Do Grow Lights Use a Lot of Electricity? [A Quick Guide]

Indoor grow lights

As you probably know, the use of grow lights has become more and more popular in recent years.

This is likely due to the increased awareness of the importance of proper lighting for indoor plants. After all, if you want your plants to thrive, you need to give them light that mimics natural sunlight as closely as possible.

And while there are a number of different types of grow lights available on the market today, one question that many people have is whether or not these lights use a lot of electricity.

In this article, we will take a closer look at how grow lights work and also explore the amount of electricity they typically use. So read on to learn more!

How Grow Lights Work

Grow lights are specially designed bulbs that emit light at specific wavelengths.

The most common type of grow light is the high-pressure sodium (HPS) bulb, which emits light in the red and orange part of the spectrum. This light is ideal for plants that are in the flowering or fruiting stage, as it encourages them to produce more flowers and fruits.

Grow lights can be used to supplement sunlight, or they can be used as the sole source of light for indoor plants.

When using grow lights, it is important to make sure that the plants are getting enough light. Too much light can damage plants, just as too little light will prevent them from growing.

We have a whole article on how long grow lights should be on for here if you’re interested!

How Much Electricity Do Grow Lights Use?

Indoor grow lighting above plants 

The amount of electricity that grow lights use depends on the type of lightbulb, the number of lightbulbs, and the length of time the light is left on.

For example, a single HPS bulb uses about 150 watts of electricity. If you leave the light on for 12 hours a day, it will use about 1,800 watts of electricity per day.

To calculate the cost of running your grow lights, you will need to know the price of electricity in your area. The average price of electricity in the USA is about $0.166 p/ kWh, while in the UK it’s about £0.189p p/kWh. This means that if you leave a 150-watt HPS bulb on for 12 hours, it will cost about £0.34 to run the light for one day in the UK, or $0.29 to run in the USA.

To put this into perspective, a 100-watt lightbulb left on for the same amount of time would cost about £0.22 per day in the UK ($0.19 in the USA). So, while grow lights do use more electricity than traditional lightbulbs, the difference is not as significant as you might think.

If you have multiple grow lights, you can use this formula to calculate the cost of running all of your lights:

(Number of lightbulbs x wattage of each bulb x number of hours the light is on) / 1000 x price of electricity.

For example, if you have two 150-watt HPS bulbs and you leave them on for 12 hours a day, the cost of running both lights would be about £0.68 per day ($0.58 in the US).

Are Grow Lights Expensive to Run?

While grow lights can be expensive to purchase, they are not necessarily expensive to run.

When compared to other appliances in your home, grow lights use a relatively small amount of electricity. For example, a typical refrigerator uses about 30 times more electricity than a 150-watt HPS bulb.

To save money on your electric bill, you can try using energy-efficient grow lights or timers to turn off the lights when they are not needed.

You can also reduce the number of hours you leave the lights on. For example, if you only need the grow lights for 8 hours a day, you can turn them off for 4 hours and save about 50% on your electric bill.

Compared to Other Lighting Options - Final Thoughts

Grow lights are more expensive to purchase than traditional lightbulbs, and they are slightly more expensive to operate than some other lighting options.

There are workarounds however. For example, fluorescent grow lights use about half as much electricity as HPS bulbs. LED grow lights are even more efficient, using about one-tenth as much electricity as HPS bulbs.

So, if you are looking for a cheap way to light your plants, grow lights may not be the best option. However, if you are willing to spend a little more money on your electric bill, grow lights can be a great way to provide your plants with the light they need.


Frequently Asked Questions

Will grow lights burn plants if they are set up too close?

Yes, if you position your grow lights too close to your plants, you risk burning/scorching their leaves.

We have a whole article about this here, as well as tips on how to prevent it from happening when building your indoor plant grow setup.

Is an indoor garden a good idea for growing plants?

Yes! Indoor gardens can be extremely efficient for growing plants, as well as a fun hobby or side hustle to take your mind off work.

The most important part of the set up will undoubtedly be installing your grow lights, as this will be the main determinant of your plant growth. Check out our article all about how to hang ceiling grow lights here.