# Large Commercial School Windows Letting Too Much Heat Through (no money / what is best way to insulate please)



## Steve2444 (Sep 28, 2020)

Is the glass thermopane? or Just single pane?

You could put a heat control window film on the inside of the glass.
I have done this over the years and have found it works very well.
If it's single pane glass your good, leave a 1/4" gap at the edges for expansion.
And use the NON glue type film.

Don't use on thermopane this is where the heat buildup problem is.

Benefit. heat reflection, some privacy from outside in the day, bright light is dimmed, 
And some extra protection incase of window breakage as it will keep shards from spraying across the room.

If interested do a test on one window, or room then do a test temp wise with another room facing the same way to the outside.


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## HotRodx10 (Aug 24, 2017)

Well, there's tinted/reflective films that can be added, similar (maybe identical?) to car window tint. Shading the window with an awning of some kind also helps alot. 

Blackout shades or curtains don't really help the overall heat gain very much, since the light/heat is absorbed inside the room. 

There's also the option of regular or roll shutters.


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## SW Dweller (Jan 6, 2021)

Sorry you can not get what you want. First windows with out solar film or shade are about 
R-ZERO. The best shade screen money can buy will raise it up to R-2. If the glass can handle it. The no money is a serious issue and I am certain short of parking a 18 wheeler in front of the glass your not going to get any relief.

I worked in a building that had west facing glass about 10 feet high that was hideously hot after 2pm. We were tenants so first thought was to put solar film on the windows. NOPE can not do that cause the glass will crack. Shade screen were out of the question. 
The solution was to put 2 5 ton ac's on the roof to cool the areas close to the glass.


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## Missouri Bound (Apr 9, 2011)

Not clear of your situation, but can you install awnings to shade the windows?
I'm guessing you have a southern exposure to deal with.
Shades will block the sumner sun and allow light and heat to come in in the winter.
Retractable shades are also an option.
Again, not knowing your budget, expertise of "permission" its hard to nail down a plan that you can execute without more details.


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## chandler48 (Jun 5, 2017)

All good advice thus far. You are correct that you cannot add XPS to the panes as it cannot be left exposed, so that's out, especially in a school situation. Look into what has been suggested, including shades, vertical or extendable.


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## Elmer-Dallas Texas (9 mo ago)

I have west facing window. I put 3 layers to block heat and light/glare.
First layer next to window. White "black-out" window fabric that is a little bigger than window. Sold by the yard at fabric store about 60 inches wide.
Second layer. I used doubled black felt because I had it already.
Third layer. Interior window curtain.
These are all hanging from curtain rods which I made from dowel rods because they are cheap.
Very comfortable and looks presentable.
If you are lucky you can find this stuff at thrift stores.


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## Zipperje (Sep 15, 2020)

I have had good luck with shades on outside, hanging about 6-12 inches away from the window to let a little air move behind them. The cheapo plastic "bamboo" roll down shades are better than nothing but the way to go is get some fabric designed to block the sun and find a seamstress who can stitch up a roll down shade. The last set of sun shades I bought were made of a fabric called Sunbrella and they still look brand new 10 years later! The salesman said it blocks x % of the UV rays (big number like 96%? but I can't remember exactly).


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## Elmer-Dallas Texas (9 mo ago)

Don't necessarily need seamstress. Can use T-pins and or glue.


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## SeniorSitizen (Sep 10, 2012)

with no money you do as i did and make X-ternal blinds of large cardboard . fixed louvers at about 20°-- non adjustable .


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## HotRodx10 (Aug 24, 2017)

In order to get relevant responses, more information is needed. How many windows? What size are they? What is your actual budget for this project? If you truly have zero money for this, you could not even do bubble foil or foam you referenced. How long do they need to last?


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## Elmer-Dallas Texas (9 mo ago)

Bubble foil has been discredited as a viable insulator according to my reading. Imo don't waste your time and money. 
One inch thick hard foam 4x8 sheets can be effective.


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## AllanJ (Nov 24, 2007)

Really, can foil covered cardboard such as those zigzag things you put in your car windshield cause the window to crack?

Does the sun shine in? School children should not sit in the sun all period long. If sunlight hits it, then foil or foil foam covered cardboard hung in the window will drastically reduce the room temperature.


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## HotRodx10 (Aug 24, 2017)

Elmer-Dallas Texas said:


> Bubble foil has been discredited as a viable insulator according to my reading.


It has limited insulation value, that's true. However, insulation is not its primary function - reflection of radiant energy is, and for that, it is fairly effective.

I haven't heard of insulation, reflective or otherwise, causing windows to crack.I had foil-faced rigid insulation board behind a window in my home for about 15 years, and had no problems with the glass cracking.


