In 1987, the best refrigerator being sold used 515 kWh/yr and the average used 979 kWh/yr. How much money would have been saved on your electric bill between then and 2000 by buying the more efficient one?
What will be an ideal response?
We are not given information about the cost of the two refrigerators, but
(amazingly enough) many times the cost is not significantly different between different
models. Assume they cost the same amount. Then, over 13 years, the cost of the more
efficient model is,
(13 years) x (515 kWh/yr) x $0.10/kWh = (13 years) x $51.50/yr = $669.50
The cost of the average model is
(13 years) x (979 kWh/yr) x $0.10/kWh = (13 years) x $97.90/yr = $1272.70
You would have saved $1272.70 - $669.50 = $603.20 over those 13 years. It is extremely
unlikely that the more efficient could have cost that much more than the average model.
In any case, if the more efficient model is more expensive than the average model, you
would just subtract the extra cost from the savings listed above to find the actual savings.
Over the 19 yr mean refrigerator lifetime, the more efficient model would actually save
$881.60 (minus the cost differential, if any) at an electricity cost of $0.10/kWh. If the
electricity cost were just $0.08/kWh, the net savings would be proportionally smaller,
$705.28 over the 19 years, $482.56 over 13 years.
You might also like to view...
All the following types of objects are found almost exclusively in the disk (rather than the halo) of the Milky Way except
A) globular clusters. B) young stars. C) x-ray binaries. D) high-mass, red supergiant stars.
Projectile Motion: A shell is launched with a velocity of 100 m/s at an angle of 30.0° above horizontal from a point on a cliff 50.0 m above a level plain below. How far from the base of the cliff does the shell strike the ground? There is no appreciable air resistance, and g = 9.80 m/s2 at the location of the cliff.
Fill in the blank(s) with the appropriate word(s).
Almost all stars on the main sequence range from 0.1 to 15 solar radii
Indicate whether the statement is true or false
A boat with mass of 1 200 kg is traveling at 12 m/s. What is the magnitude of the force required to stop the boat if it undergoes a displacement of 85 m?
a. 2 000 N b. 170 N c. 8 500 N d. 1 000 N