Mylar film - Is it the best reflective material?

[yourkiddin]

Sorry I posted this on the grow room and no one has replied.
I built a new grow box out this foam insulation. The foam has a dull sliver and it reflects light pretty well. But I'm wondering if I need to use mylar film on walls instead.

 

[dick23rk]

Hey there, great question! There are a few different answers and a lot of it comes down to personal preference in the end or what is more cost effective. Mylar is one of the most reflective materials that is the most widely used, but you don't have to use it. Some people will use tin foil, but this can create hot spots and has to be completely flat to really help. Some white poly or white painted walls are another good thing that can be used, it's not to much that it reflects the light but it will bounce off of it and make the space appear brighter.

This silver backed insulation can be used just as well as mylar I would think. How dull is it? does it have any shine to it at all? I have seen some of this insulation before, it's for under siding on houses, and it seemed like it would be fairly reflective.. but I'm sure every brand is a little different.

 

[Major PITA]

From my studies, it is hard to beat flat white paint. I've done the mylar thing. Not worth the trouble, IMO.

 

[yourkiddin]

I can say I was impressed with the foam board when I did my 12x24 shed. It has 2 of the 100 watt leds that look like a standard incanedesent bulb. And I was shocked at the difference the combination of the silver walls and bulbs made. I just wasn't sure if it would be suitable for a grow room. But I'm gonna just leave it as is and see how it performs. Thanks for the information.

 

[fanleaf]

I just built my room in the signature below. Finished the drywall and painted flat white. After using my Apogee MQ-500 full spectrum quantum meter to test my par readings I did add mylar to the walls. Did I see higher par close to the walls.......yes, I sure did. The mylar does reflect light better than the flat white paint. Is it worth it.....well that's a whole other question. Mylar while cheap is a pain in the ass to make flat and look nice and it does get dirty really easy. So while it does add a bit of the pain in the ass factor I will be using it from now on.
Either will work very very well. If your trying to keep light losses at an absolute minimum you will get 4-10% (my guesstimate) more reflected light with mylar.

 

[yourkiddin]

That's good that you tested that with a meter. I had got on here initiially to say how is it scientifically possible for flat white to reflect better than a mirrored finish . Was ur meter or gauge expensive. I guess I can look it up though. I don't see buying an expensive one . Cause I assume once u figure out the best material and best lights it a paper weight.

 

[Major PITA]

A mirrored surface can reflect light better than white paint, if that is your only criteria. However, a mirror (or similar surface) reflects light in highly directional patterns. Some spots will get lots of light (and heat), while others spots will get very little. Most mirrored surfaces are difficult to clean, or are fragile in some respect. White paint is easily washable, relatively inexpensive, easy to install and maintain, and provides diffused light so more of the space gets similar amount of light without hot spots. If you goo goo this topic, I think you'll find several others who have tested with meters along with their findings. Also, one of the more respected (and expensive) grow films for grow rooms comes from Panda. It is white - not mirrored. YMMV.

 

[fanleaf]

That's good that you tested that with a meter. I had got on here initiially to say how is it scientifically possible for flat white to reflect better than a mirrored finish . Was ur meter or gauge expensive. I guess I can look it up though. I don't see buying an expensive one . Cause I assume once u figure out the best material and best lights it a paper weight.

$500

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[Scottmaine]

I also tried the mylar thing and agree keeping it flat and clean is pia! I have since gone to semi gloss brilliant white walls ,floor and Cieling. Complete sanatorium look. It's frigin blinding bright. Just my opinion and liking.