700W LED Grow Lights

Not if you're pushing for maximum yield. A 700W LED in a 4x4 delivers roughly 44 watts per square foot, which translates to 900-1200 µmol/m²/s PPFD at 18 inches. That's the intensity range where most cultivars hit peak photosynthetic efficiency during flowering. If you're growing lower-light plants or want to reduce electricity costs, you can dim to 60-80% power and still outperform most 400-500W fixtures.

Roughly 30-40% of input power converts to heat with modern LEDs at 2.7+ µmol/J efficiency. That's 210-280 watts of thermal output, similar to a small space heater. However, this heat radiates from a large surface area (8-bar designs especially) rather than a concentrated point like HPS. Result: 5-10°F lower canopy temperatures and easier climate control. Most growers need only basic exhaust fans rather than dedicated AC units.

If you're working with 4x4 spaces, 700W hits the efficiency sweet spot. 900W fixtures make more sense for 5x5 or larger footprints where you need sustained high PPFD across more area. The jump from 700W to 1000W adds cost and heat without proportional yield gains unless you're covering 30+ square feet. For most tent growers, 700W provides the best cost-per-photon ratio.

Most commercial-grade 700W LEDs support daisy-chaining via RJ12 or RJ45 data cables. This lets you control dimming and photoperiods across multiple fixtures from a single controller. Brands like GrowPros, Iluminar, and Medic Grow support this natively. Just verify your circuit can handle the amp load; three 700W fixtures at 120V pull roughly 17.5 amps, so you'll need dedicated 20-amp circuits for safety.

Rated lifespans hit 50,000-80,000 hours, but practical performance depends on operating temperature and power cycling. Run your 700W fixture at 80-90% power with good ventilation and you'll maintain 90%+ output for 5-7 years of continuous use. Most quality manufacturers include 5-year warranties, so driver or diode failures within that window get covered. Always register your product to activate full warranty protection.

For overhead canopy lighting, a single 700W unit handles 4x4 flowering just fine. Where supplemental lighting shines is under-canopy penetration. Adding under-canopy LED bars beneath your main fixture improves lower-bud development significantly, especially in dense Sea of Green setups. UV bars can also boost terpene and trichome production during the final 2-3 weeks of flowering. Check out our guide on why under-canopy lighting matters.

Start seedlings at 30-36 inches with power dimmed to 40-50%. As plants enter vegetative growth, lower to 24-30 inches at 60-80% power. During flowering, drop to 18-24 inches at full power for maximum intensity. Always use a PAR meter rather than fixed distances; your target is 200-400 µmol/m²/s for veg and 800-1200 µmol/m²/s for flower. For more details, read our article on understanding grow light wattage.

A 1000W HPS with ballast draws 1100-1150 watts at the wall. A 700W LED pulls exactly 700 watts while delivering equivalent photon output. At $0.12/kWh electricity rates, that's $57/month savings per fixture running 18 hours daily. Factor in reduced HVAC costs from lower heat output, and most growers see 12-18 month payback periods. Your bulbs never need replacing either, unlike HPS lamps that degrade after 2-3 grows.