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Multi-coil design. The secret to efficiency. (VIDEO)

Quest Climate

If you’re in charge of a facility’s HVAC and environmental controls, you’re well aware of this: Inefficient systems can lead to so many zeros on your energy bill that it looks like a Powerball ticket – minus the fun.

That’s why Quest engineers have spent their careers dialing in dehumidifiers that are now the most energy efficient in the world. To understand how they did it – and why it matters to you — Quest applications engineer Dan Dettmers set down with fellow engineer Scott Sloan to get the details.

Sloan, a refrigeration engineer at Quest, is the godfather of the Quest 506, which since its launch several years ago remains the most energy-efficient unit in the world.


The key to efficiency is the three-coil design, known as the multi-coil system at Quest.

When air enters the dehumidifier, the first set of coils, filled with refrigerant, “take the edge off” the air, as Sloan said. That means it knocks the temperature down but doesn’t remove any moisture at this stage.

Then, the air goes through the second coil, where the unit’s evaporator drops the air temperature below the dew point. At this stage, it starts to pull water from the air.

Finally the air passes through a third coil that recovers energy from the airstream to further improve efficiency.


First and foremost, it makes Quest units up to four times more efficient than other refrigerant dehumidifiers.

But more importantly, the multi-coil system produces far less heat than other units. For example, the Quest 506 pulls 8 pints of water per kilowatt hour. The result is air coming out of the dehumidifier 4-8 degrees colder than competitors’ dehumidifiers.

That means you can turn down your AC, and it doesn’t have to work nearly as hard, which in turn leads to lower energy bills.

Other than saving money, another significant advantage is improved performance. Because the multi-coil system produces less static pressure, which means air is easier to move through ductwork.

Want more info? Check out Episode 04 of Dansplainin’ or send us a note at any time.