Kerosene/Propane vs Electricity

[Leisesturm]

Greetings and Salutations. I have set up a small plastic greenhouse that is 9'W x 4'D x 8.5'H (peaked). Summer temps in Oregon are crazy this year. Just crazy. I have been using a standard electric (oil filled) space heater all night and right up till noon to keep the temp at 70F. Then when the sun hits it, even though I have it shaded to a fare thee well, the temperature shoots up past 100F in less than two hours, even with both doors and the large vent opened. Ugh. I have a large oscillating fan running 24/7. I have no idea what this is costing me but it has only been in operation for the last 2 weeks.

But I am concerned about the coming winter. I plan to insulate the entire structure with ??? It won't need to be transparent. I can't use the summer sunlight, and there is no winter sunlight, so I have LED lights for plant growth. They are currently following the sunrise/sunset times for my latitude.

What I am reading says that Kerosene and Propane heaters are cheap to buy and cheap to run compared to electric heaters. The space heater I have, cost about $100. I have had it for years but it had never been opened. I am using the 600W setting for now. It has 900W and 1500W available. A KWH is $0.11. So ...

I know much less about Kerosene heaters but I saw one today for $159 (23K BTU). I have priced Kerosene at $95/5G. There doesn't seem to be anyway to put either Kerosene or Propane heaters on a thermostat, they either run or they don't. The electric space heater would not need to run when it isn't needed.

Is it practical to consider keeping a night temp around 65+F night, to 80F day, all winter long in Portland, OR using artificial heat? And which really is cheaper? The gas heater uses 2G in 12 hours. I don't know if that is cheap or not, but it sure looks like LOT of Kerosene to buy and store to keep it going! Thanks for any insights.

[Ray]

Orchid-growing is not a cheap hobby, but heating can be expensive - it cost me $400/month x 12 (budget payments) to heat my greenhouse in PA. I cannot imagine what it would be now with petroleum prices what they are.

Any heater burning a fuel will dump fumes into the enclosure, unless it is fully vented; I used a separated combustion propane heater specifically to avoid that, and only used an unvented space heater as an emergency backup.

Personally, I think you might do better off growing the plants indoors.

[Roberta]

Another note about GH heating in general... it's the difference between the outdoor temperature and what you're trying to maintain that determines how much heat you need for a given space. Here's a nifty little calculator to help you evaluate what you'd need:
Greenhouse Heater Size Calculator from ACF Greenhouses
You'll probably find that the 110 V electric heater is adequate on the coldest days/nights - to get above about 1500 watts, you need to go to a 220 v. heater. (Your electricity is a lot cheaper than mine...)

Ray is spot-on with regard to venting... even a small amount of combustion fumes can kill your entire collection quickly. For a small collection, I'd agree that "in the house" is the better winter solution where you live.

[Orchid Whisperer]

I agree with Ray on trying to grow indoors, it may be cheaper than your mini greenhouse. You can try your electric space heater, see what your change in heating bill costs you. You do have to consider, what do you do if the power fails, can you move your plants indoors quickly enough? I agree, avoid kerosene heaters, less because the fumes could be plant-toxic, I would be more concerned that a build-up could be "Leisesturm-toxic!!".

Orchid growing can be a relatively inexpensive hobby, if you can set expectations and limits for yourself, and know what you want to accomplish. I have an indoor 3-shelf plant stand with daylight spectrum old-fashioned fluorescent lights. I have limited myself to less than 100 plants, and focus on things I can grow with my lights during the winter, and outdoors under partial shade during the summer. I rarely buy plants these days, focusing on blooming what I have and dividing and sharing what I have with friends that grow orchids.

An indoor light setup generates heat. This is not too big a problem in the winter, and my electric bill barely budges because of my plants. Any month that your heat kicks on, I suspect you will save money just running lights indoors as compared to paying greenhouse heating bills.

Your specific conditions will dictate if indoor/outdoor growing is something you can do.

[Roberta]

If you want a backup/booster for the electric heater, I have used MH9BX Portable Buddy(R) Heater | Mr. Heater(R) (with an external propane tank, connector is extra purchase) ... it is rated for indoor use with the small cylinder, so I think pretty safe from a fume point of view. (But the bigger tank needs to live outside, potential problem if it is very cold) The first year I had my GH we had an extraordinarily cold winter, and my electric heater could not keep up, I used this to maintain temps. Then I got a proper (direct vent) heater with adequate capacity so have not had to use it lately.