6-week update on my experimental insulation project

Here is my six-weeks update on my experimental, off-label use of Solar Blanket material sold as a pool cover/water heating and heat retention.

So far my results appear to be all that I had hoped for. Both of my greenhouses heat up better (when the sun is out) but since our late fall/winter temperatures are cool or cold, the heat-up is never excessive. They appear to stay warmer without the heaters constantly coming on, so that should pay off in electrical bills in the long run. You will notice that I used two different materials, one clear/translucent and the other silvery and translucent. You really can't see anything in my greenhouses at all through the silvery material and can only make out vague images though the clear/translucent material. Both "bubble wrap" materials are a thick 16 mil and are UV stabilized. There is an 8 year warrantee on both, but since I am definitely using it off-label, I am not sure that does me any good. LOL. The silvery blanket has an aluminized inner surface that is supposed to transfer heat better but for a 20x40' roll, it cost about $100 more.

I thought I would have to remove this insulation during the spring/summer months, but perhaps I won't. The aluminized surface might just end up being a great "shade cloth" and since I have multiple fans in each greenhouse, heat build-up may not even be an issue.

The lean-to is a Solexx greenhouse with PVC framing and the free-standing one is fabricated with typical double-walled polycarbonate paneling on galvanized metal framing. I put a roll-up flap over the double sliding doors of the free-standing greenhouse since these doors open out NNW and that's where our cold winds always come from. The doors have the insulation too, I just thought that a double layering would be effective.

Ken in Mississippi

I like it please keep us up dated with this.

way to go ken.. r u keeping a log on nite /early morning/day temps?
?? does light go thru the aluminum blankets? or r u overwintering(no growth)
plants in these?

Light does go through both types, standard clear and aluminized clear, but UV is supposed to be blocked by both. The aluminized type does appear to diffuse the light more than the standard clear but according to the manufacturers literature, the aluminized type allows better heat penetration and heat retention. I cannot explain scietifically why this is, am only quoting what I read. All my various tropical plants seem to grow/bloom the same as before.

I check my greenhouses several times each day (particularly when the temperature is in the 20-40 F range, and often just before I go to bed. I like what I see so far. I also have emergency, LED lights mounted that are on AC/battery. If power fails, those lights automatically go on and I can tell that I have had power failure for some reason. These are the same kind of lights used in offices/public places/retail stores.

Ken

so was wondering how it is going with the gh? Any more updates?

Jan

Updates on December 8 and 9. Check those. If you have questions, I will be glad to answer them to the best of my ability.

Ken

did you use translucent on roof to allow sunlight in? or are you using artificial lighting?

I am afraid to put anything like this on the OUTSIDE of my greenhouse, I have windows that open, A, and B I have young dogs, could be an expensive situation. Considering doing some insulation out there though, my shelf froze in the last cold front and I lost my flame vine.

Both types are translucent, so either one would work. I get plenty of light through both types. IF you want to cut costs, use the standard clear, not the aluminized clear. Windows are not an issue. You can either, but it depends on how they open as to how you want to install the Solar Blanket material. What's the deal with the dogs?

One of them is an almost year old dobie mix in the tug and chew phase, the plastic I put on the front of the chickencoop required defense from doggy removal. I have a pair of 3 year olds and a 1 year old, tug is popular.

I gotcha about the dogs.

I notice I did not finish my train-of-thought on the 12/17 post. Dumb!

The sentence should have been, "You can either cut the material to fit the window itself, applying it to the inside of the window, or leave the material slack enough so that the window can be pushed open, but it *********".

My windows slope outward, being recycled from an 1960's house that was being remodeled. I could put bubblewrap on the inside and out and still open them at a slope, and maybe a flap of rubber around the edge, but they are metal and do conduct temp extremes pretty well. Oh, so much to do so little time. Thank you

If the windows tilt outwardly, just leave a couple of inches overlapping the window frame all around. When you close the window, that "flap" will give you a pretty darn good seal. Attaching the Solar Blanket to the inside as well will certainly give you lots and lots of insulation value.

