How To Choose and Size The Best Grow Room Air Conditioner

Keeping your plants happy and healthy when growing indoors will sometimes require you to use the best grow room air conditioner unit - but choosing and sizing one isn't easy.

This is especially important during those hot summer months, but even growers based in more mild climates can suffer from grow room heat problems year-round.

That’s because the grow lights, CO2 equipment, and other supplies we bring in the grow room create heat themselves - and sometimes a ventilation system just won’t cut it.

That’s why we’re going to discuss the best AC units for growing plants this year, with an option for every grower out there.

Ranging from small portable AC’s for grow tents up to industrial, multi-zone units for our huge MSO growers out there - and everything in between.

If you're struggling with heat in your grow room or tent, read on to learn which unit is right for you. We'll cover the best in the business as it stands today.

But first, we need to discuss the different types of units out there - and help you understand how to size yours, using a grow room BTU calculator.

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How To Choose and Size The Best Grow Room Air Conditioner


Keeping your plants happy and healthy when growing indoors will sometimes require you to use the best grow room air conditioner unit - but choosing and sizing one isn't easy.

This is especially important during those hot summer months, but even growers based in more mild climates can suffer from grow room heat problems year-round.

That’s because the grow lights, CO2 equipment, and other supplies we bring in the grow room create heat themselves - and sometimes a ventilation system just won’t cut it.

That’s why we’re going to discuss the best AC units for growing plants this year, with an option for every grower out there.

Ranging from small portable AC’s for grow tents up to industrial, multi-zone units for our huge MSO growers out there - and everything in between.

If you're struggling with heat in your grow room or tent, read on to learn which unit is right for you. We'll cover the best in the business as it stands today.

But first, we need to discuss the different types of units out there - and help you understand how to size yours, using a grow room BTU calculator.

What Are The Different Types Of Grow Room Air Conditioners?

There are a few different types of air conditioners you need to be aware of. There are portable units, mini-splits, and commercial grade units.

Portable Grow Room A/Cs

Portable Grow Room A/Cs

These air conditioners are compact and incredibly convenient. Portable A/C units can be easily wheeled into whatever space they need to cool.

They are an excellent choice for grow tents, as they do not require any intense installation.

This particular type of A/C is also great for those who do not have experience with setting up air conditioners, as they really only require the user to be able to plug in the unit for it to be able to function.

Portable air conditioners work by pulling in the heated air for the cooling process, distributing the cooled air back into the room, and exhausting the heated air through ventilation tubing that can be pointed out of a window or directed into a separate room.

While these units are great for smaller spaces and grow tents, they are typically not intended for use in large grow rooms. These lack the necessary power to control the temperature in large spaces or commercial gardens.

Mini-split Grow Room A/Cs

These units require slightly more effort for installation, however, offer much more power for cooling larger or hotter areas.

Rather than being an all-in-one unit like portable air conditioners, mini-splits come with two main components.

One part is the indoor unit referred to as an air-handler that gets mounted to a wall. This component is needed for distributing the cool air.

The other part is a condenser that expels the heated air and moisture created from the cooling process.

This piece of equipment is typically installed outside the growing space. These two separate parts are connected via a line-set consisting of conductor wire, and refrigerant line.

These types of air conditioners require more installation, due to the indoor air-handling unit needing to be mounted to a sturdy wall, so they are not ideal for grow tents.

Mini-splits are also not as simple as portable air conditioners. You may need to seek the advice or assistance of a professional.

They are however well-suited for larger grow rooms, as they are more powerful than portable units, and more capable of cooling larger and hotter spaces.

Commercial Grade A/Cs

commercial Grow Room A/Cs

These are the most powerful, largest air conditioners available. Commercial units are used in large scale commercial gardens that have major air conditioning needs.

Other units are unable to expel heat generated by all of the equipment used in these operations.

These large grow spaces can have dozens of intense light systems, carbon dioxide generators, dehumidifiers, and more running for 12+ hours daily. This can generate a tremendous amount of heat that a smaller A/C would have no hope of cooling.

These units are typically mounted on the roof of the building that they are cooling.

One unit is usually powerful enough to regulate the entire building’s temperature rather than just a single room like most other a/c systems.

The installation of this particular type of air conditioner should only be handled by a professional.

Shop For Grow Room AC’s Based On Install Type

When trying to narrow your search for an air conditioner, you can do so by the type of installation that the device requires.

  • Quick Connect or DIY- These are air conditioners that are easy to setup and use for someone that has no previous experience. Portable air conditioners fall within this category.
  • HVAC Professional - These are air conditioners that require the expertise of a professional with HVAC (heating, ventilation, & air conditioning) experience. These are units such as ceiling mount, and commercial grade air conditioners that would be unwise or dangerous to install on your own.

