BAIHP Research: B. Site Built Housing Research Cont'd

• Eastern Dakota Housing Alliance (EDHA), Applegren Construction
  Grand Forks, North Dakota
  Category A, 10 Homes
  Category B, 13 Homes
  Technical Support by BAIHP Researcher, Dave Chasar
  Awards: North Dakota Housing Finance Agency’s Champion of Affordable Housing Production Award
  Paper: Chasar, D., Moyer, N., Chandra, S., Rotvold, L., Applegren, R., "Cold Climate Case Study; High Efficiency North Dakota Twin Homes," Performances of Exterior Envelopes of Whole Buildings IX International Conference, Clearwater Beach, Florida, December 2004.
  

  Table 42 Completed Selkirk Homes
  .	Phase I	Phase II	Phase III
  Number of Homes	4	4	4
  Completion Date	Mar-03	Jan-04	Aug-04
  HERS range	88 – 90	92.5	88 – 89.5
  BA Benchmark range	25 – 30%	40%	TBD

The Eastern Dakota Housing Alliance plans to build 20 multi-family and single-family dwellings on Selkirk Circle in Grand Forks, North Dakota. Twelve homes have been completed to date and four more are currently under construction.

Four Phase I units completed in March of 2003 had HERS ratings between 88 and 90 with whole-house savings of 25 to 30% against the Building America benchmark. Four Phase II units completed in January 2004 had HERS of about 92.5 and whole-house savings of 40%. The Phase II efficiency boost comes from the addition of a whole-house tankless gas water heater and R10 sheathing on exterior walls. Lower HERS scores (88.3 – 89.5) on the Phase III units was primarily due to electric resistance water heating and higher overall duct and envelope leakage. All units have ventilation air brought to the air handler return plenum with 10 of 12 units utilizing heat recovery ventilators (HRVs).

Figure 75 Two completed Phase III units (Dec 2004)

Phase III Testing

A new floor plan was used on the Phase III homes featuring a split level design instead of a full, below grade basement and attached rather than detached garages. Another major difference between these units and previous designs was the location of the air handler in a utility room that opens into the garage. As with previously tested homes, total leakage was very high and concentrated mostly on the return side where duct pathways were partially constructed from building cavity spaces. Duct leakage to out, which was nearly zero in previously tested homes, was substantially higher in the Phase III units. Duct tester results showed that the ratio of duct leakage to out (at 25 Pascals) to conditioned floor area (or Qn) ranged from 0.05 to 0.09. As with previous phases, all Phase III units had high efficiency, sealed combustion gas furnaces.

Each Phase III unit was tested individually for envelope tightness. Leakage was higher overall compared to Phases I and II, but this was expected due to the greater exterior surface area created by the attached garage design.

Discussion on Next Set of Homes

Four Phase IV homes are currently under construction utilizing the same floor plan and envelope design as Phase III. Plans include the use of high efficiency gas water heaters (probably tankless) and a central return duct system designed to reduce duct leakage (both total and to out). Return air relief for bedrooms will be incorporated into hallway walls with either a high-low grill system or pass-through grills with sound and light baffles. Plans also include relocating air handlers within the conditioned space instead of in a room attached to the garage. This should substantially reduce duct leakage to out.

Recommendations include:

• Central return located near thermostat in center of home
• Sealed ductwork from central return to air handler
• Avoid use of building cavities as air pathways

Figure 76 East side of Selkirk Circle, Phases III & IV

Building Science Issues:

• Combining space heating and hot water with a central gas boiler. Since air conditioning is still a requirement, an air handler with an hydronic heating coil will be required.
• If only 2 of 4 units are fitted with a combined system it offers the opportunity to compare the efficiency of this system over another unit with separate space and water heating through monitoring.
• David Duly of Pilkington glass has offered to work with FSEC to determine the benefit of high solar gain glass which could provide substantial savings on space heating. Window orientation and shading are important factors that may work favorably with the remaining south-facing home sites on Selkirk Circle.

BAIHP will be conducting Building America benchmarking analysis of these homes and producing Energy Star ratings of the four Phase III homes as well as the Phase IV units upon completion in spring/summer of 2005.

• Zero Energy Affordable Housing, ORNL and Loudon County Habitat for Humanity
  Lenoir City, Tennessee
  Category A
  Research by ORNL with BAIHP Support

Figure 77 Local sponsors in front of 2nd ZEH built by Loudon County HFH in partnership with ORNL. FSEC provided monitoring for the 1 st and 4 th ZEHs .