Hi Ken,

Happy New Year to you!!! I'm so glad you have this post. I just got my first reality check for our December's electric bill. A whopping $293 !!! November's bill was $155 so I am pretty sure the heaters did it. So my question is, where did you get your solar blanket/bubble wrap? I think , I would want to wrap my windows with this and hoping it is not too late in the season. The big jump on our electric bill was very disappointing but I can't surely let my plants freeze to death so I will do what I can to help conserve heat and money in the long run.
And since this is something I may be able to leave yearlong, then it maybe worth all the investment up front. I would probably put it on the inside so I wouldn't have to remove it after the season, and will probably be a good shade cloth for the summer too. I will appreciate it if you could give me the info on where I can purchase this.
thanks a lot.
on a happy note, my orchids are thriving and looking much better in my greenhouse than when it was in my house last winter. the same with the other plants that I have in there. I just wasn't happy about the heating cost :-(


Eileen.

Eileen, I purchased all the Solar Blanket material from "In The Swim".

If you have a GH or something similar, with a lot of square feet of glass and/or polycarbonate, simply wrapping your windows won't do much good. If you are talking about a home space, then the window wrap would help.

Ken

ken I am still going to use the heaters but hoping at the very least amount of time. If the bubble wrap can extend the heat inside the greenhouse until late at night , then maybe my electric bill will not be as high;-) I have been so bad at keeping the temp in there @ the lowest of 70 and since i have it on timers, it starts to turn on when it gets dark then turns off maybe 12-13 hrs later. but i have learned my lesson and since last night didn't turn it on until about 8 pm since it was really getting cold outside. I will check out the website and again thanks

I have two GH's and an enclosed porch. My heaters don't come on until it reaches 60 F and if it gets really cold, low 20's, I am quite sure my heaters don't keep those structures warmer than 50-55 F. All my plants are tropical plants and the vast majority are orchids.

P. S. We are supposed to get down to the mid to lower teens Sunday night through Tuesday night. I just hope my heaters, running full blast, can keep the temperature above 50 F!

Ken in NE Mississippi

Ken I didn't realize that low temp is also heading this way! My low on Monday and Tuesday night is in the teens, 15 for Monday night. I am bringing my orchids in the house starting tomorrow so I don't have to used up the heat too much. I think my citrus will survive as long as it is above freezing and i can put the heat close enough to it. maybe cover them with blankets I don't know. But im glad i have the greenhouse this year. Otherwise I won't be able to fit them in the house.

Which reminds me, with your 3 greenhouses and 3 heaters each , how much does your electric bill runs up to? that is if you don't mind my asking. It is my first time to have a greenhouse and so the huge discrepancy on our electric bill last month was a huge shock both to my husband and I. We never went over $200 even in the full heat of the summer. It is just to give me an idea that what we have or December's bill is pretty normal when you have a greenhouse.

Well keep yourself warm and hopefully our plants will survive this cold blast.

Eileen

There is another thread in the greenhouse forum that discusses passive heat for greenhouses. I am in North Texas, it is dropping to 16 degrees tonight. I built my greenhouse attached to the south side of my garage. The most delicate plants are at the back, near that garage wall and next to my 110 gallon stock tank, which is black and soaks up heat from sunlight in the day time. i brought my most most delicate plant in (it's a cyclamen that lucked out and made it through the summer) but left my seed geraniums, white ginger tree and other stuff out, near the garage wall. On the perimeter by the windows I have outdoor plants that normally would not be greenhouse kept but didn't get planted, they may freeze lightly but will be fine, and a few broccoli plants.

I have champion electric, they send out a weekly energy usage report, and the 300 watt heater I'd had in the stock tank for my tropical tilapia had doubled my weekly electric usage. Went from 410 kwh to 199 in a week when I unplugged that heater. So the tilapia are in the house, and the greenhouse is on its own tonight, will see how it does in the morning, I am sure it will be fine. I also suspended heavy window plastic below the ceiling for about a foot, to let the upper roof draft just blow on through, and reduce the space I am trying to keep warm. I will see.

