they do not. Yet another urban myth. My radiators are at 60 degrees centigrade less than 10 minutes of the pump starting up. The time taken for a room to warm to a particular temperature is then dependant on radiator size compared to room volume in exactly the same way as any other 'wet' systems work.


As said above, that is a myth put around by industries and individuals with a vested interest in rubbishing the technology.

My ASHP is programmed to come on at 05:30 every morning if the house temperatures are low enough, because we get up at 06:00. The house (3 bedroom detached bungalow) is always toasty warm by then, even during the rare occasions we have snow on the ground outside, and the water heat store (300 litre water tank) will also be hot ready for our showers.

During the day the heat pump will switch on and off as required to maintain the set temperature, in a very similar way as a gas or oil boiler will. If we want more or less heat at any time during the day, the system can be over ridden on a single button, or individual rooms can be adjusted with the thermostatic control valves in each room/space.

As has been mentioned several times in this thread, the house has to be well insulated for a heat pump to work efficiently, but I would suggest the same level of insulation should be the norm for other heating methods, otherwise money is being thrown away on heat that is being lost through the house fabric.

As I said same nonsense is used to rubbish EVs, heat pumps work fine.

 

[Rolfe]

They're not suitable for every building though, so it's not really on to legislate that everyone must switch to them. The insulation thing is key. Far better to run an effective insulate-your-home campaign, which will benefit everyone, then encourage people whose houses are suitable for heat pumps to fit them when their central heating needs replacing.

This idea that you won't be able to sell your house in two years unless it has a heat pump is simply turning people off the whole idea. The idea that someone who replaced their fossil fuel boiler just a couple of years ago with the latest, most efficient model will be compelled to junk it and install a whole new system is ridiculous. Forcing people on very limited budgets to shell out for a system like this is oppressive.

Patrick Harvie can't be voted out soon enough. Unfortunately, because of the electoral system, he probably can't be voted out at all.

 

[Amun]

I did correct myself in post #42

Sorry - I was replying as I was reading through the thread, so didn't see it.

 

[BarryH]

I don't know. Last year I made several enquiries to companies I found on Google and only one responded. I've decided to go with the Tepeo Zero Emmission Boiler instead.

Interesting. I looked at Tepeo but since it can only store 40 kWh from your off-peak overnight charge and last winter despite extensive insulation I used up to 130 kWh a day Gas and average winter day 70-80 kWh I figured it was not for me. I will have my Heat Pump fitted hopefully very shortly. I see the problem with ZEB (ie the Tepeo) just as with Infrared heating they have a COP of 1 ie 100% efficient whereas Air to Air Heatpumps is around COP 5 (ie 500% efficient) and Air to Water if correctly installed a COP 3+.

 

[Amun]

A friend of mine has a heat pump and loves it. He sets the temperature to 19 C and just leaves it there so the house base temperature is constant. If a room needs to be a bit warmer because they are sitting watching the TV for example he uses an electric radiator.
He had it installed during the renovation of his property so downstairs he has underfloor heating so the solid floor acts like a large storage heater and upstairs he has radiators. His house is also well insulated.

So - in 2023 - the system is so poor that he needs additional electric radiators just to keep warm? It might save him money by keeping the house so cold, but it's not what most people are looking for when it comes to choosing a heating system.

We also have a heatpump tumble drier and agree they are amazing at their energy efficiency.

Do they fully dry the clothes, though? We've tried condensor dryers before, and the clothes always come out feeling slightly damp.

Says who, I'm sure all the people with heat pumps don't go without heat for hours on end.

The people that we know have it set to kick in at 4am, so that the house is warm when they get up at 8.30am

 

[BarryH]

They're not suitable for every building though, so it's not really on to legislate that everyone must switch to them. The insulation thing is key. Far better to run an effective insulate-your-home campaign, which will benefit everyone, then encourage people whose houses are suitable for heat pumps to fit them when their central heating needs replacing.

This idea that you won't be able to sell your house in two years unless it has a heat pump is simply turning people off the whole idea. The idea that someone who replaced their fossil fuel boiler just a couple of years ago with the latest, most efficient model will be compelled to junk it and install a whole new system is ridiculous. Forcing people on very limited budgets to shell out for a system like this is oppressive.

Patrick Harvie can't be voted out soon enough. Unfortunately, because of the electoral system, he probably can't be voted out at all.

I suppose that rather than "forcing" everyone (which be honest is an urban myth) to have a heat pump it would be cheaper and better for everyone to carry on burning gas and oil and give away free silver foil sun shades a fan and dingy for when the sea rises to flood most land masses. What ever floats you boat.