How to size your grow room air conditioner

If you are looking for a grow room BTU calculator to help choose and size your air conditioner, you are in the right place. We are going to help you size your AC properly.

Using multiple pieces of equipment, especially high powered grow light systems, is guaranteed to generate heat.

In a grow room, this heat can have a negative impact on plants. Excess heat may even be intense enough to kill them completely.

A reliable, correctly sized A/C for the grow space can be the saving grace for plants that would have otherwise wilted in the heat.

Calculating Grow Room BTU’s (British Thermal Units)

Air conditioners are rated by how many BTUs they are capable of removing from the air, per hour. BTUs, or British Thermal Units, are used to measure thermal (or heat) energy.

Calculating Grow Room BTU’s (British Thermal Units)

Sizing an air conditioner correctly is extremely important. Choosing a unit that is not powerful enough to cool the grow space will cause the air conditioner to run constantly. This will be a waste of electricity, and shorten the overall lifespan of your a/c.

Alternatively, if the air conditioner is too powerful, it may cause the unit to short cycle. This means that the air conditioner would cool the room to the desired temperature, and then shut off. It would then have to cycle back on soon after to maintain the ideal temperature.

This constant power cycling is not only a waste of electricity, but also can be detrimental to the components that the unit is composed of and it could also shorten the lifespan of the air conditioner.

Measure the size of your grow room or greenhouse

Correctly sizing an air conditioner for use within your garden doesn't need to be difficult. Sizing depends entirely upon the size of the grow area, and the equipment being used within the grow area.

As an example, let’s say you are growing in a 10x10 grow room, with four Delux 1,000 watt HPS lights, each of these powered by a Delux 1,000 watt ballast, and a Titan Ares 2, which is a CO2 burner used for supplementing extra CO2 to a garden.

To determine what size A/C you need, first calculate a rough estimate of the BTU/hr being produced by the equipment in the grow room.

Grow Room BTU calculator

We know that one 1000W HPS lights would produce 3,412 BTU/hr. This would need to be multiplied by four, as there are four lights being used in the grow space. This brings us to 13,648 BTU/hr being produced.

We would then refer to the specs for the Ares 2 to find that it produces 4,526 BTU/hr. This piece of equipment produces more heat than most, as it utilizes combustion to produce CO2 for the garden. This combustion leads to a hotter grow room.

The BTU/hr from the lights would then be combined with those being produced by the CO2 burner. This would bring us to a grand total of 18,174 BTU/hr being produced by the hottest pieces of equipment being ran most often in the garden.

Size up on your A/C to be safe

So, to regulate this heat, you want an air conditioner that is rated at least 18,174 BTU.

You would be hard pressed to find an a/c that perfectly matches that figure, so round up to be safe.

For the example we laid out a mini-split a/c rated at 24,000 BTU. We wanted to see if it would be able to handle the room on a standard day, as well as being able to still manage to keep the temperature controlled if there were a heatwave in your area, and still not too over-powered to the point of causing short cycling.

When recreating mother nature within a confined space, it is inevitable you will battle temperature.

Having a reliable and correctly sized air conditioner can be the difference between a happy harvest, or a bunch of crispy, dead and wilted plants.

Don’t make the mistake of waiting until temperatures in your tent are hitting the triple digits. Order an a/c now and be ready for whatever heat may come your way. Now, we're going to help you pick the best grow room air conditioner for you and your crop.

What Are The Best Grow Room Air Conditioners Of 2021?

Now that you know how to size your AC, and you know the different types available to growers - we want to help you pick the best grow room air conditioner for your plants.

We’re going to start with some portable options for grow tent growers, and those with smaller grow rooms. After that, we’ll progressively share more commercial-style units for our professional growers out there.

Active Air Portable Air Conditioner

Active Air Portable Air Conditioner

The best small-scale grow room air conditioner is the Active Air Portable Air Conditioner. It’s super compact, perfect for those growing in a tent or in small rooms/closets.

These small spaces are oftentimes the worst offenders when it comes to heat, yet there are few options available to combat heat in tight spaces.

Ranging from 12k-14k BTU, this AC is rated for rooms sized under 100 square feet that require cooling under 95 degrees Fahrenheit.

One really cool feature on this unit is the digital control panel, which can be controlled remotely. The side-to-side air distribution design contributes to greater cooling performance and efficiency, helping you cut down on your energy bill.

Without a doubt, this is the best portable air conditioner for grow rooms under a certain size - it's ultra-efficient and cost-effective, helping you optimize your grow room environment while saving money!

