Author Topic: Window Film to reduce solar gain?  (Read 9943 times)

GregO

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Window Film to reduce solar gain?
« on: May 16, 2014, 11:36:04 AM »
Our living room has a whole wall of windows that face west.  It makes for a great view and looks really nice, but the solar gain is brutal.  That's the room we spend all our time in, and it gets really hot during the afternoons.  It also keeps the AC working really hard in the afternoons.  We need to find a way to block some of the sun, but not really sure what to do.  The windows face the deck in the back of the house, so a pergola over the deck is definitely the best option and the long term solution.  But right now we are in the middle of a lot of other renovations and don't have the $3000+ (or the time) to build the pergola and are looking for a cheaper, short term solution.

We were originally thinking about just putting curtains up, but my wife didn't really like the look of that and then I read a post on here that they really didn't help much with solar gain.  After some more brainstorming and looking, we came across window film, which look like its basically window tint like you put on car windows.  They also offer window film that has no tint in it, but still block the UV rays (and some solar gain).  We haven't decided which one we'd get, but probably one of the slightly tinted ones.  Anyway, it seems like it might be a good option, but I haven't been able to find a lot of information about it.  There are also a lot of different options that vary a lot in price.  The cheap stuff seems to just be tint, where the more expensive ones block a lot of solar gain and aren't tinted (or at least that's what they claim to do).  Here's a link of one of the options we were looking at getting:
http://www.snaptint.com/home-tint-solar.html

Does anyone know much about it or have any experiences with it?  Or have suggestions on good places to buy it?  I found some similar stuff at Home Depot, but it is just tint and comes in rolls.  This stuff is cut to the dimensions of the window and seems like it'd look a lot better installed  (there would be seems in the middle of the windows if we got the rolls).  Anyway, just trying to get some ideas.  I'm open to other solutions too, as long as they look nice (i.e. make the wife happy) and keep the heat out.  Thanks!

Rural

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Re: Window Film to reduce solar gain?
« Reply #1 on: May 16, 2014, 02:28:58 PM »
While you're researching, look at solar screens, too. I've not done either one yet, but I started doing some research for one sliding glass door we have that gets way too hot mid-summer, and I was put off by how difficult it looks like it was to do the film and do it well. Like you, this happens on an area that it will eventually be roofed over.

Joggernot

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Re: Window Film to reduce solar gain?
« Reply #2 on: May 16, 2014, 02:35:04 PM »
Hang the roll up/roll down bamboo curtains outside the window.  We put up a window film on a couple windows, but didn't do well.  Our next project is to put the wide overhangs on the west side to shade that side of the house.

Thegoblinchief

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Re: Window Film to reduce solar gain?
« Reply #3 on: May 16, 2014, 03:30:04 PM »
We have blackout curtains. It definitely helps, but then you lose ALL of the light. I usually only pull it closed on the hottest of hot days.

Some sort of retractable awning, if you could find/make it cheap enough, would work the best. The bamboo shade up thread isn't a half-bad idea for something that only needs to weather a couple years. Except for the sheer size of the window I have, I might actually do that myself!

Generally haven't heard much good about the films, either for heating or cooking savings. No personal experience though.

deborah

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Re: Window Film to reduce solar gain?
« Reply #4 on: May 16, 2014, 03:51:08 PM »
Films have improved remarkably over the past few years, but they are like curtains in that they fix the problem once it has happened (the sun has already heated the glass of your window). They also block a certain level of light all year (includes winter). Can you put in a few posts, and cleats and attach some shade cloth between the house and the posts (or get someone to do this - putting a shade sail in)? This would be a substitute pergola, without the cost, and if you did it yourself, would also be an inexpensive way of checking whether you want a pergola there. It would also keep the views.

GregO

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Re: Window Film to reduce solar gain?
« Reply #5 on: May 16, 2014, 04:26:53 PM »
I'll have to ask my wife about bamboo shades.  I'm not sure I like the idea of having to roll them up and down every day though, that would get to be a pain.  But hey, I guess that would get us to build the pergola faster...