No matter how efficient a modern gas boiler is it still emits an awful lot of CO2 and domestic heating in the UK where we are very reliant on Gas and Oil for heating represents an enormous opportunity to decarbonise. Sadly even when people who for economic reasons fit a new gas boiler which under lab conditions meets lower emissions and higher efficiency than the boiler they replace, will often be no better once installed as a boiler swap because the boiler will be set up by the fitter to demonstrate it has been worthwhile with really hot radiators for a fast warm-up time. In reality, the trend has been to fit more powerful oversized boilers whereas lower emissions and better running costs would be achieved by lowering the boiler flow temperature and correctly balancing the radiators so the boiler can run longer and cooler. It will put the same heat into the rooms and comfort will be better with fewer temperature swings. It may be that a radiator here and there may need changing for a more appropriate size but since you would be fitting a smaller less expensive boiler it should more than compensate. On a plus come the day in the future an inexpensive Heat Pump replaces your boiler the radiators will be heat pump ready.

Personally, I'm changing to a heat pump as my gas boiler is near its end-of-life and is inefficient. I replaced the loft insulation last year as some was over 50 years old and was very patchy and degraded. I replace windows and doors 5 years ago for A++ products as the wood subframes had rotted in many of the existing Double Glazing and the draft sealing was pretty much nonexistent. I changed to an EV because it is better to drive and I wanted a simpler life so it might as well be cheaper to run and environmentally sound as well. As I've got Solar PV and storage batteries ditching Gas and saving a further ongoing standing charge is an added bonus.

 

[Gadget Geek]

Most of the horror stories I have seen about ASHP's is when heat loss calculations haven't been done and the system has been installed by a heating engineer who hasn't had any training on heat pumps.

 

[Rolfe]

I suppose that rather than "forcing" everyone (which be honest is an urban myth) to have a heat pump it would be cheaper and better for everyone to carry on burning gas and oil and give away free silver foil sun shades a fan and dingy for when the sea rises to flood most land masses. What ever floats you boat.

No matter how efficient a modern gas boiler is it still emits an awful lot of CO2 and domestic heating in the UK where we are very reliant on Gas and Oil for heating represents an enormous opportunity to decarbonise. Sadly even when people who for economic reasons fit a new gas boiler which under lab conditions meets lower emissions and higher efficiency than the boiler they replace, will often be no better once installed as a boiler swap because the boiler will be set up by the fitter to demonstrate it has been worthwhile with really hot radiators for a fast warm-up time. In reality, the trend has been to fit more powerful oversized boilers whereas lower emissions and better running costs would be achieved by lowering the boiler flow temperature and correctly balancing the radiators so the boiler can run longer and cooler. It will put the same heat into the rooms and comfort will be better with fewer temperature swings. It may be that a radiator here and there may need changing for a more appropriate size but since you would be fitting a smaller less expensive boiler it should more than compensate. On a plus come the day in the future an inexpensive Heat Pump replaces your boiler the radiators will be heat pump ready.

Personally, I'm changing to a heat pump as my gas boiler is near its end-of-life and is inefficient. I replaced the loft insulation last year as some was over 50 years old and was very patchy and degraded. I replace windows and doors 5 years ago for A++ products as the wood subframes had rotted in many of the existing Double Glazing and the draft sealing was pretty much nonexistent. I changed to an EV because it is better to drive and I wanted a simpler life so it might as well be cheaper to run and environmentally sound as well. As I've got Solar PV and storage batteries ditching Gas and saving a further ongoing standing charge is an added bonus.

I don't disagree with a word of this, but it is no urban myth that Patrick Harvie is proposing legislation that would make it illegal to sell your house unless it has a heat pump (or perhaps, if it has a gas or oil boiler). My point is that he is thereby alienating people he should be trying to keep on board. It's counterproductive.

You intend to change to a heat pump when your gas boiler nears the end of its life. Excellent. My oil boiler reached the end of its life in 2019. There wasn't the slightest hint that replacing it like for like wasn't going to be seen as a long-term proposition. I don't think I had even heard the words "heat pump" at the time. Four years ago. If the old boiler had held together until 2023 I'd have been well motivated to look at a heat pump and raid the savings to do the right thing. But it didn't.

Instead, the car gave out. Such had been the encouragement to go electric for motoring that I didn't hesitate. But there was no encouragement or even information that phasing out of oil heating was on the country's agenda when I replaced my boiler.

