Advice on elec heater for small greenhouse

We have a relatively small dome style gh that we bough from Shelter Systems many years ago. We set it up on our deck each winter and had been using 2 or 3 150 watt bulbs to keep it above freezing when needed (we're zone 7b... not too many prolonged frigid spells).

Lately however I've been wondering whether we should use a small space heater instead of the lights. I've seen some that say anti-tip (sounds useful, although there's no reason why it would tip over once the GH is closed.) Also, I've seen some that say "anti-frost" indicating that they'd only come on when the temp falls below a certain point. But the ones that I've seen say that they'd come on at 45 degrees, while I'd prefer them to not come on unless the temp dips a bit further (38 or 40). I'm not really trying to get anything to grow in the GH. Mostly it's just to keep some plants alive for the winter months.

Any ideas? advice?
thx-
jo

Have your lightbulbs been doing the job and keeping things alive? If so, I see no reason to replace them with something that's going to cost you more money to run--besides the initial up front cost to buy the heater it's going to cost more to run than a couple of lightbulbs so I'd only invest in it if you've been losing plants because the lightbulbs don't keep things warm enough. If you do decide to get a space heater you may be able to get a thermostat to go with it that will let it operate at a different temperature than what it would on its own (most GH supply places will carry thermostats).

Actually the lightbulbs have been doing the job. But I sometimes wonder whether having lights on 24 hours when it's very cold confuses the poor plants. And somebody told me that the newer little spaceheaters might require less power to run than keeping three 150 watt bulbs going. If anyone knows the answer to that one, I'd sure appreciate it. The heaters I've been looking at seem to only cost about $40, so no huge upfront expense.

Nice that you answered - maybe I should just leave well enough alone...

jo

It sounded like you weren't using the lightbulbs on that many nights so I doubt if the light is going to cause you too many problems. And I'm not sure how much it confuses most plants anyway--I have a number of plants on my front porch where they basically get 24 hrs of light between the sun during the day and my porch light that comes on at night and they have been perfectly fine. In terms of energy, it all depends on the wattage of the heater and how long it needs to run in order to keep things at the temperature you need. Your lightbulbs are using 450 watts times how ever many hours you leave them on since they're on constantly...heaters will use more than 450 watts but they won't need to be on constantly. In order to really do a cost comparison you'd need to know how much time the heater would have to run to keep the temperature where you need it. I think if you end up with a heater that comes on anytime it gets below 45 degrees it'll end up costing more than the lightbulbs to run, but if you're willing to spend money for a thermostat as well and set it to come on just barely above freezing then you may come out slightly ahead. However, since it sounded like you don't need the lightbulbs that many nights, I think it's going to take a while for you to make back the cost of the heater + thermostat.

Thanks -- Think I'll just keep with what i'm doing. Most of the plants seem to make it.

I have a 8x10 x10 tunnel style greenhouse in front of my garage,I just use a oil filled radiator heater that has a thermostat control,get them at Walmart for around $40 bucks.
Works great keeps the temps inside to right at 50* when it's zero outside.

I might look into that, Tropicman. Does it cost a lot to use?

Well I'm average billing,so I can't give you a definite answer,but it hasn't raised up much or I've noticed a increase in my bill.
Probably depending on how warm you want to keep it,I have mine set on low now,but as the colder temps get closer to a hard winter mode,I'll increase it up a little to medium.
But the sun comes in a warms it up during the daytime,so it's really not on much then,but more so at night.
Besides you can't get any safer than using one of these.

Thanks, Tropicman. I have one of those radiator heaters and never thought of using it in the greenhouse. My greenhouse is about the size of yours and I'm in the same zone, so it should work out about the same for me. I had an older heater with a thermostat I used a little last spring, but didn't want to have my electric bill sky rocket, so used it sparingly.

Well I think the reason mine works so good,I have a solar plastic cover that they use to cover swimming pools over my greenhouse plastic,and those air bubbles in the plastic create a dead air space ,which helps keep in the heat.
I also have a storm door and another screen door covered with plastic over the storm door for double protection ,it's a real tight greenhouse,I keep a fan going in there so there is no cold spots,it really circulates the air in there real well.
Another thing,is the fuller you keep the greenhouse with plants,or any other objects,the less air you have to heat!
Mine is so packed with plants,I can hardly walk down the middle,it is filled with tall palms and banana plants and big ear plants mostly which take up a lot of room.

