Keep in mind these are BASIC GUIDELINES that I have collected reading 420. Enjoy!
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Lumens At Height:
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A 1000w HPS will put out ~140,000 lumens at 1' away
A 1000w HPS will put out ~35,000 lumens at 2' away
A 1000w HPS will put out ~15,555 lumens at 3' away
600W (150 lumens per watt):
1' away: 90,000 Lumens
2' away: 22,500 Lumens
3' away: 9,999 Lumens
4' away: 6,428 Lumens
400W (125 lumens per watt):
1' away: 50,000 Lumens
2' away: 12,500 Lumens
3' away: 5,555 Lumens
4' away: 3,571 Lumens
We are advised to keep:
1000w HPS; ~3' above the tops, at 3' the 1000w put out 15,555 lumens.
600w HPS; ~2' above the tops, at 2' the 600w put out 22,500 lumens.
400w HPS; ~1' above the tops, at 1' the 400w put out 50,000 lumens.
A 1000w hps puts out approx. 140,000 lumens at 1', but this falls off to 15,555 lumens at 3'.
A 400w hps puts out approx. 51,000 lumens at 1'.
So, placing a 400w 1' above the plant will put out more than 3 times the lumens that a 1000w will at 3'.
However the 400w can't cover the area the 1000w can.
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Determining Lumens For Your Grow Area:
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We are advised to have a minimum of 3000 lumens per sqft. The sun gives off 10,000 lumens per sqft on a bright hot sunny day. We are advised to have 3000L to 7000L per sqft.
First determine the square footage of your area.
Example in a 4 foot by 4 foot area, there is 16 square feet, 2 x 2 feet is 4 Sq ft.
Divide the total amount of Lumens, by the total amount of square feet, and that's your lumens per square foot.
Example a 1000 Watt High Pressure Sodium Light Bulb produces approx 140,000 lumens. Divide this by 16 (your square footage) and 140,000 / 16 = 8750 lumens per square foot.
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Venting:
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There are a lot of variables when it comes to venting. How much CFM to use to cool lights, exchange air, static pressure, flow restriction for ducting and filters, ect.
These are some BASIC concepts to help you on your way.
The rule of thumb is to exchange the air (or more importantly the CO2) in your grow area every 5 minutes. When dealing with added Heat, that changes to every 1-2 minutes. (basic guideline)
Fans are rated at Cubic Feet per Minute (CFM), or how much air can they move in 1 minute.
You need to calculate the cubic feet of your grow room. Length x Width x Height = Cubic Feet.
Example: 4' x 4' x 7' = 112cft
To exchange the air every 5 minutes you would need
112cft / 5min = 23CFM
To exchange the air every 1 minute you would need 112CFM
To exchange the air every 2 minutes you would need 56CFM
Here is where you need to start calculating duct and filter restrictions, how much air is needed to cool your light, static pressure, ect.
A starting point would be a 6" 400CFM vent fan for a 400W or 600W HID. And of course this will VERY GREATLY on your setup and circumstances.
It is important to remember that a good rule of thumb is to have matching intake to exhaust, whether passive or not.
(this is where static pressure comes in and I stop)
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How Much $$ To Run My Light:
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Here is an explanation to help you figure out your own usage...
I found the formula... this assumes $0.12 per KW hour price.
(If you pay a different amount change the formula below)
Explanation: Watts used by device x hours used over the course of a month = total watt hours
Example: 400 watts x 24 hours a day x 30.5 days a month = 292,800 Wh
Explanation: Now you have to convert Wh (watt hours) to kWh (kilowatt hours). Wh / 1000 = kWh
Example: 292,800 Wh / 1000 Wh = 293 kWh
Explanation: Now take you kWH and multiply it by the price you pay your electric provider
Example: 293 kWh x 12¢/kWh = $35.16 a mo. or $422 a yr.
When you buy electricity they charge you by the kilowatt-hour (kWh). When you use 1000 watts for 1 hour, that's a kilowatt-hour.
Understand that a HPS may use a little more due to ballast, age of ballast and light, and small amount for a timer unit.
So with a 400 watt HPS going 12/12, an oscillating fan, and a 6" inline fan, the total cost for the month would be approx $30.05. (at $0.12 per kW per hour — Check your electric bill for your rate.)