Politicians need to figure out how to achieve their goals while taking people with them, and suddenly declaring that almost-new installations will have to be ripped out if you want to sell your house is not the way to win friends and influence people.

 

[Robf]

I don't disagree with a word of this, but it is no urban myth that Patrick Harvie is proposing legislation that would make it illegal to sell your house unless it has a heat pump (or perhaps, if it has a gas or oil boiler). My point is that he is thereby alienating people he should be trying to keep on board. It's counterproductive.

You intend to change to a heat pump when your gas boiler nears the end of its life. Excellent. My oil boiler reached the end of its life in 2019. There wasn't the slightest hint that replacing it like for like wasn't going to be seen as a long-term proposition. I don't think I had even heard the words "heat pump" at the time. Four years ago. If the old boiler had held together until 2023 I'd have been well motivated to look at a heat pump and raid the savings to do the right thing. But it didn't.

Instead, the car gave out. Such had been the encouragement to go electric for motoring that I didn't hesitate. But there was no encouragement or even information that phasing out of oil heating was on the country's agenda when I replaced my boiler.

Politicians need to figure out how to achieve their goals while taking people with them, and suddenly declaring that almost-new installations will have to be ripped out if you want to sell your house is not the way to win friends and influence people.

Might be an idea when your new boiler heads to the scrappy in the sky to look at the biomass wood pellet boilers. The pellets are made locally from locally sourced and maintained woods. They are at this time a much better option for you, and I think still get grants.

21 Biomass Boiler Pros And Cons

Biomass energy is a renewable resource that can help to heat our homes, replacing our reliance on fossil fuels. Check out all the different prod and cons

greener4life.com

 

[johnb80]

Do they fully dry the clothes, though? We've tried condensor dryers before, and the clothes always come out feeling slightly damp.

Very different to condenser dryers, yes they do dry clothes. Think of the condensate you see coming out of aircon in cars, thats exactly whats happening with a heatpump tumble dryer.

Might be an idea when your new boiler heads to the scrappy in the sky to look at the biomass wood pellet boilers. The pellets are made locally from locally sourced and maintained woods. They are at this time a much better option for you, and I think still get grants.

Amazing assessment from a few emails, brilliant, well done!

Wood pellets, how do they get delivered? I would guess not bey electric lorries.

 

[djenson]

I was really started to get a bit concerned that nobody has picked up on the main issue with heat pumps in this thread, until i finally saw this:

Most of the horror stories I have seen about ASHP's is when heat loss calculations haven't been done and the system has been installed by a heating engineer who hasn't had any training on heat pumps.

Gadget Geek finally had the answer

Most of the people installing these see it as a money machine and not as a heating system thats keeping someone warm in winter. Many also just pay the lowest bidder and don't take into account that this is a fairly complicated thing to get right, and not just a 30kw gas boiler on an s-plan.

Also minimum temp for domestic hot water (to ensure no legionella) and for a HOT bath is greater than 60 celcius. Not sure if heat pump can achieve that.

You would burn yourself if you had a bath at 50C, let alone 60. That's not even to mention it would be extremely uncomfortable. A heatpump can achieve 60C and the ones that can't have electric immersion heater with legionnaire prevention systems. That being said, the whole legionaries thing is a bit blown out of proportion on modern unvented cylinders. It was a concern when we had open top hot and cold water tanks that used to get mankey in the loft with gravity fed systems.

My daughter has an air source heat pump and is seriously thinking of changing to oil (no gas in village) once the tariff support ends. Her house is a new build, well insulated and has underfloor heating. Her electricity bills are shocking and she finds the whole system inefficient for her use. The time lag in heating from cold means she has to heat the house continually during the day in order for it to be warm enough when she gets home from work. If it turns out to be a warm evening then she’s wasted energy as well. Reminds me of the old storage heaters. It’s been continually tweaked and the engineers called out several times to adjust but she’s now wondering whether it’s been an expensive mistake.

Your daughter does not understand heat pump system operation, and I don't blame her as it was most likely not explained to her. Its also likely her system has not been installed correctly an/or has a fixed flow temp rather than weather and/or room compensation.

Your gas engineer is correct.

Heat pumps can be installed in an uninsulated property, its just that the system would need to be sized appropriately and would cost more to run, just as a gas boiler would.

