Mini split instead of a heat pump?

[anonymous]

I've got microbore piping and ageing radiators. 

 

Would a mini split work out just as efficient as a heat pump? I imagine you don't necessarily need radiators and therefore the associated piping for said radiators, for a mini split? You'd still need to heat hot water though which could become an issue 

 

 

[JohnMo]

Mini split could work, you ideally would use a multi split, so you have one outdoor unit and multiple indoor units.  You would need to route small bore refrigerant piping from the outdoor unit to the rooms with an indoor units.  So a faff as well doing that. 

 

Depending on how you are plumbed and the individual room heat loads there is a possibility that micro-bore could work. Have a read here https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/

[JamesPa]

Air to Air generally has a better CoP that Air to water plus radiators, around the same as A2W plus UFH.  So, in terms of your question, the answer is probably yes.

 

DHW is, as you say, an issue.  It depends on what you need.  There are DHW cylinders with dedicated ASHPs attached, or you could use point of use heating if you can live without large amounts of stored hot water (no bath without a very long wait, just shower).  Otherwise its either a small A2W ASHP, immersion or fossil fuel.  As you are on this forum I imagine the last of these is not the desired outcome.

[anonymous]

3 minutes ago, JamesPa said:

Air to Air generally has a better CoP that Air to water plus radiators, around the same as A2W plus UFH.  So, in terms of your question, the answer is probably yes.

 

DHW is, as you say, an issue.  It depends on what you need.  There are DHW cylinders with dedicated ASHPs attached, or you could use point of use heating if you can live without large amounts of stored hot water (no bath without a very long wait, just shower).  Otherwise its either a small A2W ASHP, immersion or fossil fuel.  As you are on this forum I imagine the last of these is not the desired outcome.

Yes I'd rather do away with fossil fuels tbh. Regarding the above, whilst microbore could still be good for a heat pump, it's not exactly advised 

 

Are you also referring to say the Vaillant arastor? When you talk of a cylinder with a dedicated heat pump? 

[anonymous]

11 minutes ago, JohnMo said:

Mini split could work, you ideally would use a multi split, so you have one outdoor unit and multiple indoor units.  You would need to route small bore refrigerant piping from the outdoor unit to the rooms with an indoor units.  So a faff as well doing that. 

 

Depending on how you are plumbed and the individual room heat loads there is a possibility that micro-bore could work. Have a read here https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/

Apologies. Yes, a multi split for all the different rooms in my house. 

 

Even heat geek have a thing where their fourth tip is to simply repipe the system. This is especially an issue when it comes to say, powerflushing

 

https://www.youtube.com/watch?v=dEDitJnRgz4&t=4s

[JamesPa]

3 minutes ago, anonymous said:

Regarding the above, whilst microbore could still be good for a heat pump, it's not exactly advised 

Most probably not but if the heat requirement is small then its not impossible that micro will suffice.  Need to do the calcs.

 

3 minutes ago, anonymous said:

Are you also referring to say the Vaillant arastor? When you talk of a cylinder with a dedicated heat pump? 

Thats on example, there are others

[JamesPa]

1 minute ago, anonymous said:

Apologies. Yes, a multi split for all the different rooms in my house. 

 

How many rooms?

[anonymous]

28 minutes ago, JamesPa said:

How many rooms?

4 bedrooms 

 

One big open plan living room. It used to be both a living and front room I think 

 

Then there's a utility room and the kitchen too. Obviously there are bathrooms which have their own towel radiators as well. 

 

One of the bathrooms has a heated towel radiator. One is just an en suite that has no such thing 

 

It's basically a 4 bedroom semi detached house with a dormer on top 

[Radian]

4 minutes ago, anonymous said:

ne big open plan living room. It used to be both a living and front room I think 

A2A work best in open-plan houses. The best solution might be a combination of both a small ASHP and A2A

 Possibly finding away to re-pipe a few radiators in the smaller rooms?

[anonymous]

7 minutes ago, Radian said:

A2A work best in open-plan houses. The best solution might be a combination of both a small ASHP and A2A

 Possibly finding away to re-pipe a few radiators in the smaller rooms?

A small ASHP for water, essentially? 

[Radian]

30 minutes ago, anonymous said:

A small ASHP for water, essentially? 

Yes, I felt it might be worth considering sharing the work between the two types of heating. A2A  is incredibly responsive and efficient but doesn't provide for your DHW needs. 