In partnership with Oak Ridge, BAIHP has instrumented two a zero energy homes (ZEH) built by Loudon County (TN) HFH in partnership with Oak Ridge National Laboratory. (Figure 77) See description in the Technical Assistance section of this report under Habitat for Humanity, Tennessee, Loudon County.

Data is available on-line at www.infomonitors.com . A paper on the study was submitted to the Buildings IX conference by Jeff Christian (ORNL) and David Beal (BAIHP-FSEC).

Federation of American Scientists’ Rasbach Provident Home

BAIHP is assisting FAS and builder Joe Ecrette with envelope and mechanical system design on this home built with cementitious faced SIP panels. The home serves as a demonstration of an affordable, efficient home that is also well-suited for areas prone to seismic disturbance. A preliminary HERS score of 89 is estimated.

BAIHP will provide data monitoring design assistance, equipment and installation to document energy savings. Data collection, processing and archiving will be provided through FSEC’s Infomonitors service, online at www.infomonitors.com.

• Hurricane Retrofit Research

Many homes in east central Florida suffered serious damages in 2004 as a result of the hurricanes. We have identified four families who would be willing partners for a U.S. DOE funded project to showcase cost effective energy efficient retrofits.

All homes are within 30 miles of FSEC and none are “luxury” homes.

All four homes have undergone a pre retrofit analysis and testing to determine the current energy usage profile and expected energy savings, enhanced comfort , indoor air quality and related benefits. Pre retrofit tests included blower door, duct blaster, pressure mapping and air conditioner system performance measurement. In addition, lighting and water heater and other opportunities will be assessed. All homes will be analyzed by the Energy Gauge USA software to quantify the expected energy savings. Pre and post utility bills will be documented for all homes.

The owners have agreed to keep track of the costs and share them publicly.

Post retrofit, Energy Gauge USA analysis will be conducted on all homes and energy savings computed relative to the Building America benchmark. This will require blower door and duct testing of the home post retrofit. A one to two page case study will be prepared for all four homes. Some homes will be monitored in more detail to examine key performance areas. The four homes offer a range of retrofit options and will provide good data on the costs and benefits of effective retrofit strategies in hot-humid climates.

• Apartment Ventilation and Humidity Study with Sandspur Housing
  Gainesville, Florida

In April and May of 2003, four of 111 newly built apartments at the Brookside Apartment Complex were evaluated for potential moisture problems. Characteristics of the four apartments are summarized in Table XX1. The ventilation strategy introduced untempreed outside air to the return side of a central air handler.

Sensors were installed in four apartments that monitored Temperature and RH in three locations: the air handler cabinet, the kitchen, and the master bedroom closet. The readings from Apartment 2 were within recommended guidelines in all living spaces monitored, with no changes recommended.

The temperature in Apartment 1 was lower than Apartment 2, the other occupied unit. The readings were within the acceptable level for comfort and mold control, but because the air conditioner ran longer, it also had a longer period to remove moisture. Inspection found that the windows were opened about 1 1/2”. When the occupant (the maintenance man for the complex) was asked why, he indicated that it was being done for “health purposes”.

Figure XX3 Apartment 3 Kitchen Temperature and RH

The master bedroom closet reflected the lower temperatures of the kitchen but with a slightly higher RH level. The higher RH level in this space was likely due to the closet door being closed which would slow the passage of the dryer kitchen air into the closet space.

The remaing apartments tested varied a large amount over the period of test. Apartment 4 had wide swings in temperature readings. With no significant period of time in which the temperature was stable, it is assumed that the AC was not running properly in this unit.

Apartment 3 is notable because this unit was vacant and its temperature should have stayed stable within three degrees. The good RH levels were likely due to the longer Air Conditioner run times required to maintain the low temperature.

Outside Temperature and RH: The test period was during the beginning of Florida summer temperature and RH trends. Daytime high temperatures reach into the low 90’s with associated high RH levels in the afternoon. These cycles are reflected in the data collected, the most obvious of these being the apartment 2 closet (Figure XX5) where daily outdoor temperature peaks mimic those of the indoor temperature peaks .

Figure XX5 Apartment 2 Walk-In Closet Temperature and RH

Recommendations

1. Educate those involved in the care and maintenance of apartment complexes in basic principles of building science.
2. In future apartments locate a supply register in the closet to provide better humidity control for this area.
3. Check Apartment 3 & 4 equipment for proper operation, and calibration of thermostat.