I had a small air source heat pump integrated into the mechanical heat recovery / air system in my last house. The efficiency would drop off at below 6c with the expelled air being well below freezing point. This would cause icing up in the heat exchangers (as air temp dropped moisture would be released) which would kick off the reverse function (to melt the ice) which stopped the house heating . In reality it really needed a pre-heat integrated which would keep the incoming air over 6c, this would have added substantially to the running costs as the heaters are just electrical coils. With a bit of work to the ducting I mixed the incoming air from outside with air from the loft (it was a warm roof) which helped keep the temp of incoming air a bit higher.
Not sure how the modern air source heat pumps deal with this problem, but at the time they started to incorporate pre heaters, which would negate any cost saving. Would be interesting to hear from those who have systems installed and monitor low temp costs?

Almost all central heating heat pumps installed including ours are actually reversible. What this means, is that they reverse the flow of refrigerant to act as an air conditioner temporary to defrost the coils. This is not noticable inside the property. They can also do this in the summer to act as an air conditioner

They're not suitable for every building though, so it's not really on to legislate that everyone must switch to them. The insulation thing is key. Far better to run an effective insulate-your-home campaign, which will benefit everyone, then encourage people whose houses are suitable for heat pumps to fit them when their central heating needs replacing.

Insulation saves money and gas/electricity, but is not essential for a heatpump installation

The people that we know have it set to kick in at 4am, so that the house is warm when they get up at 8.30am

That suggests the installer had no clue what a heat loss calculation even is.

 

[Rolfe]

Might be an idea when your new boiler heads to the scrappy in the sky to look at the biomass wood pellet boilers. The pellets are made locally from locally sourced and maintained woods. They are at this time a much better option for you, and I think still get grants.

21 Biomass Boiler Pros And Cons

Biomass energy is a renewable resource that can help to heat our homes, replacing our reliance on fossil fuels. Check out all the different prod and cons

greener4life.com

There is actually someone very close to me who is selling the biomass wood pellet system. I think it's the guy who built the astonishingly ugly new house that pissed off all his neighbours because he took it right to the edge of the plot, and is trading as "smart homes" or something like that. He has one of these VW electric vans that looks like a small version of the old iconic VW campervan, and he's the approved local installer for wall boxes.

So yes, this is certainly a reasonable suggestion. But realistically, I am hoping the new boiler will see me out. Whoever gets this house next can worry about it. Every house in this street has oil boilers and I think it might be some time before we see anyone venturing to a different system.

 

[johnb80]

I was really started to get a bit concerned that nobody has picked up on the main issue with heat pumps in this thread, until i finally saw this:

Gadget Geek finally had the answer

Most of the people installing these see it as a money machine and not as a heating system thats keeping someone warm in winter. Many also just pay the lowest bidder and don't take into account that this is a fairly complicated thing to get right, and not just a 30kw gas boiler on an s-plan.

Heatpumps should simply be considered as a replacement boiler. By looking at historic records over the previous year you know exactly how many kWh were used by the gas boiler, gas boilers are typically in the 20 to 30 kW range whereas heatpumps generally are up to 15 kW. A heatpump will not cost to run on a like for like basis because their efficiency. Gas average at the moment is 10.3p, electricity is 34p. The input to your property needs to factor in efficiency and overheads for running pumps and valves. Typical boiler is around 90% therefore the cost of a kWh of heat from a gas boiler is 11.44p plus 4p for the electricity. So 11.44+4p gives a gas total of 15.44p kWh heat. Getting the same heat from a heatpump which on average of a COP of 3 (often more) = .34/3=11.3p. Factor into this that for a good period at night (6 hrs) electricity can be as low as 7.5p which makes it even better at around 9.1p per kWh. All the guff about insulation applies to ANY heating system, cost of gas would be reduced if the same insulation was added thats recommended for a heatpump. Contractors are hell bent on selling systems and getting as much work out of you as they can.

You would burn yourself if you had a bath at 50C, let alone 60. That's not even to mention it would be extremely uncomfortable. A heatpump can achieve 60C and the ones that can't have electric immersion heater with legionnaire prevention systems. That being said, the whole legionaries thing is a bit blown out of proportion on modern unvented cylinders. It was a concern when we had open top hot and cold water tanks that used to get mankey in the loft with gravity fed systems.

Absolutely

Almost all central heating heat pumps installed including ours are actually reversible. What this means, is that they reverse the flow of refrigerant to act as an air conditioner temporary to defrost the coils. This is not noticable inside the property. They can also do this in the summer to act as an air conditioner

Nope, they wont, the heat exchanger are in the wrong place, hot air rises, thats where you need to extract the heat, just imagine the floods of condensate dripping off the rads if you tried this, you would be flooded and damaging your property. It of course can be done with air to air heatpumps which have as well as an air to water for heating the rads and underfloor.

