Greenhouse - Reducing Heating Costs II

This is the second in a series on reducing heating costs in greenhouses. This post focuses on increasing the efficiency of heating systems.

Efficient Heating Systems

• Installation of floor or under-bench heat will allow air temperature to be set 5º - 10ºF lower.
• Yearly maintenance - Check boiler, burner and backup systems to make sure they are operating at peak efficiency. Have furnaces cleaned and adjusted and an efficiency test run before heating season. A 2% increase in efficiency for a 30' x 150' greenhouse will save about 200 gallons of fuel oil or equivalent in propane.
• Clean heating pipes and other radiation surfaces frequently.
• Check accuracy of thermostats - correcting a reading that is 2ºF high will save $100-$200.
• Install electronic thermostats or controllers with a 1 ° F accuracy. Potential yearly savings of 500 gallons of fuel oil or equivalent in propane in a 30' x 100' greenhouse when changing from a mechanical to electronic thermostat or controller.
• Aspirate thermostats or sensors for more uniform temperature control. Differential between on and off can be reduced as much as 6ºF.
• Install horizontal air flow (HAF) fans to get more uniform temperature in the growing area.
• Insulate distribution pipes in areas where heat is not required.
• Check and repair leaks in valves, steam traps and pipes.

Reprinted from "Greenhouse Energy Conservation Checklist" by John W. Bartok, Jr., Agricultural Engineer, Natural Resources Mgt. & Engr. Dept., University of Connecticut , Storrs CT