Zero Energy Homes (ZEH) are homes designed to use zero net energy from the utility grid. The concept is simple — couple the maximum possible building energy efficiency with the best available renewable energy resources so as to achieve zero energy. The Home Energy Rating System (HERS) index is used to determine the likelihood of a home performing at zero energy for a typical occupant. A typical old home might have a HERS index of 120 – 140 and a typical new home around 85 to 100. A score of 70 would be projected to use 30% less energy than one at 100, and a score of zero would have a net zero energy bill. FSEC's first near Zero Energy Home was built in Lakeland, Florida in 1998.
There is now a new generation of Zero Energy Homes being designed and constructed around the country, many with technical support from Building America teams under the sponsorship of the U.S. Department of Energy (DOE) and the National Renewable Energy Laboratory (NREL) in Golden, CO.
A primary aim in each of these projects is to collect detailed performance data that will allow refinement of the approach for integrating energy efficiency measures with PV and solar thermal systems. For information about some of FSEC's currently monitored sites, visit our Building America for Improved Residential Construction Measured Data site. FSEC is collecting data from the following Zero Energy Homes:
|Gainesville, Florida (1)
This is Florida's first production built, zero energy home. Located in Gainesville, Florida, this home achieved a HERS rating of -2. Energy consumption is offset by a 6.75 kW photovoltaic system.
|Gainesville, Florida (2)
This production built, net zero energy home is located in Gainesville, Florida and achieved a HERS rating of -3. Energy consumption is offset by a 6.6 kW photovoltaic system.
|Cocoa Beach, Florida - Publication | Data
This single-family home, located in Cocoa Beach, Florida, experienced a series of retrofits targeting reductions in energy use. The project was designed to develop data about how envelope modifications in heating, ventilation, and air conditioning (HVAC), domestic hot water, and renewable measures can result in considerable energy reductions and potentially net zero energy for an existing home. Using utility billing records and recent detailed monitoring data, this study was also able to chronicle the progress of energy reduction over a 23-year period.
This revised St. Croix model is located in Melbourne, Florida and is LifeStyle Homes’ first zero energy home. The home was completed in August 2010, and final inspection and testing resulted in a HERS Index of-6, exceeding the Builders Challenge level of performance.
This home has a HERS rating of 0. It has also been recognized with certifications including the U.S. DOE Builders Challenge, U.S. Environmental Protection Agency’s ENERGY STAR® and WaterSense® qualification, LEED for Homes® Platinum and Environments for Living® Green.
Near Zero Energy Homes
Near Zero Energy Homes (NZEH) are homes designed to use near zero net energy from the utility grid. They must achieve a HERS Index of 30 or less.
|Gainesville, Florida (1) - Publication | Data
This near zero energy home in Gainesville, Florida, features all Energy Star rated appliances and hot water that is provided by a 120 gallon solar hot water system. It is a 1,772 sq ft, single story, three bedroom/ two bath home with a preliminary HERS rating of 29. Occupied by two people.
|Gainesville, Florida (2)
This home is located in Gainesville, Florida. It is a single story three bedroom/two bath home with 1,519 sq ft of living space and a HERS rating of 16. The house has all Energy Star appliances, water star plumbing fixtures, and 120 gallon solar hot water system. While it was planned to be a zero energy home, site shading and equipment issues have lowered its performance. Unoccupied as of 1/1/09.
Florida - Details & Data | Publication
In 1998, FSEC began its Zero Energy Homes research program in collaboration with the City of Lakeland municipal utility and builder Rick Strawbridge. Two homes were constructed and tested on a side-by-side basis for more than a year.
The Los Olivos Zero Energy Home (ZEH) in Livermore, California represents an initial demonstration and proof of concept of ZEH
technologies in California under the National Renewable Energy Lab Zero Energy Home Program.
Located in Newberry, Florida, this production built, near zero energy home achieved a HERS rating of 1. Energy consumption in the home is offset by a 5.4 kW photovoltaic system.
|New Smyrna Beach, Florida
A second-generation Zero Energy home was constructed in New Smyrna Beach, Florida. Many of the lessons learned during the design and construction of previous projects have helped to maximize the cost:benefit ratio of the various components.
|Panama City, Florida - Details | Data | Publication
This factory built modular home near Panama City, is the first home in Florida to achieve a LEED for Homes platinum rating. It is a two story three bedroom/two bath home with 1,371 sq ft of living space and a HERS rating of 26. Occupied by one person.
The four homes discussed in this study represent the three major forms of residential construction in Florida: site-built wood frame, site-built concrete block, and manufactured or modular housing. All of the homes were instrumented to obtain data on electrical consumption and generation, interior conditions, and basic weather parameters. By examining the energy data, audited miscellaneous electrical loads, and occupancy of these homes, this study seeks to identify sources of discrepancy in reaching performance goals