# Energy Efficient Window Coverings



## SLSTech (Jan 19, 2021)

Ever considered solar screens which you can pop off for winter? Is the real issue heat coming in through the windows or??? Might be better air sealing, checking your attic, etc...


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## Steve2444 (Sep 28, 2020)

What are your window now? Thermopane, low e ?

If they are low e I would not use any film. 

single pane or thermopane you can use Gila type film, I had it on my non low e thermopanes for over ten yrs, looked fine worked well, cravat... IF you ever have plans on removing the film, do not get the ones with GLUE.
Yes you can remove them but the mess left on the glass will leave you uttering colorful metaphors. 

Use the static cling ones.

Solar outside screens will work... just realize your view will be hampered somewhat due to the smaller holes to see through. 

I am not a fan of inside the window solar blocking as in curtains shades etc.
Heat still hits the curtain inside the home, it has to go somewhere inside the home.
Good for UV protection, heat gain not so much.


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## bkimbark1 (Dec 21, 2019)

Steve2444 said:


> What are your window now? Thermopane, low e ?
> 
> If they are low e I would not use any film.
> 
> ...


The windows were newly replaced before I moved in in 2019. I hadn’t considered to check what type of window they are but after looking at the sticker, it appears they are Low E.



http://imgur.com/a/eVne4O9


So based on that, would you say I’m best off doing nothing, other than putting some kind of external solar shade on my windows?


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## Steve2444 (Sep 28, 2020)

bkimbark1 said:


> The windows were newly replaced before I moved in in 2019. I hadn’t considered to check what type of window they are but after looking at the sticker, it appears they are Low E.
> 
> 
> 
> ...


No window film on low e glass.
External would be the best option imo.


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## Steve2444 (Sep 28, 2020)

Now when you say your a/c works into overdrive in the afternoon, is it not keeping up?
Or it really just keeps running between 4pm and 6-7pm?

Realize that between those hours is when your ac will work the hardest, NOT because of the Sun, but because your ac cannot exchange the hot from the coils as well because the air is the hottest at that time.
Shading the house and blocking the sun will help, but realize the main issue is trying to expel heat into already hot air.

I had the same issue here in TN, (although I am from NY). air exchange ac works the hardest during those hours.
Now that I have ground source heat pump (geothermal) the time of day make no difference.


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## bkimbark1 (Dec 21, 2019)

Steve2444 said:


> Now when you say your a/c works into overdrive in the afternoon, is it not keeping up?
> Or it really just keeps running between 4pm and 6-7pm?.


Yes, like you said, the AC keeps up but it kicks on much more frequently during these times. I hadn’t considered it was because the AC can't expel hot from the coils.



Steve2444 said:


> Shading the house and blocking the sun will help, but realize the main issue is trying to expel heat into already hot air.


When you say that blocking the sun will help, is that only if using external sun shades? Does using shades or curtains inside provide any heat blocking? 

Also, do my low e windows provide any thermal insulation or only UV protection?


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## Steve2444 (Sep 28, 2020)

Low e blocks heat gain in summer and heat loss in winter, and provides uv protection as well, some low e types more than others.

The more you can block your home from solar heat gain the better, and outside blocking is the best.
Installing sun screens on the outside will help, but you already have low e glass, so it will not be as much as if you did not.

Inside blocking? I am no expert, but just me thinking... the heat comes thru the window, hits the inside shades or curtains, where does the heat go? I would assume the shade or curtain gets hotter or the air between the curtain and the window gets hotter, but that heat is still in the house envelope.
It will still heat up the room. 

That's why I favor blocking on the outside, heat stays outside.


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## HotRodx10 (Aug 24, 2017)

Steve2444 said:


> Low e blocks heat gain in summer and heat loss in winter,


Well, sort of. It reflects more of the radiation in the wavelengths of the summer sun than the winter sun, so you get a larger percentage of the suns energy through the windows in the winter.



Steve2444 said:


> Inside blocking? I am no expert, but just me thinking... the heat comes thru the window, hits the inside shades or curtains, where does the heat go? I would assume the shade or curtain gets hotter or the air between the curtain and the window gets hotter, but that heat is still in the house envelope.
> It will still heat up the room.


You hit the nail of the head with that one. Reflective curtains, etc. would help a little, by reflecting the radiation back out the window, but shading the outside is a whole lot more effective.


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