Equipment Compatibility Checker
Check whether your light, fan, and dehumidifier are properly matched to your tent size and grow stage. Enter your setup specs to get a pass/warn/fail verdict for each equipment pairing — light coverage vs tent footprint, fan CFM vs tent volume, and dehumidifier capacity vs room load. Catches mismatches before they cost you a grow.
Check your equipment compatibility
Tent / grow space
Your equipment
Use actual draw (from the fixture label or Kill-A-Watt), not "equivalent" wattage.
Enter 0 if no dehumidifier — the check will flag if one is recommended.
Circuit check (optional)
Use the Power Load Calculator for a precise total. Enter approximate if known.
Setup summary
—
Fill in your equipment to see the compatibility summary.
Common equipment mismatch mistakes
- Undersized fan for the tent + filter combo. A 4×4×6 tent needs ~230 CFM minimum (96 cu ft × 1 ACM × 1.25 filter overhead). A 200 CFM fan with a carbon filter effectively delivers ~160 CFM — not enough for adequate air exchange. Always spec fan CFM for the tent volume with filter overhead.
- Under-lit tent for flower. A 200W LED in a 4×4 tent (16 sq ft) gives 12.5W/sq ft — far below the 35–50W/sq ft needed for productive flower. Plants will grow but yield will be severely limited. Light is almost always the first upgrade that produces measurable return.
- No dehumidifier in flower. RH above 50% in weeks 5–8 of flower creates significant Botrytis risk on dense buds. A dehumidifier isn't optional in humid climates or during late flower — it's the difference between a full harvest and losing buds to mold.
- Running all equipment on the same standard outlet. A 400W light + 60W fan + 300W dehumidifier = 760W — fine for a 20A dedicated circuit. But on a shared 15A household circuit with other devices, you're at risk. Use the Power Load Calculator to verify your circuit has headroom.
Check your equipment in four steps
Select tent size and grow stage
Tent size drives all three checks — light coverage is W/sq ft, fan adequacy is based on cubic feet, and dehumidifier sizing uses square footage. Select the stage you're planning for: veg requires less light intensity per square foot than flower, so a light that's marginal for flower may be perfectly adequate for a veg-only run. Custom dimensions let you enter any space size.
Enter your equipment specs
Use actual wattage from the fixture label for the light — not "equivalent" or marketing wattage. For fans, use the CFM rating at medium speed (full-speed ratings are often measured without a filter). For dehumidifiers, use the rated pints/day from the spec sheet. If you haven't bought equipment yet, enter your planned specs to check compatibility before purchasing.
Read the check results
Each check shows pass (green ✓), warn (amber !), or fail (red ✗) with the specific numbers driving the verdict. A fail means the equipment is genuinely inadequate for the space. A warn means it's marginal — workable in ideal conditions but likely to struggle in heat, high humidity, or under heavy plant load. Each warn and fail includes a specific recommendation: what to change and what target to hit.
Enable Pro mode for circuit check
Pro mode adds a circuit safety check: select your circuit type and enter total equipment wattage (use the Power Load Calculator for the precise number) to verify your electrical setup has adequate headroom. A failed circuit check is the only electrical safety issue — all other checks are about grow performance. Address circuit fails before addressing light or airflow warnings.
Use this tool before buying, not after
The most valuable use of this checker is pre-purchase — enter the specs of equipment you're considering and verify compatibility before ordering. A 200W LED might look attractive at its price point, but if you're putting it in a 4×4 tent for flower you'll immediately see the 12.5W/sq ft fail and know to look at 600W+ options instead. This tool costs nothing; returning inadequate equipment costs time and sometimes restocking fees. Run the check every time you're considering an equipment change or upgrade.
W/sq ft, air changes per minute, and why these benchmarks exist
Equipment compatibility benchmarks aren't arbitrary — each one traces back to a specific biological or physical requirement. Understanding the reasoning makes it easier to adapt the benchmarks to unusual setups and to know when a warning is actually critical versus when your specific conditions make it acceptable. See the Grow Room Setup Guide for the full equipment selection reference.
35–50
W/sq ft for flower
Derives from PPFD targets of 600–1000 µmol/m²/s at canopy. Modern LEDs produce roughly 2.5–3.0 µmol/J. At 40W/sq ft and 2.7 µmol/J efficiency, canopy PPFD is approximately 700–900 µmol/m²/s — in the productive flower range.
1× ACM
Air changes per minute
One complete air exchange per minute removes CO₂-depleted and heat/humidity-loaded air at a rate that keeps canopy conditions stable. Below 0.5 ACM, temperature and humidity stratify and build up faster than exchange removes them.
0.5 pt
Pints/day per sq ft
Based on typical plant transpiration rates during active veg/flower in a closed tent. Active cannabis plants in flower can transpire 1–2 liters/day per plant. In a 4×4 with 4 plants, that's 4–8 liters/day (8–17 pints) from plants alone.
Why W/sq ft matters more than total wattage
A 600W LED in a 4×4 tent (37.5W/sq ft) produces adequate light for productive flower. The same 600W LED in a 5×5 tent (24W/sq ft) under-lights the space and produces significantly lower yield per square foot. Total wattage is meaningless without knowing the space it's covering — W/sq ft is the metric that predicts canopy PPFD and ultimately yield potential. Manufacturers often market fixtures by "coverage area" rather than W/sq ft, which can be misleading — always calculate the W/sq ft yourself from the actual draw and your space.
