Air Conditioning

dh1981

This isn't going to save me money, far from it. But, in a top floor flat roof flat, it's so uncomfortable in here that I can't bear the thought of another summer of no sleep. This morning was already 23 degrees in here, and it's not even too warm outside. We regularly hit 30 in the summer, even after it cools down outside. We're planning on moving next year, but not before that.


So if it's going to cost me money I should probably make sure I'm spending that money sensibly. I'm hoping someone on here may have some information/advice that could help me.


I have a lot of questions in my head, and the internet isn't really helping me. Home air conditioning doesn't seem to be a big thing in London. My questions are:

• firstly, is there any options I should be considering first that can considerably lower the temperature? We already keep windows/blinds closed during the day when out at work, have various fans and an air cooler (including the dyson which is completely rubbish), sleep only under sheets and open back and front windows when possible to get cross breeze.
• wall or window mounted/split unit vs portable? are they as effective as each other? Space is an issue, but would a wall mounted be too expensive? Would a perm one add value to the flat when we sell?
• what about a portable split unit? (not wall mounted)
• I'm sensitive to the noise - hate our air cooler, but that might be because it's then hot AND loud as it's rubbish. What should I be looking for if I want a quiet one?
• buy vs rent? My searches are showing rental is at least £30 a week. We wouldn't have the trouble of storing it in cooler months, but would spend almost as much as buying one!
• energy efficiency - I want it to be cool and reasonably quiet, but how do I make sure I'm getting one that's as energy efficient as possible? Am I expecting too much?
• what sort of price am I looking at? Any suggestions on where to buy?

I can't be the only person struggling with this. Sometimes we go and stay with the parents for a few nights just to get away.

Trapdoor

A few questions first.

1) do you own the flat
2) do you have access to, or are allowed access to the roof (if it’s flat)
3) is there anything in your lease about modifications to the building?
4) is there an outside wall in the room or rooms you wish to cool?

If you are clear on the above, then I’d suggest a fixed split unit with an inverter compressor/condenser unit on the roof.

We recently replaced a single non-inverter fixed split in our lounge for a twin split to cover the lounge and master bedroom. OK, this is in a house but the installation was not particularly easy ... the condenser unit had to be mounted above head height on the wall, and pipe work taken to both indoor evaporator units.

These were 12000btu units made by Mitsubishi Heavy Industries (MHI) and the indoor evaporator units were the ZSX series, both have Wi-fi modules in too which enables them to be controlled by smartphone. All external pipe work is in INOAC trunking to keep it neat. (Do a search)

The total cost for supply and fit by a local professional AC company was just shy of £3,500 BUT we went for the top of the line units. There were much cheaper options and a single rather than multi-split system would be much cheaper too. Installation took a day, but bear in mind that one hole was already in the wall, as were the electrics, but they did have to pump down and recover the gas from the old unit and remove it.

There is an added bonus with decent professional units ... they can be used in ‘reverse’ heat pump mode so will also heat as well as cool. This is useful at the time of year when you don’t want the heating on but need a quick burst of warmth. They are also very efficient in this mode, as an example will put out around 3kW of heat but only use 1kW of energy! That depends on the COP (coefficient of performance) of the unit though ... a question to ask a supplier.

I have in the past had both a portable ‘exhaust’ type and a portable ‘split’ type. Both were very noisy as the compressor is in the indoor unit. They also need to be emptied as they act as a dehumidifier so have a water tank (some split units will pump outside though).

The MHI ZSX air handlers/evaporators (the bit on the inside room wall) on its lowest eco fan setting is very quiet. You CAN sometimes hear the gas, especially when it starts up or shuts off, but in the bedroom it’s much quieter than the old ceiling fan we had.

In your situation it may be possible to just stand the condenser unit on the roof on a suitable stand or slab, take the pipe work down the wall to the room, but I’d suggest getting a couple of commercial AC companies in to give you a quote. Any that do shops should also be able to do domestic work.

A final point, I’d never live without air conditioning in the lounge and main bedroom now ... even though we live in a rural location, having the windows open you can hear traffic noise as sound travels at night. Also open windows in our lounge (for us actually is big french doors at both ends of the room rather than windows) is a no-go because of pets. Fixed air con is something I’d always recommend if you can afford it.

Our neighbours always comment in the summer how cool and fresh our lounge feels, but they don’t seem to be able to get their heads round what they need to do to achieve the same :rotfl:

dh1981

Thank you Trapdoor. Very useful!


we do own the flat, but it's leasehold so would likely need permission to put anything on the roof or on the external wall.
We're lucky, in that the rear of the flat (where the rooms are that we'd potentially want the air con) has a terrace out the back, so access to the wall and roof wouldn't be difficult.


I didn't even think about a twin split - even better as our living room would then be cool too. I'm not sure I could stretch to £3500, but that doesn't seem excessive for what you have.


could you recommend the company you used? Or are they local?

Trapdoor

Hi, we used Franklin Air Conditioning, but they are a local company to us. You’d be better contacting some local people, get them in to quote. Without that step you are in the dark as to what is required.

Remember if you fit a twin split, it’s twice as many pipes that need to be installed ... there is the high and low pressure refrigerant lines plus the condensate drain from each, which is why it’s better to have external walls wherever the indoor unit is mounted otherwise you have to run pipe work internally and possibly need a condensate pump to push the drain water out.

We insisted on the INOAC trunking as some was already in place from our old unit (which I installed myself about 10 years ago now) but being 10 years older and due to the gas handling regs it’s not something you are now legally supposed to do as a DIY! This makes the install outside much tidier as most companies will just install the pipe work bare on clips or galvanised tray which looks rough on a domestic property.

A roof area for the condenser unit would be better than hanging it on the wall on brackets ... one of the reason for changing ours was that our wall brackets had started to rust badly, and the condenser weighed about 50kg. But after last years hot summer, plus the fact ours was getting a bit old and tired, was the main reasons for replacing it and adding the second bedroom unit.

Dunno if it’s possible to PM me your email address ... If you can I will send you some photos of our setup.