I know you cannot risk it, but I would really like you to turn off the power and not light candles!

Glad your structure provided survivability!

Reminds me of the 'do pilot lights use a lot of gas' thread... ;)

Wow, that is wonderful. I am glad you got so lucky. One of my biggest fears is a power outage and my plants getting frozen. I do have backup propane heaters in case that happens.

I am curious as to whether your solar cover wraps all the way down the sides of your greenhouse, or does it only cover the top of the greenhouse?

Chris,

Why do you want her to turn off the power?

jb

Perhaps Chris meant for me to throw the breaker on my electricity, so that when the power came back on there would not be a surge to all appliances etc. Inside the house, we had already unplugged frig, stove, computer, TV etc. Many of our applicances are on surge protectors anyway but surge protectors are also expensive and we have lost them to surges before. (The joys of living in the country, where power outages are more common!) In the greenhouse, I had unplugged the heater.
I wouldn't have chanced the candles except I was home to constantly check on them and also contained them inside metal watering cans set on the brick floor.

Wolflover- my solar pool cover does wrap all the way over my greenhouse, from groundlevel, up the wall, over the roof and down the other wall to the ground again. The greenhouse is a fairly tall building, with a regular peaked roof, just like a house. The south side of the roof is glass (built from 5 old woodframed, sliding glass doors) and the north side is insulated woodframe with asphalt shingles. I think the cover is 16'x32'. I cut a hole in the cover to accomodate my automatic venting window in the roof. It has made a big difference in the retention of heat in the greenhouse this winter. I wouldn't have been able to keep it above freezing with just candles without that cover.

When we had our ice storm in December and lost power for 4 days we discoved just how much heat a coleman lantern puts out. We had never had it inside before so we never noticed. I'm sure there is a scientific/engineering type equation for calculating all that. We were just about to resort to taking the lantern to the greenhouse when it dawned on my DH to try the camping store for propane bottles to fit my Mr Heater Buddy. They had plenty of them when everyone else was sold out. I think the clear solar pool cover made the difference then too.

Cindy

wyndyacre:

Thanks for starting this post. It really has made me think!

And a great big DUH to myself!

We know of the power outage that you guys had. We were lucky in Hamilton.

I'm always prepared for a power outage with our power backup system. As long as natural gas doesn't stop flowing, then we'd have normal heat in the house.

HOWEVER, I didn't even think about the greenhouse! I'm not prepared at all for that. The only heat source that I would have for that would be the oil lamps like you mentioned (we have several and a pretty good supply of oil). But like you said, I don't think that this would be enough to heat the house without a pool cover.

We do have a Coleman propane stove, which would produce enough heat, but I think I'd need to... GET OUR TANKS FILLED first! LOL ;) I knew that I forgot something. :)

Time for a large propane tank and automatic heater, just in case.

Questions:

- May I ask where you bought your cover from?

- Can you provide some details about it? Or better, is there info on it on the net?

- Is it clear of does it darken the greenhouse when covered?

- May I be so bold as to ask the approx. price?

- How much space does it take up when folded and put away?

Our little GH is one of those hoop type (like you see at Canadian Tire lots in the summer) only smaller.

It's almost 11X11X11, so maybe there's a smaller pool cover that's available.

But if you could let me know where you bought it

I await your input and thanks in advance.

Generator, Generator, Generator, Generator, Generator!
Did I mention generator?

We have a gen, which is what we use to keep the batteries for the backup system charged when there's no sun for the panels.

However, to save on Gasoline, it's just a small Honda which doesn't have enough UMMMFFF! to power an electric heater.

Did I mention Kerosine heater? LOL ;)
or propane... OR BOTH! ;)

Bigger generator....?
Not sure what's the difference in saving on gasoline or burning propane or kerosene?
No power = no fans. Sorry not trying to hijack.
Most folks seem to figure out to late "what happens when".

Using an electrical generator to power an electrical heater sounds very wasteful. You'd be better off running the generator in the greenhouse on idle :) (If you need electricity anyway to operate fans, this might be an effective way to heat your greenhouse - put the genny in the greenhouse with a long metal exhaust pipe running the length of the greenhouse to extract heat. Mum and dad's wood stove has an inner and outer pipe and the smoke goes up the inner and the cold outside air comes down the outer so when it gets into the room it's already hot. I bet you could arrange something like that for the genny.

petrol generators are something like 20% efficient at converting petrol energy to electrical energy (it's impossible to make them much better than 40%) - the rest of the energy gets turned into heat, just like in a propane burner, so you may as well use it :)

While on the subject of cost of heating when the power is out. How about this since you seldom are without power you will never spend as much on propane or kerosene as what the generator would cost.
If not properly maintained and run on a regular basis the generator won't start when you need it. I have a kerosene heater that has sit for years and when I needed it I just lit it and it worked. Cheap to buy no maintenance and always works and don't make all that noise while operating.

