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DAYTRONIC - How to save energy on fluorescent lighting

What is a DAYTRONIC Daylight Harvesting Ballast?

DAYTRONIC Sets (ballast + sensor) are a popular energy saving solution for fluorescent lighting. With these you can lower your electricity consumption in all areas that receive some daylight (e.g through windows or skylights).

DAYTRONIC Daylight Harvesting Ballast website link



Typical applications include

  • Offices
  • Schools / Classrooms
  • Corridors
  • Warehouses and factories

DAYTRONIC ballasts are a special type of high frequency electronic dimming ballasts. They are specially designed for Daylight Harvesting (Daylight Dimming) operation.

light fitting
(ballast + sensor)
= Energy Saving Luminaire


What is Daylight Dimming / Daylight Harvesting?

Daylight Harvesting

  • Is a very effective energy saving concept
  • Means that you harvest the available daylight
  • Means that your fluorescent lights consume only as much power as you need to get the correct lighting level on your workplace.

How DAYTRONIC reduces your energy bill

With DAYTRONIC, your fluorescent lamps sense how much daylight is available and then dim continuously during the day when enough ambient light is available. The sensor measures  the available light on the work area (combination of artificial and ambient light) and automatically adjusts the fluorescent light level depending on how much daylight is available.

For even higher savings and great comfort, Daylight Dimming can be combined with Occupancy Sensing.

How much energy can I save? 

A lot. There are 2 levels of energy savings, depending on which kind of ballast you have installed at the moment.

a.) If you upgrade from a magnetic ballast to a constant electronic ballast, you would save about 25% to 28% of energy. The reason for this are the lower losses in the ballast and the better internal efficiency of the gas in the lamp due to the high frequency operation compared to 50Hz.

b.) From here, when you compare constant electronic ballast with Daylight Dimming electronic ballasts, on average you will save another 35% due to the Daylight Dimming. This is an average value over all places which get some daylight and is derived from many projects with EPV DAYTRONIC ballasts. However, if you only install DAYTRONIC ballast near the windows your savings will even be significantly higher.

So when comparing to magnetic ballasts, you are easily looking at 60% savings and upwards of 35% when compared to constant electronic ballasts.

A typical upgrade scenario

A customer has lots of 2 x 36W T8 light fittings. The fittings have 2 magnetic ballasts and starters (one per tube) and consume in excess of 104 W at power factor of 0.86. The fittings are about 20 years old and have reached their end of life - wiring is becoming brittle and some of the fittings had to be repaired already. The customer decides to upgrade to new fittings.

He choses modern 2 x 28W fittings with high quality reflectors, louvers and DAYTRONIC ballasts. These will give him better lighting quality and same light levels (at least) as the old fittings. The DAYTRONIC ballasts make sure that any available daylight is used to save energy on fluorescent lighting. The new fittings consume 56W at power factor of 1 (at full output). The Daylight Dimming feature contributes on average another 35% savings, so the average consumption of each new fitting is 36.4 W at power factor 1.  

The customer enjoys better lighting conditions, less glare and makes huge energy savings every day.

To boost savings even further, the customer installs Occupancy Sensors in all areas that are not constantly used. His lighting now complies to all modern building codes.

What makes DAYTRONIC ballasts special?

1.) Simple Installation & extremely small sensor

Installation is like any other electronic ballasts. The only difference is that the small DAYTRONIC light sensor is also mounted into the fitting. You can retrofit existing light fittings or replace your old light fittings with modern fittings that are already equipped with DAYTRONIC. The sensor is very small and unobtrusive and integrates well into stylish, modern light fittings and ceilings.

2.) No commissioning required on site -  DAYTRONIC is precalibrated

This is a major benefit since most other Daylight Dimming system require expensive on-site commissioning. You need a luxmeter to measure the light level on the work area and then you have to adjust each light sensor accordingly. This is one of the reasons why the wonderful concept of Daylight Harvesting is not yet more widely used today.

DAYTRONIC sets come pre-calibrated to the most important building standards light levels (500 / 350 / 150 lux) ex factory. No commissioning is required on site. The selected light level can be changed anytime by swapping to one of the other coloured lenses which are supplied with each ballast.

3.) Ideal lighting comfort due to small dimming groups

Daylight Dimming works best when one sensor works on a small area. If the area gets too large (too many fittings controlled by one sensor), the users of the room will complain because not everyone receives correct lighting conditions. Ideally, every work place should have its own control system as lighting conditions in a room are different across different places in this room.

This is exactly the philosophy behind DAYTRONIC: One simple & reliable sensor per fitting.

The special thing about DAYTRONIC ballasts is that they contain all the necessary intelligence for a stable and comfortable operation in the ballast logic. Normal electronic ballasts do not have this intelligence, so it needs to be put into an external sensor. This sensor then becomes much larger, much more difficult to install elegantly and more expensive. In comparison, DAYTRONIC ballasts work with a very simple and extremely reliable photosensor which can be connected directly to the 1..10V control input.

The low price of the DAYTRONIC system and the lack of commissioning costs make this solution very economical.

Key benefits

  • Specifically designed for Daylight Dimming
  • No commissioning on site.
  • Very small and inexpensive photosensors
  • Excellent warm start - very soft on the tubes for a long lamp life.
  • Suitable for use with Occupancy Sensing
  • For retrofit and OEM applications
  • Wide range of sizes available
  • Proven in ten thousands of installations

Contact us now to upgrade your light fittings with DAYTRONIC ballasts and make the best use of the available daylight!

DAYTRONIC Set (ballast with sensor)
DAYTRONIC Set (ballast with sensor)

DAYTRONIC example fitting
DAYTRONIC example fitting

DAYTRONIC sensor in fitting
DAYTRONIC sensor in fitting

DAYTRONIC Example fitting
DAYTRONIC Example fitting

Daytronic Sensor in fitting
Daytronic Sensor in fitting

DAYTRONIC example fitting
DAYTRONIC example fitting

DAYTRONIC Retrofit clip for louver mounting
DAYTRONIC Retrofit clip for louver mounting

DAYTRONIC sensor holder for ceiling
DAYTRONIC sensor holder for ceiling

DAYTRONIC example fitting
DAYTRONIC example fitting
EPV Electronics GmbH • Sedanstr. 18, 58507 L├╝denscheid • Tel: +49 2351 6583000 • Fax: +49 2351 6583066 • info@EPVelectronics.com