RyanLo, I have 2 natural gas Southern Burner vented furnaces. The thermostats run off the gas. My backup is an electric heater. In the past I have experienced a freeze when my pilots on both furnaces shut down as they blew out from a downdraft when the furnace came on at the same time the the exhaust fan came on , on very cold days (below 0ðF). It is a kind of freak event, but it happened a few times and if I am not nearby and am unaware it was disaster. It took me a while to figure out why the auto gas shut-off kept tripping. Now I make sure the vents and fan are set high enough so they don't come on when it is very cold out. I also now have an alarm system that calls my cellphone (Freeze Alarm or Freeze Alert) to alert me to power outages, temperature drops, or too high temperatures during the summer. I can also call in and find out the temperature, the backup battery state, and check that the system is working. It is run off my land line house phone. I think they may have one that is wireless now, but you would have to have a wireless provider; maybe can run off wifi now, I haven't checked. If I remember I think the device cost $269 a few years ago. It is worth every penny spent as it has saved me from freezes several times. During cold spells something always can go wrong, especially in a greenhouse with the damp conditions that wear out equipment and electronic/digital devices constantly. I bought the slightly more advanced device that was available at the time. It was a lot cheaper than the SensaPhone. It is very easy to use and hook up. I also have a basic remote device that has an alarm and I can monitor the temperature and humidity from my house. I find that when it is really cold that device doesn't function properly. My greenhouse is stand alone and about 40ft from my house. I have a Sunglo Greenhouse that has a corrugated acrylic inner pane which serves as an air trap that provides an insulation buffer between the flat outer pane. It works pretty well. I have always bubble wrapped the vents and doors but this year I also bubble wrapped the whole interior to provide even more insulation to see if I can save even more heat. If you read on the "Bugs" series of postings, several people also cover their greenhouses with solar pool covers and even add blankets on very cold nights to conserve energy. Some use propane heaters for backup to their electric heaters. Join us there for other greenhouse growing ideas and interesting discussions.

Cory

I've thought about this, since where I live last year (before I bought my Meyer lemon tree) the power went out in January during temps in the -20's. My parents are getting a generator this winter so if the power goes out for any more than two hours I'm going to take my tree to their place, they'll have heat whereas I won't.

The simplest solution to insure your greenhouse receives heat during a power outage is to purchase a generator. -S-

I will use a generator...But I live in the city and might be a bit relaxed about it since I have never lost it before..

What my worry is is knowing when I did loose it even for a second while at work or when I am not home..

Who's going to reset my heaters, or how will I get home to check in on things if no one is there?
I wish they had some kind of alert device that would notify me when temps drop below my desired level settings or when the power goes out..I could use an alert even if I should loose it while sleeping...That is a HUGE concern for me.

If worst cane to worst and I didn't have a generator if the power should go out for just a short while, I would use my propane heater. If longer that an hour or two, then I would bring them in and hope they don't freeze from the greenhouse to my home...Sheesh..It is a thought I keep pushing to the back of my mind Ryan.

MIke

Although I have gas heat in my house, it is hot air heat and the blower is run by electricity. My greenhouse is more likely to be my backup for all my house plants, but even with the extra gas furnace and a backup electric heater I did have to deal with a freeze several times in the 15 years I have had the greenhouse. I have gone through several power outages lasting several days and as much as two weeks the past few years after never having any before that for 50 years. We have installed a small emergency ventless gas heater in our living room fireplace which helps a little bit and I boil large pots of water on my gas kitchen range which does not have an electric ignition. Even if you have an electric ignition you can still light it the old fashion way, but make sure you have matches or a lighter in your house. Close your blinds and shades and pull across your draperies to hold in heat. It got cold but the pipes did not freeze and the houseplants survived. I think I may have covered some of them with blankets and bubble wrap and newspapers. You really should have a plan. I have lost all the plants in my greenhouse when it was new thinking I was safe with 2 separate natural gas furnaces. Never dreamed both would go out at once. Got the alarm after that, but on really cold nights if you are far away, the temperature drops very quickly so you should have someone close by to help start up a backup system if you can. Remember to give them a key if your greenhouse is locked. Try to find heaters and fans that will start up again automatically when the electric power comes back on. The ones that operate with a remote device will not come back on automatically.

Mike, look into the Freeze Alarm or Freeze Alert brand on the internet. I can't remember which I have. Mine will call up to 3 phone numbers to alert you the temperature has gotten below a set temperature you choose. You can call in to find the temperature inside, reset the alarm temperature. One even allows you to turn on your heater remotely. Mine doesn't have that feature. It cost about $269 I think when I bought mine and it is worth every penny and you will just have to run a phone line from your house to the greenhouse. Very simple. It even will work around your answering machine. If you don't have a land line, I think they might have a wireless option now. There are also more advanced but more expensive systems that you can connect to your computer to track the temperature and humidity levels.

I am surprised more people have not responded to this thread as a plan is very important.

Cory

I am currently installing an insulation blanket over the top of my GH. I am hoping it fluffs out to 3 inches. See pic below.

I have not had a power outage in 50.5 years. 4 years ago Cincinnati was hit by a category 1 hurricane. houses disintegrated, trees came down Interstates where close when structures and shopping malls flew across the travel lanes. Downtown Cincinnati and my hollow were the only places that maintained power as over 95 % of the 2 million area population when dark. 4-3-1974 an F-5 tornado removed all the power lines within 2 miles of my place. fortunately my parents had to pay for the damages. I was spared.

My system is set up to be OK unless we get a winter like 1977. We had many days below negative 20F and almost every day in January was below 0F. Global warming will prevent that from happening again in my lifetime.

My greenhouse is made of glass and wood all of which I pulled out of construction dumpsters. I have enough glass for a 500 square foot surface with 4 layers of glass. This will give me a 37 foot by 15 foot tall lean-to green house at 8 feet wide against the south side of my house up from the roof of my garage.

The outside layer of glass is hermetically sealed. The 3 inside glazes breath some. The inside is kept humid. When the surface get cold the vapor in the air condenses and give the heat of fusion to the inside air. This keeps the inside warm. When the out side gets below freezing the vapor must condense first (520 cal./gram H2O) then must freeze which releases another 80 cal. per gram h2o to the in side air thus keeping it warm inside. The outer glass surface is locked at 32 F until all the moisture on its surface is ice. The next layer of glass must go through the same, then the third layer must succumb to this solid ice frosty state, The frosty state of moisture on the glass will greatly decrease the amount of heat that can slip through. This alone probable guaranties my safety to 10 F for many days in a row.

I heat the growing medium with the heat that peculates through (R-5) south basement wall While the other 3 basement wall have a value of R-150 Minimum and loose near 0 heat. I heat the basement to about 75 F. There are no ducts to heat any where else in the house. With living area walls at R-40 they loose heat slowly enough to stay warm with the heat in the basement just bleeding up though floor. The warm basement wall keeps the greenhouse soil at 60 F min. My annual natural gas heating bill is under $200 .

If the temperatures drop below 0 F I will have to place out buckets of warm water to supply the needed humidity to power the vapor to ice phase change heating system.

Next year I will be running my furnace exhaust pipe under the ground to help heat my soil. Colder outside, furnace runs more, and soil temperature says above 60F.

Steve