Split Air con

Reuben klang said:
What is an AP and LN?

Putting in something that would require a decent supply i.e >20amp so can’t run off ring/radial for sockets should be put in by an electrician.
Click to expand...

Mitsubishi's range of splits has three types of units, with various finishes and features. AP's are the middle of the range, and LN the most premium.

Yes, and I will be ensuring a ECI/Part P certification is issued as part of the services, 100%.

HungryHippos said:
23 or 24kw external unit doesn't sound right, that would exceed the combined internal unit cooling capacity.

I have 3 x Mitsubishi Electric LN25's with 1 x MXZ-3F54VF (5.4kw) external unit, cost for install for was a bit over £4K for those 2-3 years ago. These are the more premium model though so cost more than the basic ones.

I am just running that off an external plug currently, as the actual power consumption is much lower (it's not drawing 5.4KW it's just the cooling capacity) the actual load I don't think exceeds 2KW from the wall.
Click to expand...

Thank you, suggests at least the first quote is in the ballpark when you factor in the new board/supply and inflation/demand. My current board is quite close to max draw. Also I may be seeking a 4-connector outdoor unit to allow for a possible additional unit in the future.

Typo above, those figs were btus! The latter quote was for the MXZ-3F68VF, which has a 6.8kw cooling capacity.

Have a third quote on the cards, but I'm inclined to go with the most experienced, specialised and professional of the companies to avoid any nightmares.
 
Units are pretty efficient these days, and can be controlled individually. Don't have any concerns on that front. And whilst the COP for these things isn't high enough to compensate for the 4:1 elec/gas unit price ratio, that ratio will change in years to come when green levies are removed from electricity and levies are placed on gas. The units also give me heating in the loft room where I have none, and potentially in a garage conversion. Again, can be controlled individually and powered at various %.
 
Last edited:
Yofi said:
Mitsubishi's range of splits has three types of units, with various finishes and features. AP's are the middle of the range, and LN the most premium.

Yes, and I will be ensuring a ECI/Part P certification is issued as part of the services, 100%.



Thank you, suggests at least the first quote is in the ballpark when you factor in the new board/supply and inflation/demand. My current board is quite close to max draw. Also I may be seeking a 4-connector outdoor unit to allow for a possible additional unit in the future.

Typo above, those figs were btus! The latter quote was for the MXZ-3F68VF, which has a 6.8kw cooling capacity.

Have a third quote on the cards, but I'm inclined to go with the most experienced, specialised and professional of the companies to avoid any nightmares.
Click to expand...

Got you. I just refer to them all as wall mounts, there’s that many different ones out there that it’s hard to track the specific name of each one.

—

Anyway, if I was in your shoes and you’re getting a separate supply anyway I’d look at getting the bigger unit regardless and you then have the option to add to it later.

I’ve got MXZ-6F122VF with a 7kw and 2 x 5kw connected to it. That’s more than what the outdoor can produce but because I rarely have all 3 on at the same time it doesn’t matter and when I do I just get the duty that they can be given.

If you have the budget I’d slightly over size everything and use it to actually heat your house rather than use gas. It’s almost instantaneous. My house is almost always floating around 22 all year round.
 
Thanks, and agree with ensuring you have some additional capacity on both outdoor unit and wall mounts. The wall mounts are spec'ed with some leeway - think on the measurements the rooms came out at 2.7kw, 1.45 kw and 2.00kw. I'm the single occupier, so I expect I'll be sometimes turning the unit on in the lounge in preference to heating the whole house (though of course it's good to have some heat at times over the whole house). I'm not convinced that the ratios are there yet vs price of per unit elec and gas to make keeping these on is more efficient over a relatively new combi?
 
Last edited:
Yofi said:
Thanks, and agree with ensuring you have some additional capacity on both outdoor unit and wall mounts. The wall mounts are spec'ed with some leeway - think on the measurements the rooms came out at 2.7kw, 1.45 kw and 2.00kw. I'm the single occupier, so I expect I'll be sometimes turning the unit on in the lounge in preference to heating the whole house (though of course it's good to have some heat at times over the whole house). I'm not convinced that the ratios are there yet vs price of per unit elec and gas to make keeping these on is more efficient over a relatively new combi?
Click to expand...

I’d love to see the actual figures.

I don’t have gas in my house and moved from those horrid storage heaters to my current set up so can’t make a direct comparison for my needs and obviously can‘t do the same for a similar house as we all do different things and demand different heat loads. I like to leave my windows open for fresh air etc and leave all my doors open to warm the whole place.
 