[DanDee]

1 hour ago, anonymous said:

I've got microbore piping and ageing radiators. 

 

Would a mini split work out just as efficient as a heat pump? I imagine you don't necessarily need radiators and therefore the associated piping for said radiators, for a mini split? You'd still need to heat hot water though which could become an issue 

 

 

some inspiration

 

https://www.youtube.com/@dameonhill/videos 

 

https://www.youtube.com/@TimAndKatsGreenWalk/videos

[anonymous]

2 hours ago, DanDee said:

some inspiration

 

https://www.youtube.com/@dameonhill/videos 

 

https://www.youtube.com/@TimAndKatsGreenWalk/videos

I think I've watched all of Dameon's videos, and the main one I watched from Tim and Kat is where they talk about A2A and why they got it 

[RichardL]

To echo the above,  A2A is good and you can dip your toe in to phase it before removing radiators if you need to.
Its in its element when outisde is >0ºC,   still works when its below freezing but needs to work harder.


Generally you can get away without having an inside unit in every room - depending on house layout - the warm air moves around so pick some key places - perhaps a landing upstairs or the master befroom than all bedrooms for example. In my example upstairs we will put a unit in the master bedroom and infrared panels in the 2x less used rooms just to take the chill off rather than permanent heat.

You can't really put a2a in a bathroom either unless you go ducted. In my case I'm putting infrared panels in the shower room & bathroom.

 

A challenge, with the system I have anyway, is control. The default mechanism is a remote for each inside unit, each remote with a clock/timer, rather than a central timeclock. There are solutions including cloud based and cable based (I don't use cloud for my house utilities) - just need to be aware its different.

 

The system moves air - its very quiet inside and out but not silent - every now and again it may reverse the flow to stop the outside unit freezing and you may hear a swooosh when it does so. If you don't like the idea of warm air circulating, rather than oldschool radiator convection it may not be right for you.

 

Bonus right now is the solar kicked in last month with the sun higher in the sky so the a2a is run more and more from sunshine than off peak power stored in batteries.

 

I'm not an expert - just now in phase II of expanding A2A to my whole house (first install last september as an over winter test) to slowly replace oil heating. 

[anonymous]

5 hours ago, RichardL said:

To echo the above,  A2A is good and you can dip your toe in to phase it before removing radiators if you need to.
Its in its element when outisde is >0ºC,   still works when its below freezing but needs to work harder.


Generally you can get away without having an inside unit in every room - depending on house layout - the warm air moves around so pick some key places - perhaps a landing upstairs or the master befroom than all bedrooms for example. In my example upstairs we will put a unit in the master bedroom and infrared panels in the 2x less used rooms just to take the chill off rather than permanent heat.

You can't really put a2a in a bathroom either unless you go ducted. In my case I'm putting infrared panels in the shower room & bathroom.

 

A challenge, with the system I have anyway, is control. The default mechanism is a remote for each inside unit, each remote with a clock/timer, rather than a central timeclock. There are solutions including cloud based and cable based (I don't use cloud for my house utilities) - just need to be aware its different.

 

The system moves air - its very quiet inside and out but not silent - every now and again it may reverse the flow to stop the outside unit freezing and you may hear a swooosh when it does so. If you don't like the idea of warm air circulating, rather than oldschool radiator convection it may not be right for you.

 

Bonus right now is the solar kicked in last month with the sun higher in the sky so the a2a is run more and more from sunshine than off peak power stored in batteries.

 

I'm not an expert - just now in phase II of expanding A2A to my whole house (first install last september as an over winter test) to slowly replace oil heating. 

Thanks. I didn't realise you could have it in bathrooms, if you had it ducted 

 

I was thinking perhaps I could :

 

Get A2A

Use it for a bit 

Remove almost all my radiators except the two for the bathrooms 

 

Then get a much smaller air to water ASHP to heat up a water cylinder, and those two radiators. I'd have to upgrade the piping and radiators for the bathrooms but they'd be the only two things I'd need to realistically consider. 

 

Either that, or:

 

Get ducted A2A and have it in the bathroom as well 

Remove all radiators 

Still get a small ASHP just for water 

 

Would that perhaps be a good enough plan? 

