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U.K. Heat and Buildings Strategy, £450m available to homeowners

I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?
My neighbour who has heard one in use told me that particular model was similar to having a large electric air compressor constantly running.
Nice in the middle of the night when surrounded by them I surmise.
 
Yeah, I have heard heat pumps - they can be quite noisy, much louder than the refrigerator comparison usually touted, more like a low pressure / high volume compressor.

IF, it runs continuously, it would just add "white noise" to increase the background noise pollution. I would probably be able to tune that out --- but if it stops and starts, nope, that would be very intrusive. [I have a freezer in an outbuilding with a noisy compressor and I can hear that at night if it cuts in, if the door to the outbuilding is open for the visiting cat to explore]

I live in an area that is currently very quiet at night. If the wind is in the right direction I can just hear a railway and major road that are about two / three miles away ...
 
Not impressed with the idea of pumping hydrogen about, unless they have a way of making it less likely to catch fire / blow up if any leaks / escapes from custody.

And I would expect that most pipework would need upgrading
The Hindenburg going boom is one of those things that has fixed itself firmly in the public pysche but hydrogen is actually less explosive than natural gas (mostly methane) it only has about a fifth the energy density which means more has to be burnt to get the same amount of heat but it's clean only producing water vapour rather than water vapour and carbon dioxide like methane. The big problems with hydrogen are that the molecule is tiny compared to methane making it much more work to seal pipes and the fact it doesn't exist freely in nature for long, it has to be cracked out of something first (ideally water) which requires energy.
Hydrogen would be the perfect fuel in a post-fusion industrial world, using cheap energy from the reactor it could be cracked out of seawater to burn in internal combustion engines, gas boilers and turbines, power fuel cells and of course fuel the fusion reactors themselves. The massive flaw in that plan is of course we are still some years from a practical working fusion reactor but it could be cracked with renewable energy in the meantime.
 
My former employer used heat pumps at their office, they’re in a joint venture with another company for producing them in this country I think.

Recall they made a humming sound as you walked past.
 
Yeah, I have heard heat pumps - they can be quite noisy, much louder than the refrigerator comparison usually touted, more like a low pressure / high volume compressor.

IF, it runs continuously, it would just add "white noise" to increase the background noise pollution. I would probably be able to tune that out --- but if it stops and starts, nope, that would be very intrusive. [I have a freezer in an outbuilding with a noisy compressor and I can hear that at night if it cuts in, if the door to the outbuilding is open for the visiting cat to explore]

I live in an area that is currently very quiet at night. If the wind is in the right direction I can just hear a railway and major road that are about two / three miles away ...
That sounds like where I live. But the care home over the road installed something a while back that has a noisy compressor running all the time, which is quite intrusive at night. Can't imagine what it would be like if all the neighbours were doing it. I'm quite keen to get one but the noise is a problem for me as I have mild misophonia anyway.
 
I don't know how these are going to work for properties that can't be easily insulated and/or blocks of flats.
 
20% of U.K. housing stock (including my house) was built pre 1920 meaning it most likely has solid rather than cavity walls. Heat pumps are pointless without good insulation. Is the government going to rehouse us all?
 
20% of U.K. housing stock (including my house) was built pre 1920 meaning it most likely has solid rather than cavity walls. Heat pumps are pointless without good insulation. Is the government going to rehouse us all?
This is the problem. Attack the problem from the bottom up.
 
It's a problem that has to be attacked from multiple angles. It makes sense to promote the use of heat pumps in properties where it's appropriate.
 
I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element. :hmm:
 
Updating the housing stock would be a massive undertaking - and there is quite a lot of potential for other problems.
I'm thinking specifically of the "embeded" carbon in the old building and ditto for the replacement.

 
I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element. :hmm:
It just moves energy that's outside the house, into the house. The outside air gets slightly colder and the water circulating in the heating inside the house gets warmer.

Although it's true they work by magic, they don't create any free energy.
 
It just moves energy that's outside the house, into the house. The outside air gets slightly colder and the water circulating in the heating inside the house gets warmer.

Although it's true they work by magic, they don't create any free energy.
If you had a mug of water at 50C and another mug of water at 30C and mixed them together you get water at 40C not 80C.

E2a: even with a heat recovery ventilation system the air coming back in is slightly cooler than the air in the room, it doesn't come in warmer.
 
If you had a mug of water at 50C and another mug of water at 30C and mixed them together you get water at 40C not 80C.

E2a: even with a heat recovery ventilation system the air coming back in is slightly cooler than the air in the room, it doesn't come in warmer.
Through the magic of a heat pump you can make the mug of water at 30c go down to 20c and the mug of water at 50c go up to something higher than that.

Just like your fridge moves heat from the inside of it to the outside of it, using heat pump magic.

A heat recovery ventilation system doesn't use a heat pump, just a heat exchanger. And the air coming back in is slightly cooler because the heat exchanger isn't 100% effective. But it also doesn't require any energy to be put into the system other than that used by the fans to physically move the air.

A heat pump does need external energy to do the work of moving heat energy from one location to another. But if this allows it to move more energy than it needs to do the work of moving... Then you get more great energy out of the system than the electrical energy you use to run it. It's not free energy because it's not come from thin air - it's just energy that was previously in a different location.
 
