Determining Supplemental Lighting

Welcome to our tools page!
The tools below will help growers better understand the supplemental lighting needs in their greenhouses.

How many light fixtures do you need?


Determine how many lighting fixtures you need for supplemental lighting in your greenhouse with this calculator. To use the lighting fixtures calculator you will need to download the linked file and open it in Excel. For directions and more info…


LAMP Lighting Cost Calculator


Estimate supplemental lighting costs in your greenhouse with this calculator. Our LAMP Lighting Calculator onto an online application. For more info…

LAMP Lighting Cost Calculator – Excel


Estimate supplemental lighting costs for your greenhouse. To use this calculator you will need to download the file once opened in Excel. To add a custom location, instructions are linked below. For directions and more info…

DLI Interactive Maps USA


Find monthly averages for Daily Light Integrals (DLIs) for any US location by using this interactive map developed by colleagues at UT and Clemson. For more info…

Use this calculator (© Neil Mattson, Cornell University 2015) to estimate how many light fixtures you need in your greenhouse to meet your supplemental lighting needs. After opening this link, you will need to download the file into Excel for use. Once downloaded fill in your information in the yellow highlighted fields. Do not modify any boxes or go into the pink fields. Note: the placement of lamps should be determined by a lighting professional for light uniformity in the greenhouse. The number of lamps needed may be somewhat more if you want uniform lighting edges of the growing space and to account for spillage of light at the edges.

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This tool was developed for greenhouse growers as part of Project LAMP to estimate the electricity costs of supplemental lighting. You can add a location anywhere in the United States and provide your electricity rate at that location ($/kWh). Add the daily light integral (DLI) you want to achieve and a greenhouse design to get estimated electricity cost results. This is a web-based app. The lighting cost calculator provided below performs the same calculations but through an Excel spreadsheet version. Here is a video demonstration of the LAMP Lighting Cost Calculator Web App.

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LAMP Lighting Cost CalculatorExcel version

This tool was developed for greenhouse growers as part of Project LAMP to estimate electricity costs for supplemental lighting. This is the same lighting cost calculator provided above but this version is formatted in Excel. Select the link and download the file to Excel to use the calculator. Provide in the highlighted fields in the ‘Input and Output’ tab your target DLI, greenhouse design parameters and electricity rate. Select a location to get cost estimates or add your own (within the US). For directions on how to add your own location to the calculator, follow this link: Add a Location to Excel-LAMP Lighting Cost Calculator

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When thinking about supplemental lighting, it is important to know how much sun light you have in your location. Joanne Logan (University of Tennessee) and Jim Faust (Clemson University) developed these interactive maps of the average daily light integrals (DLI) throughout the US. You can find monthly averages for the DLI for any location. Keep in mind that this is the DLI outside. To calculate the DLI inside your greenhouse, you need to know how much of the sunlight is transmitted into the greenhouse. Light transmission depends on the glazing material and configuration of your greenhouse, how old it is, and how clean it is. Transmission can range anywhere from 35% to 80%. Here is a short video on light transmission, produced by the E-Gro team.  

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