Air Conditioning

A greenhouse air conditioner holds your growing space at a steady temperature through heat waves, and heat pump models warm it on cold nights. Pick an MRCOOL Olympus or DIY 4th Gen mini split for a single room or bay, and the Samsung ceiling cassette for large open spaces.

12 products

Air Conditioning

Greenhouse Air Conditioners: Mini Splits, Line Sets and Controls

A greenhouse air conditioner pulls heat out of a growing space that vents and shade cloth can't keep cool. This range covers MRCOOL Olympus and DIY 4th Gen mini splits, a Samsung 48,000 BTU ceiling cassette, line sets and a day/night controller. Not sure which size fits? Start with our mini split AC reviews for indoor grow rooms....

Greenhouse air conditioner infographic: mini split types, BTU sizing by load, line sets, controls and best uses

Sealed indoor rooms have their own page of grow room air conditioners. When moisture is the bigger problem, pair the AC with one of our dehumidifiers. Both sit in the wider HVAC range.

Types of Air Conditioning for Growers

Ductless Mini Splits

MRCOOL Olympus systems come complete in 9,000 to 24,000 BTU sizes on 230V. The 12,000 BTU model is rated 22.7 SEER, covers about 500 square feet and heats down to -13°F. The DIY 4th Gen pairs a condenser with a wall air handler and a pre-charged line set, so no vacuum pump is needed.

Ceiling Cassettes

The Samsung 48,000 BTU cassette mounts flush overhead and blows air four ways. It frees every wall for benches and suits a large room or greenhouse. It runs on 208/230V and needs a professional install.

Line Sets and Controls

MRCOOL line sets come in 1/4 x 1/2 inch for 9K to 18K units and 3/8 x 5/8 inch for 24K and 36K. A coupler kit joins two sets, up to the 75-foot system limit. The TrolMaster BETA-1 learns a mini split remote and switches day and night setpoints from a light sensor.

How Growers Use Air Conditioning

To size a sealed room, add up the running watts, multiply by 3.412 and add about 20%. A 5,500W room lands on a 24,000 BTU unit. Heat pump models also warm the space on cold nights, so one greenhouse air conditioner can cover the whole year.

Frequently Asked Questions

Can you air condition a greenhouse?

Yes. A mini split works well in an insulated or polycarbonate greenhouse that can stay closed while it runs. Seal the gaps first, since open vents let cooled air escape. Low-ambient models like the DIY 4th Gen keep cooling in cold weather, which helps on sunny winter days.

Can you use a mini split in a greenhouse?

Yes, and a heat pump mini split both cools and heats from one unit. The MRCOOL Olympus heats down to -13°F, so it covers frosty nights as well as summer afternoons. Mount the indoor head high, out of irrigation spray, with the condenser outside on a level pad.

What size mini split do I need?

For a sealed room, multiply the running watts by 3.412 to get BTU per hour, then add about 20%. One or two lights fit a 9,000 BTU unit, and a four-light room needs about 24,000 BTU. A greenhouse also gains heat from the sun, so size it with your installer.

Do mini splits dehumidify?

Yes, in cooling mode, because moisture condenses on the cold indoor coil and drains away. The MRCOOL Olympus also has a Dry mode. Plants release a lot of water, so rooms with two or more lights often add a dehumidifier alongside the AC.