Sunday, November 20, 2011

Greenhouse Update - Heating for the Winter

In Texas, we are blessed with short, reasonably warm winters.  Still, cold fronts do come, and temperatures can drop unexpectedly.  Last year’s 17 degree low was one of those little unexpected happenings that most of us probably hope will not be repeated this winter.

It’s hard to imagine cold weather will eventually arrive, when my greenhouse hit 96 degrees today.  The bottom line is that Texas temperatures can get crazy, so it’s important to be prepared with an adequate greenhouse heater.  My ideal heating system is a little beyond my budget at the moment, so this winter I am improvising.

There are 3 things that I consider necessary for heating my greenhouse; a thermostat, a greenhouse heater, and a backup heater. 

My greenhouse is 320 square feet with a high ceiling.  Calculations show that to keep the greenhouse warm under the worst conditions, I need a heater rated at about 23,000 BTU.  I can’t get that much power from a 110v heater.  So, until I can afford a 220v electric line and a super powered heater or two, I’ll be running 2 - 110v heaters and hoping for a mild winter. 

The 2 primary heaters I selected are economical, electric utility heaters designed for use in a greenhouse or workshop.  The heaters will be stationed at opposite ends of the greenhouse pointing inward towards the center.

Each heater will be operated from a separate thermostat.  The thermostat will be set at 45-50 degrees and will automatically turn the heater off and on as necessary. 

In case of an electric outage, I have purchased a propane heater to keep on standby.  This heater attaches to a standard size propane tank and will run about 27 hours on 1 tank.

I can currently view temperature conditions in my greenhouse from a weather station readout in my house.  The weather station sensor, which is located in the greenhouse, shows the current temperature and records the daily minimum and maximum temperatures.  

A weather station is very handy, but the item on my wish list is a greenhouse freeze alarm.  The alarm would alert me in case the heaters stopped working and temperatures dipped into the danger zone.  I hope to have one of these little gems before the really cold temperatures arrive.

1 comment:

  1. I think you have answered a problem that I have been tryng to overcome for 10 years. I have the same heater and find it is OK if you are around to switch it on and off otherwise it will just keep going whatever the temperature. They say to turn the knob until the required temperature is reached and then back it down. It never works. As we travel lot I find I cannot leave it on. So where did you buy the thermostat and what position do you put the knob on the heater at?