I started installing this and wondered what others might think of it. Particularly those who are using or have used it.

I bought the Hydrofarm — Reflective Metalized Film, 25' x 48", 1 mil and am part way done in my basement grow area. I will have it on the ceiling and two walls. SW corner. (I do not plan to enclose the area as I move stuff around. I use the area to overwinter numerous plants and also start a bazillion seeds.)

One possible concern I have is heat. Near my ceiling I have 2 400 watt metal halide warehouse lights which I really like. (Picked them up about 2 years ago, rewired them and hung them with rope for adjustment on my ceiling. Got them for $ 25 each - a real good deal. )

Those lights do put out heat. I never worried before since I have them mounted between rafters and about 12 " below the sub-floor above. Based on the location the light "fixture" will be about 3 inches below the film. I appreciate the heat they and the ballasts (on the floor nearby) put out as I want the area to be warmer than it would otherwise be. I have no heat exhaust installed and do not plan to install any.

Should I be concerned?

Could the heat be problematic so close to the film?

If it is, I could cut out a larger area where the fixture hangs.

TIA

A fan should help with that, to dissipate the heat as it forms, and air circulation is great for inside plants anyway.

I think maybe Joannabanana @ Joannabanana does this??

CarolineScott said:I think maybe Joannabanana @ Joannabanana does this??

@Joannabanana

Be sure to check how warm it gets after it gets dirty or dusty. It will probably reflect 90-99% of all light and heat while clean, but who know how much it will absorb when dirty?

This is only from reading, not experience, but I've read that flat white paint reflects lots more light than standard aluminum foil.

But I think that designed-for-the-purpose metalized film is a better reflector than kitchen aluminium foil. Is it better than white-painted surfaces? Googling shows different opinions.

Gloss white paint is easiest to keep clean, and dust can cut reflectivity more than the difference between different kinds of white paint and aluminized Mylar.

I use the mylar emergency blankets at $1 each. I will use them on the 2 walls around my T5 lights and on my two end walls in my little GH. I can only cover part of my north wall (heated garage) because my natural gas heater is located there as are my thermostat-controlled venting fans. I'm sure that mylar would go up quick if exposed to open flame or intense heat.

On the mylar, I'd be inclined to put it on the walls, but not up around the light fixtures. Light from your T5's is already reflected downwards by the fixtures, isn't it? How about painting the floor white, too? That would bounce a lot of light back up for your plants to gather.

Old mirrors (garage sale or second-hand store) would be another option that would not present a fire hazard, and would be easy to keep clean. I have a ratty old full-length mirror that I move around outside to reflect some extra sunlight, during these short days of winter.

dyzzypyxxy said:On the mylar, I'd be inclined to put it on the walls, but not up around the light fixtures. Light from your T5's is already reflected downwards by the fixtures, isn't it? How about painting the floor white, too? That would bounce a lot of light back up for your plants to gather.

Hanging from the ceiling over the grow area, I have two 400 Watt metal Halide warehouse lights. I will monitor the heat near the fixtures and mount a fan there if needed.

Painting the floor white is certainly a good idea! I thought of that myself and it is on my to do list. It is currently brown.

I have 3 and 4 foot shelving units where I have fluorescents installed with two fixtures hanging from the beams above. They have reflectors, but a lot of light will now be reflected. The walls were painted white, but it was very flat. Very flat.

Final thing I may do is build a hanging wall with firring strips and place the film on it so I have another area to reflect. If needed or desired, I could easily roll it up.

Thanks for everyone's comments.

Instead of painting the floor white, you could lay out one of those mylar sheets on the floor. I usually buy a package of 10 for $10 and that keeps me in stock for a couple of years. With the fan blowing, make sure whatever sheet product you use is firmly attached so that the fans don't blow the sheets into dangerous areas.

What product are you referring to and where do you get it?

I used a staple gun to attach the ceiling film.

Mylar on the floor would be really slippery if it got wet, though.

I use the mylar emergency blankets. Very thin stuff so no insulation value although highly reflective. Elaine might have a point with it being slippery but you could line shelves with it.

@DavidLMO, you have a T-Mail.

I am not gonna put anything on the floor other than perhaps some white paint .... next summer when it is empty.

Are those emergency blankets sold in like Sporting Goods section? Never heard of them.

David, they're also called "space blankets" and are widely available. I just googled "space blankets". Here's a link to packs of 10 for $8.47 on Amazon. Or it seems you can get a pack of 20 for $16.

https://www.amazon.com/dp/B000GCRWCG/

David, don't your metal halide lights have hoods that direct the light downward? If they do, perhaps I am missing something. If you put reflective material above them, I just can't see how reflecting already reflected light (because that's the only light that would reach the ceiling) would help anything. The amount, and especially the quality, of light would be very poor.

dyzzypyxxy said:David, they're also called "space blankets" and are widely available.

Thanks Elaine. now that you explain it I have seen them tossed over runners at the end of Marathons.

Rick ... The way they were built, the ballast sat on top of a small box that attached to the bulb/fixture. An open area maybe 10 " in diameter at the top of the shroud ( reflector) was covered nearly completely by the ballast. I rebuilt them and placed the ballasts on the floor and ran a wire (from a heavy duty extension cord) up and into a 2 inch diameter box I am using as a J box to which is attached the bulb/fixture.

As a result, an open area nearly 75 square inches is at the top of the entire unit. Light exits thru those openings. Before it went into wood - now it is reflected.

DavidLMO said:As a result, an open area nearly 75 square inches is at the top of the entire unit. Light exits thru those openings. Before it went into wood - now it is reflected.

Smart!

Thanks Rick. Had that big opening not been there, I would not have covered the ceiling. I have 2 of the warehouse lights, so that was a lot of light going up into the wood. And so far, I see no heat problem. I can either run a fan and/or lower the lights easily.

While I do not have a light meter, one can easily see that it is much brighter. My wife checked it out and said Wow --- Much brighter.

My WAG is ~ 15 - 20 % brighter. Once I turn on the 7 banks of fluorescents, it will be even more so. I have material left and am thinking about placing some on the shelves below the fluors.