Reflecting heat from south facing windows

Errrrr - curtains?

Tinfoil on the outside?? Oh, and curtains 🤷🏼‍♂️

+1 for curtains deployed in the heat of summer

Haven't ruled out curtains, but internal room layout and window surround (didn't want to go into too much detail in original post) means they wouldn't be ideal due to fixings and the bulk.

A kind of DIY fabric solution kept within the window recess could be an option, but at this point I'm seeing search results like temporary car-like window screens, window film, as well as the range of thermal blinds etc.

But if the straight forward best answer is curtains?... [Edit] Which it sounds like it is!

large eaves overhang or a shaded awning over the window ?

works for us - large solar gain in winter when its sunny and low... and then big overhang to keep the high angle sun out in summer.

Window film would be a fairly easy option to do very neatly even with zero experience on modern double glazing (i.e. where the UPVC overlaps the glass with no silicone bead or putty). You can either tint them or put mirrored film up. Only downside is it works 24/7 so the rooms will also be darker in the evenings when you might want some more light.

Anything that absorbs the light inside the room (like a curtain) is inherently trapping heat in the room and you're then limited to how much can be lost back through the window again.

Window film would be a fairly easy option to do very neatly even with zero experience

You must be a lot less clumsy than me!

Anything that absorbs the light inside the room (like a curtain) is inherently trapping heat in the room and you’re then limited to how much can be lost back through the window again.

This.

You want shutters on the outside, not curtains on the inside.

So what are the good (internal) options?

The heat is already in then. You have lost some of the battle.

More effective to look outdoors - overhangs and sails, reflective window coatings, get planting close to the building, reduce other 'heat island' surfaces such as brick, concrete, tarmac that are up against the building, get running water as close as you can.

there is a reason most houses in hotter areas have these:

window blind

We get those over the south facing windows.
Open them fully and they fold down over the entire window.

Give it a go, on a flat surface it's really straightforward.

Stick it to the window with soapy water, trim roughly to size, squeegee it on, trim exactly, flip it over, seperate the backing from the tint, spray window and tint liberally with soapy water, stick to window and slide in to position, more soapy water, squeegee, more soapy water and a credit card to press out the last of the moisture from under the film.

I've only ever done one car and a few office windows and even I managed to do a 20ft X 8ft office window with a few odd shapes and joins in a couple of hours over the weekend. It's certainly no harder than putting blinds up.

I put jysk blackout blinds inside window recess. They do what they say, IE, block out light, but the window behind is like a panel heater.

Where the external recess is enough I put them outside, kitchen and bathrooms. It does get windy so u need to secure the bottom edge.

Previous owners installed an awning above patio doors and it was in full use last summer (when not too windy).

Partly wonder whether poor insulation levels south end of the loft is having a big difference in making things worse for rooms below, though that's a whole new topic to get my head around.

Thanks for comments, will pivot to Googling exterior shades/shutters!

Thanks for comments, will pivot to Googling exterior shades/shutters

Currently doing likewise!

No gardneing,
Good for Wildlife
Good for urban drainage
Provision of shade
No cold callers
infact... probably no callers at all

can't see a downside

Also, ventilate - get windows open at opposite sides of the house (if possible) to get some crossflow going. if you have an upstairs, get opposite windows open.

if you have a lot of exposed brick/comncrete internally, make sure the windows are open overnight for as much free cooling as possible next day. security concerns aside, its one of the best things you can do to get passive cooling.

Sorted

Simply rotate the house 90' so that the windows are East-facing.

(NB: this won't work if you currently also have West-facing windows.)

We got a weather station with a few thermometers and it really helped manage the ventilation. Don't open windows if it's hotter outside, open on the best side of the building etc. It gave a really good insight into how things heated up.

When it hit 40C last year our hall was roasting, the dark front door was radiating into the hall. I taped a couple of silver carry mats over the door and it dropped the hall temp by 4 degrees! Was considering getting a few mats and making some frames to shield the big window and the door.

Planting makes a big difference too - non damaging vines, tree for shade etc.

What you want is a brise soleil. Might not suit a Victorian terrace.

In the 35' heatwave of 2022 we had new kittens contained in one room facing southwest, I draped an old duvet cover over the closed windows on the outside and it really helped keep the room temperature down. If we get another crazy heatwave in '23 I'd consider doing the same to all our south facing windows.

I found white blinds with curtains drawn behind them worked ok last summer, in conjunction with allowing airflow through the whole house and windows opposite the sun opened helped.

Along with a good fan or two for spot cooling.

I know you said this OP

The boss has chosen aluminium venetian blinds as the preferred primary window shade (I would have gone for the honeycomb type structure blind, but that got dismissed for the flexibility of the venetian in terms of being able to see out),

But these guys have top down / bottom up blinds for uPVC windows?

I found white blinds with curtains drawn behind them worked ok last summer, in conjunction with allowing airflow through the whole house and windows opposite the sun opened helped.

There's a logic there. The air gap can help significantly reduce the temperature.