GregO

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Re: Window Film to reduce solar gain?
« Reply #6 on: May 16, 2014, 04:32:49 PM »
Films have improved remarkably over the past few years, but they are like curtains in that they fix the problem once it has happened (the sun has already heated the glass of your window). They also block a certain level of light all year (includes winter). Can you put in a few posts, and cleats and attach some shade cloth between the house and the posts (or get someone to do this - putting a shade sail in)? This would be a substitute pergola, without the cost, and if you did it yourself, would also be an inexpensive way of checking whether you want a pergola there. It would also keep the views.

Yes, I could do that.  But setting the posts is going to be the hardest part.  I've dug in our soil to put a gas line in recently, and it is tough.  There are tons of roots and the soil is decomposed granite that acts like it's one big rock.  So setting the posts would be the long part, but you're right its not the expensive part.

As for the film.  I understand that the window and film will still heat up and radiate heat, but does it still reflect a significant portion of the sun's heat?

MountainFlower

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Re: Window Film to reduce solar gain?
« Reply #7 on: May 16, 2014, 04:50:55 PM »
We have black solar shades from blinds.com.  We like them because you can still see out of them, but they block a ton of solar and heat. 

totoro

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Re: Window Film to reduce solar gain?
« Reply #8 on: May 16, 2014, 04:52:38 PM »
I was looking at this too for our skylights.  It seems like window film can impact your skylight integrity due to overheating but I'm not sure it is the same for windows in general.  I think we are going to bite the bullet and buy shades.

deborah

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Re: Window Film to reduce solar gain?
« Reply #9 on: May 16, 2014, 05:28:24 PM »
I was looking at this too for our skylights.  It seems like window film can impact your skylight integrity due to overheating but I'm not sure it is the same for windows in general.  I think we are going to bite the bullet and buy shades.
Not if you put it at the bottom of the skylight - but our local energy efficiency team recommend 2 layers of bubblewrap rather than film. This worked out to be FREE!

ZMonet

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Re: Window Film to reduce solar gain?
« Reply #10 on: May 16, 2014, 05:40:23 PM »
We also have a huge wall of windows, two stories high.  My wife and I feel in love with the look pre-this website.  Anyway, the prior owner did the tinting on the windows because boy can it get hot in there.  Still, even in the Winter the place gets heated up pretty well (a good thing then).  Also, the seals on many of the windows are failing, causing a choice between costly replacement and cloudy windows.  I spoke to the window guy and he said that the tinting heats up the double-window pane an incredible amount and my windows have some sort of caulking sealant (a lot of windows I see have metal seals) that has failed considerably -- and we're talking just 10 year old windows.

So, look into the tinting but ask about whether it might cause the seals to fail and know that a lot of heat will still be generated.

totoro

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Re: Window Film to reduce solar gain?
« Reply #11 on: May 16, 2014, 05:57:33 PM »
I was looking at this too for our skylights.  It seems like window film can impact your skylight integrity due to overheating but I'm not sure it is the same for windows in general.  I think we are going to bite the bullet and buy shades.
Not if you put it at the bottom of the skylight - but our local energy efficiency team recommend 2 layers of bubblewrap rather than film. This worked out to be FREE!

Thanks - good tip.

SDREMNGR

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Re: Window Film to reduce solar gain?
« Reply #12 on: May 16, 2014, 06:22:23 PM »
Definitely do window reflective films.  Cuts down on heat by 1/2 and eliminates UV by nearly 100%.  I did it in my cars (even front winshield with clear UV film) and now doing the windows of the house.  Even the low-e ones.

But the biggest heat reducer that I just did was to paint my asphalt shingle roof with an elastomeric roof paint.  I just got the most expensive one at Lowes.  It took 4 - 5 gal buckets to do 1 coat (planning on 2nd coat this weekend) and already it reduced the temperature in my house by 15 degrees.  I am not exaggerating.  2 days ago, it was 105 outside and 99 inside.  Unbearably hot.  Yesterday, after I painted, it was 109 outside and 88 inside.  That's a huge temperature differential.

