How do I pick a heater for my greenhouse?
Printer-friendly versionIf I wanted to heat an 8' x 12' Easy Grow greenhouse, what would be my best heating option?
Thanks for the info on the plug-in thermostat.
I have a heater similar to the one you suggested, but it has a freeze-proof setting at the low end of a graduated temperature dial. Any idea how accurate something like this might be, or should I invest in a plug-in thermostat as well?
Also, I'm currently using a heavy-duty outdoor extension cord to run power from the house (outside weather-shielded outlet) to my new greenhouse. Will the plug-in thermostat work with the extension cord, or does it have to be plugged directly into the wall outlet?
Thanks in advance.
Jay
Falls Church, Virginia
The no-freeze thermostat will probably do a good enough job not allowing the temp to drop below freezing, but as far as being able to control accurately, to the degree, you'll probably need the plug-in thermostat. With that you can plug the heater into it and turn it all the way up, then set the temp on the thermostat and not have to worry about it.
As for plugging it into an extension cord, that should not be a problem. The only way it could potentially pose a problem would be if it is very long extension cord or several cords put together. The voltage drop over long runs can cause some devices not to work, but if you keep it under 50' it should be OK.
So these heaters have no problems operating in a humid enclosure? (That is, could I run a humidifier with the heater in a 8 x 10 gh?)
Thanks,
Michael
Our small electric utility heater will operate and function in a humid environment. We do not recommend there be any direct spray on the heater(electric), but humidity will not adversly affect the heater. It also helps to put the heater on a bench, or elevated off the ground some.
We purchased this unit for out greenhouse. http://www.greenhousemegastore.com/prod ... ber=HT-RCH We haven't quite finished the greenhouse yet so it will probably be later this winter before we find out how well it works for us, however.
Ken in Glassboro, NJ
Unless you have a much better built-in thermostat than most heaters I would recommend the plug in thermostat discussed in an earlier post. The "thermostat" on most of the heaters are not accurate at all. It's discouraging to walk in the greenhouse when the sun has come out and find the temp up high enough to run the cooling exhaust fan and at the same time your heater is cooking away. The plug in themostat I got here is accurate to within a couple of degrees. It installs easily (just plug it in and plug the heater into the piggy-back plug). It should work fine with an extension cord, but does require a three wire grounded plug.
I am in a zone where outside temperatures in winter rarely get below 30 or so, and I have a heat sink in the gh (black water barrels, bricks, etc.) and only the south sloping face has glazing (fiberglass) with the rest being 2x6 insullated construction. It is 12x10. After monitoring the night time temperatures in the gh and outside for a while, it appears I will not have a frequent need for much additional heating. I have just started using the gh this winter, and monitoring the temperature inside - it appears that the heat sink will keep it about 8-10 degrees warmer than the outside temps at night unless we have several days of little sun in the day time (rare). What I started doing when it recently snowed and I thought temps would drop too much was hook up an electric heater to a timer. Then I set the timer to turn the heater on for an hour about 1 pm and again at 4pm. I can also adjust the thermostat on the heater but this does not appear to be really necessary. It seems to work, and I can adjust the duration the heater runs. This takes more attention than a thermostat control, but it is my short term solution - and works for me as I do not need to add much heat.
Great information from zacman about the difference the passive solar heat sinks make. This is good information for any greenhouser to know!
For small hobby greenhouses like this one, something as simple as this small electric heater will work. It's able to heat an area of about 150 sq. ft. and this greenhouse is only 96 sq. ft. This heater only has a low, medium, or high setting though, so if you want to set it to turn on and off at a certain temperature, then use a plug in thermostat. Just plug it into the wall, plug the heater into the thermostat and you're all set.
Of course, you may need different heating needs than what this heater can give you. This is especially true if you aren't able to provide electricity to your greenhouse. In that case, look at our hobby greenhouse heating solutions page. There are several that can be run on propane, kerosene, etc.
If you need more heating than this, first you should figure out exactly what you BTU requirements are by using our simple calculator. There is also a version of the calculator for garages and other non-greenhouse structures.. With the information you obtain from the calculator, you can size your heater accordingly.