Total Solar Energy Rejected in Tints

[new6ton]

Total Solar Energy Rejected (TSER) = The percentage of total solar energy rejected by filmed glass. The higher this value, the less solar heat is transmitted.

Here is something puzzling. I bought two tints to try on windows. The lower one on the left (NR Smoke 20) has Total Solar Energy Rejected value of 37% while the one 2nd to the top of right (Charcoal 22) has Total Solar Energy Rejected value of 55%. When I tried them. The Charcoal 22 is lighter and you can see the outside more clearly. but it has higher Total Solar Energy Rejected value of 55% versus the NR Smoke 20 which is darker but lower TSER value of 37%.

Total Solar Energy Rejected value is based on the visible, UV and IR filtering values. So the higher it is. The less is the light passing through so the higher is the value it should be darker, yet in actual it is clearer.

Can anyone explains why?

Thank you.

 

[Drakkith]

Perhaps the Charcoal 22 is rejecting much more infrared than the NR Smoke 20?

 

[new6ton]

Perhaps the Charcoal 22 is rejecting much more infrared than the NR Smoke 20?

You have a point. Infrared is related to heat (as in thermal imagers). But is infrared the sole contributor of heat and not visible light. What nanometers in wavelength are involved in the heat of normal objects?

 

[new6ton]

Here is something unexplained that I'm figuring out. What is the explanation where some tints were dark looking at daytime yet at night is clearer? Actually I have bought both NR Smoke 20 and Charcoal 22 in my windows. The supplier told me I can get 50% discount if I would replace it in my windows since it was just installed 3 days ago. What can make me decide is the technical explanation of visibility of tint at daytime with sun based light versus night time with city light.

 

[new6ton]

Here is the great puzzle:

Tint 1 is darker at daytime compared to Tint 2 as you can clearly see. But at nightime. The scenes or brightness outside look the same. One expects Tint 1 to be darker at night. So why are they similar at night?

 

[Drakkith]

You have a point. Infrared is related to heat (as in thermal imagers). But is infrared the sole contributor of heat and not visible light. What nanometers in wavelength are involved in the heat of normal objects?

No, IR is not the sole contributor of heat, but it makes up a significant portion of the incoming solar radiation. In reality, all wavelengths contribute to thermal heating. This includes UV and visible light.

What is the explanation where some tints were dark looking at daytime yet at night is clearer?

The only way that I know of is to make your tint out of something that automatically darkens when exposed to bright light, and goes clear when that light is missing. Like the tint in eyeglasses that darken when you go outside and lighten when you come back in.

Tint 1 is darker at daytime compared to Tint 2 as you can clearly see. But at nightime. The scenes or brightness outside look the same. One expects Tint 1 to be darker at night. So why are they similar at night?

Tints and other filters usually work by blocking out a percentage of the incoming light, regardless of the intensity of the light source. So both the Sun and a streetlight may be cut down by, say, 50%. However, at night, your light sources are generally MUCH dimmer than the Sun. If one tint cuts down the light by 50% and another by 40%, then that difference may not be noticeable because the light sources are already so dim.

Imagine you're holding two weights, one in each hand. One is 100 lbs and one is 50 lbs. You can clearly tell that the 100 lb weight is the heavier one. However, if we reduce the weights to, say, 1/10 lb and 1/20 lb, it becomes very difficult to tell which weight is heavier because the absolute difference between them is very small even though the larger weight is twice as heavy as the smaller in both cases.

The same might be true for your tints. The light sources at night are already so dim that both tints may seem to be similar, even though one tint might be 10% darker than another. But that's mostly a guess on my part.

 

[new6ton]

No, IR is not the sole contributor of heat, but it makes up a significant portion of the incoming solar radiation. In reality, all wavelengths contribute to thermal heating. This includes UV and visible light.
The only way that I know of is to make your tint out of something that automatically darkens when exposed to bright light, and goes clear when that light is missing. Like the tint in eyeglasses that darken when you go outside and lighten when you come back in.

Is this an existing technology in window tints where it darkens when exposed to bright light, and goes clear when sun light based photons are missing? Where can I find these? What terms are these that I can find in googles?

 

[Drakkith]

I don't know about window tints, but the technology in eyeglasses is called photochromic lenses (marketed as transition lenses). I'm afraid that's about the extent of my knowledge on the subject.

 

[Tom.G]

but the technology in eyeglasses is called photochromic lenses (marketed as transition lenses).

The drawback is they lose their activity over a period of a few years and don't darken as much.