I think this product works best in dry weather places like SoCal or AZ.  I think people have had problems with the fact that it is waterproof and places with humidity can have issues with the air in the attic not breathing as well.  But I'd think you can get around it with an electric fan vent for the roof.  Anyhow, take a look at it.  It'll cut down your A/C bills by a lot.

GregO

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Re: Window Film to reduce solar gain?
« Reply #13 on: May 16, 2014, 06:24:29 PM »
Films have improved remarkably over the past few years, but they are like curtains in that they fix the problem once it has happened (the sun has already heated the glass of your window).
So, look into the tinting but ask about whether it might cause the seals to fail and know that a lot of heat will still be generated.

What about something like these Sentinel OSWs:
http://www.snaptint.com/product.php?productid=16225

Are they still masking the same problem?  I'm sure they still heat the window up, but does it still trap heat between the window and the film?  Also, I have single-pane windows.  It is 2 big massive windows that flank a sliding glass door.  All the glass is single-pane.  And I live in Los Angeles, so I'm not too worried about cold weather or storms damaging the film if it's on the outside.

GregO

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Re: Window Film to reduce solar gain?
« Reply #14 on: May 16, 2014, 06:37:16 PM »
Definitely do window reflective films.  Cuts down on heat by 1/2 and eliminates UV by nearly 100%.  I did it in my cars (even front winshield with clear UV film) and now doing the windows of the house.  Even the low-e ones.

But the biggest heat reducer that I just did was to paint my asphalt shingle roof with an elastomeric roof paint.  I just got the most expensive one at Lowes.  It took 4 - 5 gal buckets to do 1 coat (planning on 2nd coat this weekend) and already it reduced the temperature in my house by 15 degrees.  I am not exaggerating.  2 days ago, it was 105 outside and 99 inside.  Unbearably hot.  Yesterday, after I painted, it was 109 outside and 88 inside.  That's a huge temperature differential.

I think this product works best in dry weather places like SoCal or AZ.  I think people have had problems with the fact that it is waterproof and places with humidity can have issues with the air in the attic not breathing as well.  But I'd think you can get around it with an electric fan vent for the roof.  Anyhow, take a look at it.  It'll cut down your A/C bills by a lot.

Interesting.  I wonder what my wife would think about a white roof.  I looked it up and that stuff is expensive, but I'm sure it would pay itself off quickly.  All I have to do is stand on the roof or peak my head in the attic during the day to know that it would make a huge difference, it gets really hot up there.  Thanks for the idea.

As for the window films, where did you get yours?  And you have noticed a substantial difference?

Rural

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Re: Window Film to reduce solar gain?
« Reply #15 on: May 16, 2014, 07:13:29 PM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

GregO

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Re: Window Film to reduce solar gain?
« Reply #16 on: May 16, 2014, 11:06:49 PM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

Thanks, I'll check them out.  I'm not sure I want to put screens on these windows though and block the view.  The windows aren't operable and I think screens would probably look a little weird.

SDREMNGR

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Re: Window Film to reduce solar gain?
« Reply #17 on: May 16, 2014, 11:35:29 PM »
Call me the guy who doesn't care what his neighbors think.  They aren't paying my power bills or sweating in my house.  When they form a group fund for my electricity bills, I'll give a crud about what they think.

I think it looks clean having a white roof.  Why do people hate white roofs?  And who thought black roofs in sunny areas was a good idea??

TomTX

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Re: Window Film to reduce solar gain?
« Reply #18 on: May 17, 2014, 05:44:26 AM »
Definitely do window reflective films.  Cuts down on heat by 1/2 and eliminates UV by nearly 100%.  I did it in my cars (even front winshield with clear UV film) and now doing the windows of the house.  Even the low-e ones.

