Help with air source heat pump

[thenight]

Hi 

 

I’m new here and hoping someone can help.

 

I’m looking to install an air source heat pump to my property using the free £7500 grant from the government. 

 

I have a few questions before I start getting quotes:

 

1. I know lots of electricians and a couple of plumbers who have experience in heating. How difficult is it to install them? 
2. Will heat pumps work with my designer radiators?
3. House is already well insulated but do I need more?
4. I’ve briefly spoke with this company https://allseasonsenergy.co.uk/ who seem to know their stuff and have some cracking reviews. Anyone know them?

 

Thanks in advance

 

Theo (Jack of all trades, master of none!)

[Gary68]

Hi welcome. 

 

Apologies for the brief response but some starters for 10.

 

1 You need an MCS registered installer to be eligible for BUS so can't just use anyone in the trade.

2 That will be part of the assessment prior to installation if they are large you should be ok

3 You need an EPC that is less than 10 years old, if its got recommendations for loft or cavity wall insulation then that may need to be addressed

 

You have to remove the old boiler and the ASHP has to be used for Hot water and heating, heating only is not allowed

 

 

Edited November 23, 2023 by Gary68

[sharpener]

1. I know lots of electricians and a couple of plumbers who have experience in heating. How difficult is it to install them? 
   Not difficult but needs familiarity with heat pumps. To get the grant your installer must be MCS registered (like allseasonenergy). To provide extended warranty the installer must be approved by the HP manufacturer.
    
2. Will heat pumps work with my designer radiators?
   Possibly. As part of the quote process an MCS firm has to do a full room-by-room heat loss and emitter survey, this will determine whether rads need upgrading.
    
3. House is already well insulated but do I need more?
   Possibly. You will need to have an Energy Performance Certificate which does not have recommendations for more cavity wall or loft insulation. This normally means you need 270mm already in the loft.
    
4. I’ve briefly spoke with this company https://allseasonsenergy.co.uk/ who seem to know their stuff and have some cracking reviews. Anyone know them?
   No. They look similar to many other MCS registered firms. Their web site is quite impressive but that's the easy bit. Talking to several bidders (ideally local) will give you more of a feel. Also the energy firms like Octopus and Good Energy are entering the market now for simple straightforward installs.
   
   Whereabouts in the country are you? Can you give us an idea of the age and construction of the house and its floor area in sq m?

 

Edited November 23, 2023 by sharpener

[thenight]

13 minutes ago, Gary68 said:

Hi welcome. 

 

Apologies for the brief response but some starters for 10.

 

1 You need an MCS registered installer to be eligible for BUS so can't just use anyone in the trade.

2 That will be part of the assessment prior to installation if they are large you should be ok

3 You need an EPC that is less than 10 years old, if its got recommendations for loft or cavity wall insulation then that may need to be addressed

 

You have to remove the old boiler and the ASHP has to be used for Hot water and heating, heating only is not allowed

 

 

 

Thanks for this, very helpful.

I didn't realise there are conditions to be met for the grant, so I'll take a look. Reading some of topics on here it doesn't sound like an easy installation process.

[SteamyTea]

5 minutes ago, thenight said:

Reading some of topics on here it doesn't sound like an easy installation process.

Why do you think that.

They work just like any other wet heating system.

The first thing you should do is calculate your heat losses. This means finding out about your house construction i.e. walls, floor, doors and windows, roof, then assume you have ventilation losses of between 3 and 6 air changes an hour. Estimate your hit water usage as well 

Knowing all that will lead you into the size of system you are likely to need.

Once you have that information, then it is worth talking to installers.

And your free £7500 grant isn't really free. It is a subsidy to installers. So you are likely to still be paying something.

[thenight]

18 minutes ago, sharpener said:

1. I know lots of electricians and a couple of plumbers who have experience in heating. How difficult is it to install them? 
   Not difficult but needs familiarity with heat pumps. To get the grant your installer must be MCS registered (like allseasonenergy). To provide extended warranty the installer must be approved by the HP manufacturer.
    
2. Will heat pumps work with my designer radiators?
   Possibly. As part of the quote process an MCS firm has to do a full room-by-room heat loss and emitter survey, this will determine whether rads need upgrading.
    
3. House is already well insulated but do I need more?
   Possibly. You will need to have an Energy Performance Certificate which does not have recommendations for more cavity wall or loft insulation. This normally means you need 270mm already in the loft.
    
4. I’ve briefly spoke with this company https://allseasonsenergy.co.uk/ who seem to know their stuff and have some cracking reviews. Anyone know them?
   No. They look similar to many other MCS registered firms. Their web site is quite impressive but that's the easy bit. Talking to several bidders (ideally local) will give you more of a feel. Also the energy firms like Octopus and Good Energy are entering the market now for simple straightforward installs.
   
   Whereabouts in the country are you? Can you give us an idea of the age and construction of the house and its floor area in sq m?

 

 

Hi, I'm in Derbyshire. My house is a 3 bed dettached built late 70s. I'm not 100% sure on sqm but I would guess it's around 130.