I really don't know. My wife pays all the bills. I would have to get the receipts from last year and compare. But I don't know whether that would even be meaningful since last winter was very, very mild and this winter - well you know. Last winter I believe we have four mornings in the mid to upper 20's. We have already had 20 mornings in the 20's this fall/winter and now a morning in the teens and another one in the single digits are predicted this evening. Our wind chill at 7:00 AM was 9 F and this evening's wind chill is predicted to be -4 F. I'm in NE MS, zone 8b.

I can tell you this however. When I walk into the GH's, and the temperature outside is in the 20's, the GH's are warm and I find that the temperature remains steady for quite a long time. I am doing a lot of re-potting of my orchids and mounting some staghorn ferns, so I might stay in the two GH's for an hour or more at a time. I do think the wrap has made a tremendous difference.

Ken

At $41, it might be worth it. Can't do right now, plates are out, and stuff is coming due, but maybe before I start seeds.

Which thickness are you using?
http://www.poolcenter.com/c/solarCoversAndReelsSolarBlankets/searchByShapeAndSize?size=12x20&shape=rectangle

Everything is 16 mil, the thickest. I wanted the wrap to last as long as possible. You can save by going with the standard clear rather than the aluminized clear. Both come in the same 16 mil thickness. If you want to save even more, use a lighter weight solar wrap material.

I used the aluminized material on the roofs (I did not know what would work the best, LOL, and since I ordered a longer roll of that, I used it on the long runs [side wall-roof-side wall] of the free-standing GH). I have seen a big difference in how that diffuses the sunlight compared to the standard clear on the end walls. I hope that I might not even need to put up the shade cloth in the spring, just letting the aluminized surface replace it. Time will tell.

16 mil is out of my budget this year, but thank you for the quick reply and detailed info. Maybe in the fall.

We have 2 GH's one is polycarbonate the other is a temp. Covered seasonly in 6ml clear uv shrink wrap, this material stays fluid year after year...easy to work with..etc. Over this GH we place a pool cover. Have used this system for years & works so efficiently. Have had a GH since '74 & run the gammon over the years. Our temp swings here in N.Texas are crazy, constantly adjusting the temp in there. I love the nice diffused light that the pool cover provides + the insulating properties. We are so blessed to be living in a time of space age developed materials having such a profound effect on GH gardening is just so cool!!

Great work with your GH always reading & learning !!

Thanks, Coco.

Is your pool cover material the same as my solar blanket material? Does it look like bubble-wrap or is it flat material?

Ken

Ken it is a quarter inch air pockets sealed in between two rather thick layers of clear plastic. It is heavy & uv. This house hold the brugmansias & assorted tropicals

Sounds similar to the solar blanket material but the air-pockets on mine are 3/8" wide on the non-aluminized material and 1/2" wide on the aluminized material. Both are 16 mil thick and UV resistant.

Ken

Ken well are about to have a snow/ice event will post some up close pics when I can... All these products are so cool!!

Don't send that bad weather our way. We have had enough!

Ken

We love N.Texas weather..we just got passed over....only got Rain/sleet mix & NO stick :)

Looked up our cover it is a solar blanket. I suspect this was added around 2003ish??? It works like a champ. We also when I have time LOL add a perimeter skirting inside the Temp GH of a 4x8 insulation sheet cut in half lengthwise with the shiny side facing inside the GH. This helps protect that crucial 2ft cold zone. Reflects heat & light as well as added cold protection. We are always reading & learning, but we have great products to to make GH temp management so much easier.

Nice meeting you Ken!!!