But the biggest heat reducer that I just did was to paint my asphalt shingle roof with an elastomeric roof paint.  I just got the most expensive one at Lowes.  It took 4 - 5 gal buckets to do 1 coat (planning on 2nd coat this weekend) and already it reduced the temperature in my house by 15 degrees.  I am not exaggerating.  2 days ago, it was 105 outside and 99 inside.  Unbearably hot.  Yesterday, after I painted, it was 109 outside and 88 inside.  That's a huge temperature differential.

I think this product works best in dry weather places like SoCal or AZ.  I think people have had problems with the fact that it is waterproof and places with humidity can have issues with the air in the attic not breathing as well.  But I'd think you can get around it with an electric fan vent for the roof.  Anyhow, take a look at it.  It'll cut down your A/C bills by a lot.

Interesting.  I wonder what my wife would think about a white roof.  I looked it up and that stuff is expensive, but I'm sure it would pay itself off quickly.  All I have to do is stand on the roof or peak my head in the attic during the day to know that it would make a huge difference, it gets really hot up there.  Thanks for the idea.

White paint makes a HUGE difference. Not only does it make the house cooler, it significantly extends the lifespan of an asphalt shingle roof. The specialized elastomeric roof paints often are designed to go over older roofs, and also prevent leaks (to some extent.) Anyway, there have been numerous scientific studies over the years, and it really does work, even with just standard white paint.*

I painted the roof white on my last house** using regular 100% acrylic exterior paint. Worked well. No doubt, the specialty paints work better - but I haven't priced them recently.

The asphalt shingle industry HATES HATES HATES if you paint your shingles, as they get a lot of their business from replacement of old, brittle shingles. Keeping the roof cooler dramatically slows the ageing of the shingles, and so your replacement times are much longer. They bullshitted their way to making it very difficult to paint asphalt shingles in Florida and still remain within code.


*Just using white paint reflects the visible spectrum and some of the UV. Some roof paints do a better job reflecting in the infrared region as well, due to pigment selection. Reflectivity can be up to 10 times better than asphalt shingles.

**When I bought this house, the roof was almost ready for replacement, in large part due to the really shitty install. One hailstorm later, and I now have white, Energy Star rated shingles, and got a 30% .gov tax credit they were offering for a couple of years. Win. The previous house also had a low-pitch roof, not visible from the street. Current house has a VERY VERY visible steep roof.
« Last Edit: May 17, 2014, 02:34:17 PM by TomTX »

deborah

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Re: Window Film to reduce solar gain?
« Reply #19 on: May 17, 2014, 03:10:57 PM »
Another way to reduce the heat of a roof is to use solar panels. You get two advantages in one - power, plus a cooler roof. The panels are converting sun - heat - to electricity, and they are a couple of inches above the roof, so they are shading it. To top it off, if the the panels are parallel to the roof they are providing a convection current that is also cooling the roof.

Simple Abundant Living

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Re: Window Film to reduce solar gain?
« Reply #20 on: May 17, 2014, 03:25:40 PM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

I think those are the ones I put up last year on west and east facing windows. I think they helped a ton. I just put up the 3m dual lock in two inch strips on the corners and middle of each window. I tacked the dual lock to the screen fabric with a basting gun (think quilting) so it would stay attached in wind and weather. I took them off in the fall, marked them and stored them in the garage for the winter. I'll be putting them up again soon. The whole thing cost me less than $150.

Rural

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Re: Window Film to reduce solar gain?
« Reply #21 on: May 17, 2014, 05:39:01 PM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

I think those are the ones I put up last year on west and east facing windows. I think they helped a ton. I just put up the 3m dual lock in two inch strips on the corners and middle of each window. I tacked the dual lock to the screen fabric with a basting gun (think quilting) so it would stay attached in wind and weather. I took them off in the fall, marked them and stored them in the garage for the winter. I'll be putting them up again soon. The whole thing cost me less than $150.


Basting is a great idea, though I'll probably do it by hand since I don't have a basting gun. Thanks!

