Without an air gap (or bubbles etc) a film will do nothing except reduce air infiltration. The thermal conductivity of 6mm of vinyl is negligable compared to the air next to it.

Do a search on this forum for 'solar pool covers' and you will find lots of discussion regarding using them as gh covers.

I think most people were very pleased with the results.

Good luck on your decision.

Thank's for the input. It seems I should be looking at bubble wrap.

So far, I've found it on Charley's and Farmtek websites.

Any other sources I should be checking for prices?

Birdwidow, I don't have a basis for comparison, but read somewhere on these threads last November that a solar pool cover will last much longer than the bubble wrap. I got mine from Amerimerc L.L.C. (www.amerimerc.com) for $99.75, a total of $107.74 with shipping. There was a smaller size that would have been adequate, but I got the 14x28 so I could completely wrap the house with some left over ... just in case. The excess has come in handy for a variety of purposes.

I felt a little more secure with the pool cover on during winter storms, figuring that it would also help prevent panels from being dislodged by distributing winds as well as ice or snow weight more evenly over the entire structure.

Thank you for your input agardenstate, but I want something that will admit light.

I've also given Nathan's input more thought and as usual, he is right. I need air space, so the bubble wrap, mounted on the inside would seem my easiest if not ultimate solution.

Which leads to another question:

What makes the clear bubble wrap sold by GH suppliers any different than the bubble wrap sold for packaging?

I searched and found a lot of packaging sellers, and many different weights, bubble sizes, widths and lengths of rolls of the stuff, and other than those factors, couldn't see anything that would make them different from what is offered on the GH sites, other than price, which is a lot less if bought in bulk from packaging materials distributors.

BTW: I also found self adhesieve bubble wrap. It's claimed to be absolutely safe and removable with no residue, but is only available with small bubbles.

I don't know how safe it would be if left for any length of time on the polycarb, but glass GH owners might find it handy. On the other hand: the polycarb came with protective sheets of plastic on them, coated with removable adhesive.

Could at least some the answer for easy to apply and remove additional R-values be a bubble version of the same thing polycarb mfg. use to protect their products for shipping and storage?

Any 3-M chemists out there?

Pool cover is essentially extra tough bubble wrap. Have you considered my earlier suggestion of gluing heat shrink plastic (sometimes sold as 'storm window') to the inside to form another layer of glaze? If your film is clear enough you can leave it on all year (keeps heat in in winter, out in summer).

A completely separated film will have a higher R value than bubble wrap, as there is no heat transfered through the bubble walls. It also is easier to see through.

Yes Nathan, I've thought about it, but if I were to go that route, I'd use double faced tape, but until we get all the electrical work done and the heater installed, I may just slap some bubble between the alumunim uprights and hold them in place with cleophane tape.

My ambition to have it ready for use this winter proved overly optomistic. At least the building is finished and sealed, and once we have the heater up and running, and lights, we can work on the interior regardless of the weather.

I'm still hoping to learn if the bubble sold for packaging is the same stuff as sold for GH's.

I found a local packaging goods distributor and can buy 2, continuous rolls, 2 X 125 ft ea.: 250 ft. total, for less than $50.00, with no shipping.

I have no first-hand knowledge of the bubble-wraps; I hope someone who has had a chance to compare these will have some advice for you. In the meantime, the Charlie's Greenhouse catalog claims their bubble insulation is superior to bubble packing material and seems to run about 25 cents/square foot compared to your 20-cent/square foot material above. (Of course, there's also shipping.) You can check their website, www.charleysgreenhouse.com for details. There are several other suppliers, Farmtek is one, can't think of the others just now.

BTW, my solar pool cover is a clear one, so doesn't interfere terribly with light transmission. In addition to flowering plants, I grew lettuces/mixed greens and herbs through winter without auxiliary lighting, even the cherry tomato produced lightly. I realize, however, that you are considerably farther north, so have correspondingly shorter daylight hours.

Good luck this winter! I trust you'll have a very enjoyable time.

Di

Di: I will look into clear solar pool covers. I didn't know they were available in clear. The photos on the seller's website gave me the impression they were opaque. Thank you for the info.

Birdwidow, if you'd like, I can cut off a small piece of the excess that's in storage (I have plenty) and mail it to you so you can see first-hand what it looks and feels like; I realize the degree of light transmission is going to be important to you, and it is quite an investment.

Click on my member name to reach my GW page and from there you can send me an e-mail of you wish.

Di

Cactusfreak reported on this forum that the clear solar pool cover admits 80% of the light.

Many people are quite happy with them. However, I tried it last year, I won't use it again. It proved too difficult to secure against the wind. This year I intend to cut the cover into strips and use it on the inside.

I remember that, Stressbaby, and that's one reason I opted for the larger cover; it allowed me to wrap almost the entire greenhouse like a package. Careful cutting when we got to the entrance wall permitted bringing the cover around and almost up to the doorframe. My goal was to have no gaps, spots, flaps, whatever, that would catch the wind and give it a foothold for mischief. We had no problems with the wind.

Not sure how big of a greenhouse you are trying to cover, but I wrapped mine when I was back in Ohio with bubble wrap, got the big rolls at Staples or something like that. I only had a 6X6 though, so one roll pretty much did the job. I added an extra layer on the top, I think I wrapped the rest twice around. I was able to maintain 40F in Ohio winter with just a small electric heater. Since mine was a portable greenhouse, we had also made a wooden floor (I think about a 4'' high platform) and sat it on our cement patio to insulate the bottom. This made an air pocket underneath.

Kim

Use swimming pool clear bubble wrap (Magni-Clear brand). I has a six year garuntee and is very strong. It will let all the sun light in you will need but add an additional R-4 insulation factor. Below is a link to just one of many pool suppliers out there that sell the Magni-Clear, do a Google or Froogle search for pricing. Be sure that it is the clear and not the blue or silver.

Here is a link that might be useful: Aqua Pool Wharehouse

Insulation

A great product to insulate GH foil bubble. It's the shiny foil on bubble product and it comes in Rolls. It protects from cold damage and heat as well. Many large Gh's use it. You can buy it from Insulated Products Corp. They ship around the country at very good rates. www.ipcpack.com 323-585-0900

Here is a link that might be useful: Insulated Products Corp.