Monoblock or Split

[Mr Blobby]

Two years ago I decided we would install a 7kW panasonic monoblock unit (Aquera J series) into our house when we finally get to building it.  A releatively simple decision I thought.

 

Now that the house is finally watertight (mostly) the time has come to get on with the plumbing.  On site today and the plumber said that all his recent installs over the last year have been split units.  Nobody installs monoblocks any more he said and suggested I review my heat pump decsion.  Which is fair enough.

 

I had always thought the split units were for larger unit seeking higher temps, and the split unit brings the noise of the compressor inside.  Plumber says the split units have smaller holes in the wall and no chance of freezing. 

I understand the difference between split and mono, but is the monoblock really dead?

 

Another thing that has made me stop and think, as well as plumber comments, is that Panasonic lateset series K and L series, all now seem to be split units. 

I've not been keeping up with latest ASHP technical developements for the last couple of years.  Is the monoblock really dead, or should I stick with my original simple choice (and keep the compressor noise outside) ? 

 

Edited April 19 by Mr Blobby

[Bramco]

1 hour ago, Mr Blobby said:

I understand the difference between split and mono, but is the monoblock really dead?

 

No - call one of the suppliers, I'll bet they'll tell you monoblocs are what they sell most of. 

 

Worrying about the size of the holes in the wall is also daft. There are ducts to handle either system.  Probably the main question is - do you want the compressor running at night in the house?   If you're hard of hearing it may be OK but for everyone else, it's a non starter.   There's a long thread on here somewhere about the noise from a split system which drove the OP mad.  And you need a refrigerant engineer to install a split system - whereas with a monbloc it's just normal plumbing.

 

Our monbloc is against the outside wall under the stairs - you can't hear it in the bedrooms but if I have a wander at night, you can hear it at the bottom of the stairs - that would be 10x as bad with a monobloc.

 

I'm sure the experts will be along before long but from a user perspective monbloc is the way to go.

 

Simon

 

PS - and if you believe plumbers, then .....    ours insisted that all he had to do with ASHPs was ripping them out and installing gas boilers - and that was 3 years ago when there weren't many ASHPs installed.   He's probably now working for Octopus installing ASHPs....   

Edited April 19 by Bramco

[JohnMo]

1 hour ago, Mr Blobby said:

always thought the split units were for larger unit seeking higher temps, and the split unit brings the noise of the compressor inside.  Plumber says the split units have smaller holes in the wall and no chance of freezing. 

I understand the difference between split and mono, but is the monoblock really dead?

Generally smaller external unit, as no circulation pump and heat exchangers, these move inside. You need an F gas installer (possibly not if R290). The inside unit is the size of gas boiler, so not small.

 

Both need holes through wall monobloc bigger, but still holes to seal up.

 

Monobloc is long from dead, I would give a split unit house room. Just looked on City Plumbing they don't list any split units. Your plumber is talking out of somewhere that the sun doesn't shine.

 

Did have a look at Panasonic site, don't believe they do offer refrigerant split units (R290), as their blurb and video states hydraulically split.  The indoor unit is for the water circulation pump and mixing valves so you can do two different zones at independent temperatures.

[ProDave]

As above.  Why would I want a split unit that requires an F gas engineer, so I could not fit it myself, and why would i want the noisy bit with the compressor inside the house?

[joe90]

I think I read that in house noise was a problem with GSHP,s ?, however how much noise, more than a gas or oil boiler?.

[Adsibob]

27 minutes ago, joe90 said:

I think I read that in house noise was a problem with GSHP,s ?, however how much noise, more than a gas or oil boiler?.

My gas boiler is virtually silent. All 35kw of it, but perhaps that’s because it only ever fires up to a maximum of 60% of its modulation, on amount of the fact that the bloody installer oversized it by so much!

[SteamyTea]

3 hours ago, Bramco said:

There's a long thread on here somewhere about the noise from a split system which drove the OP mad

They were mad to start with.

 

Go monoblock and consider a different plumber.

