The heat generated by an incandescent light bulb is accepted as part of the operation of having artificial lighting ever since Edison patented the light bulb in 1879. It is also accepted that the average life span of an incandescent lamp is around 1000 hours as the heat generated shortens its life span and it literally burns out.
Fluorescent lamps, however:
- generate a similar amount of light as incandescent lighting,
- with far less heat,
- last for between six and 15 times longer and
- use about a quarter of the electricity required to provide the same amount of light.
Where an incandescent lamp produces five watts of light and 95 watts of heat for every 100 watts of electricity used, a fluorescent lamp will produce 50 watts of light and 50 watts of heat for every 100 watts of electricity used.
If we compare the average running costs of the different lamps, the cost savings are clear. For example:
- The electricity for a 100 watt bulb, used for an average of 3 hours a day, costs $23.00 each year (at $0.21/kw).
- A compact flourescent lamp providing the same light output for 3 hours a day will cost about $5.75 and saving $17.25 each year.
While the purchase price of a compact fluorescent lamp appears more expensive than an incandescent bulb, the savings in electricity quickly offset the purchase price. The extended life of the compact flourescent will mean that a single lamp will continue to save you money during the life span of five or six incandescent bulbs.
When the first compact fluorescent lamps appeared on the market, they looked strange and unattractive. Slowly we have become accustomed to the shape of these lamps, but the manufacturers have also given the matter some thought and come up with a myriad of designs that are more aesthetically pleasing.
Projects
Using this new lighting technology, the City Council has undertaken several projects to improve the energy efficiency around the city.
Replacing incandescent with energy efficient lighting in City Council housing
In 2008, the City Council undertook a project to replace the incandescent light bulbs in the living room of every Elderly Persons Housing unit owned by the Council. Using compact fluorescent lamps saves the occupants of these homes approximately $17.25 a year..
Offering energy efficient lighting to City Council employees
A call went out from Central Government in Autumn 2003 requesting consumers to drop their electricity consumption by 10 per cent. The City Council reacted by cutting electricity use by 13 per cent, but also decided to assist staff to save electricity at home as well. The City Council offered, at discounted prices, Osram Energy Saving lamps to City Council employees and the offer was enthusiastically taken up.
Over that winter the use of energy efficient lighting at home by staff saved, at least, 72,000 kilowatts of electricity or $10,000.
Replacing incandescent lamps with compact fluorescent lamps
If you looked up at the lights in the Tuam Street Civic building, the likelihood was that you would not see an incandescent light bulb. Almost all of the incandescent lamps were removed and replaced with a form of energy efficient lighting.
This attention to energy efficiency even extended to architectural and mood lighting in the reception rooms.
Making use of natural light
Every new development by the City Council is automatically commissioned with state-of-the-art energy efficient lighting and, where appropriate, proximity and ambient light sensors. In the picture above of South Library, you can see that the light fittings closest to the windows are dimmer than the lights further into the building. This is where the light sensors have adjusted the amount of light required from the light fitting.
Replacing incandescent traffic lights with energy efficient Lights
Traffic lights consist of lots of small energy users – in the case of the traffic lights around Christchurch, there used to be 67 watt lamps at about 240 controlled intersections. At each intersection, there are between 32 and 42 lamps, averaging at about 34 lamps, half of which will be on at any time.
These traffic lights use about 2,394, 600 kilowatts each year. It is easy to see that lots of little energy users may add up to a huge bill!
The Christchurch City Council decided that reducing this load would be immediately beneficial and easy to implement. All of the 67 watt incandescent lamps were therefore changed to 35 watt quartz halogen lamps. This simple step saved about 1,143,700 kilowatts of electricity each year.
Upgrading ballasts in City Council lights
Fluorescent light fittings require a ballast to start the ignition of the gases in the tube and to regulate the current once the lamp is alight. Upgrades in ballast technology have resulted in electronic ballasts that make changing from old technology well worth while in terms of:
- energy efficiency: there is an average drop in electricity use of 40 per cent
- light quality is improved with reduced flickering
- there is no buzzing from the light fitting
- the design is such that the ballast simply replaces the older technology with no changes required to the light fitting.
Lighting upgrade at the Central Library
Lighting is a key component and cost to library design. If the lighting is poor it:
The lighting at the Central Library was not poor but it was expensive. The original light fittings installed contained two fluorescent tubes per fitting, the technology available when the library was commissioned. The City Council, however, determined that an upgrade in technology would rapidly pay for itself and thus the following upgrades were used to reduce the lighting costs and increase the lighting at the Library:
- With minimal requirement for change, the two old fluorescent tubes were removed and a semi circular reflector was installed that reflects all the light from the tube down and out of the fitting.
- The old tubes were replaced with efficient new tubes.
- Electronic ballasts were installed.
- Lights around the perimeter of the building, where natural light is available, were fitted with light sensors and dimmers, so that these lights dim as more natural light becomes available.
The energy savings for this upgrade amount to more than $40,000 a year.
Summary
When one takes all of these projects and calculates the energy savings a year, the City Council, by merely changing the type of lighting installed in many sites, has reduced energy use in the City of Christchurch substantially, to the benefit of elderly persons in City Council Housing, City Council staff, the Ratepayer and the environment.
The benefits of these projects
- reduction in electricity use and thus in energy costs.
- Reduced maintenance costs as compact fluorescent lamps last between 6 and 15 times longer than incandescent lamps.
- Upgrades in lighting technology have extended the life of the light fittings and thus reduced renovation costs.
- Improved lighting
- Reduction of flicker and buzzing from older fluorescent fittings
- Use of natural light
Things to consider for your business or home
- Where do I have incandescent lamps installed that could easily change to compact fluorescent lamps?
- Are there accent or spotlights that could change to energy efficient lighting?
- Are lights switched off when they are needed?
- Would an upgrade in lighting technology reduce my company energy costs?
