What is the LED equivalent to 400w MH light?

Old 11-02-15, 06:16 AM
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What is the LED equivalent to 400w MH light?

I need to replace 4 garden lights and was wondering about the economics of changing the bulbs vs changing the fixtures for LED.

What would be the LED equivalent in watts and how much longer would they last?
Old 11-02-15, 08:50 AM
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Just look at the specs regarding the lumen output of the lights you are considering. In general I think you'll find LED's that equal a metal halide to be quite expensive especially if your lights are higher wattage and that might end the search before you even get to matching the light output
Old 11-02-15, 09:06 AM
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Search LED street lights and you will find lights and prices in that range. Just be sitting down.

Old 11-02-15, 09:49 AM
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If you just look at initial lumens per watt, MH and high efficiency LEDs overlap, with the best LEDs exceeding l/w of MH. But there are a lot of other factors. MH drop to something like 60% of initial output pretty fast, in a year or two depending on duty cycle, where LED's generally stay around 90% of initial lumens. MH radiate light in all directions so the fixture reflector efficiency is a factor, and that can be as bad as 75%. Most LEDs are directional, which is ideal for high mounted downlights.

So, with top quality LEDs and fixtures you may get as much usable light from 200-300 watts of LED's as you do from your 400 watt MH. They will last much longer, especially if you factor in changing MH bulbs every couple of years to maintain high output. The initial cost will be high, offset over time by lower power use and no re-lamping cost.

If you're using these as grow lights, you also have to consider the spectrums of the two sources.

Bottom line, as almost always: it depends on specifics of your situation.

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