I have also installed a 12mil solar bubble pool blanket in my greenhouse as insulation.
The first 3 seasons I used the large bubble ,4 ft wide bubble wrap Like you use for shipping, and it was OK, but it started to degrade ,so I replaced it last Fall. The pool cover is much tougher of course. And UV protected. The pool cover being heavier was a bit more of a challenge to hang inside, because of the way this greenhouse is constructed. All aluminum frame, so we had to get creative.
I hung it on the INSIDE of my 8'x24' Snap&Grow greenhouse. So as not to interfere with the auto vents opening.
What I have noticed is that the temperature fluctuations are much less.Both during the day and at night. I have a lot of wind here and keeping a constant temperature can be a nightmare. The pool blanket not only made a big difference in my ability to regulate the night time temps , but also the amount of heat that builds up during the day. This winter has been extreme, to say the least!
I have fans that run 24/7 for circulation and an automated exhaust fan to work with the hydraulic vent openers on sunny days. I have also installed Reflectix foil insulation on the North wall to minimize heat loss. My greenhouse is one huge science project. I am constantly trying to find ways to improve it and keep it cost-efficient. Well ...good luck on that, huh?
I am still trying to find the best, most economical heat source. I have experimented with different types of electric heaters and found that the oil filled radiator type seem to keep a more even heat and also a softer heat that doesn't seem to dry the plants out as bad. The drawback with them is if you have below zero temps for a sustained period, you are going to need supplemental heating for backup. I use a 18,000 btu kerosene heater (on the lowest setting) for that. It will keep my greenhouse at about 65* when outside temps are in the teens. This winter I had to use Both types of heat, because the kerosene heater will only burn 12 hours on low, 8 hours on high and it was -5* with a wind chill of -30*. I didn't get much sleep that night!
Anyway I thought I would Share my greenhouse trials. It is great to see other members are having the same issues and how you are solving those issues. It has been very interesting to read everyone's posts here. Thanks you all!

Nanny, why did you decide to put the solar blanket material inside rather than outside the polycarbonate? Do you going to leave the solar blanket material on all year? That's a question I ask myself, since like you, my solar blanket covering was placed on my two GH's last fall.

Ken in NE Mississippi

Ken, I decided to put it inside because I couldn't figure out how to secure it around the vents on the roof to allow them to open and close automatically. There is really no good way to attach it on the outside. here are some before pictures to show what I mean. I will post some after pics too. as soon as I find them. There might have been a way, but I couldn't come up with anything that would withstand the wind and weather.

We added the bars that run the length of the greenhouse for hanging baskets and the lights are also hung from them, where before they were hung by plastic clips that hook into the frame. I will probably leave it on year round except I may have to remove it at some point to inspect the structure and clean. But it is not going to be easy removing it with all those rails. They were added after the insulation was hung.

This message was edited Mar 16, 2014 11:22 AM

I used one piece of solar panel to cover both the top and two sides, leaving me only the door-way and then the other end to apply. The single long piece simply was draped over the roof and then hands down the sides. I used 16 mil solar blanket material. I strung light gage aluminum wiring every 2-3', crossing over the roof and down and sides and then strung the same wiring around the two sides and the (non-door) end. I also screwed the end pieces into place. Since I used the heavier mil blanket material, it is plenty thick to hold with the screws, but the wiring just adds retention when the wind blows. The material is so heavy, that the long run (roof and two sides) won't move with the wires holding it down.

I may just remove that long run of material, since all I have to do is remove the wire to do so. I will leave the two ends as is.

I show the GH with shade cloth (before I covered the GH's with solar blanket material) just to show how the vent elevates that cloth when open. It does the same thing with the solar blanket material, so there is no need to cut out for the vents. The final photo shows the wire placements, drawn in for detail. I have two greenhouses covered in this way. The flap you see covers the door and is facing north. This just adds another layer (and is wired down) when there is a wind coming out of the north. Otherwise it is rolled up and secured with Velcro.

Ken

Very nice setup. I love your walkway! that is on my project list, to lay pavers or some sort of walk. Is your greenhouse Built from a kit How large is it? Just curious for comparisons sake.
I was afraid to move my orchids to the greenhouse because of this crazy below normal temps we have been having, but I do have tropical plants out there. Hibiscus ,Banana trees,cannas,Citrus, as well as several annuals and some tender perennials.
Right now it is sleeting mixed with snow and windy. 32* outside and dropping,. and the greenhouse is holding at 59*. I will keep a close eye on it in case I need to turn on an extra heater. Mine are set to come on in the 55-58* range give or take a degree or so.
I am also going to purchase a digital thermostat to control my heater with more precision. Later on when I have recovered from the high electric bills from this winter. Just the house heat bill was awful. The greenhouse is on a separate meter along with a garage that is heated on the colder nights, so it is difficult to tell how much was greenhouse and how much was garage.. My hubby says it was all greenhouse and therefore the greenhouse needs to be closed down in the winter month's. Hello! That is the main reason I got the thing!!!!!He is a bit of a non-enthusiast at times, especially if it affects his wallet, lol.