The claimed COP on the 2.5kw LN units is 5.42, 4.88 on the 3.5kw, and 4.00 on the 5kw. I'm with Octopus Energy, and on my September (pre=rise) tariff, electricity was 28.57p per kW/h, and gas 6.93p/kWh, so a ratio of 4.12:1. There will be some boiler inefficiencies on top of that, but you can see that even the wall mounts were as efficient as claimed them it's a close run thing. I guess there may be an argument that you can fine tune the wall mounts better than rads with thermostats (some use sensing technology to provide additional warmth where its needed, over areas where less heat is needed), and that possibly having heated air circulating from both top and bottom might have efficiencies.
 
Last edited:
Yofi said:
The claimed COP on the 2.5kw LN units is 5.42, 4.88 on the 3.5kw, and 4.00 on the 5kw. I'm with Octopus Energy, and on my September (pre=rise) tariff, electricity was 28.57p per kW/h, and gas 6.93p/kWh, so a ratio of 4.12:1. There will be some boiler inefficiencies on top of that, but you can see that even the wall mounts were as efficient as claimed them it's a close run thing. I guess there may be an argument that you can fine tune the wall mounts better than rads with thermostats (some use sensing technology to provide additional warmth where its needed, over areas where less heat is needed), and that possibly having heated air circulating from both top and bottom might have efficiencies.
Click to expand...

That’s the COP running under perfect working conditions, with clean filters and coils. Will have to have perfect ambient temps as well. Someone could throw a plastic bag, leaves falling off the trees and block half the outdoor HE and dramatically increase the consumption. The condenser likely jammed against a well increasing it too. Some units may have built in pumps etc

Theres just too many factors involved to just read off what they’re claiming and taking it as gospel.
 
Last edited:
Reuben klang said:
That’s the COP running under perfect working conditions, with clean filters and coils. Will have to have perfect ambient temps as well. Someone could throw a plastic bag, leaves falling off the trees and block half the outdoor HE and dramatically increase the consumption. The condenser likely jammed against a well increasing it too. Some units may have built in pumps etc

Theres just too many factors involved to just read off what they’re claiming and taking it as gospel.
Click to expand...

Totally agree, which is where I was going with that! My main reason for purchasing is the a/c, but I can see some additional benefits along the lines mentioned.
 
Last edited:
Greetings, apologies for reviving this thread. As the summer is getting closer, we will probably have more discussions about air conditioning.

I have a 2 year old son, and another baby boy on the way. The summer of 2021 we had a heatwave, and it was difficult to keep my then baby son's nursery cool enough. I had to resort to putting bubble foil on the outside of the windows, but a lot of heat was still coming through the loft.

Last summer (2022) we had a proper heatwave and then a shorter one, and again it was difficult to keep temperatures low. I was quite militant about keeping all the windows closed while the indoor temperature was lower than outdoor, etc. In the end I caved in and bought a single tube aircon, which does work but only just.

Ever since I'm thinking about a permanent air conditioning installation. It is a luxury, but at the same time it is almost becoming a necessity. Not so long ago in the UK central heating was rare or non existent, yet now we would not think about central heating being as a luxury. Also, the benefit of air conditioning that it is a heat pump, and a modern unit can be used for heating.

I would like air conditioning to be available in as many spaces of the house as possible, but that is very difficult to do with a single multi split outdoor unit. So I'm thinking having a high capacity wall mounted (ductless) unit in the living room (ground floor), then one or two additional wall mounted units on the first floor for the main and for the guest bedroom. That leaves two small rooms, which I'd like to cool via a ducted loft unit. My loft hatch is just about big enough to fit a ducted unit, but worst case I'll enlarge the loft hatch.

Does anyone have any experience of running multiple ductless + ducted indoor units off a single outdoor condenser?
 
anyone running a ducted unit in the loft, what sort of money did you pay ?

Just been quoted north of £4500 to cool 5 bedrooms and 2 downstairs rooms with a 7kw unit.
I thought that was very high
 
MassiveJim said:
anyone running a ducted unit in the loft, what sort of money did you pay ?

Just been quoted north of £4500 to cool 5 bedrooms and 2 downstairs rooms with a 7kw unit.
I thought that was very high
Click to expand...
Ducted unit here, That sounds pretty cheap to me. I paid 5.5k a couple of years ago for a ducted unit for 4 rooms, separate wall unit downstairs and a separate system in an outside office.
 
You must log in or register to reply here.
Back
Top Bottom