UKH

We have just had our attic converted and as expected, it is hot up there! Does anyone have a recommendation for an air conditioning unit which we could install?
 

Happy with either wall mounted or free standing. There seems to be lots of choice available but I don’t really have any idea what I’m looking for.

The room is 5x5m with 2m headroom so total volume is around 25m^3, plus a bit for the staircase.

Any advice or recommendations would be welcomed.

Don't buy a freestanding unit that requires an open window for the waste heat, incredibly wasteful, if you are going to buy one get someone from an AC company to spec it and hard plumb it in so that there is no need for windows to be open while you are using. That, or open your velux windows and buy a fan

Thanks for that. I hadn't thought that a unit would need to send the waste heat somewhere. It would have been very wise to have thought about this before the work was all finished and we had finished decorating and putting carpets down...

All the photos of them (on curry's etc) lead with a lovely free-standing unit with no ducting visible. 

Maybe in the short term a good fan would be the best option...

A good rule of thumb for AC is 120W per square metre, so you'd be looking at around a 3kW system for a 5m x 5m room

Get a split unit, refrigerant pipe linking inside and external parts. Also acts as an efficient heat pump in winter

https://www.appliancesdirect.co.uk/ct/heating-and-air-conditioning/air-cond...

Do you know the approximate size of the refrigerant pipe for such a setup?

Depending on capacity maybe an inch with some insulation? You could probably google an installation manual for a particular unit

The ones I've seen fitted use a single 3" hole, there are the two insulated feed and return pipes and the other the other one you forgot, the condensation water drain.

I can recommended this.

 https://www.amazon.co.uk/Inventor-Chilly-9-000BTU-Portable-Conditioner/dp/B...

We have it in our lounge and it cools it down nicely. 15' square room. Use it with a small fan to circulate the coolness and it works well. It's on now. The vent goes out the top of out window and the pipe is behind the curtain. You will need an extension duct to do that though. You'd probably need one anyway as the supplied duct isn't very long. Not ideal, but it cools the room down.

You can get vents for the wall to pipe the warm air through them, but it means drilling a big hole in the wall. Good if you never move the unit.

Erm call your builder back and get them to insulate it properly to building regs. Sorry not a terribly helpful advice but if it has been insulated correctly it really shouldn't be over hot right now. 

Limewash the roof in the spring. The white reflects the heat and keeps it cooler in summer. The autumn rains will wash it off leaving a darker roof to absorb the sun in winter and keep it warmer. Commercial tomato greenhouses used to do this over here.

It may be that effective insulation has caused the problem not allowing heat to dissipate that has risen by convection from downstairs via the apparently open stairwell?

Does the new attic space have a window?

My own attic conversion is well insulated, open to the space below and has a large Velux, but at this time of year, it still gets very warm by the end of the day. Opening the window and closing the blind in the morning makes quite a difference though. Can't help with an actual AC unit/solution I'm afraid.

Is there any way in which you have the funds for looking into alternatives to an AC unit? It's an aspect of climate change that people will be buying more AC units, and they're rather bad too in terms of contributing to it. 

That’ll help the greenhouse effect assume one or more vlux type windows in the roof.

I regret the amount of insulation I’ve put in every summer. I’d like external shutters but the council planners disagree.

Rather than A/C, I open some upstairs windows and run a high volume ducted fan after sundown with the flexi hose shoved out of the cat flap.  Insulation foam and space blanket over a few square meters below the down facing pipe to draw air in over a surface at the temperature of the night sky.  On a clear night it can bring air in 12C below ambient.  Tonight with the humidity and clouds, not so much…

I digress, opening a window in the roof and using a fan to move air through can do wonders.

https://www.roofingsuperstore.co.uk/product/velux-sml-p06-0000e-external-el...

Could shutters like these be less noticed by them?

Edit: The council that is. They look vaguely like solar panels.

It’s all been done to full building regs spec, and all signed off as a bedroom. I’d have loved it it it wasn’t as we would have had so much more head height!

I suspect it is the 3 large velux that’s causing the issue. They get direct sunlight from sunrise until about 1pm. We do have blinds but haven’t had them down the last few days. Probably had the windows open a bit too due to lots of painting and trying to get rid of the smell.

The whole house is pretty warm at the moment. Currently (11pm) our living room is 23 degrees (doesn’t get much direct sunlight) and the attic is 26 degrees.

