Figure 43.  New datalogger monitoring computer system with remote monitoring and control capacity

House Monitoring:

$           Monitor Overview: Monitors on the Hoak residence include 11 attic temperature and relative humidity sensors, three indoor sensors, a Hobo event logger to record the dehumidifier cycling time, and a tipping bucket rain gauge with Hobo logger to monitor the combined condensate of the air conditioner, dehumidifier, and heat pump water heater .  In 2002, Alten Design also assembled a new logger monitoring computer with the capability of reading data from two Campbell 21X loggers.  This computer was configured with remote monitoring and control capacity so that team members can program and maintain the system without traveling to the site. (Please see Figure 43).

$           Attic Sensors:  There are nine Hobo temperature/relative humidity sensors located in the unvented attic spaces.  The living space and unvented attic are split in the house, with the unvented space divided into front and rear attics by a cathedral ceiling. Two of the Hobo sensors are located in the front unvented attic.  The air conditioning ductwork and zone dampers also are located in this attic space.  They are located on the far left and right of the front mid-body section.  (Please see Figure 44, below.)

Figure 44.  Drawing shows placement of Hobo temperature/relative humidity sensors at the Hoak residence attic

Figure 45.  Three indoor sensors monitor daily temperature humidity swings in the residence.

There are six Hobo sensors in the rear unvented attic.  This space is about twice the square footage of the front attic and because of its orientation receives a larger amount of solar radiation in a day. Because there is a large elevation difference between the bottom and top of this attic, sensors were located at the bottom, middle, top, and on each end of the attic.  Behind the rear unvented attic is another unvented attic which covers the back porch.  This space is separated from the rear attic by an Icynene insulated kneewall. The porch attic is uninsulated and has no flow ventilation between it and the outside.   This attic contains one Hobo temperature/relative humidity sensor.

$           Indoor Sensors:  There are three Hobo temperature/relative humidity sensors located inside the home, one on each of the three floors.  These are used to monitor the normal day-to-day temperature swings in the living space.  (Please see Figure 45, above.)

$           Moisture Removal Sensors:  There is one Hobo sensor that monitors indoor moisture removal.  It monitors the periodic cycle time of the dehumidifier as well as the moisture removed by the air conditioning system and heat pump water heater.

$           Moisture Levels:  FSEC and Alten Design installed new moisture detection sensors in the Hoak house unvented attic.  The purpose of these sensors is to determine moisture level in the wood members of the attic. Previously, only ambient attic moisture levels were logged.

In this reporting period, Alten Design installed an additional sensor to detect duration and time of supplemental dehumidification.  Another sensor collects condensation data from the home's air conditioning system, dehumidification system, and heat pump water heater.  Data from both new sensors are being included with other weekly data uploads to provide a complete picture of temperature and humidity changes throughout the day.

Preliminary Findings

$           Duct Leakage:  Duct leakage test results showed the Hoak home air loss was only 50 CFM at 25 Pa or 1.2% leakage per square foot of conditioned floor area - far below the amount of leakage normally found in new Florida homes.

Total duct leakage is less than 10% of air handler flow (200 CFM).  Blower door performance tests verified the home's level of airtightness at two air changes per hour at 50 Pa (ACH50 = 2.0).  When including leakage around the supply grills, house leakage increased about 30%.  Slightly more than half of the house leakage (1479 CFM at 50 Pa) is located in the sealed attic space (760 CFM at 50 Pa).

Figure 46. Cooling energy use comparison Hoak home, PV Res home, Lakeland control home, and central Florida frame home.

Table 12.  HERS scores generated with Energy Gauge.

Data collected at the Hoak home shows the cooling energy is nearly on par with the PVRes Home on a per square foot basis. (Please see Figures 46 and 47 below.)

$           Envelope:  Weekly data logs of the Hoak home provided by Alten Design from the 14 Hobo temperature and relative humidity sensors and pressure tests through March 2003, confirm that air pathways between the unvented attic and outdoors still exist.  Researchers suspect that these pathways may be the primary source of moisture intrusion into the unvented attic space.  Several whole house pressure tests (smoke tests) were performed by Alten Design and FSEC to isolate these external sources of air infiltration.  Identified leaks were sealed, though actions have shown some benefit moisture levels are still higher than desired. 

Figure 47. Cooling energy use comparison per thousand square feet of Hoak residence, PV Res home, Lakeland control home, and central Florida frame home.