I have loft insulation but it's definitely not 270mm and I already have cavity... according to the old owners. I will look into getting an Energy Performance certificate asap.

I did see that British Gas were advertising a heat pump at £499 but I don't think that was genuine as the grant is £7.5k.

Thanks for your help. very useful

[thenight]

4 minutes ago, SteamyTea said:

Why do you think that.

They work just like any other wet heating system.

The first thing you should do is calculate your heat losses. This means finding out about your house construction i.e. walls, floor, doors and windows, roof, then assume you have ventilation losses of between 3 and 6 air changes an hour. Estimate your hit water usage as well 

Knowing all that will lead you into the size of system you are likely to need.

Once you have that information, then it is worth talking to installers.

And your free £7500 grant isn't really free. It is a subsidy to installers. So you are likely to still be paying something.

Thanks for you reply.

Just some of the terminology used. I'm not in the trade but very handy (or so I like to think) when it comes to home improvements, and I have contacts in the trade. I didn't realise that the heat pump installation company had to be registered.

Calculating heat losses sounds even more complicated 😂

[sharpener]

36 minutes ago, thenight said:

Hi, I'm in Derbyshire. My house is a 3 bed dettached built late 70s. I'm not 100% sure on sqm but I would guess it's around 130.

 

Can get quite cold there esp if up in the dales, the MCS design rules take account of predicted min temps and altitude.

 

According to my go to cheat sheet yr house could need anything from 40 to 65 W/m^2, so a 5 to 8 kW unit. This means almost every manufacturer's single fan models so it will come within Permitted Development under the planning legislation. Also you need to verify your house power connection is adequate, but not likely to be a problem with this size of HP and age of property.

 

Another consideration is choice of refrigerant, R290 will enable you to reach higher flow temps than R32 and if the rad sizes are marginal it might help, but the MCS (and hence BUS grant) rules don't really allow best advantage to be taken of this anyway.

 

26 minutes ago, thenight said:

Calculating heat losses sounds even more complicated 😂

 

Try playing with this interactive toolkit.

 

Edited November 23, 2023 by sharpener

[crispy_wafer]

What's your current heating system and motivation to change?  

[SteamyTea]

25 minutes ago, thenight said:

Calculating heat losses sounds even more complicated

It is only addition and multiplication, which are the same thing.

 

Start by measuring your house. That way you have the dimensions of everything.

[thenight]

18 minutes ago, crispy_wafer said:

What's your current heating system and motivation to change?  

 

It's a gas boiler but it's around 8 years old. So really just thinking about the future 

[thenight]

22 minutes ago, SteamyTea said:

It is only addition and multiplication, which are the same thing.

 

Start by measuring your house. That way you have the dimensions of everything.

I'll do this tonight!

[crispy_wafer]

46 minutes ago, thenight said:

 

It's a gas boiler but it's around 8 years old. So really just thinking about the future 

Yeah probably a few years of life left in it before it’s due to be replaced, I’ve never had gas but by all accounts they don’t last like they used too!  If you haven’t already got one, would you have room for a hot water cylinder?

[Originaltwist]

 

The values on this chart vary from time to time but will,  I hope, help clarify your strategy. So option 1/. A new gas boiler is cheap, makes lots of high grade heat and your valued radiators (and the pipes) will work as they do now.  Option 2/. ASHP. The drop off in radiator performance might lead to regret. To get to high temperatures the heat pump COP will be lower than advertised and your running cost will be high. Option3/.??? Divert funds to some solar panels and run a mini-split alongside them - it's a lovely partnership and gives you a heat pump without messing with your pipes.. BTW, I love heat pumps ... just saying, don't rush in.

[Bozza]

@thenight you have asked the right questions and indeed received the right answers/advice from folk with some great knowledge and experience.
 

I’m overall very happy with my ASHP, and the grants and funding I receive for it.  But in the context of it being installed and integrated in a highly insulated self build, and I had no gas main options.    I’d be very, very wary & tread carefully, as you are doing, in researching the feasibility for retro installation in an older property.   

 

The main reason ASHPs get bad press for poor performance is they’ve been installed in houses that simply aren’t insulated/airtight enough.     They are not a holy grail for all houses.  Be very suspicious regarding companies who suggest anything contrary to this and bear in mind they’re trying to flog you something they want to sell, we most certainly are not :)

 

 

[SteamyTea]

49 minutes ago, Originaltwist said:

The values on this chart vary from time to time but will,  I hope, help clarify your strategy

When was the chart first made?

Town gas was phased out in the very early 1970s.

And what is a Kw hours.

K = Kelvin, the measure of temperature.

w = nothing really, but is, when italicised, used, in formulas, for angular speed, in radians per second. 

 

2 hours ago, thenight said:

I'll do this tonight

You will need a torch as you need to know the external dimensions as well as the internal ones.

[ReedRichards]

5 hours ago, thenight said:

2 Will heat pumps work with my designer radiators?

 

Heat pumps typically run at lower water temperatures than a gas boiler so each radiator will give out less heat.  But your existing radiators might be over-specified, they often are, in which case you could be okay with a heat pump.  Or you might be able to keep your existing radiators but add some more to achieve the necessary heat output.  We added a small low extra radiator in a bathroom to avoid having to replace the towel rail.