LOL my Mom says its cold in Tallapoosa and to me it gets cold there a lot. I just built a new GH and we put a small gas heater in it.
I thought about ceramic heat but a friend said hers ran $80 for the 1st month elec. and her GH is 6 x 8 only and the roof isn't that high.
I would stick with the lights if I were you unless the electric goes out.

Lavina Who is originally from Tallapoosa.

I did a consumer search,ceramic heaters are only good if you stand right in front of them,and do cost a lot more to operate and are less efficient.
This is what I found out about oil filled radiators.
Oil-filled radiators are the most popular type of convection space heater, having established a loyal following over the years. Tests at Which? magazine, the British equivalent of Consumer Reports, find that oil-filled radiators are quiet and economical to use, but less effective than other types. We were surprised to find so many reports of quality control and reliability problems, however, at Amazon.com, Epinions and other review sites. That's why we haven't included an oil-filled space heater as one of ConsumerSearch's Best Reviewed models.

Oil-filled space heaters take a long time to heat up, but then they stay warm for a long time without using much electricity. Natural convection distributes the heat, so there's no fan to make noise. Owners point out that this type of heater works best when it's the only source of heat in a relatively small room; the temperature controls seem to get confused when the room has another source of heat as well. Also, a drafty room or one with poor insulation may just never get warm.

These heaters get hot to the touch on the surface, but a casual touch seldom causes a burn. They're heavy but stable, with castors and handles that make them easy to roll around on a level surface. The oil-filled radiator fins are permanently sealed, so they never need refilling. The main drawback is the time required to start producing significant warmth; they're not recommended for situations where you need either quick heat, directional heat, or warmth for only a short period of time.
I think it all boils down what type of plants you want to grow in your greenhouse
and how much they mean to you,and how much your wanting to pay to keep alive.
If you go to the extremes of insulating your greenhouse,to avoid cold drafts,and make it as air tight as possible,the heat you do create no matter the heat source,will last longer and cost less to heat.
I take my hand and go around the greenhouse and feel for cold air coming in,sometimes I use the stuff in the can and other times I use just foam and squeeze it into the crack to keep the cold air from coming in,spend a few minutes will save a lot in electric bill.

I just built a 6x8 GH and heat it with a Mr. Heater Buddy gas heater. It is connected to a 20lb propane tank. It has worked like a champ. I go out when the GH temp is 34 just before I go to bed and light it. It keeps the GH at the least 45 when the temps are below freezing. At freezing or just above it keeps the GH at 56. I then go out in the A.M. and turn it off. By the time the temp starts to drop inside, the sun is on the GH and heating it up again. Believe it or not, we have had those very cold temps already. Tonight will be the same. I will get approximately 110 hrs per tank of gas. It will cost $25 to refill.

I have a D'Longhi electric oil heater for my sun room when I'm not using my wood burning stove. I love it. It is quiet and heats the 19x 11 room nicely. It has a timer on it so I can set it to come on 2 hrs before we get up and the room is nice and warm. I love that it is quiet.

Good luck with whatever you use to heat your GH.

Guess I should have found this thread first. Purchased a ceramic heater last weekend for the 6X8 GH. Last two nights have been 31-28 degrees. Problem is this is running off the same circuit as the other electric stove which is in the tool shed with lots more tropicals.
If we turn on anything inside the house that is on this circuit, you got it, the power is off. So I have that problem in addition to the fact that Don, advises they don't work that well after all. I looked at the oil heater but the manager at Ace Hardware recommended the ceramic. Sure don't need to add $80 to the power bill.

Christi

Now I wonder why the mgr at Ace recommended a ceramic for the GH. They do pull a lot of electricity. I love my little gas heater. I think my plants do too. I struggled for a long time on how to heat my 6X8 and finally on another thread found someone who used gas heat too. Then I talked to a man who said some of the commercial growers use gas so that is what I settled on.

Good luck Christi on whatever heat source you choose.

Sorry to hear about all that Chrisiti,IMHO those oil filled heaters don't put out a lot of heat but if you have a small 9 inch fan on above them a couple feet they spread the warm air
around the greenhouse pretty good.

I still have the box and receipt. Will be taking this back to Ace.

wise decision Christi.

eden-pure
we have one that the kids are using for the upstairs here in Michigan
but come spring and its mine!!!

