Common Mistakes with Growroom Ducting

By Kent Gruetzmacher
Published: December 22, 2022
Presented by AC Infinity Inc.
Key Takeaways

Airflow in a growroom is vital so when it comes to duct work, make sure you take your time and do it properly, as Kent Gruetzmacher explains.

When it comes to setting up a new growroom, good planning can save you major heartache in the long run.

When seemingly simple design oversights manifest themselves in an indoor garden, they almost always negatively impact your cannabis plants. As such, when planning the HVAC system in your growroom or tent, be sure to carefully consider ducting.

Airflow is one of the most critical design considerations for indoor gardens. By creating the right amount of negative pressure in your growroom, you can carefully regulate temperature and humidity. Without such precision control, it would be nearly impossible to grow high-quality indoor cannabis.

Regardless of how important airflow might be for indoor growing, it's easy to rush through the process of planning your ducting. Nonetheless, avoiding common mistakes with growroom ducting design will help your garden perform its very best.


The Goal of Ducting is to Move Air

grow tent ductingGrowers use ducting for a few key reasons in modern growroom design.

Whether it be air-cooled lights or an intake system, the goal of ducting in any growroom is to move air efficiently. With this notion in mind, it's best to visualize how air will move through your ducting when designing an HVAC system. Importantly, any leaks and blocks will inhibit your ability to regulate your growroom environment. While some applications are more popular than others, growers use ducting for a few key reasons in modern growroom design. Mistakes in any of the critical systems can have reverberating impacts on your indoor garden.


Exhaust Systems

Exhaust systems are likely the most important application for ducting in indoor gardens. Since exhaust systems handle air exchange in growrooms, they utilize the largest inline fans and widest diameter ducting. If your exhaust ducting is poorly designed, it inhibits your ability to remove hot and humid air from your growroom.


Intake systems are another principal application for growroom ducting. The primary use for intakes is to lower temperatures in growrooms by pulling fresh air from the outside. Especially in the heat of summer, your intake system needs to be running at 100% to keep your garden at acceptable temperatures.

Air Cooled Lights

A leak or obstruction in the ducting system for air-cooled lights will keep unnecessary heat in your growroom.


While not as popular today, many cannabis growers still use air-cooled lights for their indoor gardens. With single-ended HPS and MH lights, inline fans and ducting are critical for removing excess heat from light fixtures. If there is a leak or obstruction in the ducting system for your air-cooled lights, it will keep unnecessary heat in your growroom.

Mixing & Matching Ducting Sizes

The practice of mixing and matching different sizes of ducting is particularly problematic among novice growers. Whether it's to save money with free materials or just a simple oversight, using different diameters of ducting in a single system will greatly hinder airflow.

When you add reducers to your ducting, you create irregularities in the path of moving air. To illustrate, if you run a 12-inch inline fan for your exhaust, reducing the diameter to 6 or 8 inches will restrict the cubic feet per minute (CFM) rating of your fan.

To maximize the performance of your system, always match ducting size with fan size.



Cheap & Refurbished Ducting

It’s easy to get sticker shock from all the equipment and materials that must be purchased for a new indoor grow. As a result, some growers make the mistake of purchasing used ducting from thrift stores. In other instances, people use cheap, uninsulated ducting that easily lets heat escape.

Going with a quality ducting brand is a surefire way to help ensure that your growroom HVAC system works in top shape. In fact, companies like AC Infinity make top-of-the-line ducting specifically to be used by indoor growers. AC Infinity’s ducting features four-layer protection—making it more durable and resistant to leaks than cheaper brands.

Duct Tape Instead of Clamps

duct tapeYou can’t rely on duct tape to hold together a network of ducting, fans, and lights.

Another common mistake that people make with ducting is —using duct tape instead of clamps to connect different pieces. While duct tape can help create air-tight seals in your HVAC system, you can’t rely on it to hold together a network of ducting, fans, and lights.

When setting up a ducting system in your growroom or tent, you should use high quality metal clamps to hold everything together. In such situations, adding additional duct tape to where the pieces are adjoined can be helpful in keeping preventing air-leaks in your ducting network.

Spending a little extra money on metal clamps will help protect the overall integrity of your HVAC system.

Too Many Bends in Ducting

The most common mistake with growroom ducting is putting too many bends in your duct network. Importantly, every time you add a bend or curve to a piece of ducting, you hinder the overall performance of your inline fan.

Inline fan manufacturers give their products CFM ratings to describe how efficiently they move air from one place to another. These CFM ratings are used by indoor growers to size inline fans for exhaust systems, air-cooled lights, and intakes. However, every time you add a bend to ducting, it lowers your inline fan’s overall CFM ratings.

To ensure that your inline fans are working at 100% capacity, be sure to set up the ducting to be as straight as possible. A helpful tip is to aim an inline fan directly at the intended exhaust port when setting up your growroom or tent.

Well-planned indoor gardens are often those that produce the best cannabis harvests. Within this spectrum, proper airflow principles are a critical part of growroom design—no matter how big or small your operation. Yet, while nobody denies the importance of airflow in indoor growing, not many people talk about proper ducting design.

Due to overhead costs and utility expenses, growing cannabis indoors is not cheap. That being said, putting some forethought into getting the most out of electrical expenses is a really smart move. With airflow, thinking your way through your ducting network to maximize efficiency will ensure you get the most bang for your buck with electricity.

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AC Infinity is the foremost name in air delivery systems, designing and developing the latest innovations in cooling and ventilation technology. They offer a suite of quiet inline fans that automate the growing progress and track key metrics. Visit or contact [email protected] to learn more.


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Presented By

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Written by Kent Gruetzmacher | Writer, Owner of KCG Content

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Kent Gruetzmacher MFA is a Colorado-based writer and owner of the writing and marketing firm KCG Content. Kent has been working in the cannabis and hydroponics space for over a decade. Beginning in California in 2009, he has held positions in cultivation, operations, marketing, and business development. Looking specifically to writing, Kent has worked with many of the leading publications and marketing agencies in the cannabis space. His writing has been recognized by such icons as Steve D’Angelo and Rick Simpson.

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