HEM January/February 1994 - Home Energy Magazine Online January/February 1994

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Home Energy Magazine Online January/February 1994

TRENDS IN ENERGY

Rebuilding Dade County, Florida

Whole neighborhoods in South Florida must be recreated in the aftermath of Hurricane Andrew, which in August 1992 left a trail of debris more than 25 miles wide. But the disaster is giving energy experts a chance to demonstrate how building energy-efficient homes can save property owners thousands of dollars.

With some 35,000 homes needing to be rebuilt and more than 85,000 needing repair, state officials asked the Florida Solar Energy Center (FSEC) to suggest ways to build more efficiently. Results of FSEC's analysis showed that it would be technically feasible to reduce household electricity use in South Florida by 73%-84%, and that cost-effective savings efforts could reduce electricity use by 39%-48%. In the analysis, a group of economically superior measures were identified and ranked by cost-effectiveness (see Tables 1 and 2).

Habitat for Humanity--the nonprofit group that helps build and rehabilitate owner-occupied low-income housing--is acting on FSEC's recommendations. In Homestead, a community that was particularly hard-hit by the hurricane, Habitat is developing 213 affordable and energy-efficient single-family homes. The development is called the Ecological Housing Project, or Jordan Commons, and it will serve as a model for future developments throughout the state.

Utility bills "need to be brought under control," says Robin Adair of Homestead's chapter of Habitat for Humanity. "We take a much more holistic attitude toward our homeowners than a typical developer. What we're concerned about is the success of these families."

Since these homes will be owned by people earning $10,000-$15,000 per year, a key goal is to provide homeowners with an affordable lifestyle. While the added costs of energy-efficient building will be about $3,000 per unit, the savings are estimated at 5,350 kWh, or $430 per year. This translates into a simple payback of seven years.

Habitat embraced FSEC's recommendations. "Habitat pretty much took the ball and ran with it," says Danny Parker, the lead project scientist with FSEC.

The FSEC research team developed efficiency improvements by creating a computer prototype of a typical single-family detached home in South Florida. Energy improvements that would reduce utility costs for both concrete block and wood-frame homes were simulated, taking into account the extreme summer temperatures. The recommendations included better roof insulation, more efficient and properly sized air conditioners, and reflective roofs, walls, and windows.

"The typical duct system in Florida is in the attic," says Parker, "the worst possible location in a cooling climate for the air distribution system." Duct systems usually leak, so Parker recommended putting the ducts within the air-conditioned space.

Low-flow showerheads and low-cost solar water heaters will be installed to save electricity and water. (An owner-installed solar water heater can cost as little as $700.) Reflective roofs and windows will help cut the amount of heat absorbed by the homes, and the reflective roofs will also greatly reduce the amount of heat transfer to the attic. A radiant barrier will be placed beneath the plywood roof decking to reduce the amount of radiant transfer to the insulation in the house. Reflective film on windows or special reflective glass will help prevent heat from getting absorbed in the home. The homes will also have energy-efficient lighting: compact fluorescent and halogen incandescent lamps.

Efficient appliances will be used, with very efficient refrigerators given priority. Habitat's Ecological Housing Project will also be extensively landscaped, with trees planted to shade homes and lower the indoor temperatures. "The ambient air temperature of the whole community can be reduced with the planting of certain trees," says Habitat's Adair. Every effort to reduce the use of electricity "is money well spent, especially when you factor in the escalating cost for utilities," he says. Even the streets will be more reflective, with light-colored asphalt replacing the typical black-tar coating.

Parker will monitor the homes and compare the actual energy savings with simulated energy savings estimates. He plans to install measuring devices in ten of the Ecological Housing Project's 213 homes as they are built. FSEC will test electricity consumption and meteorological conditions, indoor temperature, and relative humidity, and will compare the results with data gathered from ten identical "control" homes that lack the efficiency measures.

Through its Ecological Housing Project, Habitat hopes it can inspire other builders to help homeowners defer extra energy costs. "We have an obligation to showcase these things to developers," Adair said. "Although the upfront cost is -- Linda Berlin

Linda Berlin is a freelance writer based in Stinson Beach, California.

Table 1. Recommended Energy Saving Measures for Homes in South Florida

              New Housing                                      Existing Housing     
Envelope      * Attic radiant barrier or reflective roof       * Reflective roof or attic radiant barrier if feasible
              * Single-pane reflective east and west windows   * White colored walls
              * White colored walls                            * Reflective window film on east and west windows

Heating       * AC with SEER > 12.0* Sealed duct system        * Air conditioner with SEER >12.0 
and Cooling   * Proper AC sizing                               * Proper AC sizing
              * Sealed duct system                             * Sealed duct system
              * Ducts within conditioned space, attic          * Programmable thermostat
                radiant barrier or reflective roof

Water         * Low-flow showerheads                           * Low flow showerheads
Heating       * Add-on solar water heater                      * Add-on solar water heater
              * Extra hot water tank insulation
 
Appliances    * Most efficient refrigerator for size and type  * Replace older refrigerators
              * Compact fluorescent lighting                   * Compact fluorescent lighting
              * Halogen incandescent lighting                  * Halogen incandescent lighting
              * Down-sized pool pump with oversized piping 
                and filter                                     * Down-sized pool pump
              * Pool-pump timer                                * Add pool pump timer
The package of measures for new construction in South Florida would cost-effectively reduce annual electric consumption by 47% in homes with pools and by 39% in homes without pools. In either case, the measures would cost about $3,000, providing annual cost savings of $430-$600. In existing homes with pools, the measures would reduce electric consumption by 48%, while existing homes without pools would realize savings of 42%. The package of measures would cost about $3,800 for existing homes with pools and about $3,400 for existing homes without pools. Simple paypacks range from 5-7 years. These packages of measures save electricity for less than half of current average retail electric costs. For details see Rebuilding For Efficiency: Improving the Energy Use of Reconstructed Residences in South Florida. Contact: Florida Solar Energy Center, 300 State Road 401, Cape Canaveral, Florida, 32920, Tel: (407)783-0300; Fax: (407)783-2571.
Table 2. Economics of Energy-Efficiency Measures for New and Existing Homes in South Florida 
                                                                     Cost of    
                                      Annual         Annual         Conserved
                                      Saved          Total            Energy 
Measure Description                    kWh            kWh            ($/kWh)
NEW RESIDENCES                    
1. Reference case                         0          16,143           $0.000    
2. Smaller pool pump                  2,260          13,883           $0.003
3. Low-flow showerheads                 213          13,670           $0.024    
4. Compact fluorescent lights           630          13,040           $0.036 
5. Heating and cooling package        2,625          10,415           $0.044
6. Halogen lights                        42          10,373           $0.048 
7. High-efficiency refrigerator         100          10,273           $0.048
8. Extra hot water tank insulation      192          10,081           $0.050
9. Water pipe insulation                 64          10,017           $0.050
10. Add-on solar water heater         1,494           8,523           $0.068

EXISTING RESIDENCES                    
1. Reference case                         0          18,641           $0.000 
2. Smaller pool pump                  1,870          16,771           $0.010
3. Low-flow showerheads                 213          16,558           $0.024 
4. Compact fluorescent lights           315          16,243           $0.036 
5. Heating and cooling package        4,123          12,120           $0.043 
6. Halogen lights                        84          12,036           $0.048 
7. Extra hot water tank wrap            192          11,844           $0.050 
8. Add-on solar water heater          1,494          10,350           $0.068
9. High-efficiency refrigerator         710           9,640           $0.081

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