Office buildings normally use parabolic fixtures with T8 fluorescent tubes, which offer a decent performance but are outclassed by LED lighting in terms of both efficiency and service life.
When upgrading linear fluorescent lighting in office spaces, there are two main options:
- Keeping the existing fixtures and using T8-equivalent LED tubes, which are designed for the same lamp holders used by fluorescent tubes.
- Using integral LED panels, which are designed to replace the whole fluorescent fixture, not only the tubes.
There are significant energy savings to achieve with both upgrade options, and neither can be considered better than the other; the best option is determined by project conditions.
LED Replacement Tubes
There are a broad selection of LED products designed to replace T8 tubes directly, and the main advantages they offer are low cost and fast installation. Some of these LED tubes are compatible with T8 ballasts and can be replaced directly while others are designed for the main power supply and require the ballast to be disconnected and bypassed.
The former replacement tubes do not save as much power as the tubes that are designed to run with a bypassed ballast. Bypassing the ballast enables the LED to consume the least amount of power possible leading to greater savings.
LED replacements for 36-watt T8 lamps typically consume between 15 and 22 watts, which means energy savings between 30 and 50 percent can be expected. If the ballast is bypassed the unit will use an additional 10 watts less as this 10 watts is normally consumed by the ballast itself.
LED tubes offer a service life of 50,000 hours on average, which is 2.5 times longer than the 20,000 hours offered by T8 fluorescent lamps. Other than reducing energy consumption, LED tubes also provide savings by avoiding frequent lamp replacements.
LED replacement tubes are an excellent choice in existing facilities, since they allow a quick and affordable upgrade with minimal disruption of work activities.
Integral LED Fixtures
This approach yields an efficiency that is 10 to 15 percent higher than that achieved when only the tubes are upgraded, but the installation also has a higher cost in terms of both materials and labour. This type of upgrade is more cost-effective when a major renovation is carried out, or in new projects where it allows ballasts and tubes to be avoided completely. Although a full fixture upgrade is also financially attractive in existing projects where no major renovations are planned, the building owner must be aware that the project cost is increased.
Integral LED fixtures are extremely efficient because their geometry is designed to maximise lighting output. For example, it is possible to replace a fixture with three T8 fluorescent tubes, consuming over 90 watts in total, with an LED panels that only draws 45 watts that yields savings of over 50 percent. These fixtures also offer a remarkable service life: some models are rated for up to 100,000 hours, which is equivalent to more than a decade of continuous operation.
When office lighting will be upgraded to LED, both tube upgrades and fixture upgrades are viable options. The advantages of a tube replacement are low cost, fast installation and minimal disruption; while a fixture replacement offers a higher efficiency and service life.
The energy savings achieved with a tube replacement can range from 30 to 50 percent, while a fixture upgrade can offer savings from 40 percent onwards. The service life in both cases is far superior to that of conventional T8 lamps: LED tubes offer up to 50,000 hours, and LED fixtures up to 100,000 hours.