Dehumidifier sizing Last reviewed June 30, 2026
What Size Dehumidifier for a Grow Room? Tent Sizing Guide
By the WhatSize editorial team 5 min read Standards-reviewed
A standard 4x4 grow tent (16 sq ft) needs a 35-pint dehumidifier. For 5x5 tents, go with 50 pints. Cannabis plants transpire 0.25-0.5 gallons/day per plant, so standard AHAM room-size estimates don't apply.
Why Grow Rooms Need Oversized Dehumidifiers
Grow rooms are a unique case in dehumidifier sizing. Unlike standard rooms, plants actively transpire moisture into the air. A single mature cannabis plant can release 0.25-0.5 gallons of water per day. In a 4x4 tent with 4 plants, that's 1-2 gallons of daily moisture load.
The AHAM DH-1-2022 standard, as tested under the DOE 2019 procedure, assumes conditions of 65°F/60% RH, but grow rooms operate at higher temperatures (75-85°F) and need lower RH targets (40-55% in flower). These conditions mean a dehumidifier must work 1.5x harder than in a standard room of the same size.
Top picks for this size
These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.
Grow Room Sizing by Tent Size
- 2x2 or 2x4 tent (4-8 sq ft, 1-2 plants): 22-pint sufficient for veg, 35-pint for flower
- 4x4 tent (16 sq ft, 4 plants): 35-pint minimum, 50-pint for heavy feeders or high-humidity climates
- 5x5 tent (25 sq ft, 6-9 plants): 50-pint — extra capacity helps during high-humidity dark cycle
- 8x8 room (64+ sq ft, 12+ plants): 70-pint or commercial-grade system
Frequently asked questions
What size dehumidifier for a 4x4 grow tent?
A 4x4 tent with 4 plants needs a 35-pint dehumidifier during veg and 50-pint during flower. Place the unit outside the tent with ducting to avoid raising internal temperatures.
Can I use a standard home dehumidifier in a grow room?
Yes. Look for a model with continuous drain capability so you don't need to empty the tank daily. A standard home dehumidifier works fine as long as the pint rating matches the moisture load.
Where should I place the dehumidifier in my grow room?
Outside the tent if possible, with exhaust ducted in. This prevents heat buildup. If it must go inside, position at canopy level with 12 inches of clearance on all sides.
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More dehumidifier sizing guides
- What Size Dehumidifier for a 500 Sq Ft Room?
- What Size Dehumidifier for a 1,000 Sq Ft Space?
- What Size Dehumidifier for a 1,500 Sq Ft Space?
- What Size Dehumidifier for a 2,000 Sq Ft Space?
- What Size Dehumidifier for a Basement?
- What Size Dehumidifier for a Bedroom?
- What Size Dehumidifier for a Crawl Space?
- 50-Pint vs 70-Pint Dehumidifier: Which Size Do You Need?
- What Temperature Does a Dehumidifier Stop Working? Winter Guide
Still choosing between sizes? Compare: 50 vs 70 pint