Blondboy- to answer your questions....I bought my pool cover at Americasbestpoolsupply.com
Cactusfreak of this forum reccommended this site to us all and I know there are a bunch of people here that have also bought these covers.
The cover is clear....the company originally called these covers MagniClear but now they are called UltraTherm. My 16'x32' cover cost $59.95 American with about 15.00 for shipping. Because I live so close to the border (near Sarnia) I was able to have it shipped to a friends' in Michigan and pick it up there. Customs didn't charge me any duty when crossing back.
If you put Solar Pool Cover in the Search box you'll get 74 matches! where we've discussed these covers, methods used to attach them etc. all of which were extremely helpful to me. In the one titled 'Solar Pool Cover Makes a Great Sail', I have a description of my greenhouse and how I attached the cover to it.
The cover comes nicely rolled in a reuseable bag for storage. Rolled up, it was about 4'tall x 3'wide and weighed about 70 lbs.
An interesting sidenote....a couple people on the Forum asked America Best Pool Supply where the cover came from originally and got the reply that it was made or came from Canada somewhere. Search for the thread titled 'Bubble Wrap Supplier in Canada'.
Dokutaagurin was researching this address with the possiblity the cover came from there-
Cantar/Polyair Canada Ltd.
330 Humberline Dr.
Etobicoke, Ontario
M9W 1R5

Here is a link that might be useful: Americas Best Pool Supply

We Lost Power A month Ago.No Problem-My Propane Heater Kept It Warm An Toasty In the Greenhouse.No electricity required.I use My Generator For the House!

Please do not get me started on the subject of cogeneration.

If I could get my hands on a small diesel engine then my greenhouse would turn into everything I ever want. However do not worry, I will not be boring everyone with long discussions and pictures as a small diesel engine in Iowa is about as much use as an ashtray on a motorbike so they are not many around here.

But when I find one, watch out!!!!!

I was floating around the big box hardware store this arvo and they have 750W GMC petrol gennies for $98 (about $50 US). I'm pondering using one to heat the house and cogenerate power. Nick Pine mentions that to sync power into the grid you just wire the genny, mains and 2 light bulbs in series. I think his idea is half right (it gets the genny in sync): the genny may no be able to generate a high enough voltage to push a significant amount back, but I think with the addition of a small transformer wired as a booster it may just work.

Then I'll get electricity for free whilst heating my house and greenhouse.

A 750W generator will make about 3kW (10000 btu/hr) of heat.

A 750W generator will make about 3kW (10000 btu/hr) of heat.
Please explain how you plan to get three thousand watts from a 750 watt generator.

wyndyacre,
I'm still trying to figure out how you got your solar cover for so cheap. :) I paid $149.95 for mine, plus around $50 shipping for a 20 X 40' cover. How long ago did you buy yours? Perhaps they had a big price increase before I bought mine shortly before Christmas. If I could get one at the price you paid, I'd order another one. Mine barely covers the top of my greenhouse and I would love to have the sides covered too. :)

Here is a link that might be useful: The cover I bought

Wolflover-I bought mine just before Xmas too. I actually couldn't remember exactly how much I paid so I looked up the website and a 16x32 UltraTherm IG Cover was listed as $59.95. I think I may have paid a little more than that but I also had to consider conversion from American to Canadian dollars. The covers were called MagniClear when I bought one. I'm pretty sure I only paid around 15.00 in shipping. In Canadian dollars it all worked out to be around 100-120.00 dollars, if I stretch my memory. I didn't save the receipt.
My cover was somewhat smaller than yours so that may account for some of the price and shipping difference.
BTW-I checked out your website and pictures of your wolves, horses, garden etc. Very nice! A Palomino/half Arab horse once owned me :) We were together for 22 years when she passed away at age 34.
Loved your garden too...did you grow the Red Abyssinian Ensete from seed? I have been growing the green ensetes from seed for the last couple of years. I have quite a few now but have to bring them in for the winter. I experimented this year with leaving one outside and will see whether it made it in the spring. We've had a pretty mild winter so one can hope. I would love to grow the red ones but have never seen seed for it around here. I looked for banana seed last winter in Florida but when I asked for it, was looked at like I was crazy. They all just get them from the pups down there and I couldn't bring back live plant material. :(
You should have a picture of your greenhouse too on your site-I'd love to see it.

gardenerwantabe,

Most of the energy you put into a generator as fuel is wasted as heat. The engine itself needs cooling and a lot of heat goes out the exhaust. Now, if you put the generator inside the greenhouse and recovered the heat from the exhaust gasses not only are you generating your 750 watts you are getting a 3kw heater as well.