[Beelbeebub]

1 hour ago, ReedRichards said:

 

Heat pumps typically run at lower water temperatures than a gas boiler so each radiator will give out less heat.  But your existing radiators might be over-specified, they often are, in which case you could be okay with a heat pump.  Or you might be able to keep your existing radiators but add some more to achieve the necessary heat output.  We added a small low extra radiator in a bathroom to avoid having to replace the towel rail.

That said, "designer" radiators often have a lower output than big standard radiators so it's probable you won't get enough heat from the "designer" ones at efficient flow temperatures (typically less than 45C)

[ReedRichards]

I have two Grant aluminium radiators that look very nice to me; I would consider then "Designer".  But their heat output is good.

 

https://www.grantuk.com/products/aluminium-radiators/afinia-radiators/   

[sharpener]

Some of the claims in that link are pretty doubtful though.

• Afinia aluminium radiators are more efficient than traditional radiator materials, such as steel and cast iron
• Incredibly effective thermal conductors and with low energy consumption, Afinia radiators can help lower energy bills
• The range can deliver exceptional room comfort, heating up and cooling down very quickly which allows Afinia radiators to respond quickly to any changes in the temperature demand set by the thermostat

Except for heat lost from the back via an external wall (which will not vary a great deal) all radiators are 100% efficient in terms of the heat getting from the pipework into the room.

 

The radiators themselves do not and cannot have any intrinsic "energy consumption", low or otherwise. (Even with fan-assisted radiators the motor power ends up in the room.)

 

Claims about warm-up time are I think illusory, the thermal mass of the metalwork is small compared with the water content and very small compared with the room itself.

 

All the usual misleading advertising guff IMO.

[Marvin]

2 minutes ago, sharpener said:

Some of the claims in that link are pretty doubtful though.

• Afinia aluminium radiators are more efficient than traditional radiator materials, such as steel and cast iron
• Incredibly effective thermal conductors and with low energy consumption, Afinia radiators can help lower energy bills
• The range can deliver exceptional room comfort, heating up and cooling down very quickly which allows Afinia radiators to respond quickly to any changes in the temperature demand set by the thermostat

Except for heat lost from the back via an external wall (which will not vary a great deal) all radiators are 100% efficient in terms of the heat getting from the pipework into the room.

 

The radiators themselves do not and cannot have any intrinsic "energy consumption", low or otherwise. (Even with fan-assisted radiators the motor power ends up in the room.)

 

Claims about warm-up time are I think illusory, the thermal mass of the metalwork is small compared with the water content and very small compared with the room itself.

 

All the usual misleading advertising guff IMO.

I'm glad you wrote this!

 

 

 

[thenight]

18 hours ago, crispy_wafer said:

Yeah probably a few years of life left in it before it’s due to be replaced, I’ve never had gas but by all accounts they don’t last like they used too!  If you haven’t already got one, would you have room for a hot water cylinder?

We have the airing cupboard which is a good size.

How do you heat your property.. electric?

[thenight]

17 hours ago, Originaltwist said:

 

The values on this chart vary from time to time but will,  I hope, help clarify your strategy. So option 1/. A new gas boiler is cheap, makes lots of high grade heat and your valued radiators (and the pipes) will work as they do now.  Option 2/. ASHP. The drop off in radiator performance might lead to regret. To get to high temperatures the heat pump COP will be lower than advertised and your running cost will be high. Option3/.??? Divert funds to some solar panels and run a mini-split alongside them - it's a lovely partnership and gives you a heat pump without messing with your pipes.. BTW, I love heat pumps ... just saying, don't rush in.

This is great. Thank you!

[thenight]

17 hours ago, Bozza said:

@thenight you have asked the right questions and indeed received the right answers/advice from folk with some great knowledge and experience.
 

I’m overall very happy with my ASHP, and the grants and funding I receive for it.  But in the context of it being installed and integrated in a highly insulated self build, and I had no gas main options.    I’d be very, very wary & tread carefully, as you are doing, in researching the feasibility for retro installation in an older property.   

 

The main reason ASHPs get bad press for poor performance is they’ve been installed in houses that simply aren’t insulated/airtight enough.     They are not a holy grail for all houses.  Be very suspicious regarding companies who suggest anything contrary to this and bear in mind they’re trying to flog you something they want to sell, we most certainly are not

 

 

Very useful, thank you.

The more I read, I'm starting to understand that they aren't a great solution for all properties.

[thenight]

15 hours ago, ReedRichards said:

 

Heat pumps typically run at lower water temperatures than a gas boiler so each radiator will give out less heat.  But your existing radiators might be over-specified, they often are, in which case you could be okay with a heat pump.  Or you might be able to keep your existing radiators but add some more to achieve the necessary heat output.  We added a small low extra radiator in a bathroom to avoid having to replace the towel rail.

Understood. We also have a towel rail in one of the bathrooms. Thank you