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## Elmer-Dallas Texas (9 mo ago)

Sun glare is horrible especially in a school learning environment. Put something up now! Appearance is irrelevant. Anything you put up is better than nothing. 
Using plain cardboard that has been discarded by a furniture store will work if you can't afford anything else. 
Reducing the heat that comes through the window could reduce your air conditioning costs.
But children having a good learning environment is top priority for you.


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## Michaelgrant (4 mo ago)

Technical.Builder said:


> Hi I been reading about foil and bubble foil? yet after much research and about to do that or cardboard and foil and bubble foil etc etc ... i read that it can cause window to crack by excessive heat so that is not an option, replace windows is not option ... thus what is cheapest and best ways? is blackout blinds good? its for a school so i want it kind of look nice by it being in front of building ... please share thoughts - thank you in advance (and oh ... i dont want stress some reads i found in here by some doing the application as to what I was really thinking of doing until further study which was simply use the huge block foam board - (again who have done this i would not stress as we are over scared - but this is a school so i need to be really care of material) that said I was going to use this stuff, read all over net how great and vids etc etc but i always being a old builder ... i always check final steps which is "can i use this stuff to where it is going?" answer i believe for this foam is NO ... its a bit toxic and there is fire rating or something ... meaning you cannot use this interior and inside of windows and i am not putting a sheet of Sheetrock over it etc etc ... mays well just build a wall at that point over windows (hey an idea  ) ... but then again i am in same boat of anything use be it foam board (which cant) or even a wall as heat will build up and i am scared it will break glass over time. Thoughts please - Thank you!!


I have planted trees in front of the windows, no other ideas(


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## chandler48 (Jun 5, 2017)

@Michaelgrant Then why have windows?


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## Old Thomas (Nov 28, 2019)

You need to research your state’s requirements for school windows and interior finishes. My state Ed dept. says anything applied to vertical surfaces has to meet flame spread ratings and smoke developed ratings, eliminating things like foam boards or plastic bubbles. There are also requirements for minimum allowable glass areas for natural light and emergency egress requirements. Planting trees too close will block egress. They do allow tint film if it is the right stuff. Check requirements in your state, you don’t want to be responsible if something bad happens. That is why we always had an architect involved for modifications at the school.


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## chandler48 (Jun 5, 2017)

Odd. Going past my old high school where we had hopper windows and hand held fans, they remodeled it to include vertical slit windows, central heat and air conditioning. Sissies.


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## Michaelgrant (4 mo ago)

chandler48 said:


> @Michaelgrant Then why have windows?


You can see through them anyway. I suppose it's much better that way anyway, rather than the sun and heat being impossible to resist.


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## Elmer-Dallas Texas (9 mo ago)

chandler48 said:


> @Michaelgrant Then why have windows?


In Texas windows are source of scorching heat and blinding light, a total torture. They are 40 times less efficient than walls for R factor. Windows are the weakest part of a building. If you drive through an area hit by a disaster, natural or bomb, the windows are blown out even if walls still standing.
In OP case the windows are a problem to be dealt with.
So the question is : Why have windows?


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## carpdad (Oct 11, 2010)

I think white curtain to reflect the light as much as possible. Never searched myself but no loss to search. See if there are materials that also reflect ultra and infrared lights.



https://www.3m.com/3M/en_US/home-window-solutions-us/solutions/uv-protection/



Films like above can be expensive. Roofing companies use some paint to reflect heat and maybe such paints are used on curtains?


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## keshaun (3 mo ago)

Technical.Builder said:


> Hi I been reading about foil and bubble foil? yet after much research and about to do that or cardboard and foil and bubble foil etc etc ... i read that it can cause window to crack by excessive heat so that is not an option, replace windows is not option ... thus what is cheapest and best ways? is blackout blinds good? its for a school so i want it kind of look nice by it being in front of building ... please share thoughts - thank you in advance (and oh ... i dont want stress some reads i found in here by some doing the application as to what I was really thinking of doing until further study which was simply use the huge block foam board - (again who have done this i would not stress as we are over scared - but this is a school so i need to be really care of material) that said I was going to use this stuff, read all over net how great and vids etc etc but i always being a old builder ... i always check final steps which is "can i use this stuff to where it is going?" answer i believe for this foam is NO ... its a bit toxic and there is fire rating or something ... meaning you cannot use this interior and inside of windows and i am not putting a sheet of Sheetrock over it etc etc ... mays well just build a wall at that point over windows (hey an idea  ) ... but then again i am in same boat of anything use be it foam board (which cant) or even a wall as heat will build up and i am scared it will break glass over time. The main focus is on the topic of health, I even read a couple of essays on https://samplius.com/free-essay-examples/health/ about the effects of overheating on the body. Thoughts please - Thank you!!


It seems to me that a reflective film can help in this situation and it should not lead to problems with the destruction of glass. There is also the option of darkening the windows, but I think this can worsen the situation.


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