I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element. :hmm:
Although they may appear to be unproven new technology from the perspective of the U.K. market where they’ve been rare until now, in other places around the world heat pumps have been heating people’s homes for over 50 years. They’ve been common in Sweden since the 1970s and are now the most mainstream choice. If they didn’t “actually work”, I think people would have noticed by now.

They do work, as the electrical energy it takes to move heat energy from one place (outside) to another (inside) and release it is much less than the energy which creating that amount of heat directly from electrical heating would consume.
 
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Although they may appear to be unproven new technology from the perspective of the U.K. market where they’ve been rare until now, in other places around the world heat pumps have been heating people’s homes for over 50 years. They’ve been common in Sweden since the 1970s and are now the most mainstream choice. If they didn’t “actually work”, I think people would have noticed by now.

They do work, as the electrical energy it takes to move heat energy from one place (outside) to another (inside) and release it is much less than the energy which creating that amount of heat directly from electrical heating would consume.
Sorry you've misunderstood. They do work but not how people think they work.

They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.

And heat pumps may work well in Scandinavia as the houses have always been much better insulated than houses in the UK.
 
Show us the maths that doesn't add up.
Really?

When you were a kid did you ever put your thumb over the end of a bike pump and pump operate it?

The end of the pump didn't get hot due to some mystical heat exchange, it got hot due to you compressing the gas in the pump.
 
Sorry you've misunderstood. They do work but not how people think they work.

They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.

And heat pumps may work well in Scandinavia as the houses have always been much better insulated than houses in the UK.
Righto - you’re clearly quite an expert. I’ll leave you to it and hope, in due course, the rest of the world catches up with your advanced understanding of the technology :thumbs:
 
Maybe, but the post below mine from StoneRoad appears to agree with my shite talking neighbour, who works in building control for North Lincolnshire Council.
I've heard more compressors than I could possibly remember. I've also heard my mate's heat pump compressor. It's a scroll compressor and it's almost silent, and certainly quieter than any piston compressor I've ever heard, so regardless of where he works, your neighbour is wrong.

Ground Source Heat Pumps​

Volume isn’t much associated with GSHPs, because of the lack of fan unit. However, people do still ask whether ground source heat pumps are noisy or silent. Indeed, there are components that make some noise, but this is always less than the noise of an air source heat pump.

Heat from the ground is more consistent, and therefore the power capacity of the compressor isn’t as high. The heat pump doesn’t need to operate at full throttle, and this keeps it quieter.

If you stand one metre away in the plant room, a ground source heat pump has a maximum decibel level of 42 decibels. This is similar to a typical domestic refrigerator. This is much less noisy than any fossil fuel boiler, and the noisiest parts are inside your home so the neighbours will not experience any change in outdoor environment.

If the system is installed correctly by a qualified contractor, noise will not be a problem.

Also read: How much space do I need for a ground source heat pump?


Air Source Heat Pumps​

Typically, ASHPs will be noisier than GSHPs. However, this is in no way prohibitive and will not be a problem if planned carefully.

You often you get what you pay for. Depending on the system, quality of installation, and quality of maintenance – an air source heat pump will have 40 to 60 decibels of noise. Again, this is assuming you are one metre away from the unit. The upper limit is not a common phenomenon.

There are official planning requirements with regards to air source heat pump noise. ASHPs must be below 42 decibels, measured from a distance equal to that separating the unit and the next door property. The noise might be between 40 to 60 decibels from just a metre distance (probably much quieter in reality), and the levels drop significantly as you move away.

Most piston compressors operate above the noise level that would require ear protection (85dB>)
decibel-scale-chart-vector-illustration-decibel-scale-chart-vector-illustration-measuring-noise-pollution-levels-work-safety-173114173.jpg


Example​

Noise level (decibels)​

Breathing10
Whispering / rustling leaves20
Quiet rural area30
Library / bird calls40
Heat pump noise limit (MCS)42
Conversation at home50
Conversation in an office or restaurant60
Vacuum cleaner70
Alarm clock / dishwasher80
 
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I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?
I've just spent a couple of months living in a place heated only by an air source heat pump system. I didn't notice the unit was running unless I was standing outside within a couple of metres of it. No louder than the fridge; less intrusive than the dishwasher.
I don't see how air in a fridge at 5C can make the "radiator" at the back of the fridge run at 50-60C. The maths doesn't add up.
A heat pump does not create thermal energy. It just moves around thermal energy that already exists.

Before we leap into thermodynamics, try thinking in terms of 278K and 323K and thus using a unit of (electrical) energy to move a very small amount of (several units of thermal) energy from a vast warm object/volume to ever-so-slightly warm up a (relatively) minuscule object/volume.
 
Really?

When you were a kid did you ever put your thumb over the end of a bike pump and pump operate it?

The end of the pump didn't get hot due to some mystical heat exchange, it got hot due to you compressing the gas in the pump.
If you want to understand how a heat pump works, you can look it up on the internet. The heat is moved from one location to another, not generated by the compressor, as several people people have now pointed out.
 
They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.
All resistive element heating systems are by definition 100% efficient at converting electricity into heat. They all have a COP of 1.0. So for every watt of electricity you put into the system, you get 1 watt or 3.41 BTU of heat out. The only thing you can effect is how you distribute that heat.
 
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