@chickenbig

Posted by: @chickenbig

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I'd be tempted to just drop rule i) as it seems unenforceable and puts additional red-tape on A2A heat pumps. Alternatively perhaps it could be inverted to "the air source heat pump must be used for heating purposes" to rule out cooling-only applications?

I don't think it puts additional red tape on A2A because it says 'used' not 'capable of' (fortunately).  Most A2W HPs are also 'capable of' cooling.  To the best of my knowledge only Vaillant sell A2W heat pumps which are not capable of cooling (well they are of course, but you need to buy a £200 resistor worth no more than £5, probably no more than 5p, as an accessory to 'convert' them, and in the UK they sell them without this resistor fitted I am told.)

I don't know what the authors were thinking but, based on my interactions with my LPA, I think a good rationale is as follows:

Dropping this constraint muddies the water on the noise issue. 

A HP used solely for heating is only used when its cold, and most people (in particular the neighbours) are inside with windows closed.  So the MCS-020 fixed sound constraint (sound pressure <= -37dBA at the assessment points), which is readily calculated by anyone, is also justifiable even if the background noise is lower than this value, because -37dBA will be inaudible inside.

As soon as you permit cooling then you have to assume that the unit will be used when windows are open and people outside.  At this point background level needs to be considered if the HP is not to cause nuisance, in which case you introduce the need for a house-specific assessment, requiring a sound consultant and additional expense which burdens the installation of HPs for heating unnecessarily.

The current wording permits you to install a heat pump and use it for heating with a very simple noise calculation which makes sense given the characteristics of when they make most noise.  If you want to use it for cooling you can always apply for planning consent later to do this and go through the full noise assessment  etc. which matter for cooling. 

Now you might say, once its in, how is this enforceable?  I think the answer is that, if there were a complaint about noise whilst cooling, the LPA (which is also responsible for environmental nuisance) would investigate and either issue a planning enforcement notice or a noise abatement notice.  Either is enforceable.  And if there isn't a complaint about noise it doesn't matter that the rule has been breached!  On balance its actually a well written part of the regs as far as I can see(!)

Posted by: @jamespa

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@chickenbig

Posted by: @chickenbig

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I'd be tempted to just drop rule i) as it seems unenforceable and puts additional red-tape on A2A heat pumps. Alternatively perhaps it could be inverted to "the air source heat pump must be used for heating purposes" to rule out cooling-only applications?

I don't think it puts additional red tape on A2A because it says 'used' not 'capable of' (fortunately).  Most A2W HPs are also 'capable of' cooling.  To the best of my knowledge only Vaillant sell A2W heat pumps which are not capable of cooling (well they are of course, but you need to buy a £200 resistor worth no more than £5, probably no more than 5p, as an accessory to 'convert' them, and in the UK they sell them without this resistor fitted I am told.)

I don't know what the authors were thinking but, based on my interactions with my LPA, I think a good rationale is as follows:

Dropping this constraint muddies the water on the noise issue. 

A HP used solely for heating is only used when its cold, and most people (in particular the neighbours) are inside with windows closed.  So the MCS-020 fixed sound constraint (sound pressure <= -37dBA at the assessment points), which is readily calculated by anyone, is also justifiable even if the background noise is lower than this value, because -37dBA will be inaudible inside.

As soon as you permit cooling then you have to assume that the unit will be used when windows are open and people outside.  At this point background level needs to be considered if the HP is not to cause nuisance, in which case you introduce the need for a house-specific assessment, requiring a sound consultant and additional expense which burdens the installation of HPs for heating unnecessarily.

 

The current wording permits you to install a heat pump and use it for heating with a very simple noise calculation which makes sense given the characteristics of when they make most noise.  If you want to use it for cooling you can always apply for planning consent later to do this and go through the full noise assessment  etc. which matter for cooling. 

Now you might say, once its in, how is this enforceable?  I think the answer is that, if there were a complaint about noise whilst cooling, the LPA (which is also responsible for environmental nuisance) would investigate and either issue a planning enforcement notice or a notice to cease making the noise.  Either is enforceable.  And if there isn't a complaint about noise it doesn't matter that the rule has been breached!  On balance its actually a well written part of the regs as far as I can see(!)

I suppose the noise aspect is very much a 'can of worms' and also subjective, since different individuals will have varying levels of noise tolerance.

We have an A2A heat pump which is used predominantly for heating, and only occasionally for cooling, and I would assess is not as noisy as our bathroom extractor fan. It is quite possible that A2W heat pumps will be used to produce hot water in the Summer months, so heating is not just a Winter pastime.

We live in a noisy World and most have become accustomed to a certain level of noise, so whatever system is used for heating and producing hot water, should be acceptable, provided that it is below the maximum acceptable noise levels.

I would personally suggest that A2A heat pumps are not included in the BUS scheme, since I suspect the net effect would be to increase the price of A2A systems, which at the moment are much cheaper than A2W. I also suspect, though don't have the data to prove it, that A2A heat pumps may be more efficient than A2W heat pumps, since they introduce at least one less heat exchanger into the equation. An A2A heat pump also raises the indoor air temperature much quicker than a water based heating system, since the fan coil unit is directly heating the air. I also read an article yesterday giving details of an A2A heat pump that could be used to provide DHW, when operating in cooling mode.

