# Normal heat loss for windows



## Rick Hill (Jan 25, 2015)

I live in a 40+ year old house near Houston. Some of the windows are about 6 years old, and some are probably original. What I'm trying to figure out is what is "acceptable" heat loss/gain, as I am trying to decide whether shell out a bunch of cash to replace the windows.

For instance, if the outside air temp is 30 degrees, and the inside temp is 70 degrees what temp should I see on the inside of a well made energy efficient window. Conversely, if the outside air temp is 95, with direct sun, and the inside temp is 72, what temp should I see inside.

I'm measuring the temp using a B&D Infrared Thermometer.


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## Fix'n it (Mar 12, 2012)

idk. but my new windows = 25 outside, 65ish on the inside window pane. 72ish inside temp.


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## Windows on Wash (Aug 30, 2011)

Fix'n it said:


> idk. but my new windows = 25 outside, 65ish on the inside window pane. 72ish inside temp.


What did you get? Weren't you looking at Oknas before?

Did you go with triple pane?


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## Windows on Wash (Aug 30, 2011)

Copied and pasted from my buddy Oberon:

_Some real numbers: _
_When it is 0°F outside and 70°F inside and you have very little wind, the interior surface temperature of a single pane of glass is going to be right about 16°F; which is definitely going to contribute to those convection currents. _

_Add the second lite, be it storm or dual pane and you increase the interior glass surface temperature to 44°F. That is a very significant improvement. And once again, that is not simulation, it is real measurement data. _

_Add the LowE coating in a dual pane and the temperature of the glass surface increases to the mid 50’s F (53°F – 57°F) depending on the coating and the glass surface that has the coating. _


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> What did you get?
> 
> 
> Weren't you looking at Oknas before?
> ...


they are called CLIMATE GUARD. but, you know, that some factory somewhere, makes a window, then puts who knows how many different names on it.
they are sliders, and while they are ok, i wish i would have gone casements, oh-well. they are a decent quality and are working well for me. they don't leak at all. 

i was looking for what you guys recommended. not to be found, by me anyway.

no. they are a basic dual with low-e. nothing fancy.


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## mikegp (Jul 17, 2011)

Are there windows that don't leak where the sliders are? I thought they all have some air leakage.


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## Windows on Wash (Aug 30, 2011)

Sliders leak by design. Tighter windows are going to be a casement or double hung.


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> Sliders leak by design.


ok, sure. but how little mine leak. they are the least of my problems. 
and, btw, i don't feel mine leaking.


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## Windows on Wash (Aug 30, 2011)

I should probably clarify my earlier comments. Sliders, by comparison to double hungs and casements, will usually leak a bit more air.

New replacement windows are quite good about keeping the air inside or outside, depending on the season, the home.


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## mikegp (Jul 17, 2011)

Windows on Wash said:


> Sliders leak by design. Tighter windows are going to be a casement or double hung.


When I said they leak around the slider I was talking about double hung. Right in the corner where the two window parts meet, don't they all leak a little air? I stuff a little foam in mine every winter. Figure it can't hurt.


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