Lighting
Most people tend to think more about the style of lamp they buy than the
type of bulb. But it's important to know there are many things you can do to
make the lighting in your home more effective and efficient.
Here are answers to some frequently asked questions about lighting.
Please select a category from the list at the left.
Below are some frequently asked questions about lighting. Choose a category
to the left to view the related questions and answers.
Q: Our home has six recessed lights in the ceiling. The homebuilder suggests using 75-watt indoor floodlights. These bulbs get a lot
of use because they are in the kitchen and dining area. They cost between
five and $10 each to replace, so I am considering fluorescent lights instead.
What are the pros and cons of fluorescent fixtures, and would the energy
savings be enough to warrant changing the lighting?
A: Going with fluorescent is a very good choice. There is
a compact fluorescent lamp (CFL, flood-light type) that can just screw into the
existing fixtures. They typically can be purchased at a hardware store for
between $15 and $25 each.
Yes, that is more than the $5 to $10 dollars you currently pay, but, a
75-watt incandescent can be replaced by 20 watts of CFL while maintaining
the same light level. They are also rated for 10,000 hours, whereas the
standard flood lamps are rated at only 1,000 hours. So, over the life of the
lamp, the CFLs pay for themselves about three times in the amount of energy
they save and you don't have to replace as often.
Q: Are any full-spectrum lights energy efficient?
A: Full-spectrum refers to the light source's ability to
render the color of objects correctly, or in their natural state. In other words,
objects that look like they should under natural light, or daylight.
Full spectrum fluorescent lights are a good choice. The color rendering index
(CRI) is the measurement. On a scale of zero to 100, the closer the CRI is to
100, the more correct, or natural any object will look. Standard fluorescent is
typically around mid 60s on this index.
The higher the CRI, the more expensive the lamp. Be sure to check to see if
your current ballasts will operate these type lamps. This information is indicated
on the ballast.
Q: Is it cheaper to continually turn your lights off whenever you leave
the room very briefly, or is it better to just leave them on and only turn them off
when you'll be out of the room for long periods?
A: The answer to your question really depends on the type of
light bulb you use. Incandescent bulbs (standard light bulbs) are very inefficient as
a light source. Only about 10% of the energy consumed by the bulb actually goes
to producing light, the rest of it is turned into heat. So if it's an incandescent bulb,
turn it off when you leave the room, especially during the summer when the air
conditioner is running.
Fluorescent lighting, on the other hand, is more efficient and cool burning so you can
leave these fixtures on if you're planning on returning to the room within five to 10
minutes. If you'll be away longer, you should turn them off.
Q: My lights dim slightly when I operate my portable space heater.
Is this a result of operating the heater? Does it indicate a dangerous situation?
A: Dimming of the lights when the heater is operating does not
indicate a dangerous condition. Sending electricity through the wires always causes
a reduction in the voltage because of the resistance of the wires. When the voltage is
reduced beyond a certain level, and depending on a person's sensitivity, type of lighting
and other factors, the effect can become noticeable.
The effect is similar to a drop in water pressure in the shower when the toilet is flushed.
In both the electric and plumbing case, there is resistance to the flow of the fluid in the
conductors (pipes or wires). To fix this effect requires elimination of some of the resistance,
such as by installing larger pipes or wires, or more circuits so that each circuit has less water
or power load to serve.
Though no hazard is necessarily indicated, if the circuit breaker isn't in good order, or if it is
not the appropriate size, there could be a dangerous condition. A circuit breaker is designed
to protect the wires against being overloaded.
Assuming that the electric system in the house is in good order, the dimming is not a technical
problem. However, further concerns only can be addressed by hiring an electrician to inspect
and test the house wiring and circuit breakers.
Please note: It is not sufficient to test the GFI (ground fault interrupter) which is mandatory
in bathroom circuits. Most bathroom circuits have their GFI protection in the form of an outlet
with GFI capabilities. GFIs are intended to protect people from being shocked, not to protect
the house wiring. Protecting the house wiring is the function of the panel-mounted circuit breakers.