These are how we make sleeping shelters on desert survival.
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Stick it to the window with soapy water, trim roughly to size, squeegee it on, trim exactly, flip it over, seperate the backing from the tint, spray window and tint liberally with soapy water, stick to window and slide in to position, more soapy water, squeegee, more soapy water and a credit card to press out the last of the moisture from under the film.

I’ve only ever done one car and a few office windows and even I managed to do a 20ft X 8ft office window with a few odd shapes and joins in a couple of hours over the weekend. It’s certainly no harder than putting blinds up.

This. I’ve been putting the decals onto AA and BSM cars for the last year, and the only thing I would correct with the above is using a credit card to squeegee the film; a credit card can often have a rough edge and scratch the surface of the film. You can get proper squeegees from Amazon which have a sort of synthetic suede strip along the working edge, which you spray with the soapy water, which allows the squeegee to slide over the surface without scratching or snagging. For spraying, just clean out an empty trigger spray bottle, then fill with water and put in some baby bath liquid soap. It’s usually more or less clear, which is useful when you want to be able to see out of the window,

Also, clean the glass thoroughly, then spray with isopropanol and wipe over with a clean microfibre cloth, to avoid dust or fibres getting under the film. I’ve not done any windows, but I have done several dozen cars.

These are the squeegees I’ve been using, they’re the best I’ve found, and work really well.

But these guys have top down / bottom up blinds for uPVC windows?

Thanks, they are a good option which we'd considered. Will take another look, but we ruled them out previously due to the fixings requiring pushing in between the UPVC frame - I asked our window supplier about them and they said a few customers had subsequent damage to window/glass, and it voided the warranty.

We have got window film on our upstairs windows, about 50:50 self fitted against factory.
I put tarps up over the windows upstairs last summer which helped a lot but have got some solar shades now.
Also i found that even shaded, the glass in the windows got really hot so we replaced the windows (turns out they were 25+ years old).
Would love shutters but we have external opening windows so wouldn't work here

I am considering a sun shade sail thing on the front of our house with 1 fixing point either side of the top of the bedroom window and then 2 fixing points on the pergola below, this will then shade the bedroom window and kitchen window which is less needed as I have integral blinds in the glazing on the kitchen window. Issue will be fitting the shade when required as it's bloomin high up there and the shade sagging in the middle. The window is far too wide for shutters, you can get some funky expensive sliding shutters but again width of the window and available space either side of the window just won't allow it, plus they are roughly 3 grand! I'll talk to my builder about decent fixings for the mounting points and have a think of how to fit the shade with a pole or something.

I put the cheap window tint film in our top floor master bedroom last year during the worst of the heatwave. It looks like a mirror from outside. It made a big difference to how much heat makes it through the glass. You can close the blinds on the Velux windows but then the whole unit feels like a radiator. They were much cooler after fitting the film. Not bad for a £10 experiment.

I'll be doing the next floor down this year, with junior sleeping in a south facing bedroom. It'll be temporary as I don't want the chromed out skyscraper look all year round.

The issue I have with the window reflective coating / films, is that during the cooler months I want solar gain in the house. The last week, despite outside temperatures around freezing, our south facing windows have collected heat into the rooms - really warm radiating off the glass inside.

It seems that shutters or blinds and curtains, despite needing some user effort, offer a gain when needed and reduction when needed.

Yeah it's got to be adaptable to allow for solar gain over winter. I was just imagining some kind of small cartridge fitted above a window recess (externally), with a pull down blind that would deal with the worst of it.

Like one of those wall mounted clothes airers/lines, but you pull down a sun shade instead.

Issue will be fitting the shade when required as it’s bloomin high up there and the shade sagging in the middle.

Once you've done the initial drilling and screwing, you can leave ropes attached, flagpole style and hoist up and tension with cleats/pulleys/eyelets.

Yeah it’s got to be adaptable to allow for solar gain over winter. I was just imagining some kind of small cartridge fitted above a window recess (externally), with a pull down blind that would deal with the worst of it.

Like one of those wall mounted clothes airers/lines, but you pull down a sun shade instead.

Once again, our European friends have this covered. Literally.

It gets quite warm here in Summer so wee have light coloured walls, insulation on the outside, shutters and a curtain on the outside:

Also, ventilate – get windows open at opposite sides of the house (if possible) to get some crossflow going. if you have an upstairs, get opposite windows open.

Not if the outside temp is higher than the inside temp !

I stuck a thermoter outside last year, windows were only opened once the outside temp was lower than the internal made a massive difference, psychologically hard for some apparently to keep doors and windows closed ....

Once again, our European friends have this covered. Literally.

Are there 'lite' versions that don't double up as some kind of security layer, and are a fraction of the cost?

Maybe that's an Ikea roller blind glued to the wall and replaced each year!

These window awnings look like the kind of thing.

Put in the window recess dimensions and it's £174 compared to £255 for the roller shutter type.

Food for thought.

^beaten to it.

The more expensive, and rather security looking ones, are much more durable and repairable. And many are electric powered, and designed to fit into recesses of beams above windows.