Preparing for Winter - Greenhouse Insulation

There are simple and inexpensive steps you can take to reduce energy use during the heating season. These recommendations are derived from the fact sheet Practical Ideas to Cut Your Greenhouse Energy Bill in Half by Agricultural Engineer
John W. Bartok, Jr.

• Reduce air leaks by weather stripping doors, vents, and fan openings. Lubricate fan shutters frequently so that they close tight. Shut off some fans during the winter and cover openings with insulation or plastic.

• Make certain to apply two layers of poly as glazing. Choose a brand with an infrared inhibitor for the inner layer.

• Insulate the perimeter below ground – installing 1 - 2 inch thick insulation board to feet below ground level will reduce the heat loss from the warm interior soil to the cold ground outside.

• Insulate sidewalls and endwalls to bench height using either a 2 inch foam board, or an inexpensive aluminumcovered
bubble insulation. Insulating existing structures is worthwhile. Cost of foam board insulation is about $1/ sq ft with a payback of less than one heating season.

• Insulate behind sidewall heat pipes. Use insulation board or aluminum-faced building paper to radiate heat back into the greenhouse. Leave an air space next to the wall to prevent frost damage to the wall.

• Install an energy screen and save as much as 20%- 50% on heating costs. Screens trap the heat inside and reduce the heat loss surface area. Tight closures should be maintained where curtains meet sidewalls, framing or gutters. Add roll-up or drop down sidewall screens for additional savings. These can be either manual or mechanized.

• Perform yearly maintenance on boilers, burners and back-up systems. Clean and adjust furnaces and do an efficien-cy test run before heating season. Consider upgrading the efficiency of your system with installation of root-zone
heat tubing, a high-efficiency heater or boiler, or an insulated water tank for heat storage. Cost-effective alternatives to fossil fuels are also available.

If you have more involved greenhouse retrofits in mind, but aren’t sure where to begin, contact the Massachusetts Farm Energy Program at http://www.berkshirepioneerrcd.org/mfep or read up on your options in the Farm Energy Best Management Practices Guide for Greenhouses.

Additional information can also be found in the publication Energy Conservation for Commercial Greenhouses available from the CIT Resource Store, University of Connecticut

Source: University of Massachusetts