Ideal-Air Pro Series Air Conditioner

Ideal-Air Pro Series Air Conditioner

If you need something with a bit more cooling capability, the Ideal-Air Pro Series Air Conditioner may be for you.

This unit is available both in 24k & 36K BTU to help fit a range of different grow rooms. This is a mini-split style unit, with 1 indoor and 1 outdoor unit.

The indoor unit can easily be installed on the wall to save up floor space for more plants or other equipment - helping you get the most out of this investment.

They operate in a wide temperature range, cooling spaces as hot as 122 degrees Fahrenheit! Another really cool feature is that you can help heat your greenhouse or grow room during the winter with the same unit!

With high energy efficiency of 16 SEER and inverter compressor technology, you’ll achieve savings up to 50% compared to other AC units.

Other features include a programmable remote controller (with an LCD screen!), auto restart, and more. These units do need surge protection, and will require professional HVAC installation.

MRCOOL DIY Mini Split Air Conditioners

MRCOOL DIY Mini Split Air Conditioners

The best for most small-mid scale commercial growers is without a doubt the MRCOOL DIY Series.

These are the most advanced in the industry, and are perfect for growers looking for quick connect, “do it yourself” installation. You can get these up and running in your grow room without a hassle.

While some growers only have one room they’re cultivating plants in, others have multiple rooms, with multiple unique BTU’s they need to remove.

No matter how many grow rooms you need to cool, there is a MRCOOL DIY Series suited for you.

They come in just one zone or multi-zone packages, and range all the way up to four different zones!

We can’t say enough good things about these - they truly are the best grow room air conditioner units on the market right now.

These can be configured a ton of different ways to choose whichever BTU combination you need to meet for your different rooms.

Once you click on one of the product pages, you’ll be met with every configuration imaginable - and one of these will be exactly what you need. Here are some of the features that make this truly the best grow room AC:

  • Energy Star Certified
  • Single or Multi-Zone (endless configuration possibilities)
  • Easy DIY installation
  • Controllable with a smartphone app
  • Integrated heat pump
  • Leakage detection
  • Low ambient cooling (as low as 5 degrees Fahrenheit)
  • Auto restart
  • Sleep mode
  • Adjustable louver position (with memory built in)
  • Corrosion resistant, gold fin condenser
  • Digital assistant ready (Alexa, Google assistant)

MRCOOL Olympus Ductless Split Air Conditioner

MRCOOL Olympus Ductless Split Air

Another incredible option for commercial growers is the MRCOOL Olympus Ductless Split Air Conditioner System. Unlike the DIY series, these are meant to be installed by a certified HVAC professional.

One great thing about the Olympus series is that it can be configured to save space. We know your commercial growing space isn’t cheap, so don’t limit yourself on the number of plants you can fit in there!

It also is even more customizable than the DIY series, with more zones and lineset combinations than ever before. It’s available in:

These offer many of the same benefits as the DIY series - the main difference is really just the installation type.

You still get all the great features as the DIY, like ultra-efficient operation, heating capabilities, auto swing, auto restart, leakage detection, etc.

The MRCOOL brand produces the best mini split air conditioners for grow rooms - they have a ton of other options you might want to check out, too!

Quest IQ Commercial HVAC System

If you have a huge commercial warehouse you need to control the climate in, sure - you could figure out a configuration with multiple air conditioning systems, dehumidifiers, etc.

best grow room air conditioner for commercial growers

But this is going to end up being super costly & inefficient. Instead, invest in the best grow room air conditioner for commercial growers - the Quest IQ Commercial HVAC System.

This is a complete commercial climate control system that can be configured to your exact grow room. While the MRCOOL series above are great for a lot of growers, some operations need ultra-specific configuration. The folks at Quest will actually build a system to suit your floorplan!

It’s the most precise, reliable grow room climate control system on the market - keeping your atmosphere dialed into the ideal range in terms of both temperature and humidity.

Achieve up to 30% in energy savings and unlock 24/7 real time monitoring of your conditions remotely. There is no better way to keep things cool in hot commercial warehouses than with this system.

We actually wrote an entire Quest IQ Series Review because this system is so revolutionary - read it to learn more! Otherwise, click the button below to request more information on this system, and find out how it can help you.

Final Thoughts On The Choosing & Sizing The Best Grow Room AC Unit

Now, you know what the best grow room AC units of the year are - whether you’re growing in a tent or a 10,000 sq foot warehouse.

All that’s left now is to determine the cooling capability of your space, size your unit effectively, and get it installed.

Your plants will reward you with healthy growth and heavy yields - so invest in them today!

Have questions about your grow? We're Here To Help!

Our Northern California based experts can help. We're here to make sure you get what you need to maximize your harvest.

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