Switch from HPS to LED Lighting

Four Factors To Consider When Choosing LED Greenhouse Lights

LED Greenhouse lights

Light is a limiting factor in greenhouses in the winter. Supplemental lighting can often offset the effects of darker, shorter days. Many growers have come to rely on LED lighting to increase their crop quality and yield. 

LED horticulture lighting has myriad benefits for your plants. The ability to experiment with varying light spectrums allows you to customize everything from potency to smell to color. LED grow lights are more energy efficient and produce less heat than options like HID lighting. However, investing in any new lighting system is a major decision – and not one to be taken lightly. 

Before investing in LED lighting, it is important you have a rough idea of the cost of setting up and maintaining your system. Below, we will break down important factors to consider when investing in a supplemental lighting system. 

Your Daily Light Integral 

The daily light integral (DLI) is the total amount of photosynthetically active radiation your plants receive each day from the sun. It is measured in moles (one mole = 6.02214076 × 1023 photons!) of photons per square meter per day.  You do not need to be an expert on the science to understand what your plants need. You just need to have a rough understanding of the ideal DLI for your plants, the general DLI levels inside your greenhouse, and how much DLI must be generated by supplemental lighting. 

For example, imagine you are growing a type of plant that thrives with a DIL of 14 and the average outdoor DLI during the winter in your area is 10. A greenhouse will usually transmit only about 65% of that light, meaning your greenhouse DLI is 6.5 in the winter. This means – during winter – 7.5 of your DLI must come from supplemental lighting. 

This information can help you measure the rough light intensity you will need when choosing LED lights. LED lights have a measurement called the Photosynthetic Photon Flux Density (PPFD), measured in micromoles or uMoles (one uMol = 1 millionth of a mole) per square meter per second. This determines roughly how much usable light your plants receive from your lighting setup. 

Once you know the amount of DLI you must generate from supplemental lighting, there is a calculation you can do to determine the rough PPFD range you should look for in a LED lamp. Multiply the amount of DLI you need through supplement lighting by 1,000,000 and then divide it the number of hours you will be running lamps per day. Then, divide this amount by 3,600. 

In our example, say you will be running your lights 20 hours a day. Your calculation would be 7.5 X 1,000,000 divided by 20 divided by 3,600. This comes out to roughly 104 umol. Look for lamps with a PPFD within that range. 

The Effects On Plant Temperature 

One reason LED lighting is becoming increasingly popular is because they generate significantly less heat than HPS lighting. This is – for the most part – a positive as it helps your temperature stay stable and saves cost on air conditioning and fans. In the winter, however, this can pose a slight setback you will need to consider. 

Plants are usually 1 to 2 degrees warmer under HPS lamps. While usually this increase in heat is a source of frustration, in the winter plants often benefit from the added heat. If you are making the switch to LED lighting – or simply starting off with an LED setup – you need to take this into consideration when estimating cost.  

Heating inputs over the winter may need to be increased when working with LEDs – especially if you are growing year-round. Make sure you know the ideal temperature for your plants, the expected temperature dip in the winter, and the rough cost of heating your greenhouse to an adequate temperature. 

While there is sometimes extra cost associated with LED lighting in the winter, keep in mind that any added cost is usually offset by significantly lower costs on air conditioning and fans over the summer months. 

Your Rough Operating Costs 

A lot of factors go into operating costs. Getting a quote from a reputable company is the best means to determine a rough estimate – especially if you are new to LED lighting. There is some information you should know going into a consultation. 

How many hours will your lamps operate per year? Do you plan on running your lights 20 hours per day 365 days per year, for example, or will you be running lights longer or shorter depending on the time of year? The aforementioned DLI estimates can help you determine how often you need to run your lights to provide ideal conditions for your plants.  

What is the electrical capacity of the lights you are considering? LED lighting comes with a higher price tag upfront, but on the plus side operating costs are much lower due to their energy efficiency. While you may pay more for purchase and installation, you may gain a faster return on investment due to the efficiency of LED lighting. 

Having a rough answer to the above questions can help you get a reasonably accurate quote on your operating costs. Keep in mind, a professional can help you parse through this information if you are at all uncertain. You can reach out here to talk to someone from California Lightworks about pricing. 


Accidents happen with even the best made lights. As LED lights cost more upfront, you should absolutely opt for lamps that come with warranties. If a fixture is damaged due to factors beyond your control – like a manufacturing defect or damage accrued during shipping – you do not want to be out thousands of dollars needlessly. 

At California Lightworks, we have a 90 day money back guarantee if you are unsatisfied with your lamps for any reason. Our SolarXtreme products have a three year limited warranty against manufacturing defects and our SolarSystem and Greenhouse Professional products have a five year limited warranty. 

The Bottom Line 

LED lighting can help you grow better crops and save money in the long run. More and more companies and private growers are making the switch to LED lighting. While this is a wise investment, it is also a complicated one that requires careful consideration and budgeting. 

At California Lightworks, we are always here to help growers of all levels reach their full potential. If you have any questions about making the switch to LED lighting, feel free to reach out any time. 


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