Energy Needs of the Home

            A standard home with 2 bedrooms, no basement, and 1000 sq. ft. of area was started with.  R-values of building materials were calculated and assumed; these results can be seen in Table 1 below.  

 

Table 1: R-values for a 1000 Sq. Ft. House.

Parameter
	Siding	4
	Insulation	20
	Wood Studs	7
Plaster inside		1
Roof		15

As can be seen, the insulation and roof account for most of the resistance of the house, which makes sense.  These R-values were then used to calculate the overall thermal conductance of the house.  This value was found to be .315966 BTU/hF.  After doing a little research, properties of the house needed to calculate the heating and cooling degree days were assumed to be the contents of Table 2.

Table 2: Air Properties for 1000 Sq. Ft. House

Cpair	0.239706	Btu (therm.)/lb-°F
Air volume	9000	ft^3
Rate	18000	ft^3/hour
Q	5	ft^3/s
Mdot	0.01185	lbm/s

Heating and cooling degree days could then be obtained through degreedays.net; this website produced an excel file showing the heating and cooling degree days by month in Boulder, Co.   These heating and cooling degree days could then be used to calculate the heating and cooling needed for the house; the results of these calculations can be seen in Table 3.

Table 3: Heating and Cooling Degree Days Results

HDD	7600
Qheat	17618.5	kWh/Year
CDD	356
Qcooling	825.2	kWh/Year

Heating uses almost three times as much energy per year as cooling; this would make sense because the average temperature is quite low throughout the year in Boulder.  After calculating the heating and cooling needs, other sources of energy usage were estimated using manufacturer estimates of normal, everyday appliances and fixtures; these values can be seen in Table 4.

Table 4: Estimates of KWh/Year of Everyday Appliances and Fixtures

Appliance	Energy use(kWh/Year)
Refrig	411
TV*2	358
Lighting	1552.8
Dish Washer	422
Microwave	131.4
Washer	267
Dryer	413
Water heating	1424
Internet	84
Qheat	17618.5
Qcooling	825.2
Total	28570.1

To better visually represent this data, a pie chart was created to see where the most energy usage was taking place; this can be seen in Figure 1.  

Figure 1: Calculated Energy Usage of the House.