Hot conservatory - again

bullinn1

Hi chaps, unusable conservatory in the summer, does solar window film work ? I find it difficult to believe but there are some good reviews out there. The roof is d/glazed glass panels.

My idea was to cut to size polystyrene 1" thick sheets and stick them to the inside of the glass. I've done a basic test and it doesn't look too bad and the cost will be well under £200 but there seems nowhere on the net is this solution mentioned ... anyone any thoughts please. The image is the 'trial' panel, it's a nasty piece of 'flecked' poly but plain smooth white is available.

Davesnave

The problem with the vast majority of conservatories is inadequate ventilation and insulation, not just that they have translucent roofs of some kind. In good summer weather, such as we've had, with outdoor temperatures regularly hitting 24c, it would be a devil of a job to keep inside temperatures below 30c without having massive changes of air. This is especially true if it faces anywhere near south.

So if heat is the problem, it's possible that without other changes, adding insulation to the roof will be a waste of time.

Our conservatory is well insulated. Apart from the roof, it's built to building regs and it has 8m2 of ventilation built in, tinted glass etc, but it was never intended as a summer space. We like it best at other times of the year, when the extra light and the feeling of being outdoors are its strengths.

shaun_from_Africa

My conservatory (glass, double glazed) is south east facing and on a sunny day in the summer can easily reach an internal temperature of 45c. The highest I've ever noticed was 54c when I forgot to open any doors or windows during the heatwave a couple of months ago. (even during the sunny days last week, it got up to 32c)

I have lots of windows and even opening these (both low and high) doesn't have a great deal of effect as without a fan there is little airflow.

However, I have a good quality ceiling fan fitted and when this is operated in reverse mode so it draws cooler air upwards into the roof area, the temperature inside the conservatory will drop by a good 20c.

If you have a set up that allows for a fan to be fitted and there are a few high level window openings then I would recommend getting one.

Pennywise

Don't know about the film you refer to. But we used to have a basic conservatory with "normal" double glazed windows and a plastic roof. It was too cold in winter and too hot in summer so we barely used it.

We replaced it a few years ago. We asked the firms to quote using whatever glass etc they could to reduce heat in summer and reduce heat loss in winter. We ended up with a glass roof and double glazing which they said had a special film on to reflect the sun - there's a slight blue tinge to the roof but the windows look the same. It's made a massive difference. We were still sat in it throughout Summer (yes it's South facing) and it's also warm enough in Winter too. Made a massive difference. Like I say, I don't know if that's the same thing as you are proposing, but in our experience, it's certainly possible to make them habitable all year round. Cost was only about £2k extra compared with quotes for "like for like" replacement, i.e. normal glazing and plastic roof for a 5 sided one roughly 15 feet square.

shaun_from_Africa

Pennywise wrote: »

We ended up with a glass roof and double glazing which they said had a special film on to reflect the sun - there's a slight blue tinge to the roof but the windows look the same

At a guess, I would say that you have Pilkington Activ Blue glass in the roof.
This is what I have and although it cost a bit more that standard tinted glass, it is a vast improvement on what my previous conservatory had fitted.

TheCyclingProgrammer

Yes, solar film works - to an extent. We had it applied to our roof (10 panels, about £500). It reduced peak temperatures during summer from just over 40C to just over 30C. So still very hot, but better than it was. I don't think you'll ever get the temperatures down to a "comfortable" level. It does also filter out 99% of UV and more importantly it greatly reduces glare which IMO was a bigger problem than the heat (ours is south facing) as you couldn't use it without sunglasses!

One thing to consider is if a panel gets damaged and needs replacing you'll need to replace the film too. One of our panels is still missing film as we had to have the glazing unit replaced after it shattered earlier this year. No company is interested in coming out to replace the film on a single panel so its a DIY job for me at some point.

bullinn1

Thanks to all, I'll try the fan - sounds good - and maybe try my polystyrene idea as it's quite cheap and reversible ... take a more expensive route if it fails. Good of you chaps to take the time - Roger

martinthebandit

Not sure your polystyrene idea will actually achieve much, it would be far more effective and efficient to put something on the outside of the glass.

If you do really want to put something under the glass please be aware that polystyrene can begin to flow (liquify) at less than 100 degrees C which is one of the reasons why polystyrene ceiling tiles were a bad idea.

Perhaps you would be as well to consider greenhouse paint which is designed to achieve the results you want https://thorndown.co.uk/projects/shade-greenhouses-peelable-glass-paint/

bullinn1

Thanks martin ... I did have a big "shade" rigged up above the roof but in high winds it got a bit dangerous despite being well secured. I agree "outer" cover would be better but, other than the shade I don't know ... apart from re-roofing the thing (too expensive). What did you mean please ? "polystyrene can begin to flow (liquify) at less than 100 degrees C "

martinthebandit

rogertb wrote: »

What did you mean please ? "polystyrene can begin to flow (liquify) at less than 100 degrees C "

Basically it means it starts to melt, though it'll more likely sag than drip, I'm not sure if it will get hot enough but it's certainly something you should consider.

Have you seen my edit to my first post suggesting greenhouse paint?

bullinn1

That paint looks interesting Martin, thank you.