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Plants and low-e windows

Posted by earthbru (My Page) on
Mon, Jul 11, 05 at 16:53

A friend of mine recently installed Low-e windows, after which all her plants that were lighted through these windows died. Has anyone ever heard of this before?

Follow-Up Postings:

RE: Plants and low-e windows

Yes! A friend of mine, who is very knowledgeable in both building technologies and gardening, mentioned this pit fall to me at a home show. Apparently, from what I remember, he said these low E glazings block the radiation from the sun necessary for plant sustainability and growth, without which they would not do well and die sorry!
I guess grow lamps may be in order now.


RE: Plants and low-e windows

I have about 50 house plants healthy and doing great.(OK one dead and one that is sick but I found bugs on them)
My mother, Aunt and Grandmother rival my plant collection and none of them have had any trouble with their low e windows and plants.

Wonder why it's selective?

RE: Plants and low-e windows

There are different types of low-e coatings, it's not all the same product, although I can't recall the specific differences. I would assume that some affect plants and others don't.

RE: Plants and low-e windows

I am not a plant-guy and I admit that this is mostly guess if I say anything grossly incorrect about plant growth I hope someone who knows better will correct me! '

Plants like to use the red and the blue of the visible light section of the electromagnetic spectrum...opposite ends of the spectrum. The middle part of the spectrum, the softer yellows and the like, have very little effect on plant growth or overall health. Contrary to a somewhat widely held opinion, plants do not generally like the UV spectrum. There is something of a misconception that plants thrive in UV light...this is not true, most (if not virtually all)plants do very well in the total absence of UV light. If someone wants to test this, place a plant ina dark room or closet with only a UV light as company. Your plant will die.

LowE coatings are designed to block radiation in the UV (ultraviolet) and IR (infrared) parts of the red and blue, the opposite ends of visible light.

Since, as Bry84 pointed out, not all LowE coatings are exactly the same, I would suspect that if it was the LowE coating that affected the plants, then it was possibly a LowE that was designed to cover "deeper" into the visible light part of the spectrum and that it may have caused light loss in the blue or red light range - or both.

Possibly a high tint LowE coating could have caused problems due to blocking the colors plants need to thrive.

There have been a number of studies concerning plant growth and LowE windows, and I have yet to find a single study that proves LowE coatings affect plant growth. I can find several that state that LowE coatings have no effect on plant growth...but, there is some anecdotal evidence - as earthbru noted - that suggests at least some correlation between plant growth and LowE windows.

Although I would consider another cause besides the windows, as Bry84 said, I would also assume that some coatings may have more effect than others.

RE: Plants and low-e windows

Would not the visible light transmission
(the 3rd number on the NFRC label)
have an effect on the amount of light
that window allows to enter conditioned space?
I have noticed that windows with low-e can
have varying degrees of tinting. The windows
with the darker tinted allow less light to be
transmitted into the home.
Looking forward to your input on this
Oh OZ of windows aka Oberon!

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