=======================================
Lumens At Height:
=======================================
A 1000w HPS will put out ~140,000 lumens at 1' away
A 1000w HPS will put out ~35,000 lumens at 2' away
A 1000w HPS will put out ~15,555 lumens at 3' away
600W (150 lumens per watt):
1' away: 90,000 Lumens
2' away: 22,500 Lumens
3' away: 9,999 Lumens
4' away: 6,428 Lumens
400W (125 lumens per watt):
1' away: 50,000 Lumens
2' away: 12,500 Lumens
3' away: 5,555 Lumens
4' away: 3,571 Lumens
We are advised to keep:
1000w HPS; ~3' above the tops, at 3' the 1000w put out 15,555 lumens.
600w HPS; ~2' above the tops, at 2' the 600w put out 22,500 lumens.
400w HPS; ~1' above the tops, at 1' the 400w put out 50,000 lumens.
A 1000w hps puts out approx. 140,000 lumens at 1', but this falls off to 15,555 lumens at 3'.
A 400w hps puts out approx. 51,000 lumens at 1'.
So, placing a 400w 1' above the plant will put out more than 3 times the lumens that a 1000w will at 3'.
However the 400w can't cover the area the 1000w can.
=======================================
Determining Lumens For Your Grow Area:
=======================================
We are advised to have a minimum of 3000 lumens per sqft. The sun gives off 10,000 lumens per sqft on a bright hot sunny day. We are advised to have 3000L to 7000L per sqft.
First determine the square footage of your area.
Example in a 4 foot by 4 foot area, there is 16 square feet, 2 x 2 feet is 4 Sq ft.
Divide the total amount of Lumens, by the total amount of square feet, and that's your lumens per square foot.
Example a 1000 Watt High Pressure Sodium Light Bulb produces approx 140,000 lumens. Divide this by 16 (your square footage) and 140,000 / 16 = 8750 lumens per square foot.
=======================================
Venting:
=======================================
There are a lot of variables when it comes to venting. How much CFM to use to cool lights, exchange air, static pressure, flow restriction for ducting and filters, ect.
These are some BASIC concepts to help you on your way.
The rule of thumb is to exchange the air (or more importantly the CO2) in your grow area every 5 minutes. When dealing with added Heat, that changes to every 1-2 minutes. (basic guideline)
Fans are rated at Cubic Feet per Minute (CFM), or how much air can they move in 1 minute.
You need to calculate the cubic feet of your grow room. Length x Width x Height = Cubic Feet.
Example: 4' x 4' x 7' = 112cft
To exchange the air every 5 minutes you would need
112cft / 5min = 23CFM
To exchange the air every 1 minute you would need 112CFM
To exchange the air every 2 minutes you would need 56CFM
Here is where you need to start calculating duct and filter restrictions, how much air is needed to cool your light, static pressure, ect.
A starting point would be a 6" 400CFM vent fan for a 400W or 600W HID. And of course this will VERY GREATLY on your setup and circumstances.
It is important to remember that a good rule of thumb is to have matching intake to exhaust, whether passive or not.
(this is where static pressure comes in and I stop)
=======================================
How Much $$ To Run My Light:
=======================================
Here is an explanation to help you figure out your own usage...
I found the formula... this assumes $0.12 per KW hour price.
(If you pay a different amount change the formula below)
Explanation: Watts used by device x hours used over the course of a month = total watt hours
Example: 400 watts x 24 hours a day x 30.5 days a month = 292,800 Wh
Explanation: Now you have to convert Wh (watt hours) to kWh (kilowatt hours). Wh / 1000 = kWh
Example: 292,800 Wh / 1000 Wh = 293 kWh
Explanation: Now take you kWH and multiply it by the price you pay your electric provider
Example: 293 kWh x 12¢/kWh = $35.16 a mo. or $422 a yr.
When you buy electricity they charge you by the kilowatt-hour (kWh). When you use 1000 watts for 1 hour, that's a kilowatt-hour.
Understand that a HPS may use a little more due to ballast, age of ballast and light, and small amount for a timer unit.
So with a 400 watt HPS going 12/12, an oscillating fan, and a 6" inline fan, the total cost for the month would be approx $30.05. (at $0.12 per kW per hour — Check your electric bill for your rate.)
But here it is..., the 430 watt Son Agro HPS. Two bulbs are available. There's a standard Phillips 430 and my weapon of choice... The Eye Hortilux 430 watt Super HPS packing 58,000 lumens at 12". I run two of these haymakers + some LED for bloom
Thanks Bandit! I appreciate the add, you ROCK! 
