Upgrading Greenhouse Unit Heaters

Upgrading Greenhouse Unit Heaters

Upgrading Greenhouse Unit Heaters

Shortly after Modine introduced the Effinity93 in the fall of 2009, Andy Buist from Micandy Garden Greenhouses in Hudsonville, Mich., realized he needed to replace a few of his older, 78 percent efficient unit heaters and decided to take action. Hesitant at first, he purchased two new Effinity93 unit heaters, but by the time that first order arrived, he already made a decision to order more.


The key reason that convinced Micandy to upgrade to newer heaters is one that affects greenhouse owners the most–the pocket book. “As a greenhouse owner, you spend tens of thousands of dollars annually on energy, especially here in Michigan,” Buist says. “We investigated the investment as much as possible, looking at our historical gas usage along with Modine’s heat savings calculator to determine our payback, and it just made economic sense to try the Effinity93 heaters. We’ve been nothing short of pleased ever since.”

How pleased has the operation been? Since the initial purchase of a couple units, Micandy now has two dozen Effinity93 heaters installed, with more on the way.

The installation strategy that has worked best for Micandy is to make the Effinity93 units the primary stage heaters throughout the greenhouse. Because the primary stage units run constantly in the winter, it makes sense to have 93 percent efficient units there, leaving the less efficient 78 percent and 65 percent heaters setup as the second- and third-stage units.

“We replaced all of our old 65 percent efficient units even if they were operable simply due to their inefficiency,” Buist says.

The one byproduct of high efficiency heaters is condensation, and as Micandy found out, there can be a lot of it. “In the dead of winter, each heater puts out a couple gallons of water per running hour which we pipe into our drain system,” he says. “It’s an easy challenge for any greenhouse to overcome and the way we view it, every drip of water coming out of that heater is more money staying in our pocket.”

The ability to handle the condensation along with the expulsion of potentially dangerous gasses is another reason Micandy prefers unit heaters as its heating method. Direct-fired heaters burn outside air and dump it directly into the greenhouse, bringing with it potentially lethal chemicals to certain crops. Also, this method of heating brings a significant amount of moisture and condensation into an area that is already oversaturated.

“Another nice feature of the Effinity93 is that it’s separated combustion,” Buist says. “So all the combustion air is taken from and released outside the greenhouse. This eliminates the risk of loss to chemical vapors in the air, and also relieves the greenhouse of any additional moisture.”

Installing the new heaters proved to be a breeze for Micandy thanks to Modine’s Contractor Convenience Package. “It didn’t take long to replace our older, more inefficient units with the Effinity93,” he adds. “The intake and exhaust outlets were easy to connect, too, along with the electrical work.”

As Micandy looks forward to more Michigan winters, the owners have already made up their minds on what to do with unit heaters that need to be replaced.

“Pretty much every unit heater in our greenhouse is a Modine and they’ve done great, but from now on, when we need to replace a unit, we’ll be stepping up to the Effinity93,” Buist says. “The cost savings are just too substantial to pass up.”