Aircon in loft struggling to bring temp down

[rsgaz]

Yeah, true, lol. We don't know that hatch size, maybe it's huge. Maybe they are a gymnast?!

I was thinking more along the lines of...

Bung a thermometer up there, within arms reach.
Set all this up from below.
Leave it running for two hours.
Compare 'now' temperature to before.

Remember, this is just an experiment to find out whether the unit has enough BTUs to cope, not a permanent idea! Just to avoid spending out on ducting adapters/hose/etc for the "cold out", only to find out the unit just can't manage it.

 

[b737]

I did do a test the other day but not this test.

It was just using it the standard way.

At 6pm in the event. 23C outside. 29.5C in the loft.

In 1 hour it cooled from 29.5C to 27.3C so 2.2C cooler in 1 hour.

Is this good or bad?

It did seem to slow cooling after that so maybe some of the cool air came in when I opened up the hatch to try it.

 

[Dan Robinson]

BTW: I'm replying to this whilst sitting in my lovely air conditioned transit

I'm replying to this whilst waiting for a fireworks display over the Pacific ocean. Just got in from a rooftop spring bath.

So feck all you's.

 

[rsgaz]

In 1 hour it cooled from 29.5C to 27.3C so 2.2C cooler in 1 hour.
Is this good or bad?

It's difficult to say, it could have been partly due to some airflow from in the house.

For comparison's sake, the one I bought that I linked to earlier, 15000BTU, cooled a room which is 32 cubic metres from 26.0° to 21.8° in exactly 1 hour, midday-ish, when it was 28 outside. To be able to compare, you would need to work out the volume of your loft room. Why the manufacturers of these units give their 'suitable room sizes' in floor area, I'll never know. The height of the ceiling matters, too!!

This was with the unit sat in the doorway, pointing the cold in and exhausting hot through the wall.

 

[dilalio]

a rooftop so ring bath.

Is that a 'sore ring' bath?

 

[Dan Robinson]

Bloody autokorrect

 

[John D v2.0]

allt his is addressing one side of the problem but don't look too hard at room sizes - an AC will work a lot better in a massive passivehouse than in a small greenhouse in full sun (uninsulated loft is closer to the latter). If you get a decent layer of wool or celotex that would prevent most of the heat getting in in the first place, although at a higher up front cost.

 

[b737]

I’ve had a quick look at the unit to see if I could easily tape a 3” vent hose to the front but because of the flap size and fact it moves I need something 6.5” x 3” even though the vent itself is only 2” x 3”.

Any suggestions? We have a screw fix near me so could pop down there.

 

[copea]

I have to say, I think 5000 BTU is far too little for that space and the temperatures we're having at the moment, together with the inefficiencies already mentioned.
It's also quite likely that that 5000 BTU is achieved in a lab in optimum conditions.

What you're trying to set up is a referred to as a 'spot cooler'.
The Fral SC14 being one such suitable device.

I've not used it, but it's designed for the application you have in mind.

Are you able to return yours?

 

[rsgaz]

flap size and fact it moves I need something 6.5” x 3”

This would fit over that...

https://www.i-sells.co.uk/rectangul...e)-to-round-150mm-(male)-elbow-bend-90-degree

...and then 150mm duct fits over the round bit. Attaching it securely and keeping it air tight might be tricky. Probably best with epoxy glue and tape it all together for 24 hours while the epoxy fully sets.

 

[John D v2.0]

epoxy glue is quite rigid, for something small like that silicone or even acrylic sealant would hold it OK and be a bit flexible

 

[b737]

Thanks all for the feedback and suggestions so far.

I'm pretty much stuck with the unit I have so will work on the adaption tests to see if keeping it outside the loft and venting just the cool air in will work better, however ultimately the message I am getting is that this unit isn't powerful enough to cool such an area as a loft at this size. With this in mind, what about if I were to get more of the foil bubble insulation and section off part of the 3 x 3 loft area to maybe 2 x 2 area by drapping down the foil insulation from the loft roof to create almost a new smaller room inside the loft. Maybe then I could cool it down more successfully?

 

[b737]

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

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

This should cover the front vent (if I cut off the narrow part).. I then just need to get my 100mm vent hose to fit..

The fixing this in place (for a temporary test) is going to be the hardest part I imagine. I wonder if there were any innvoative suggestions? I could look to tape it in place with some aluminium tape etc?

If it all works better this way then I will look to glue/silicon it in place.

 

[dilalio]

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

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

This should cover the front vent (if I cut off the narrow part).. I then just need to get my 100mm vent hose to fit..

The fixing this in place (for a temporary test) is going to be the hardest part I imagine. I wonder if there were any innvoative suggestions? I could look to tape it in place with some aluminium tape etc?

If it all works better this way then I will look to glue/silicon it in place.

You'd need something better than the foil/bubble wrap stuff to improve the insulation... Celotex and rock wool would be better.
Just use duct tape to fashion a mount for the hose adaptor.

 

[arkie]

I wouldn't waste your time, its not going to work with just bubble wrap in the loft, and if you want to use it all year you will need to do it properly anyway, with it being so small it shouldn't cost too much to use 50mm or 100mm Kingspan xps board, even 25mm would help if its just for summer use.