Most people probably assume that when they use a high-intensity discharge (HID) (most commonly a High Pressure Sodium (HPS) or Ceramic Metal Halide (CMH)), going to be drawing near enough the exact power referenced on the box. For example, a 600w HPS will use 600 watts of electricity, a 315w CMH will use 315 watts. This simply isn't true.
That number being used will be based upon the bulb’s draw, not the system’s. The full system will invariably use more than that.
So how much more?
You're looking at about 10% on a good quality digital ballast, more on a magnetic. We’ve provided three examples below: digital 600w HPS, 600w 400V HPS and 315w CMH.
As you can see from the photo, a traditional 600w HPS light on a digital ballast, will use 667+ watts of your electricity.
As you can see from the photo, a 600w, 400V HPS light will use 635+ watts of your electricity.
We tested a CMH in the same way. Again, as you can see from the photo, a traditional 315w Ceramic Metal Halide light will use quite a bit more than what you'd think; in this case 339+ watts of your electricity.
Always check you wattage with a power meter, you can find them for sale in our tools section here https://diyleduk.com/collections/grow-room-tools/products/plug-in-power-meter
Want to work out your running costs? Try our calculator download here https://diyleduk.myshopify.com/admin/articles/384181567585