How does infrared light harm dark periods?

http://www.amazon.com/gp/product/B0002AQCQO/ref=pd_luc_sbs_02_03

I want to buy this to warm up my grow space at night. Does anyone know if these emit light that will effect my plants during dark periods?

The description clearly states it doesn't emit any light at all, but it does obviously give of infrared heat which is a type of light....or is it not?

With recent temperatures reaching -30F at night, my grow room has been dropping below the dreaded 55F mark for night. It hit 47 last night!

I'm not a science guy!

Any help would be awesome. Thanks!

Nobody? Really?

I can't really answer your question because - duh, I don't know right off hand! But here are a couple of things to think about:

Cannabis does respond to ultra-violet light, so it may respond to infra-red as well. Cannabis certainly responds to far-red light when it combines with other spectra to produce "The Emerson Effect". What we, humans, perceive as visible light, isn't neccesarily what plants "see". Plants don't "see" green, yet our vision is most highly sensative at exactly that color. Dogs and bats can hear outside of our limited range, so it wouldn't surprise me if plants can detect light that is beyond our capability also!

Whether infra-red "light" would be counter productive, or not, I can't really say. But there ought to be some way to wrap that device up with "infra-red proof" material - something that would absorb and re-radiate the heat, but block the actual infra-red light.

Sorry, but that's the best I can come up with on short notice!

thanks for the ideas. Anyone else got some thoughts on the subject?