A water cooled Lister type single cylinder diesel engine is perfect in this application. And, as a bonus this type of engine can run quite happily on straight waste veggie oil. No need to convert it to biodiesel.

Anyway that is how a 750w generater can be a 3kw heater.

gardenerwantabe: as chris said, practical heat engines in general produce more heat than mechanical energy, a small petrol generator is about 20% efficient, producing 80% heat.

750W * 80%/20% = 3kW

But even better, if you can run a heat pump off the generator you can probably get another 2kW of heat, giving a total of 5kW heat from 3kW of fossil energy. (i.e. nearly 20 btu/hr)

I can buy a 1HP generator for $100, a 1HP heat pump for $300 and suitable bits and pieces for another $100. So for $500 I can produce heat from fossil fuel at 160% efficiency (and have reliable power). That compares well with a cheap vented lpg heater at about $250 and 80% efficiency.

(of course it will be a little less reliable than the heater, with all those moving parts and whatnot)

Hi blondeboy47,
Further to wyndyacre's post above, I also came across this manufacturer of various covers
http://www.hinspergers.com/
645 Needham Lane
Mississauga, Ontario
L5A 1T9 Canada
Since you live next door in Hamilton, perhaps you might have better luck trying to find a clear solar pool cover in Canada than I have had. I did send them an email the other day, but they have yet to respond. Any information you can find out would be greatly appreciated.
Jeff, who lives in an area where an inground pool is VERY RARE (as in a town of 27,000 with only a single homeowner has an inground pool)(LOL)

Wyndyacres,
Thanks for your kind comments. The Arabians are much like owning large dogs. They are so curious and affectionate. I haven't added any pictures since I built my greenhouse, and I really should. I've doubled the size of the front tropical bed, so it's a lot nicer now. I have a very obsessive personality, so I tend to overdo things I love. :) I really get into tropical plants, which lead to building the greenhouse to store them in.

I don't believe you can grow the red Ensete 'Maurelii' from seed. I think you'll have to buy a live plant. I got my first 'Maurelii' at Wal*Mart for $11. I loved it so much I've bought two more at local nurseries. I see them for sale on eBay a lot too. Maybe you can persuade a local nursery to order you some (they're too nice to just have one). I also grow Ensete 'Glaucum', the Snow Banana, and Ensete ventricosum 'Red Stripe, which I love... The one banana left on my Wish List is Ensete 'Superbum'. If you don't have that one, I think you'd love it, and the seeds are readily available. I overwinter all my bananas dormant in my cellar because there's no room for them in the greenhouse.

Thanks for the info on the solar cover. I would really like to buy at least one more, or hopefully two. Our electric company had a rate increase last month of .03 per kilowatt, which doubled my electric bill. I had been thinking electricity was cheaper to heat with than propane (paying 1.90 a gallon here), but now I'm having to rethink that. Both ways are OUTRAGEOUS. I suppose a wood burning stove may be in my future. :)

Here is a link that might be useful: Ensete 'Superbum'

Thanks wyndyacre. From the description on that website, it looks like these "solar blankets" are just large bubblewrap sheets.

I wish I would have found those before. It sure would make the fall hoop house set up party easier! LOL

However, dokutaaguriin posted a site for a place very near to me, so I'll call them today and see if they have anything similar.

But now that I know that it's basically bubblewrap, I'm not sure that putting those blankets on would actually help. I think that it may actually stop some of the heat entering the GH.

I say that because, like I had mentioned in a prev. post, our first year,we had 3 layers of bubblewrap. Then, the 2nd year, we tried 5 layers, for better insulation. But this actually stopped too much sun from entering and it was actually harder to heat the greenhouse and therefore, more expensive. Not enough heat entered during the day to heat up the ground, water barrels and pond.

This year we went back to 3 layers and added more insulation to the ends of the GH. This has made a huge difference.

But I'll give them a call, because it certainly would help on those very cold nights when temps could hit -18C (which thank god, we haven't had this year! WOO HOO!) ;) :D

As for the generator..... HUMPH! I consider myself pretty much up on energy saving and up on ideas of how to recoup energy.

