Aircon in loft struggling to bring temp down

b737 · 7 Aug 2018

b737 said:
I've managed to get hold of one of these:-

https://www.drainagepipe.co.uk/prod...MI5vbR6bLY3AIVQ7DtCh13cgnwEAQYASABEgIjuPD_BwE

Well this thing didn’t fit. I will look to get hold of the one ragaz linked.

Out of interest, we are saying 5000 BTU isn’t really enough for a loft of this space. What BTU would be ok for a loft of this space? Just thinking if I ever change the unit I would get bigger, ie 15000 BTU (would they be enough even in this in efficient to space)?

copea · 7 Aug 2018

I've got a 17,000 BTU portable split unit up in my loft conversion and within minutes of turning it on the temperature drops by 4°c.
So yes, it can be done, but that's a split unit, not an all-in-one, so it doesn't have the same inefficiency issues as none of the internal air is vented outside.

b737 · 7 Aug 2018

I’ve just been looking at the spot cooler that u mentioned (Fral SC14). Looks like it would tick the box but trying to get something in stock anywhere at the min seems impossible.

Also £500 is way over my budget of around £350 but I guess u get what u pay for!

dilalio · 7 Aug 2018

Funny things 'budgets'... they're really a way of saying you can't afford what you need, let alone want!

copea · 7 Aug 2018

Time to find a shady place in the garden to read.

b737 · 7 Aug 2018

Or save up.. By then the hot weather will be gone and the 5000 BTU unit will be doing ok... until next summer...

arkie · 7 Aug 2018

copea said:
I've got a 17,000 BTU portable split unit up in my loft conversion and within minutes of turning it on the temperature drops by 4°c.
So yes, it can be done, but that's a split unit, not an all-in-one, so it doesn't have the same inefficiency issues as none of the internal air is vented outside.

Whats a "portable split unit" i know portable, And i know split unit? link?

Ok i see them on google, but no prices for the uk that i can find.

Edit, No Home home market prices... Amazon. Price: £1,184.94 15000 BTU

stem · 7 Aug 2018

arkie said:
Whats a "portable split unit"

It has the two separate parts, evaporator and condenser, but they are connected by a flexible 'cord' containing the refrigerant and electrical connections, which can pass through a window thus allowing condenser to be located outside. The evaporator is on castors and can be moved about as much as the cord will allow. A 15,000 BTU unit costs about £1,500.

b737 · 8 Aug 2018

Another thought... around the positive pressure approach

It was previously mentioned about putting my unit outside of my loft and then vent the cold air in, creating a positive pressure. I'm yet to do this test as trying to source a connector that will fit on the front - work in progress.

However I was wondering if a slightly different approach may work.

My loft has the clean area (which I am trying to cool) which is made by the foil bubble insulation being fitted down the loft roof and drapped half-way down to the floor. Would the aircon cooling in the clean area work better if I were to put the aircon unit on the dirty side (other side of the insulation) and then just vent in the cool air into the clean area of the loft, again creating a positive pressure?

Obviously the dirty area of the loft is hotter/colder than the clean area (depending on the weather out). Its also a lot more dusty so not sure if this would be very bad for the unit? Would the unit struggle even more as its dealing with even more hotter air? etc

Let me know your thoughts.

dilalio · 8 Aug 2018

I'm starting to think you might be...

MV5BMTM5MjkwMTI0MV5BMl5BanBnXkFtZTcwODQwMTc0OQ@@._V1_UY268_CR7,0,182,268_AL_.jpg

stem · 8 Aug 2018

b737 said:
It was previously mentioned about putting my unit outside of my loft and then vent the cold air in, creating a positive pressure.

All that will do is push any cold air you have produced out of the loft. Think about it for a minute. Why do you think that 'Max AC' in a car works in the recycle mode, rather than bringing the air in from the outside?

I would forget all about this if I were you, unless you are prepared to get something that is up to the duty. You are attempting to pull a caravan with a lawnmower, and no matter what you do to it, you will never get it up to 60mph on the motorway.

dilalio · 8 Aug 2018

stem said:
Why do you think that 'Max AC' in a car works in the recycle mode, rather than bringing the air in from the outside?

Its actually better to use fresh air and have the windows open for the first 5 mins or so, to clear the hot and stale air and then put it on recirc once temp has fallen. In my van, leaving it on recirc for too long gets a bit smelly

stem · 8 Aug 2018

Indeed....opening the windows that is.. (I can't comment on the smell

) ..when starting out with the inside hotter than the outside. Unfortunately the OP might have difficulty removing his tiles.

dilalio · 8 Aug 2018

As you said... I'd give up. Bubble wrap foil is not going to help in any of this

b737 · 8 Aug 2018

stem said:
Think about it for a minute. Why do you think that 'Max AC' in a car works in the recycle mode, rather than bringing the air in from the outside?

This contradicts what was previously said by another poster about positive pressure via a spot cooler?

I guess im struggling here to get the best from it. Maybe just have to resign to the fact I need something bigger like 15000 btu or it’s just gonna be warm up there. I don’t want to spend or go to the hassle of more disruption in the loft by installing celotex etc.

Thanks for all your help

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Aircon in loft struggling to bring temp down

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