Simple Abundant Living

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Re: Window Film to reduce solar gain?
« Reply #22 on: May 18, 2014, 09:11:41 AM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

I think those are the ones I put up last year on west and east facing windows. I think they helped a ton. I just put up the 3m dual lock in two inch strips on the corners and middle of each window. I tacked the dual lock to the screen fabric with a basting gun (think quilting) so it would stay attached in wind and weather. I took them off in the fall, marked them and stored them in the garage for the winter. I'll be putting them up again soon. The whole thing cost me less than $150.


Basting is a great idea, though I'll probably do it by hand since I don't have a basting gun. Thanks!

The problem you will run into is that the adhesive on the dual lock will gum up your needle and make it hard to sew. Staples will rust. Right now at Joanns, the basting gun is $13.99. Depending on how many screens you are attaching, that tool may save you time and pain. Unless you can think of a better way to attach, I would buy that. You could resell it after to a quilter for $5-7. I did seven windows, so I would have bought it (had I not already owned it).

Rural

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Re: Window Film to reduce solar gain?
« Reply #23 on: May 18, 2014, 09:58:11 AM »
Here's the solar screen I'm considering. Looks like a lot less trouble (and less heating of the window) than film, and I'd take it down in winter to get back my solar gain, which is important to us since it's our primary heat source.


http://t.homedepot.com/p/Phifer-36-in-x-25-ft-Charcoal-Super-Solar-Screen-3021116-Dot-Com-SOM-3018851-Store/100552677

I think those are the ones I put up last year on west and east facing windows. I think they helped a ton. I just put up the 3m dual lock in two inch strips on the corners and middle of each window. I tacked the dual lock to the screen fabric with a basting gun (think quilting) so it would stay attached in wind and weather. I took them off in the fall, marked them and stored them in the garage for the winter. I'll be putting them up again soon. The whole thing cost me less than $150.


Basting is a great idea, though I'll probably do it by hand since I don't have a basting gun. Thanks!

The problem you will run into is that the adhesive on the dual lock will gum up your needle and make it hard to sew. Staples will rust. Right now at Joanns, the basting gun is $13.99. Depending on how many screens you are attaching, that tool may save you time and pain. Unless you can think of a better way to attach, I would buy that. You could resell it after to a quilter for $5-7. I did seven windows, so I would have bought it (had I not already owned it).


Hmm. As a quilter, I might just keep it, too. It's a dilemma for me, actually; I don't have time for hardly any quilting, but when I do, I quilt the way my grandmother and great grandmother taught me, all by hand and with a rack I can store at ceiling level on pulleys. But basting? Perhaps it's okay if just the basting is done by machine...


Why doesn't the basting gum gum up on the adhesive, though? I don't know what one is or looks like, if you can't tell.

deborah

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Re: Window Film to reduce solar gain?
« Reply #24 on: May 18, 2014, 03:01:47 PM »
Why doesn't the basting gum gum up on the adhesive, though? I don't know what one is or looks like, if you can't tell.
It's like a nail gun, in that it shoots things. The things it shoots are plastic and shaped like a capital I, so they catch both sides of what you are basting together. As the basting gun isn't going through the materials, it's not going to get gummed up.

Simple Abundant Living

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Re: Window Film to reduce solar gain?
« Reply #25 on: May 18, 2014, 04:55:37 PM »
Why doesn't the basting gum gum up on the adhesive, though? I don't know what one is or looks like, if you can't tell.
It's like a nail gun, in that it shoots things. The things it shoots are plastic and shaped like a capital I, so they catch both sides of what you are basting together. As the basting gun isn't going through the materials, it's not going to get gummed up.

There's a thick needle thru which the aforementioned I-shaped tags shoot through. It's really like a price tag gun.  The tags only come in red (probably so people don't use it as a price tag gun).  But they are small enough that they don't draw attention.  The needle can get a bit gummed, but it never slowed me down. The handle gives you more leverage to get through the dual lock tape. Here's a link with a visual:
http://www.joann.com/quilters-basting-gun/4792792.html

Oh, and I have priced clothing for a yard sale with this!

Rural

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Re: Window Film to reduce solar gain?
« Reply #26 on: May 18, 2014, 07:08:19 PM »
Thanks, both of you.