Insulation saves money and gas/electricity, but is not essential for a heatpump installation

That suggests the installer had no clue what a heat loss calculation even is.

Totally agree.

 

[SteveRW]

Yes, I have urged my daughter to pay for an independent review of her system as the whole thing seems unacceptable to me.

I would just say that in my limited experience there actually is a time lag in heating from cold. Apart from my daughter’s home, I once taught in an ultra modern ‘smart’ venue that had air source heating with underfloor heating. Occasionally if the thing had been switched off over the weekend in the winter, students throughout the day had to sit there with coats on and the centre manager apologising profusely and that it would be warmer tomorrow! As I say, it’s a limited experience but It does tend to influence my opinion. I’m happy to be convinced otherwise.

 

[johnb80]

Yes, I have urged my daughter to pay for an independent review of her system as the whole thing seems unacceptable to me.

I would just say that in my limited experience there actually is a time lag in heating from cold. Apart from my daughter’s home, I once taught in an ultra modern ‘smart’ venue that had air source heating with underfloor heating. Occasionally if the thing had been switched off over the weekend in the winter, students throughout the day had to sit there with coats on and the centre manager apologising profusely and that it would be warmer tomorrow! As I say, it’s a limited experience but It does tend to influence my opinion. I’m happy to be convinced otherwise.

Run it 24/7 with lower temperatures overnight and when the house isnt occupied then increase the temperatures when youre going to be in residence.
Last winter I reduced our boiler flow temperature to 35 deg C, way lower than heatpump and left it running 24/7. We used a lot less gas, the house was warmer which gave me the confidence to install a heatpump which i have done, I bought a used one from eBay that was in perfect condition. Looking forward to the colder weather to see how it goes, next year I will have the gas supply removed if it all good.

 

[Gomev]

Yes, I have urged my daughter to pay for an independent review of her system as the whole thing seems unacceptable to me.

I would just say that in my limited experience there actually is a time lag in heating from cold. Apart from my daughter’s home, I once taught in an ultra modern ‘smart’ venue that had air source heating with underfloor heating. Occasionally if the thing had been switched off over the weekend in the winter, students throughout the day had to sit there with coats on and the centre manager apologising profusely and that it would be warmer tomorrow! As I say, it’s a limited experience but It does tend to influence my opinion. I’m happy to be convinced otherwise.

Doesn't that apply to underfloor heating regardless of heat source ?

 

[johnb80]

Doesn't that apply to underfloor heating regardless of heat source ?

I have underfloor heating in my 50 sqm mtr conservatory, it literally takes days for the concrete slab to heat up, it has a tiled floor on top of concrete which is one of the best setups for UFH. The heating from it is absolutely superb just very slow to respond, we make it a comfortable area by having 2 x air conditioners in there which we can use for heat in the winter if we need to raise the temperature quickly. We maintain 19 deg C with the UFH and then raise it to 21 deg C when we use the room with the AC units.

 

[Exdro]

We also have a heatpump tumble drier and agree they are amazing at their energy efficiency.
Heatpumps for domestic heating are operated in a different way to a gas / oil / solid fuel boiler, you run them constantly and they are very efficient at heating your home.

You are correct. Don’t let the house get cold in the first place. Leave the heat pump running and set your desired temperature for different times if the day and Leave the ASHP to run efficiently.

 

[djenson]

Nope, they wont, the heat exchanger are in the wrong place, hot air rises, thats where you need to extract the heat, just imagine the floods of condensate dripping off the rads if you tried this, you would be flooded and damaging your property. It of course can be done with air to air heatpumps which have as well as an air to water for heating the rads and underfloor.

Mitsubishi makes some radiators (i-life2 slim) that are able to be used as air conditioners - They have a condense line. i guess they are air-water-air. Valliant has a controller that takes humidity and temperature measurements to calculate the dew point, then runs the flow temp just above that - Less effective, but can still provide some cooling on very hot days.

 

[johnb80]

Mitsubishi makes some radiators (i-life2 slim) that are able to be used as air conditioners - They have a condense line. i guess they are air-water-air. Valliant has a controller that takes humidity and temperature measurements to calculate the dew point, then runs the flow temp just above that - Less effective, but can still provide some cooling on very hot days.

I suspect that sort of radiator is a fan assisted type rather than conventional radiators. The efficiency as aircon would be absolutely dire, dreadful performance and incredibly inefficient.