Indoor HVAC Vs Dehumidification – Grow Room Humidity Control

Indoor grow rooms are naturally humid environments. The combination of living plants and high intensity lighting, in a closed space, inevitably leads to high humidity. So, what’s the best way to control indoor humidity?

One of the most common solutions to humidity in indoor cultivation is HVAC. But HVAC has its limitations and inefficiencies. The other method, which is a sure-fire solution to humidity, is dehumidification.

So, what’s better for indoor humidity control – HVAC or dehumidification?

Overview of Indoor HVAC Systems

Before comparing HVAC and dehumidification, it’s important to understand what HVAC is, and what types of systems are out there.

HVAC stands for heating, venting and air conditioning. It’s often seen as an all-around climate controller, capable of fully controlling the environment. Though it’s not always the case.

There are two main types of HVAC – packaged systems and split systems.

A packaged unit contains all of the machinery in a single cabinet. So the evaporator coil, compressors, and condensers are all in the same place. It may also include a gas furnace or heat pump. Packaged HVAC systems are usually positioned outside, with ducts carrying the treated air indoors.

A split system, on the other hand, divides the HVAC into separate cabinets. The compressor and condenser would normally be in an outdoor unit, and the evaporator coil in an indoor unit, with an air handler to disperse the air through the ducts.

There are mini splits and ductless mini splits as well, which allow separate control over separate spaces.

Why Indoor HVAC Doesn’t Control Humidity Efficiently

HVAC is designed for the heating and cooling of an indoor space. And it performs these tasks efficiently. But when it comes to controlling humidity, HVAC simply isn’t very efficient.

Like any other air conditioner, HVAC does remove some moisture from the air. It does so as a side-effect of its operation. As cool air can hold less water vapor than warm air, any cooling will cause water to condense, removing it from the air.

However, in grow rooms, the indoor air is extremely humid, due to the plants’ constant transpiration. So, in order to constantly reduce humidity, the HVAC needs to constantly cool. This raises an obvious problem, as temperatures can’t drop too low without harming the crops.

The solution many growers turn to is cooling and heating alternatingly, at very high energy costs. Needless to say, this method isn’t very efficient, and ends up costing growers a lot of money.

Additionally, in order to be able to handle the massive amounts of water vapor in the grow room, HVAC systems need to be very large. In fact, they need to be almost twice as large as would be necessary for heating and air conditioning alone, increasing the amount of maintenance required as well.

So, in terms of infrastructure, initial investment, and maintenance, using HVAC for humidity control is very expensive.

How Grow Room Dehumidification Works

If HVAC isn’t optimal for indoor humidity control, then what is? The answer is dehumidification.

Horticultural dehumidifiers use a controlled-condensation technique to reduce humidity. This works similarly to an air conditioning system, removing water vapor from the air by running it through a cooling coil. The air is then reheated and expelled back to the grow room, and the extracted water is collected to be reused.

As dehumidifiers are engineered to perform this single task, they’re highly efficient at it. The DryGair DG-12, for example, extracts 45 liters of water an hour, at only 10kW of electricity.

 

Dehumidification Combined with HVAC Is the Most Efficient Solution

Dehumidifiers are the most efficient at reducing humidity. But they provide an added benefit of relieving the HVAC from this task.

Using dehumidification allows growers to use their HVAC only for its intended purpose – heating and cooling. It allows them to shut the HVAC off when temperatures are optimal, which saves a lot of energy. After all, HVAC is one of the most energy intensive pieces of machinery in a grow room.

Integrating dehumidifiers in indoor grow rooms also lets growers install smaller HVAC systems, at lower initial and maintenance costs. As the HVAC doesn’t have to perform humidity control, it doesn’t need to be as large.

Additionally, by allowing it to shut off at certain periods, it requires less maintenance, and the system may last longer.

To conclude, the best way to control the climate in indoor grow rooms, is by combining dehumidifiers and HVAC. Letting each perform for the task it’s designed for, and at which it’s most efficient.

Interested in integrating DryGair with HVAC? Contact us!