North Carolina A&T University (NCATU) is a BAIHP partner that has procured two high visibility manufactured homes on its campus in Greensboro, NC. Built by Palm Harbor Homes, Siler City, they have 1,528 sq. feet of living area, with 3 bedrooms and 2 baths.

During testing, each model house was unoccupied; however, the use of lights and appliances were simulated with timers. One of the homes was conventional and the other was expected to be 50% more energy efficient. Measured data shows that an overall savings of 55% was achieved for the combined heating, cooling and water heating loads, surpassing the design goal! Good data collection periods were:

Season	Dates	Savings
Heating season	Nov 1, 2001 - April 14, 2002	70%
Cooling Season	April 16, 2002 - August 15, 2002	33%
Water heating	August 16, 2001 - August 15, 2002	33%

Construction differences between the two homes are listed in the table below. The results of testing are described below.

FSEC and NCATU monitored energy performance in both homes. All data was downloaded daily to FSEC via modem. Data summaries can be accessed online at the InfoMonitors web site. Detailed data queries and graphs can also be generated through FSEC's WebGet database.

Heating Energy Savings

	Heating Avg.	Heating Max.
Base House	1.95 kW	3.23 kW
Energy House	0.58 kW	0.96 kW
Savings	70%	70%

Data collected From Nov 1, 2001 through April 14, 2002 show an average heating energy savings of 70% and an average peak kW savings of 70%.

Average hourly data during the period is plotted below. It shows an average 24 hour period over the months of November, 2001 thru April, 2002.

Interior temperatures in the base house averaged 74.8 over this period, while the energy house averaged 74.3.

Daily average HVAC energy use from Nov. 1, 2001 through Apr. 14, 2002

Heating Peak Day

Below is a plot of the heating energy use at the NC A&T demonstration homes on the likely heating peak day for 2001-2002 of Friday, January 4th.

The 99% design dry bulb temperature for Greensboro, NC is 19°F; the temperature on this day reached a low of 15.9°F at 6:45 AM. The area has received considerable snowfall in recent days. The average temperature was 31.8 F over the course of the day (red line on plot).

The total measured heating power for the base house with electric resistance heat was 109.3 kWh (green line on plot). The heat pump used a total of 39.7 kWh with auxiliary strip heat being used during the coldest part of the morning (see spikes between 4 and 9 AM on blue dashed line) .

This corresponds to a savings of 64% in space heating on the likely coldest day of the year-- capping off excellent performance for the project.

Cooling Energy Savings

	Cooling Avg.	Cooling Max.
Base House	1.12 kW	2.01 kW
Energy House	0.72 kW	1.18 kW
Savings	33%	41%

Data collected From April 16, 2002 through August 15, 2002 show an average cooling energy savings of 33% and an average peak kW savings of 41%.

Average hourly data during the period is plotted below. It shows an average 24 hour period over the months of April, 2002 thru August, 2002.

Interior temperatures in the base house averaged 73.3 over this period, while the energy house averaged 73.2.

Cooling Peak Day

Below is a plot of the cooling energy use at the NC A&T demonstration homes on the cooling peak day for 2001-2002 of Tuesday, August 13th.

The 1% dry bulb tempearture for Greensboro, NC is 90°F; the temperature on this day reached a high of 105°F at 1:45PM. The average temperature was 87.8°F over the course of the day (red line on plot).

The total measured cooling energy for the base house with SEER 10 central air conditioning was 44.4 kWh (green line on plot) while the energy house with SEER 12 central heat pump was 28.0 kWH (blue line on plot). This corresponds to a savings of 37% in cooling on the likely hottest day of the year.

Hot Water Energy Use

.	HW Power Avg.
Base House	0.33 kW
Energy House	0.22 kW
Savings	33%

Data collected From Aug 16, 2001 through Aug 15, 2002 show an average hot water energy savings of 33%. The base house averaged 0.33 kW while the energy house averaged 0.22 kW

Average hourly data during the period is plotted below. It shows an average 24 hour period over the year of Aug, 2001 -2002.

Both the base house and energy house averaged 52.8 gallons/day over this period.

The solar water heating system in the Energy house saved 33% of the water heating energy. The solar water heating system is an antifreeze system consisting of two 3'x7' solar collectors and a 66 gallon storage tank. The solar collectors are partially shaded in the late afternoon by large trees on the west side.

In an effort to improve the solar system performance, NCATU researchers insulated the tank piping on March 6, 2002 and installed additional tank insulation on May 1, 2002. The following table illustrates the performance for comparable periods in 2001 (before pipe and tank insulation) and 2002 (after insulation).

Water Heating Energy Use
	May 2001		June 2001		July 2001		May - July 2001
House	Base	Energy	Base	Energy	Base	Energy	Base	Energy
Tot kWh	258	183	227	141	204	151	690	475
Savings	29%		38%		26%		31%
	May 2002		June 2002		July 2002		May - July 2002
House	Base	Energy	Base	Energy	Base	Energy	Base	Energy
Tot kWh	250	138	192	75	200	80	642	293
Savings	45%		61%		60%		54%

Note that the performance during May-Jul, 2002 increased significantly. However, the experiments could not be continued for a full year after insulation as a lightning strike caused data logger failure on Aug 16, 2002. Soon after that the homes had to be moved to meet other needs on the NCATU campus.

NCATU Side-by-Side Study of HUD Code Homes Specifications of Standard and Energy Construction
Characteristic	Standard Home	Energy Home
Floor Insulation	R-11	R-13
Wall Insulation	R-11	R-22
Ceiling Insulation	R-20	R-33 + roof deck radiant barrier
Windows	Single Pane with Storm	Low-E Thermopane
Exterior Doors	Storm Door on Front	Storm Door on All
Marriage Wall Seal	Fiberglass Pad	Sof-Seal Gasket
Heating System	Electric Resistance	Heat Pump HSPF 7.5
Cooling System	Central Air Conditioning SEER 10	Central Heat Pump SEER 12
Water Heater	Electric Water Heater	Solar Water Heater
Duct Joints	Industry Standard	Sealed with Mastic
Duct Leakage*	CFM25out = 145	CFM25out = 83
House Leakage*	ACH50 = 10	ACH50 = 9

For more information and pictures visit the NCATU Center for Energy Research and Technology (CERT) project web page.