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Signals through Low E glass

user-5946022 | Posted in General Questions on

My windows are Low E.   This may be blocking various signals through the glass.

I believe I read on this site that the Low E coating precludes using a solar panel on the inside to recharge motor operated shades, as the Low E blocks the panel from collecting sufficient light to recharge.  Can someone confirm or refute this?

Based on experience, something associated with the glass blocks an RF signal.  My exterior deck fan can be operated with a remote, but when I point the remote from the inside through the glass in the shortest path from remote to fan, the fan does not respond to the remote.  If I point the remote to the wall (drywall, cellulose insulation/wood studs, zip sheathing, brick) the fan responds immediately.  

I presume the Low E or some other component of the glass also blocks the wifi, as reception outside is terrible.

Does anyone know if certain frequencies will work better than others, or certain systems will work better than others to get through the low E (or whatever other component of the glass is blocking the signal)?

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  1. walta100 | | #1

    Something does not sound right about your remote-control test to my ear.

    If your remote is an RF (Radio Frequency) type pointing will have almost zero affect on its operation as the radio waves are emitted in every direction and tend to get reflected for coverage behind most obstacles.

    If your remote is an IR (InferRed light) type then pointing it is important but there is no way the light can pass thru the wall as you described.

    I can’t think of any remote that could behave in the way you are describing.

    Uncoated glass blocks a high percentage of inferred light lowE even more as that is its design goal is to pass visible light and reflect invisible light and heat.

    There are many flavors of “lowE” coatings some are metallic and no doubt would reflect some radio waves but 100% seems very unlikely.

    Some times with IR remotes you can reflect the light off a white surface and get a bank shot or a double bank shot to the sensor and that maybe what you are seeing.

    Note that sun light can overload IR sensors if it hits the sensor directly.


  2. Expert Member
    BILL WICHERS | | #2

    Infrared remotes will likely not work through low SHGC Low-E coatings, since low SHGC coatings block a big chunk of the infrared light spectrum by design, since that's what breings in heat. I haven't tried solar panels behind Low-E windows before, but from some quick looks at silicon solar cell spectrum, and I'd guess (from eyeballing graphs) about 50% reduction in output from solar cells that are behind Low-E glass due primarily to the Low-E glass reflecting most of the IR spectrum that would otherwise be used by the solar cell to produce power.

    RF signals are far lower frequencies than light (megahertz and gigahertz, instead of terahertz), but metalized coatings can have a shield-like effect that can attenuate (reduce) signal strengths. Foil-faced polyiso is even more extreme here, since the foil facer is a pretty good RF shield. I would tend to agree with Walta that RF signals tend to bounce around a fair bit and usually find a way out, but with a really weak signal, I could see a metalized piece of glass possibly blocking enough signal to be a problem. I've never tested that, although I do have the equipment to do it (I'm really an RF engineer, even though I don't really work in that field anymore).


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