Today I watched an episode of 'The Climate Show' on sky news, were one of the topics was district heating at a village with older, difficult to heat, type homes. A district heating facility, using both GSHP's and ASHP's, produced a supply of hot water at temperature up to 70C, which was used to supply the homes without the need for any internal changes to be made.

Posted by: @derek-m

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I suppose the noise aspect is very much a 'can of worms' and also subjective, since different individuals will have varying levels of noise tolerance.

We have an A2A heat pump which is used predominantly for heating, and only occasionally for cooling, and I would assess is not as noisy as our bathroom extractor fan.

Quite possibly not.  However ASHPs are associated with air-conditioning and LPAs are accustomed to imposing noise constraints.  So I think we have to be thankful that there is a simple PD rule for ASHPs used for heating, bank that and move on.

Posted by: @derek-m

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It is quite possible that A2W heat pumps will be used to produce hot water in the Summer months, so heating is not just a Winter pastime.

In summer they are unlikely to be working at their maximum noise level, because its warm.  And producing water is not all day.  So its a diminished level of issue in summer (when people are outside/windows open.

Posted by: @derek-m

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We live in a noisy World and most have become accustomed to a certain level of noise, so whatever system is used for heating and producing hot water, should be acceptable, provided that it is below the maximum acceptable noise levels.

The problem is 'maximum acceptable'  Its a fair argument that a higher level of noise is acceptable in winter than in summer because in winter people are inside.  So Again, I think we have to be thankful that there is a simple PD rule for ASHPs used for heating, bank that and move on.

Posted by: @derek-m

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I would personally suggest that A2A heat pumps are not included in the BUS scheme, since I suspect the net effect would be to increase the price of A2A systems, which at the moment are much cheaper than A2W. I also suspect, though don't have the data to prove it, that A2A heat pumps may be more efficient than A2W heat pumps, since they introduce at least one less heat exchanger into the equation. An A2A heat pump also raises the indoor air temperature much quicker than a water based heating system, since the fan coil unit is directly heating the air. I also read an article yesterday giving details of an A2A heat pump that could be used to provide DHW, when operating in cooling mode.

I too am in two minds about this (and you are right they are more efficient).  The person who suggested it, and those who supported it, on the Buildhub forum, were making that case that A2A is unfamiliar technology in the UK but, in open plan houses particularly, has a real place to play.  I think they are right.  They also argued that even in houses which aren't open plan, a single A2A downstairs may well eliminate 60% plus of the emissions.  Personally I think this argument is strong enough to give the benefit of the doubt.  I grant however that there is a risk of a price increase, although perhaps less so since there are plenty of A2A installers out there, nothing to do with MCS, who install in commercial premises where A2A is more or less the norm.

@jamespa

It is my understanding that air conditioning units (A2A heat pumps) have the same limitations for permitted development as A2W heat pumps, the main reason that they are excluded from the BUS scheme is because they can more readily be used for cooling as well as heating, whereas an A2W heat pump requires additional equipment to be used for cooling as well as heating.

It is therefore permissible to install a A2A heat pump under permitted development, but you cannot claim the £5000 'bribe'.

Posted by: @derek-m

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@jamespa

It is my understanding that air conditioning units (A2A heat pumps) have the same limitations for permitted development as A2W heat pumps, the main reason that they are excluded from the BUS scheme is because they can more readily be used for cooling as well as heating, whereas an A2W heat pump requires additional equipment to be used for cooling as well as heating.

It is therefore permissible to install a A2A heat pump under permitted development, but you cannot claim the £5000 'bribe'.

FUN FACT

Although the heat pumps have the ability to cool, they need a 2p resistor sold as a £250-£300 chip 🤣 

£7 for the same thing for the gas boilers

https://www.mpmoran.co.uk/vaillant-boiler-spare-part-plug-coding-yellow-0020242593-109135116

€46-67 over the continent 

https://zet-shop.be/fr/verwarming/warmtepompen/toebehoren-warmtepomp/25085-codeerstekker-vaillant-voor-activatie-van-de-koelfunctie-arotherm.html

https://lbge.be/product/vaillant-codeerstekker-voor-activatie-van-de-koelfunctie-0020269259/

@fazel

That's because we live in 'rip-off Britain'. 😡 

Just something I noticed but according to USwitch- 80% of boilers in the UK are combis so the cost of a new DHW cylinder and related plumbing often included in ASHP quotes is going to be unavoidable for a large part of the prospective market. https://www.uswitch.com/energy/boilers/boiler-statistics/

@dougmlancs interesting, I'm surprised it's that high although with new properties being small it's perhaps not surprising.

Having had combos in the past I think this is a big challenge for the ashp market, space is a definite issue and the lack of physical variety in solutions (they are pretty much all a cylinder) is limiting.

I was in France recently and the rental property I had was fitted with a 90 litre wall hung rectangular tank with a 1.5kW immersion fitted in a little alcove.  I googled it and they appear quite common and are as cheap as chips.  Not sure how teenagers accustomed to unlimited power showers would cope.

I've so far deliberately avoided thinking about the combi/ashp issue as it's too difficult.