10 Tips For Improving Heating In The Greenhouse

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Winter drafts. They’re enough to send chills down your back, especially when you start thinking about possible gaps, tears and holes in and around your greenhouse. Nothing’s worse than escaping heat and losing money at the same time.

What follows are 10 action items that will help keep more of your heating dollars safely in your pocket as the temperature dips. Bob Fritchen, sales manager at Modine Manufacturing Company, says it best: “Make sure the first cold blast is not the first time you turn on your system.”

1. Reduce The Space

Morris Brink, West Coast territory sales manager for TrueLeaf Technologies, says, “The first thing we encourage growers to do is reduce the heated area in the early spring.” When getting crops started, cordon off a small section of the greenhouse in a pot-to-pot tight environment, rather than using an entire greenhouse range, he adds.

With micro-climate heating, “You can just heat the pots that you’re starting by utilizing a bottom heating system, instead of trying to heat the air of an entire greenhouse.”

2. Crank It Up

Turning up the heat is another option, even though it’s not commonly thought of. The growing practice of starting a bit later, turning up the heat and growing a little faster is something that’s actually been endorsed and promoted by some of the university studies, Brink says.

Modine’s Bob Fritchen agrees, “If you can wait an extra week, that’ll help. And in general, you’re shaving the coldest week of that period,” he says.

3. Pre-Spring Cleaning

If you’re not cleaning out the heaters and boilers before the season starts, you’re simply wasting your money. Cleaning costs are usually paid back within the first few weeks of the season. “Anyone who doesn’t bother to do that isn’t concerned with the cost of heat,” Brink says.

This means surfaces and burners are clean and unobstructed, the inlet for combustion air is clean and not clogged, and filters are cleaned or replaced.
Tune-ups are also important. “For smaller operations who don’t have a professional maintenance crew, make sure to locate a reputable HVAC equipment contractor,” Fritchen says.

Tune-ups will ensure gas pressure is adequate and correct, says Brink. “It can cost you a tremendous amount of money if your gas pressure isn’t correct and your heater is running below rated efficiency or capacity.”

4. Got The Flue…Gas Condenser?

Contact your greenhouse heating company about flue gas condensers,” Brink advises. They can increase fuel efficiency of the boilers and optimize the amount of heat energy you can get out of a boiler.

About 15 to 20 percent of all the energy in gas ends up leaving through the chimney. A flue gas condenser can recapture roughly 15 percent of that energy.

5. Still Using A Thermostat?

Brink recommends replacing thermostats with a computerized controller or a simple zone controller with a single sensor. These will typically pay for themselves within one season by reducing heating overshoot and undershoot and by eliminating overlapping controls.

6. Boost Your Unit’s Efficiency

“If you’re using unit heaters, look at replacing them with hot water heat,” Brink says. “That can boost your efficiency by 25 to 40 percent.”

If you keep your unit heaters, retrofit them with combustion air separators. These will take combustion air from outside of the greenhouse. They can reduce energy consumption up to 7 percent. Also, if you have a hot water system, add pipe insulation in any area that is not being heated.

7. A Must Have

“No matter what kind of greenhouse you have, a curtain system is inexpensive, can pay for itself quite quickly and reduce your energy consumption by about 15 to 25 percent − often times even more,” Brink says.

When checking your curtain system, make sure it closes all the way. A curtain system that has a few cracks in it is almost worthless when it comes to saving heat and energy.

8. Energy Audits

One thing TrueLeaf Technologies specializes in is energy audits. “We can look at the greenhouse layout and get all the details of your facility, and look at what the greenhouses should be using compared to what you are actually using,” Brink says.

Efficient greenhouses usually rate between 70 and 80 percent. “We find a lot of places in the 40 to 50 percent range,” he says. An audit provides a fresh set of eyes in and around your greenhouse, and it usually pays for itself within one season.

9. Thermostat Set Points

For those growers with thermostats, Bob Fritchen suggests using lower set points at night. This can save you a lot of energy.

“If it’s 25 degrees out, and your thermostat is set at 70 degrees inside, setting it to 60 or 65 degrees will lessen the temperature difference between outside and in, therefore significantly reducing your heat loss,” Fritchen says.

10. Energy Task Force

Before winter strikes, Brink recommends assigning an energy task force of employees to go around and look for every gap and opening in the greenhouse. All seals and vents should be checked, along with any tears in the poly-film.

Mihalek is a former Meister Media Worldwide editor.

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    One comment on “10 Tips For Improving Heating In The Greenhouse

    1. Peter Stuyt

      Good points all by one of the icons of the industry Al Zylstra. It should be noted however that Al left Trueleaf years ago and is now with Dramm. Peter Stuyt Total Energy Group Inc Summerland California