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Will low e windows effect plant growth in a greenhouse? Answered

I have a bunch of low e, argon filled double pane windows that I want to build a greenhouse with. Will the plants inside the greenhouse be adversely effected by this type of glass? I am not a "sciency" type - please advise me.


I'm in a similar position re: building a greenhouse with low-e glass units.  There's a really good discussion here:


Most of the stuff I've found on the web suggests that if your glass _only_ has low-e coating, and not heat-reflective coating, tint, mirroring, etc. then it'll probably be fine.  You may lose 5-10% of visible light transmission.  It also blocks ultraviolet (UV) light, which most of the discussions I've read indicate plants don't generally care about.  Finally, if you're trying to gain heat from the sun, it apparently is best to have your low-e coating on the outer face of the inner sheet of glass.  If you're trying to avoid solar heat gain, install the windows so the low-e coating is on the inner face of the _outer_ sheet of glass.  Hope this helps.

The 'e' in Low-E windows stands for emissivity.

Our friends at wikipedia say:
Low-Emittance (Low-E) is a term used for a surface that radiates, or emits, low levels of radiant energy.

From this we can understand that if you used low-e glazing on your greenhouse:
radiant heat originating from indoors is reflected back inside, thus keeping heat inside in the winter, and infrared radiation from the sun is reflected away, keeping it cooler inside in the summer.
This would suggest that a greenhouse using low-e glazing would not have that 'hot house' effect typified by greenhouses.

The real question is what you plan to grow inside your greenhouse, as different plants have different requirements. I would suggest not using low-e glass as most greenhouses look to trap as much light and heat as possible, not reflect radiant heat.

Hope that helps!