Fan de-pressurization (blower door) tests conducted on the SIP's home when it was temporarily set up on the factory lot found 4.0 air changes per hour (ACH) at 50 Pascals (PA) of pressure (OOE 2000). Tests conducted after permanent set up showed the house to be slightly tighter at 3.55 ACH at 50PA. This difference may be explained in that the set-up on the plant lot was temporary, and sections were not taped and textured and as well sealed at the marriage line as during the final on-site home installation. Depending on the climate, shielding, and terrain factors 4.0 ACH at 50PA may result in average seasonal ventilation rates of 0.16 ACH.  The tighter measurement found at the permanent site results in 0.142 ACH of infiltration.  (Conversion method of dividing the de-pressurization results (ACH at 50PA) by 25 taken from Baylon, Davis & Palmiter 1995).  Smoke-stick tests conducted on site found typical leaks at window and skylight rough openings, supply duct registers, and plumbing fixtures.

This SIP home is tighter than the average air tightness found in 49 randomly selected Super Good Cents (SGC) homes built in 1997 and tested in 2000. These homes average was 4.76 ACH at 50PA (Davis 2000).  The SIP's home was also tighter than the average of a sample of 157 random SGC manufactured homes at 5.5ACH (Baylon 95).  Finally, the SIP's home was over twice as tight as the average of 29 non-SGC current practice manufactured homes, which averaged 8.75 ACH in tests done in the early 90s (Palmiter 92). Table 1 compares the results of manufactured home house tightness throughout the US.

Long-term Monitoring

Installation of the metering equipment in the SIPs home was completed in late September 2001.  The data logger used was an electrical metering system capable of recording power and energy.  The particular logger installed in the SIPs home was configured with four power input channels, four digital input channels and four analog signal input channels.  Communication with the logger is via a dedicated phone line installed specifically for this purpose. 

The energy end uses metered were the1) building total, 2) electric furnace, and 3) electric hot water heater.  In addition, an "Other" end use category representing all other energy consumption in the home, consisting primarily of the lighting and plug-in appliances, was calculated as the difference between the building total and sum of the furnace and the hot water heater.  Room air temperature was recorded in the laundry room near the furnace system's return air register. 

All power data were collected as 15-minute demand and downloaded nightly to the PNNL data collection workstation in Richland, Washington.  The raw 15-minute data were archived daily as part of the project's original data records and working copies of the data files created for subsequent analysis.  The data were reviewed for equipment problems weekly.  Monitoring data can be viewed at Florida Solar Energy Center’s web site dedicated to energy monitoring:  http://www.infomonitors.com/sip/

Data were available for analysis for the period September 27, 2001 through February 22, 2002.  During this period, which spanned most of the heating season, the total energy consumption was 7166 kWh, split among the major end uses as follows:  42% for the electric furnace, 34% for the electric hot water heater, and 24% for the Other end use category.  The month energy consumption for the each of the three end uses is shown in the bar graph in Figure 3.  Data for September 2001 was not included in this analysis because that limited data collected would not be representative of the entire month.  As can be seen, the water heater and Other end uses do not vary significantly between months.  However, as expected, the furnace use ramped up during the fall and was relatively constant during the three winter months (December – February).

Although difficult to compare without a full year of monitored data from the SIPs house, Baylon, et al estimated, based on electric bills, that annual heating requirements for a 1337 square foot SGC manufactured home in the same climate zone would use 5652 kWh/year (Baylon, Davis, and Palmiter 1995).   Total annual energy consumption amounted to 15202 kWh.   This same study found in an engineering analysis that a hypothetical HUD-code home would consume 8364 kWh/year for space heating and a SGC manufactured home would consume 4737 kWh/year in the same climate zone as the SIPs house.  For comparison also see the section of this web site on modeling. 

A daily profile of energy use is shown in Figure 4 for the same end uses for all days combined.  This profile is constructed by averaging the hourly energy consumption for each hour of the day.  In this case, the entire data sample was used.  Again the pattern is typical of residential energy use with a morning and evening peak in total consumption.  The furnace energy use responded to the diurnal pattern of outdoor temperature with a maximum in the early morning (coincident with the minimum temperature) and a minimum in the late afternoon (maximum temperature).

The energy use for different day-types is summarized in Table 2 for all data Sept 27, 2001 through Feb 22, 2002.   In this comparison, weekdays are defined as Monday through Friday; weekends are Saturday and Sunday.  No distinction was made for holidays.  Four consecutive days, Saturday, January 27 through Tuesday, January 30, 2002, were among the coldest of the winter season in southwest Washington.  Daily high and low temperatures during this cold spell were 34^oF and 30 ^oF, 33 ^oF and 29 ^oF, 39 ^oF and 24 ^oF, and 33 ^oF and 25 ^oF, as measured at the WSU Energy House in Olympia, Washington.