 

Edited April 5, 2023 by anonymous

[RichardL]

21 minutes ago, anonymous said:

Thanks. I didn't realise you could have it in bathrooms, if you had it ducted 

 

I was thinking perhaps I could :

 

Get A2A

Use it for a bit 

Remove almost all my radiators except the two for the bathrooms 

 

Then get a much smaller air to water ASHP to heat up a water cylinder, and those two radiators. I'd have to upgrade the piping and radiators for the bathrooms but they'd be the only two things I'd need to realistically consider. 

 

Either that, or:

 

Get ducted A2A and have it in the bathroom as well 

Remove all radiators 

Still get a small ASHP just for water 

 

Would that perhaps be a good enough plan? 

 

Hi,
I looked at ducted - but in the end an IR panel (Herschel) + electric towel rail on low in the bathroom was a more practicable install.
The shower room only needs to heat in the early morning really, then just take the edge off all day.

Re your plan: Try A2A, then extend, + you can get combined Cylinders with ASHPs (Vaillant:Arostor Dimplex:Edel etc do them) is exactly what I'm in the middle of.

I'd advise planning up front the outside units required and which rooms they will service so you don't end up with too many.
Research control too - the usual standard 1x remote per inside unit is great for flexibility but not a good fit for whole house control.

My project eventually will be:
- Outside 10kW unit to 3x inside rooms on the ground floor.
- Outside 5.4kW unit to a bedroom + one other room the other side of the house.
- Combined tank+integrated ASHP for hot water.

Control they'll be linked logically to a controller for downstairs, one for upstairs and back to the standard time-clock for the house.

Removing radiators as I go, and eventually the oil burner and its tank!
 

[anonymous]

8 minutes ago, RichardL said:

Hi,
I looked at ducted - but in the end an IR panel (Herschel) + electric towel rail on low in the bathroom was a more practicable install.
The shower room only needs to heat in the early morning really, then just take the edge off all day.

Re your plan: Try A2A, then extend, + you can get combined Cylinders with ASHPs (Vaillant:Arostor Dimplex:Edel etc do them) is exactly what I'm in the middle of.

I'd advise planning up front the outside units required and which rooms they will service so you i house.
- Combined tank+integrated ASHP for hot water.

Control they'll be linked logically to a controller for downstairs, one for upstairs and back to the standard time-clock for the house.

Removing radiators as I go, and eventually the oil burner and its tank!
 

Thanks. I've been watching the Tim and Kat video where he said he went for something with WiFi, largely because it's much easier for a whole house system. Remote controls aren't amazing for that 

 

That to me makes sense. I've got a fair chunk of space on the side of my house too. By "then extend", do you mean to essentially get say one room, and then extend it to the house as a whole? 

 

I do also have lodgers who insist on having the heated towel radiator on, which is annoying but they're paying me for it, so I think I'd need that in at least one bathroom to be on most of the day

[RichardL]

Re extend
I have a house of two halves with challenging routing for the A2A - so it made sense, for me, to heat my living room and home office first with a multisplit - see how that went over the winter, and only now extending to the rest of the house with another outside unit (Multisplit).

The wifi thing is cool and all - and I work in technology (perhaps because of)  - I wanted basic wires and OEM control on the heating relying as little as possible on other infrastructure or configuration - i.e. if its plugged in it works. You take your pick here - no wrong answers


Heated towel rad I'm using a TCP200-  very low tech, but on a low setting its the equivalent of 150W (an old-school lightbulb) i.e. low enough to just keep the radiator warm.

[anonymous]

2 hours ago, RichardL said:

Re extend
I have a house of two halves with challenging routing for the A2A - so it made sense, for me, to heat my living room and home office first with a multisplit - see how that went over the winter, and only now extending to the rest of the house with another outside unit (Multisplit).

The wifi thing is cool and all - and I work in technology (perhaps because of)  - I wanted basic wires and OEM control on the heating relying as little as possible on other infrastructure or configuration - i.e. if its plugged in it works. You take your pick here - no wrong answers


Heated towel rad I'm using a TCP200-  very low tech, but on a low setting its the equivalent of 150W (an old-school lightbulb) i.e. low enough to just keep the radiator warm.

Ah. I'm a network engineer in my day job . I like the simplicity of WiFi even with the potential security concerns. Ultimately you decide if the benefit is worth the security risk. 

 

That also makes sense. My house is semi detached so routing shouldn't be an issue. The previous owner did have AC going into the attic but nowhere else do I know where one AC unit already is

 

They basically left the non functioning AC on the side of the building. The AC they put on stopped working years ago. There's no "cassette" either