# Whole tent planner

> Free whole grow tent planner: enter the tent and lights once and get the exhaust fan, passive intake, carbon filter, AC, dehumidifier, CO₂ and circuit summary, shareable as a link and printable.

Interactive: https://genetixbay.com/knowledge/tools/planner.html

Enter your tent and lights once. The planner chains every calculator: fan, intake, filter, cooling, dehumidifier, CO₂ and circuits, sized for the worst case (lights at 100%) with a typical dimmed figure alongside. Copy the link to share it or print it for the shop.

## How it works

### The order

Light first, then the heat it makes, then the water the plants breathe out, then the air or AC to remove both, CO₂ only if the room is sealed, and finally the circuits for all of it.

### Oversized lights

Left blank, the planner uses the GenetixBay recommendation of 50 W/ft² of dimmable light (the founder's rule of thumb: 800–900 W for a 4 × 4, about 50–56 W/ft²). Often called overkill, but cannabis can use far more light than most guides assume: yield kept rising up to ~1,800 µmol/m²/s in trials (Rodriguez-Morrison 2021). Ramp up gradually, with the climate and CO₂ to match.

### Worst case and typical

The cooling and the wiring must cope with everything at 100%, so they use your lights' full wall watts (or 50 W/ft² if you leave it blank). The dimmed figure is a typical day at the stage's target.

### Vented or sealed

Vented: the exhaust fan, passive intake and carbon filter carry the heat and water out, and the AC figure only matters if the intake air is too warm. Sealed: the exhaust stays off at lights-on, and the AC and dehumidifier do the work.

### Estimates in the plan

The fan's power (about 0.12 W per rated CFM) and the AC's power (BTU/h ÷ 10) are rough figures for the circuit count. Use your equipment's real wall watts in the electrical calculator.

## Constants

| Constant | Value | Unit | What it is | Evidence |
|---|---|---|---|---|
| BTU_PER_W | 3.412 | BTU/h per W | Every watt drawn from the wall becomes 3.412 BTU/h of heat in the room, whatever the device | Established |
| SENSIBLE_AIR | 1.08 | BTU/h per CFM per °F | Heat one CFM of standard air carries per °F of temperature rise (60 min × 0.075 lb/ft³ × 0.24 BTU/lb·°F) | Established |
| INTAKE_RATIO | 2.5 | × exhaust duct area | Passive intake opening area (KB rule of thumb 2–3×; we default to the middle) | Grower practice |
| CANOPY_CAPTURE | 0.85 | fraction | Share of the fixture's photons that land on the canopy in a reflective tent (assumption) | Estimate |
| GB_W_PER_FT2 | 50 | W/ft² of dimmable capacity | GenetixBay recommendation: oversize and dim down. Too much is better than not enough | House position (founder) |
| AC_MARGIN | 0.2 | + | Cooling margin over the calculated load (homes keep within ~15%; grow rooms run near flat out, so 20% is common) | Grower practice |
| AC_EER | 10 | BTU/h per W | Rough efficiency of a room or portable AC, for the electrical estimate (mini-splits do better) | Estimate |
| FAN_W_PER_CFM | 0.12 | W per rated CFM | Rough power draw of an EC mixed-flow inline fan at full speed (for the planner's electrical total) | Estimate |
| DEHU_MARGIN | 1.25 | × | Dehumidifier margin over the average daily water (the AC also pulls water while it runs) | Grower practice |
| CONTINUOUS | 0.8 | × breaker rating | Continuous loads (3 h or more, which every grow light is) may use only 80% of the breaker | Established (code) |

## Sources

1. NIST. Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors (1 W = 3.412 142 BTU/h; 1 ft³ = 0.028 316 8 m³; 1 US gal = 3.785 412 L). https://www.nist.gov/pml/special-publication-811
2. ASHRAE. 2021. ASHRAE Handbook: Fundamentals. Ch. 1 (psychrometrics: sensible heat of air, q = 1.08 × cfm × ΔT at standard air), Ch. 18 (heat gain from people, lighting and equipment), Ch. 21 (duct design: fitting and friction losses), Ch. 26–27 (thermal resistance of building assemblies). ASHRAE, Atlanta. https://www.ashrae.org/technical-resources/ashrae-handbook
3. GenetixBay Knowledge Base. LED vs HPS: the heat and power-bill hype, and an LED buyer-beware guide (fixture µmol/J tiers, 85% canopy capture, watt-for-watt house advice, 1 W = 3.412 BTU/h). https://genetixbay.com/knowledge/equipment/led-vs-hps-hype-and-buyer-beware.html
4. GenetixBay Knowledge Base. Airflow: air exchange, canopy air speed and fan placement (one tent volume every 1–3 min; +25–50% for a carbon filter and ducting; passive intake ≈ 2–3× exhaust duct area). https://genetixbay.com/knowledge/environment/airflow.html
5. GenetixBay house position (founder's field experience, decades of indoor rooms): passive intake for most growers; oversize lights and dim down; replace HPS watt for watt unless the LED is top tier. https://genetixbay.com/editorial-policy
6. Rodriguez-Morrison V, Llewellyn D, Zheng Y. 2021. Cannabis yield, potency, and leaf photosynthesis respond differently to increasing light levels in an indoor environment. Frontiers in Plant Science 12:646020. https://doi.org/10.3389/fpls.2021.646020
7. ACCA. Manual S: Residential Equipment Selection (cooling equipment kept close to the calculated load; oversizing short-cycles and dehumidifies poorly). https://www.acca.org/standards/technical-manuals/manual-s
8. US DOE. 10 CFR 430 Subpart B, Appendix CC: Uniform test method for portable air conditioners (seasonally adjusted cooling capacity, which counts the infiltration a single-hose unit causes). https://www.ecfr.gov/current/title-10/chapter-II/subchapter-D/part-430/subpart-B/appendix-Appendix%20CC%20to%20Subpart%20B%20of%20Part%20430
9. GenetixBay survey of published free-air ratings for mixed-flow inline fans sold for grow rooms, 2026 (ranges only; no brands).
10. NFPA 70, National Electrical Code (2023): Art. 100 (continuous load = 3 hours or more), 210.19(A)(1) and 210.20(A) (conductors and breakers at 125% of continuous load, i.e. load ≤ 80%), 210.8 (GFCI locations), 400.12 (flexible cords not a substitute for fixed wiring). https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70
11. CSA C22.1, Canadian Electrical Code, Part I: Rule 8-104 (continuous loads limited to 80% of the breaker rating) and Rule 26-700 series (receptacles and GFCI). https://www.csagroup.org/store/product/CSA%20C22.1:24/
12. GenetixBay Knowledge Base. PPFD and DLI by stage, with the evidence (stage targets; DLI = PPFD × hours × 0.0036). https://genetixbay.com/knowledge/environment/ppfd-dli-by-stage.html
13. GenetixBay Knowledge Base. CO₂ enrichment (targets 800–1,200 ppm at lights-on only; worth it only sealed and at high light). https://genetixbay.com/knowledge/environment/co2-enrichment.html