We will probably end up just getting a fan as the weather probably won’t stay like this for long. But I’d be interested to hear about the alternatives (I’m pretty clueless on what’s available…)

Every single window we have is a different size and shape.  I want white painted slatted wooden shutters that let general light and wind through but scatter direct sunlight away.   The alignment of our house means we  have windows facing the morning and afternoon sun.  The greenhouse effect is immense.

Shutters like this were quite common in distant times past.

About half the recent works in our conservation area don’t have the requisite engagement with planning or section 211 notification.  But I just don’t have the bandwidth in life to deal with the fallout if I do something without due process then get pulled up on it…

Maybe you could engage in a psychological game, where you put up giant screens, and then when pulled up, suggest tasteful white shutters as an alternative? I guess a muted colour may be more unnoticed, but the white ones sound nice.

As a random tangent, the guy who owns/runs the Coppermines business in the Lake District, for a long time was at odds with the local planning people about the large building he'd renovated and put additions on to without planning permission which is at the top of the valley, until he got himself onto one of the boards, the tourism related board IIRC, and found himself a position of influence enough that he was able to have things go his way.

While walking past the youth hostel there one year with a lifelong friend and our dads, we encountered a mountain rescue guy who told us about it, we used to stay in the Barrow Mountaineering Ski & Club hut in the noughties, and he'd always drive too fast to be considerate up and down the track between Coniston and the YHA etc in his Range Rover.

The little raise bit in the middle of the roof on the large building above the YHA akin to what one finds in a Swiss building was/is particularly against the planning rules, from not matching what is found throughout the Lake District. It looks pretty cool, but it's in the Lake District.

I've never understood why shutters are so rare in the UK. Here in France they are installed on most houses & flats - very effective and without them there would be a lot more energy using air conditioning. Maybe the planning regulations will have to adapt to the warmer climate ?

Use the blinds - they make a huge difference - but also velum do ones that mount externally to manage heat:

https://www.velux.co.uk/products/blinds-and-shutters/exterior-heat-protecti.....

An alternative to air conditioning would be one of those whirligig devices that you stick on your roof to draw the air through your house. They work either by the hot air rising through the house and exiting through the device by thermal conductivity or when the wind blows the device spins and draws the air upwards naturally. No need for electricity. They can make a slight sound; when the bearings go (after 10 or more years), they grind and you know it’s time to replace them. Their design prevents rain getting in.

We have two in the roof of our house in SE Asia and don’t run air con; they really make a difference as we live with open doors and windows.

If you are looking for something simple to cool things on the days were we do get sun!  I have one similar to this..

https://www.amazon.co.uk/gp/aw/d/B084ZLMFMJ/?_encoding=UTF8&pd_rd_plhdr...

It is quite effective in blowing nice cool air, and whilst it wont have the same cooling effect as a proper air con unit, its simple/lightweight and unobtrusive.  We have ours in the conservatory to help take the edge off.  You add those cooler bricks to the top and water... slightly more hassle to have to add water, but less hassle probably than getting the plumber in for an air con unit..

Use the blinds and a fan if you need to. You'll be glad it's warm in the winter, if anything it will probably be quite cold up there then. 

Don't call your builder back, call a different builder.

Loft conversions are notorious for getting hot in summer. Even with modern insulation specs it's a common problem. Not every single conversion needs it, but a lot do.

If your builder didn't have any kind of conversation whether you'd want (or should have) aircon fitted during the build, IMHO... you should consider a different builder to remedy what the first builder failed to discuss.

I find it amazing how much difference closing blinds on the sunny side of the house makes. 

When it's really hot I often open downstairs windows in the evening and leave all internal doors open, to try and create a draught up through the house in order to cool the bedrooms.

Building regs, at least historically, deal very poorly with overheating risk. The most commonly used insulation materials tend to be low density, such as PIR. Think kingspan etc. These aren't good at buffering heat gain from solar radiation in the same way as high density materials like Woodfibre, which is rarely used.  

The flip side to that is that you need a much thicker layer of woodfibre insulation to achieve the same U-value as PIR. Horses for courses....

Yes very true, and it's more expensive, but probably worth it in roofs where the overheating risk is considerable. It's a shame that we're insulating these buildings (with petroleum based products) and then making them so unbearable in summer that we have to fit them with AC as well!

My naive exception is that something that is good at insulating to retain heat should be good at insulating to retain cool too. Why is that not the case with solar gain and you get different performance in 'keeping cool' for insulations with the same U-value?

The answer is something to do with physics, and the difference between radiation and conduction. Common insulation materials are really good at preventing the latter, but not the former. 

There's more info in this rather rambly  webpage: https://greenbuildingencyclopaedia.uk/encyclopaedia/code/gbe-issues-navigat...