Just tell him to SUCK IT UP! LOL

My two greenhouses are both 10' x 12'. One is free standing and the one is on the other side of the pathway is a lean-to. The lean-to was built first (kit) and then a year later the free-standing was built (kit from another mfg). I wish I had built the second one twice as large. Hind site is usually 20/20. My lean-to is my "Orchid" GH and the free-standing one the "Everything Else" GH. I have only tropical plants in them and also use the EEGH to start my vegetables and plumeria cuttings/seedling.

My thermostats are set at 60 F. A central (whether digital or not matters little) thermostat is what I use in each, but for a large GH, thermostats at each end would do better. These central thermostats do an excellent job, at least with my electric heaters. If I could get it to you, I would gift you a like-new, oil-filled (radiator) electric heater. It draws 1500 W but the heat is simply too little for me. I actually have electric heaters in each end of both GH's, and in the orchid GH, an extra one on another circuit just in case a breaker trips.

Ken

I did tell him that... in so many words. But that is an ongoing issue and wiil probably continue til this weather straightens up! Wow, I could use another heater, too bad you are so far away. What type of heaters are you using? Where do you find a "central Thermostat" ? Is it hardwired or portable? Forgive my curiousity but as I said I am trying to get the most efficient setup that I can afford. I know there are some high tech setups available but they usually have big price tags.
I use a heater at each end an sometimes end up sticking one in the middle if I am not using the kerosene heater. Kerosene is ok to use in an emergency, but at $4.37 a gallon I can't use it for primary heat. I also have a My Buddy, portable propane heater that I can use in an emergency, such as the electricity going out. It is 9000 btu and will run about 110 hrs on a 20# propane cylinder, you know like you use for a gas grill. None of the options are cheaper than electric though. I am considering putting in a propane space heater, providing I can find a reasonable model that has a thermostat.
I wish I could have afforded to build mine twice as large. If we ever win the lottery...LOOK OUT!

There are numerous greenhouse supply houses that sell thermostats. I use the T118P from ACF Greenhouses. It is a plug in and go type and you don't have to do any hard wiring. You just plug in your heater, set the thermostat to the temperature you want the heater to come on at, and that's it. Just be sure you set your HEATER'S THERMOSTAT to the highest setting, so you know it will turn on. In other words, the external thermostat will override the heater's thermostat. These thermostats are not expensive.

I use pretty inexpensive heaters. All are 750/1500 W heaters. In milder weather I will use the 750 W settings. I have several Sunbeam ones but a couple of other brands that work OK. You want to be sure and check the heater though, being sure that it really does come on when wanted. Almost all heaters are now made in China and some just won't work. I have returned two in the last year that were defective.

There are commercial-grade heaters, available from the GH supply houses, but they are high wattage and pretty expense.

I would use my propane heaters in a pinch (I have two of them for football tailgating), but I haven't had to use them.
Ken

Thanks Ken. I will check ACF Greenhouses out. I do have portable thermostats but they are the type with a dial and I am not convinced of their accuracy. So I thought a digital thermostat might give me the ability to set the heaters to a more precise temperature. A few degrees can make a difference in the heat bill over a period of time. I don't mean to sound like a mizer but I am sure you are aware of the cost of running even a small greenhouse in the winter. Especially THIS winter.

This message was edited Mar 18, 2014 8:06 AM

My greenhouse is my "guilty pleasure" so to speak, so I am trying to lessen the burden on the household expenses any way I can. Got to keep the natives from getting restless.
I do have a question for you. It sounds like you have your greenhouse pretty snug. Are you running fans for circulation? Your vents are covered , right? Just wondering how that is working for you.
On a warm sunny day say 50* ,my greenhouse temps are above 80* before noon and can get close to 100* with the vents closed. But I have no shade at all from sunrise to sunset. Except for the Aluminet shade clothes, that is.