I got a gas heater w/thermostat and it was put in the last Friday in Nov. Its working great. I will not have to worry about power outages.

Lavina

I agree, a gas heater is the way to go. Mine will be on tonight for sure. Probably during the day tomorrow too if the sun doesn't show itself.

Didn't show here today,but cold north winds couple inches of snow did!

Hey Tropicman...this year, I did it..I put a pond in the green house...a big watering trough.. It's perfect, has mosquito fish in it...with water plants..and boy..does it keep the greenhouse nicely humid! Thanks for the idea!

looks like we will be using the heat tonight too

Anytime Rj,

The humidity helps keeping the heat up too!
Plus,you don't have to water as much either!
I got some palms coming in the mail,glad they didn't show today,that wind was evil today.
I was eating supper few minutes ago and was looking out the bay window from the dinning room,noticed ice plastered on the window with couple inches of snow on top of that,main how it builds up on the corners of the window pane,Brrr!

Our daughter lives 2 miles from us. Went to her house tonight for chili. All of a sudden we hear sleet on the skylight, then snow. In no time at all our car was covered and it was piling up on the streets and yards. Decided we better get home while we could. Half way between here and there---nothing. It isn't doing anything at all here at my house other than high winds and low temps. That's ok. I worry about all of those that have to get out in the morning and go to work in bad weather.

we're supposed to have sleet/snow mix here as well into the morning hours. But there isn't supposed to be any accumulation. Tommorowshigh is what bothers me, only 46. But there is supposed to be some sun, so the GH will heat up.

Here you all got a New Neighbor in a couple months!!!!
Watch out for all those secret service men,wondering around the neighbor hood!!!!

Oh now I gotta fix a pond. OK
Its gonna be in the mid 70s here tomorrow and everyone is getting a cold/allergys/etc. And they are saying thunder storms tomorrow also. What whacky weather.

Pond huh. Good idea can't wait to tell hubby. hehehehe

Lavina

"He" lived here before he was guvna. Number 2 "he" lived just down the street until the election and because of the constitution ruling #2 took up residence in Wyoming. Verrry pricey neighborhood. Already one of those areas where you are watched if you even drive by. Local news reports a lot of gawkers right now. A brand new 5 bedroom, 5 bath house going up right next door. Speculation it is for the SS men. Wonder what that costs?

Very cold this morning.

It's miserable here this morning...wet and cold. I left a window open in the greenhouse, but everything was fine.
I do love the pond. It fit right in the back of the greenhouse and really doesn't take up much space. I re-arranged shelves so that things fit better. Speaking of lemonade out of lemons Christi, I used the old fence the hurricane blew down to build new shelves.
I have a nice pond pump in the pond, and it helps humidify too. I wonder if we will survive defoliation the next two nights...suppose to be 32F tonight..better check the hourly and fill my deck heater propane tank in case. Usually it's a couple of degrees warmer here than the forecast temps...

We are at 28 right now and the wind is howling. My poor tropicals look so pitiful. I'm already looking to add on the greenhouse for next year. Wonder if I could get my "pond" inside?

Whatever comes your way, RJ, it always seems to better than before when you get through rearranging. Start getting a trip to DeSoto on your calender for the Spring.

It is so dreary today. Going to a Book Review and I love the lady who is the reviewer. She is a one man band.

Aloha,

PK

22* here ,sure glad the wind has settled down to a breeze only,but sun is shining!
Randy,how much to fill a 20lb tank of propane there?
About $16 bucks here now,it has doubled in the last couple years.
Christi,Tax payers,you and I are paying for the building and up keep of that new house!

It's been hovering around 34F here...meanwhile in the nations capital and NY city it's 65F!
We actually have snow showers in the forecast. Tommorrow it's forecasted to 60F ...this is what really messes up the plants is the 20 degree temperature swings...
Yes spring trip in the planning Christi. Ya'll need to plan a trip back here too.

I just exchange my tanks..it's 20 bucks...

Sunshine and a balmy 28* now!!!

We've advanced to 36F

We are 77F here.

Fox news said it lightly snowing In Austin and San Antonio!
Were 31* now,heatwave!

a distant memory..77F...that was yesterday here

The temps have been up and down so much here I am not surprised at any of it. Its 80 here now and by Saturday it will be down to around 37.

oh..so this is headed your way then...it's suppose to get 42F today..but hasn't broken 36F, and it's on it's way back down...70F/61F forecasted for saturday...