[JohnMo]

2 hours ago, JohnMo said:

Monobloc is long from dead, I would give a split unit house room.

Just noticed my miss spell - I wouldn't give a split unit house room

[joe90]

1 hour ago, joe90 said:

however how much noise,

Specifics please (purely out of interest)

[Mr Blobby]

Thanks all, I'd forgotten about the requirement to get an f gas registered engineer to sign off the spilt unit because of the refrigerant.

 

You all confirm what I had thought, that the monoblocks are nice and simple and quiet.  I suspect the scaremongering I got from the plumber over monoblocks stuck in a defrost cycle come from poorly designed installations demanding unrealistic high temps.

 

Monoblock it is then.

 

[Mr Blobby]

3 hours ago, JohnMo said:

Did have a look at Panasonic site, don't believe they do offer refrigerant split units (R290), as their blurb and video states hydraulically split.  The indoor unit is for the water circulation pump and mixing valves so you can do two different zones at independent temperatures

 

Saw the panasonic inside unit and assumed split unit with compressor inside. Serves me right for skimming, thank you for the update, very useful.

[Nick Laslett]

I am just fitting my Panasonic J series ASHP. I looked at the K & L series, Panasonic appears to be creating forced bundles of components. As a package this might be cheaper, simpler to fit and less hassle for the installer. It is difficult to tell whether this is a good thing or not. Other manufacturers have a similar bundled approaches. All my research was around a simple standalone monoblock. I think the prices of the J series have been reduced a little to fit in the K & L series. I could see no actual spec advantages.

[Roundtuit]

Split unit here.  Yes, you can hear it if you're close, but I don't find it intrusive, it just adds to the 'heartbeat' of the house.  Never noticed it whilst in bed or watching TV.

That said, the installer that recommended it turned out to be a bit $hit, so I've no loyalty either way...

[Iceverge]

In John Cantors Heat pump videos he made a good point that as the monoblock is a factory sealed unit there's less risk of a refrigerant leak, which could wipe out any CO2 savings over the life of the heat pump. 

 

On manufacturers that insist on packaged tanks etc I'd be keen to avoid as it might mean it's impossible to repair when just one component breaks in future.

 

 

[JamesPa]

To my mind splits have two unique advantages, namely that the condenser unit can be distant from the house with a much smaller penalty.  They also don't have water outside.  However if you don't need those advantages, then monoblocs are much more common in the UK (not necessarily the case elsewhere) which from me says monobloc if you can just because of industry familiarity.

[Beelbeebub]

Split units are basically a "normal" air to air unit outside (including the compressor) and then inside, instead of an air to air room unit, an air to water room unit with a conventional central hearing pump, plate heater exchanger, some valve and other gubbins. 

 

I believe Panasonic are confusing things with "hyro split" which is a mono block outside unit and an inside unit with some pumps etc in.

 

The main characteristic of split systems is the fluid that goes through the wall is refrigerant not water. As such you need an F-gas installer. I don't believe there are any R290 systems as r290 is a bit of a grey area in Europe and america so the big players are holding back

 

For what it's worth, most of the effort in the UK seems to be towards monoblock as they don't require fgas certs to install. I know other countries are going down the split route as f-gas trained installers are. More common due to higher air con usage. 

[HughF]

Split if you’ve got a long (>20m) pipe run externally…. Personally I wouldn’t bother with the f-gas bod and would just get on with it, but then I’ve got the gear from doing r290 mini splits and r134 cars.

 

Monobloc is better in that you don’t need to find room for any internal components (provided you don’t get a Samsung )

Edited April 23 by HughF

[sharpener]

On 21/04/2024 at 08:47, Beelbeebub said:

As such you need an F-gas installer. I don't believe there are any R290 systems as r290 is a bit of a grey area in Europe and america so the big players are holding back

 

Which means that you can't get the 70C plus flow temp that R290 brings.

 

Midsummer Wholesale has this wonderful typo:

 

*For Vaillant aroTHERM Split systems we will require evidence of your F-gas certifiction*