But GEEZE! I didn't even consider augmenting the exhast on the gen to recoup heat!

Thanks for the idea, because this now opens up a few other ideas. Like, putting a gen in the greenhouse that has auto on feature. Perhaps I could design something where, when the power goes out, the gen comes on, provides power to the fans (but not the heaters) and routes the power into the battery bank.

Then, design some kind of water heat exchanger that would cirulate water through it to capture the output heat and put it into either the barrels or the pond.... nice warm fishies! LOL ;)

Ok, just kidding to a point. But perhaps a heat exchanger that directs some of the heat to the barrels and out into the air or into the ground. I'm sure more ideas will surface now that I've received this kickstart. :)

Thanks gang!

Or you could just get an unvented propane heater at 30000 thousand btu with a thermostat and pilot for $160, some gas pipe and a regulator for $50, and a 100lb tank and fill for $137 and heat your greenhouse for a month without doing any manual labor. This will recover 93K BTU per gallon of propane instead of 20% of 125K BTU per gallon (for a gasoline generator and heater).

dokutaaguriin

THANKS!!!!!!!

I called Hinspergers Poly and all I can say, is WHERE WAS THIS INFO 3 YEARS AGO!!!???? :)p

After all my labors with bubblewrap, here they can sell me the following:

12' X 24', 11 Mil, with a bag so that if folds.rolls up into a 4' by 1.5' roll!

for only $55 CAN$!!!

I was also informed by "Lee" that there is always someone there on a Saturday so pickup can be arranged!

Sure, it's more expensive that the 250' rolls of bubblewrap, but a lot easier to work with.

So, I'll be ordering this for next year for sure.

Boy leave for a few days and look what happens. You have to remember to put it in perspective. I realize most of you all have small hobby houses and that's were your perspective comes from. We have about 20k worth of stock in one house that's our perspective.

I love the chat back and forth about how you can save 20% here and be 80% more efficient there. It makes for good discussion and makes folks think about the environment ect.

That said. If we lose our power right now, tonight. My assumption is not going to be "we just have to make it through the night" (although that is true) Our assumption is what are we going to do to make it till the power comes on. Will it be an hour or a week? We can't wipe out a crop with bad judgment. We must be prepared for the long hall. If that means running the generator for a week then we'll do it and not even blink at the fuel cost.

BTW we did lose the cap the fan on our largest heater the other night. (dang thing seem to break every February and always late at night) The kerosene heaters proved their worth again.

It just depends on how much your plants are worth to you, not how much is it going to cost to save them. Maybe I should think about every ones perspective before I speak, who knows.

cottagefarmer: 30000 thousand btu[/hr] = 8MW. That's a mighty big burner. I think you might mean 30k btu/hour? Anyway, nitpicks aside, if you need a generator running anyway (for fans, lights, computers, house whatever), and you need heat, why not use the generator heat output? Having one less device running sounds like a good plan (particularly if you still have that backup heater ready to run).

mylu, I understand where you are coming from, but the point was not saving 80%, but rather, getting 5 times as much energy from a given amount of fuel (or 10 times using a heat pump).

Furthermore, using the generator heat in a power failure might mean reducing your heating requirements to 0 over the cost of running the generator.

Running a generator to produce electricity to resistance heat a greenhouse is a massive waste of energy, it would be far better to just burn the petrol. A good way to burn petrol is using a generator :)

Well, I agree with the last sentence! ;) :D (Ok, I'm just evil! LOL )

But seriously, you make a good point about the length of time the power would be out.

Here in our area of the country, we don't have power outages, just a lot of threats that we'll have them unless the Gov. kicks in some $$$ for upgrades to power generation.... a whole different political thread.

The last time we had a power outage where I live, was that massive blackout in Aug 2 years ago.

That being said, it can... no, (reality check) it WILL happen and you make a great point, `be ready'.

While I can't do anything right now, I should be able to concentrate on something during the summer and get it implemented next fall.

I guess the propane thing will be the best option as it can be automatic. But I wouldn't want one with a pilot light. It'll have to have one of those auto starters.

I don't know if any of them come with anything like our travel trailer had. It was an Electrolux trailer from Germany (imported) and its furnace has the same idea that BBQs have, except, that it ran on D-sized batteries and was automatic. Very cool.

Anyway, good points.

Nathen, You would need one heck of a generator to provide enough heat to replace a 200k heater. (nathen starts doing the math :)

As I said we don't care at 2:00 in the morning when the heater/power goes out how much energy we will waste for the short amount of time the problem exist, it's insignificant.

