Green House covering - Page 3

RinTinTin · January 6, 2011

It will depend on how big your greenhouse is, and how draft-free you can make it. To save money on electricity, you could tarp off sections you will not be storing plants in. Why try to heat 200 sq ft if your plants are only occupying 50 sq ft?

With your 8' x 8', it should not need too big of a heater.

snappybob · January 6, 2011

You're right I could petition it off if needed to save on energy but this is a test to see how it will do under normal circumstances. I'll be heating about 64 sq ft and roughly 350 cu ft.

alamo5000 · January 6, 2011

Quote:

Originally Posted by snappybob

We are supposed to have a few days of lows in the mid 20's here next week. This would be a great time to gain some knowledge on heating the greenhouse. I plan to buy a heater this weekend and some tarps to close up the ends. I'm going to get an electric heater with a fan. How big of a heater do you guys think I will need to keep it above freezing enough to have my tomato plants in there at mid 20's? I'm not going to put them in there this weekend but I want to see what would happen if I did. I don't want to risk some calamity like popping a circuit breaker in the middle of the night. This will be a test run.

Snappy...

If you go to Lowes they sell a yellow stanley fan forced 1500 watt heater.

That will be more than sufficient for your purposes.

My greenhouse is partitioned off to dimensions about 12 feet by 15 feet approximately.

In a greenhouse that size with one of those yellow fan forced heaters on a 24 degree day my inside the greenhouse temp was 42 degrees.

With a much smaller space your temps will easily be higher on cold nights.

I have a policy... 40 to 45 degrees and under on the forecast and my heater is on.

With one of those heaters any wall socket can give ample electricity without fear of tripping the breaker. If you use an extension cord though make sure it is rated AT LEAST for 12.5 amps and up.

snappybob · January 6, 2011

Thanks, that's just the kind of info I was looking for.

ireilly · January 6, 2011

The larger the wire diameter, the less the voltage drop per foot will be, and thus the amperage draw will be correspondingly lower (V * A = Volt-Amperes, VA roughly the same as Watts except when considering motors).

So.... if you have any appreciable distance to go, you are better spending more on a heavier extension cord. More peace of mind, and it "builds strong muscles 12 ways" every time you have to haul all that copper out or coil it all back up.

alamo5000 · January 6, 2011

Just get yourself a 14 gauge extention cord and you will be fine. 100 foot or less and you will be fine as long as the end use heater is 1500 watts or less.

Just read the box.

David Marek · January 6, 2011

I use two 1500 w fan heaters hooked up to high voltage thermostats* on separate breakers. They can keep the 8x12 double poly house at 60 no problem down to about 10 degrees outside.

When I used the heater's built in thermostat, I had to turn it up a bit higher than I thought would be necessary at early evening- it would run and cycle, but it would be cold by morning.

*High voltage= less wiring for me to mess with. I spent more on the thermostats than I did on the heaters- heater, $18 each; standard thermostat, $26; programmable thermostat, $50.

It costs about $2 + or - $.50 a day in the dead of winter.

snappybob · January 7, 2011

I wasn't able to get the Stanley heater that I wanted. All they had was an off brand 1500W forced are heater for about $20. If I can find a Stanley I might get it also and see whichone works better. The Stanley has a 3 year warranty. As far as extension cords go I don't have far to go. Maybe 30 ft.

alamo5000 · January 7, 2011

Sears also sells those stanley heaters. I compared a bunch and that one was the best one I could locate.

There is a reason one is $20 and one is $55.

snappybob · January 7, 2011

I found a Stanley at another Lowes and bought it online. I just have to go and pick it up. Did I understand correctly that you (Alamo5000) have personal experience with this heater? I'm going to inspect and try both of them out side by side and then take one back.

alamo5000 · January 7, 2011

Quote:

Originally Posted by snappybob

I found a Stanley at another Lowes and bought it online. I just have to go and pick it up. Did I understand correctly that you (Alamo5000) have personal experience with this heater? I'm going to inspect and try both of them out side by side and then take one back.

Thats the one I use in my greenhouse. If you can find better ones I am all ears. From my search though that one works great.

snappybob · January 9, 2011

Well, the big thunder storms turned out to be thunder showers....so far and the big artic winter event with 'mid 20's looks like it will be mid 30's but test conditions are free so I'll take it.

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January 6, 2011	#31
RinTinTin Tomatovillian™ Join Date: Aug 2010 Location: Seattle Posts: 581	It will depend on how big your greenhouse is, and how draft-free you can make it. To save money on electricity, you could tarp off sections you will not be storing plants in. Why try to heat 200 sq ft if your plants are only occupying 50 sq ft? With your 8' x 8', it should not need too big of a heater.

January 6, 2011	#32
snappybob SETTFest™ Coordinator Join Date: Mar 2006 Location: San Antonio, Texas Posts: 214	You're right I could petition it off if needed to save on energy but this is a test to see how it will do under normal circumstances. I'll be heating about 64 sq ft and roughly 350 cu ft.

January 6, 2011	#35
ireilly Tomatovillian™ Join Date: May 2010 Location: Dallas Posts: 344	The larger the wire diameter, the less the voltage drop per foot will be, and thus the amperage draw will be correspondingly lower (V * A = Volt-Amperes, VA roughly the same as Watts except when considering motors). So.... if you have any appreciable distance to go, you are better spending more on a heavier extension cord. More peace of mind, and it "builds strong muscles 12 ways" every time you have to haul all that copper out or coil it all back up.

January 6, 2011	#36
alamo5000 Tomatovillian™ Join Date: Nov 2010 Location: near Houston Texas, zone 8b/9a Posts: 114	Just get yourself a 14 gauge extention cord and you will be fine. 100 foot or less and you will be fine as long as the end use heater is 1500 watts or less. Just read the box.

January 6, 2011	#37
David Marek Tomatovillian™ Join Date: Jan 2010 Location: St Charles, IL zone 5a Posts: 142	I use two 1500 w fan heaters hooked up to high voltage thermostats* on separate breakers. They can keep the 8x12 double poly house at 60 no problem down to about 10 degrees outside. When I used the heater's built in thermostat, I had to turn it up a bit higher than I thought would be necessary at early evening- it would run and cycle, but it would be cold by morning. *High voltage= less wiring for me to mess with. I spent more on the thermostats than I did on the heaters- heater, $18 each; standard thermostat, $26; programmable thermostat, $50. It costs about $2 + or - $.50 a day in the dead of winter.

January 7, 2011	#38
snappybob SETTFest™ Coordinator Join Date: Mar 2006 Location: San Antonio, Texas Posts: 214	I wasn't able to get the Stanley heater that I wanted. All they had was an off brand 1500W forced are heater for about $20. If I can find a Stanley I might get it also and see whichone works better. The Stanley has a 3 year warranty. As far as extension cords go I don't have far to go. Maybe 30 ft.

January 9, 2011	#42
snappybob SETTFest™ Coordinator Join Date: Mar 2006 Location: San Antonio, Texas Posts: 214	Well, the big thunder storms turned out to be thunder showers....so far and the big artic winter event with 'mid 20's looks like it will be mid 30's but test conditions are free so I'll take it.