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Grow Lights: Which One Really Costs Less?

Grow Lights: Which One Really Costs Less?

Alex Grady

Don’t be fooled into thinking that the cheapest grow light costs less overall – that’s just false economy. After all, better lights cost less to run, last longer and give better yields, which can lead to huge savings.

How much could you save by switching? Find out now.

When working out which grow light really costs less, you need to consider:

  • Initial cost
  • Running cost
  • Light intensity (how much is the extra yield worth?)
  • Lamp life
  • Light quality (spectrum, frequency)
  • Reflector quality
  • Ballast type (more on ballasts here)
  • Is it worth getting a tent & lighting kit?


If you’ve got a tight budget, magnetic ballasts will get the job done. But, you’ll save tons in the long run with a digital ballast.

Digital Ballasts

  • Use 3 - 4% less energy (per light!)
  • Need replacing less often (digital = 10 years, magnetic = 3 years!)
  • Lead to a longer lamp life
  • Greater frequency (better output, accurate colour rendering)
  • Are dimmable – easier, safer, more flexible
Digital ballast

Since digital ballasts are dimmable, you won't need a separate light when you want a lower intensity, which can be a huge space saver and cost saver.

Cost Calculator:

Magnetic: 600W BAY6 Ballast - £14.98 per year (£44.95 initial cost, over 3 yrs)

Digital: 600W Exolux Pro Ballast - £10.99 per year (£109.95 initial cost, over 10 yrs)

If you can get a 400V digital ballast (like the one that comes with GAVITA lighting systems) you’re really onto a winner. You’ll get 8% more light, which produces better growth and on average 10% higher yields compared to 230V.

More on ballasts here.

Light Intensity / Light Output

Light intensity is directly proportional to loss in yield.

1% of light = roughly 1% of your overall yield.

It doesn’t sound like a lot, until you look at an example: GAVITA grow lights produce 8% more grow light, leading to a 10% yield increase.

The question you need to ask, is how much that extra yield is worth.

If you’re going to measure light output…

… forget about lumens – measure micromoles.

Plants only use wavelengths of light between 400nm – 700nm for growth (the PAR range).

Light Intensity / Light Output

Lumens tell you how much light is emitted overall (some can’t be used by plants for growth)

Micromoles tell how many particles of light from the PAR range are emitted (all plant usable)

More on measuring light here

Lamp Light Maintenance

Some lamps are faster to degrade than others (more on lamp degradation here).


  • 600W BAY6 Lamps: Need replacing every 3 - 6 months
  • 600W GAVITA Grow Lamps: Need replacing every year

To keep costs low, you can replace your BAY6 lamp every 6 months, in which case BAY6 lamps cost less.

However, to maximise light, some growers replace them every 3 months. If you’re one of these growers, you’d spend less on lamps and get much more light if you had a GAVITA grow light.

Lamp Light Maintenance

Reflector Build

Around 50% of light emitted by your grow lamp is focussed down by your reflector. That’s a lot of light.

That means that every 1% of reflectivity lost costs you 0.5% of your yield!

It’s why you need a good reflector.

The best ones are made from 96/97% reflective vega / MIRO® aluminium.

Reflector Build

Can you Save Money with a Tent & Light Kit?

Normally, yes – if you don’t already have a suitable tent.

Firstly, it’s cheaper to buy the kit than it would be to buy everything in it separately.

Secondly, you know you’re getting the right tent, so you don’t have to worry about:

  • Losing light and yield with the wrong shape & size tent
  • Spending extra money countering heat problems
  • Overpowering plants

Instead, you’ll get a tent that:

  • Maximises light to plants
  • Suits the shape of your reflector/s
  • Supports your light intensity
  • Lessens the chance of heat problems
Tent & Light Kit?

The tents that feature in the G1 and G2 Tent Kit were actually designed specifically to support GAVITA’s high intensity lights. Your yields will be phenomenal!

More on grow tents here.

Example Comparison:

Gavita 600W Lighting Systems BAY6 600W Lighting System
Lamp Life 1 year (recommended) 3-6 months (recommended)
Warranty 3 years 1 year
Ballast Energy-Saving 3-4% per ballast 0
Output Stable, constant Dependant on supply
Yield Increase 10% increase 0
Ballast Life 10 years (recommended) 3 years (recommended)
Dimmable Yes No
Controllable Yes No
Light Output Medium High

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