Last week when we lost our fan the night temp was 15F. The generator will not put out enough heat to save the crop. Although it is an interesting concept.

And knowing me, running a generator at 2:00am inside our g/h, I'd probably die from carbon monoxide being sleeping and all. And I was just throwing numbers out as examples. Not as points.

Hey Blondboy- I have found with just one layer of solar pool cover over my glass greenhouse, the sunlight is barely cut down at all. I have geraniums blooming inside, no internodal stretch, in fact have a succulant I've owned for 5 years flowering profusely for the very first time.
From a base temperature of 50* (from small eclectric heater) the greenhouse warms up to above 85* everyday that we have sun. It would get much warmer but I have an automatic roof vent in the ridgeline (my building is quite tall) Even on cloudy days it will get 60-65* inside. It didn't get that warm on cloudy days last year, without the pool cover and lost its' heat very quickly once the sun started to slide down the western sky. Now that heat is held many hours after dark until the heater finally needs to come on for my setpoint of 50*.
I don't know how many mil the pool covers are but they are quite a heavy gauge, fairly stiff to handle.
One thing I've also done which I neglected to mention in other posts, is to seal around every window with a removable caulking to seal out drafts. This caulking is available at HD. It's clear and sets up very flexible and strips off very easily in the spring. All my windows on the north side and east/west endwalls can be opened in the spring for ventilation, in addition to doors in both endwalls as well. I've put weatherstripping in the doors and rolled up a piece of burlap to act as a draft dodger on the floor.
The only downside of the strippable caulking is that the fumes right after applying it are HORRENDUS! Could get you higher than a kite! :) I caulk everything while the weather is still fairly mild so I can leave the doors open for a couple days to air the place out. Hasn't seemed to hurt any plants.

mylu, yep you'd need a 15kW generator, generating 15kW of electricity and 60kW of heat to match a 200kbtu/hour heater. I agree that this is probably too much electricity for a greenhouse (unless you have lights). But what are you going to use for power in the blackout?

Obviously you vent the exhaust outside. As I mentioned in another post, a simple heat exchanger like used for high efficiency wood heaters would be quite effective.

Are you saying that you don't actually need a 200kbtu/hour heater?

Blondboy - I'll second everything Wyndyacre said in her last post above; I get the same kind of temps. Pool cover does seem to lessen slightly the daytime rise in temp, but that is definitely outweighed by the better heat retention at night. There doesn't seem to be any adverse effect on plants - last summer's annuals were to be the "guinea pigs" for this experiment and they're growing and blooming better than they did outside! The 6 geraniums just had 4 to 6 full flower heads apiece, with more on the way; petunias and bacopa blooming away. Cherry tomato (also from last summer) is still producing, the herbs are full, and lettuce and pea seedlings are coming along nicely. I don't use any supplemental light.
Diane

We do have and use a 200k heater. Probably could have gone 250. As long as the outside temp doesn't go to 20F below we're gtg.
We use a generator for power outages, kerosene for heater malfunctions, Grace of god for no large hail storms! And I really have a distaste for winter. 34 days till spring and counting!

Wyndyacre, agardenstateof_mind.

Unfortunatately, some of those things don't apply to our GH since it's a hoop house covered with the 2layers poly with bubblewrap inside.

If we had the glass thing going on, then yes, I'd agree that 1 layer of pool cover would be enough. But in our case, I think that while the dual layer poly is a neat idea for quick up/down of the GH, all that plastic does reduce the light more than you guys are seeing.

Unfortunately, with our yard's size/shape, which is like 25' wide X 60' long in the backyard where the GH is. Therefore, the hoopy is the only way we can go as we don't want a permanent GH in that restricted area.

We disassemble 95% of it in the spring to leave the yard open.

If we ever do decide to demolish this garage extention thing that we've got going on, then I would consider what you've suggested since it would be the best way to go for sure. But, $$$ talks and right now, it's using a low voice! LOL :)

Absolutely blondboy-you have a different setup to work with than I since the double layer of poly already cuts down on more light than glass, even before you add bubblewrap or a pool cover for insulation.

BTW-if you ever do decide to build a different greenhouse onto your garage and get rid of the hoophouse perhaps we could talk about my buying it from you. I just need the hoops to build a shade house and I have the perfect spot to put one that is 11x11 :) And I'm only a couple hours drive from you.
I have a huge perennial plant sale every spring, starting small divisions in my greenhouse and then have to kick everything outside for a couple months until the sale. A shade house would really cut down on wind damage and the need to water a couple thousand plants so much.