Civil Engineering Reference
In-Depth Information
of tracking our energy efficiency during different weather conditions we could track
our energy consumed per degree day as BTU/DD. Here's an example for my home
during the month of January.
• January ElectrickWh
(
)
=
1 678 3 412 1414799
,
×
,
.
=
5 725 573 2BTU
,
,
.
• January Propane gallons
(
)
=× =
52 95 5
,
00
4 966
,
,
000
BTU
• JanuaryDegreeDays(heating)=1301
• (, ,
5 725 573 2BTU 4 966
.
+
,
,
000
BTU131DD 8 217 9654 BTUDD
)/
0
=
,
.
/
Anyone can find the degree days for their location for any month at the BIZEE
Degree Days web site (http://www.degreedays.net). Now, let's do this same calcula-
tion for my home in April when I have very little (if any) heating or cooling energy
consumption.
• AprilElectrickWh 85 3 412 1414799
0
• AprilPropane(gallons)=0
• AprilDegreeDays(heating)=337
• 2 746 773 8BTU 337 DD 815 664 BTUDD
(
)
=×
,
.
=
2 746 773 8BTU
,
,
.
,
,
.
/
=
,
0
.
/
As you can see the BTU/DD values for January and April are nearly the same even
though the outside temperature where I live in January is very cold, sometimes way
below 0 °F. In April, it's very mild averaging near 60° F. So, by using degree days
as a factor in tracking our energy consumption we can get a consistent value to com-
pare our energy efficiency month to month no matter how cold or hot the outside
temperature is where we live.
2.6
Living Area Units
It's fairly obvious that homeowners measure the living area of their homes in
square
feet
(SF). This represents the area serviced by the energy consuming appliances and
equipment. The exact value may vary from utility to utility. For instance certain ar-
eas of a home may not be heated with natural gas but still have electricity for lights
and appliances.
We define the living area of the home or a single room by the multiple of its
length and width dimensions. We can measure homes serviced completely by all
utilities by multiplying the length of the home by the width to arrive at an area value
for each floor. If it is a two-story home, we multiply that result by two. This gets
complicated for split-level homes and homes that do not provide utility services to
all rooms. Another method is to calculate the area of each room and add them all
together. The goal is to arrive at a living area value expressed in
square feet
(SF)
for each utility provided to the home. So, if a home is all electric you just have one
living area value. For a home serviced by both electric and natural gas there are two
values, electric living area and natural gas living area. Also, since the size of our
home could change, we need to record the living area(s) each month along with our
energy consumption values.
