HPS and MH 700-800W Lamps: High-Power Lighting for Your Indoor Grows
HPS and MH lamps of 700-800W represent the high-end of traditional indoor grow lighting. This power range offers exceptional light intensity, perfect for medium to large grow spaces and growers who want to maximize their yields. Whether you opt for HPS during flowering or MH during vegetative growth, this power ensures optimal light penetration even on tall plants.
Why choose 700-800W lighting for your setup
Frankly, when we talk about 700-800W, we're entering the big leagues. This power delivers between 90,000 and 120,000 lumens depending on the model, which is more than enough to effectively cover a surface area of 1.2x1.2m to 1.5x1.5m. This is where it makes all the difference compared to lower wattages: light penetration easily reaches 80-100cm deep into the canopy.
700-800W HPS lamps excel in flowering with their red-orange spectrum that stimulates flower and fruit production. Their luminous efficacy is around 140-150 lm/W for the best models. MH lamps of this wattage, on the other hand, dominate in vegetative growth thanks to their blue-white spectrum which promotes compact and vigorous development of young plants.
Another significant advantage: the heat generated. With 700-800W, you produce enough heat to maintain a stable temperature even in winter, which can significantly reduce your auxiliary heating costs.
How to choose your 700-800W lamp
First criterion: available space. A 700W lamp is perfect for a 1.2x1.2m space, while an 800W can cover up to 1.5x1.5m without a problem. Ceiling height also matters: plan for a minimum of 2.5m to be able to hang your lamp 60-80cm from the plants without risking burning them.
Technically, check compatibility with your ballast. 700W models often require specific ballasts, while 800W models are generally compatible with 1000W ballasts set to a reduced position. Lifespan varies between 10,000 and 24,000 hours depending on the manufacturer's quality.
Don't forget extraction: with this power, plan for a minimum of 600-800 m³/h of extraction to effectively evacuate heat. An enclosed reflector with dedicated extraction can reduce the thermal load in your grow space by 30%.
Frequently Asked Questions
Which 700-800W HPS or MH lamp should I choose to replace my old setup?
It all depends on your current grow phase. If you are replacing a flowering setup, opt for a 750W HPS which offers the best efficiency/heat compromise. For vegetative growth, a 750W MH will be perfect. Make sure your ballast supports this wattage – old 600W ballasts are not compatible. If you have a 1000W ballast, an 800W lamp will work perfectly in a reduced position. The investment quickly pays for itself thanks to the increased yield, generally +20-30% compared to a 600W.
At what height should I hang a 700-800W lamp to avoid burning plants?
The optimal distance is between 60 and 80cm from the top of the plants for a 700-800W lamp. Start at 80cm and gradually move closer while monitoring for signs of heat stress: leaves curling upwards or tip bleaching. With an air-cooled reflector, you can go down to 50-60cm without a problem. Use the hand test: if you feel uncomfortable heat at canopy level, it's too close. Foliar temperature should never exceed 28°C, ideally staying between 24-26°C.
What will be my monthly electricity consumption with a 700-800W lamp in an indoor grow?
A 700W lamp consumes exactly 0.7 kWh per hour of use, or 8.4 kWh per day on a 12/12 cycle or 16.8 kWh on an 18/6 cycle. Over a month (30 days), count 252 kWh during flowering and 504 kWh during vegetative growth. With a standard electricity rate of €0.20/kWh, this represents approximately €50/month during flowering and €100/month during vegetative growth. An 800W adds about 15% to these figures. Don't forget to include the ballast consumption (an additional 5-10%) and continuous forced extraction.
Does a 700-800W lamp heat a 1.2x1.2m tent enough in winter?
Absolutely, and often too much! A 700-800W lamp emits between 600 and 700W of pure heat, equivalent to a small electric heater. In a well-insulated 1.2x1.2m tent, you will easily maintain 24-26°C even at -5°C outside. The challenge will rather be not to overheat: plan for variable extraction and possibly regulated fresh air intake. In the middle of winter, you can even reduce extraction to a minimum to retain heat, which also reduces noise pollution.
How to clean and maintain a 700-800W HPS/MH lamp so that it lasts a long time?
Maintenance begins with monthly dusting of the reflector with a slightly damp microfiber cloth – never direct water on a hot bulb! Replace the bulb every 12-18 months even if it still works: after 12 months, it loses 20-30% of its luminous efficacy. Regularly check electrical connections and replace the reflector if the aluminum becomes too dull. A clean and shiny reflector can improve light reflection by 15%. Store spare bulbs upright, in their original packaging, away from humidity.
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