The carbon filter CFM penalty
Carbon filters create resistance in the airflow path — the fan has to work harder to move the same volume of air through the filter medium. This resistance reduces effective CFM by 20–35% depending on filter condition and size match. A fan rated at 200 CFM may deliver only 150–170 CFM with a carbon filter inline. The NEC 25% overhead rule (size the fan at 125% of tent-volume requirement when using a filter) accounts for this. As filters fill with use, restriction increases — a heavily loaded filter can cut effective CFM by 40–50%. Replace carbon filter media every 1–2 years or when you notice reduced airflow.
Common equipment compatibility questions
My light failed the check — do I have to upgrade?
For flower: yes, if you want productive yields. A light delivering under 25W/sq ft in flower will grow plants but produce significantly reduced yield per square foot — often 30–50% less than an adequately lit canopy. If you're growing for personal use and yield isn't the priority, an under-powered light will still work. For veg: the threshold is lower (20W/sq ft minimum), so a light that fails the flower check may still pass for veg-only grows. The checker uses flower targets as the default because most growers are running full cycles. Switch the stage selector to veg if that's your use case.
My fan "passed" but my tent is still hot — why?
The fan check verifies air exchange rate, not temperature management. A fan that moves adequate CFM still can't cool a tent if the incoming air is already warm (hot climate, warm room). Temperature management requires either cool incoming air or active cooling (portable AC). If your tent is running hot despite adequate CFM, the problem is inlet air temperature, not fan size. Add an AC unit sized for your heat load, or move the tent to a cooler location. The Climate Equipment Sizer calculates AC capacity requirements based on your tent size, light wattage, and ambient temperature.
Do I really need a dehumidifier for a small 2×2 tent?
In most cases, no — the checker passes a 2×2 with no dehumidifier because adequate airflow from a properly sized inline fan is often enough to maintain RH in a small space. The exception: late flower in a humid climate, or if you're growing dense, mold-susceptible strains. If RH consistently exceeds 60% in weeks 5–8 of flower and you've already maximized airflow, a small dehumidifier is worth adding. For larger tents (4×4 and up), a dehumidifier becomes increasingly important because plant transpiration load is significant and airflow alone can't compensate.
Can I use this tool to plan a setup before buying anything?
Yes — this is the ideal use case. Enter your planned tent size, look at the minimum light wattage required for a pass, then cross-reference with the PPFD/DLI Calculator to verify the fixture you're considering actually delivers target PPFD at your planned hang height. For fans, the minimum CFM from the check gives you the spec to look for on fan listings. Share the URL with the equipment specs filled in to get a second opinion from a grow forum or the tool community. The Grow Tent Sizer also recommends specific equipment specs for your plant count and training method.
Equipment that passes the checks
If the compatibility checker flagged any of your equipment, these are the categories to address first — in priority order: light, then fan, then dehumidifier.
LED grow lights
Full-spectrum LED panels ($150–600+). Lighting is the single highest-yield-impact equipment decision. Use the checker's W/sq ft calculation to find the minimum wattage for your space, then use the PPFD/DLI Calculator to verify a specific fixture delivers target PPFD at your planned hang height. Multi-bar quantum board designs produce more uniform coverage (lower CV) than compact panels — relevant if the PAR Map Visualizer showed poor uniformity.
Inline fans
4" fans ($35–60), 6" fans ($55–90), 8" fans ($80–130). Size to 125% of minimum CFM when using a carbon filter. AC Infinity CLOUDLINE series with variable speed and temperature control is the standard recommendation. EC motor designs use 30–50% less electricity than comparable AC induction fans at the same CFM.
Dehumidifiers
Compact units ($35–80), 30-pint units ($90–150), Energy Star rated ($120–200). Size to the checker's recommended pints/day minimum and verify the unit has a continuous drain option for unattended operation. Undersized dehumidifiers that constantly run at full capacity fail early. Always size with 25–50% headroom above the minimum.
Grow tents
2×2 through 10×10 ($60–400). Sometimes the right fix for a light-coverage fail is a smaller tent rather than a bigger light — a 400W LED is well-matched to a 3×3 at 44W/sq ft but fails in a 4×4 at 25W/sq ft. If you're budget-constrained on the light, downsizing the tent to match your light is a valid strategy.
Carbon filters
4" filters ($35–60), 6" filters ($50–90). Match filter diameter to your fan diameter. A mismatched filter (fan bigger than filter) reduces effective CFM significantly. Replace filter media every 12–18 months — a heavily loaded filter can cut airflow by 40–50%, causing a previously passing fan to effectively fail the airflow check.
Environment controllers
Fan speed controllers ($20–40), temp/RH controllers ($60–150), smart multi-device controllers ($150–250). A controller that automatically adjusts fan speed based on temperature and humidity bridges the gap between "equipment that technically passes" and "equipment that consistently performs." Passive fan speed management without a controller often means running at full speed continuously, which wastes electricity and creates noise.