Zero-Net-Energy Homes need Smart Ventilation
California is on a path toward zero net energy (ZNE) homes. The air-tightness of new and existing homes with electric heating/cooling will increase as homes become more energy efficient. The tightening of homes to save energy could increase poor indoor air quality (IAQ) (Levin and Phillips 2015). Poor IAQ associated with stringent energy-efficiency requirements is a major barrier to the state’s energy-savings goals. In addition, reductions in home’s energy losses mean that ventilation represents an increasing fraction of home energy use. California needs new strategies and technologies on its path toward healthy ZNE homes. Smart ventilation can provide these new strategies and technologies.
IEQ Roadmap Recommendations
The Indoor Environmental Quality Research Roadmap recommended the integration of indoor environmental quality (IEQ) into California’s future plans. The roadmap identified ventilation as a priority research topic. Two specific high-priority research projects were listed:
- Understand the best ventilation systems for high-performance buildings, include ventilation systems and air cleaning systems that are
- Develop and demonstrate IEQ-optimized ventilation, heating, and cooling systems for different building types and different climate zones in California for both new and retrofit applications.
Our project addresses both of these high-priority project areas for residential buildings by developing smart ventilation technology approaches that can incorporate air cleaning and, more generally, by developing IAQ metrics for optimizing ventilation.
The Road to Efficient and Effective Ventilation
To reduce the problems of poor IAQ, California adopted the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62.2 for minimum residential IAQ. Standard 62.2 specifies minimum requirements for mechanically ventilating homes. Generally, mechanical ventilation requirements are met through use of continuously operating fans or fans that operate on a fixed intermittent schedule.
In recent years, Lawrence Berkeley National Laboratory (LBNL) developed “smart ventilation,” which replaces fixed fans with fans that are controlled to minimize energy use. Smart ventilation minimizes energy use by employing three important strategies.
- Time-shifting to ventilate less when energy costs to society and to the customer our highest,
- Accounting for the operation of other air-moving equipment (such as bath fans and dryers),
- Using the equivalent ventilation principle to ensure that a building’s exposure to pollutants is the same for the smart ventilation system as for a continuously operating system (Walker et al. 2012, Sherman and Walker 2011, Sherman et al. 2012).
This three-tiered approach saves energy and contributes to achieving ZNE homes without compromising IAQ.
The primary public benefit of SVACH is to encourage and enable the next generation of smart ventilation technologies for use in new and existing ZNE homes. Achieving that goal will require revisions to these standards and guidelines.
- California Title 24,
- Various State guidelines and rebates,
- ASHRAE Standard 62.2, to which the State regulations refer.
An interim goal is facilitating the adoption of smart residential ventilation technologies in the 2019 Title 24 standards.
The competitive market currently offers no incentive to develop smarter ventilation systems. This is because contractors can’t put a quantitative value on the improvements in IAQ and energy efficiency. Nor do the codes and standards give credit for improved IAQ. This lack of a quantitative value makes it difficult to use smart ventilation for competitive marketing for ZNE homes and their ventilation systems. Regulated markets could, in theory, support portions of the necessary work to achieve smart ventilation. Pacific Gas and Electric supports this approach by providing a letter of support for SVACH.
We hope that the California investor-owned utilities can help with the interim goal of adopting smart ventilation in the 2019 Title 24. Private industry isn’t investing in smart ventilation research. This is because the benefits accrue to society as better health and reductions in healthcare costs. Ventilation companies and private enterprise doesn’t think at the level of societal benefit. The U.S. DOE along with other public entities provides financial support because smart-ventilation research and development targets public-benefit.
Funding Public Benefit
The project is particularly suitable for EPIC funding because it responds directly to Funding Initiative S1.7 (Develop and Evaluate Ideal Strategies to Improve Indoor Air Quality in Energy-Efficient Buildings) in the Applied Research and Development program area for California homes. No other entity in the state is or would be funding this effort. EPIC funding for the applied research and development aspects would provide the pre-competitive basis for the regulated or competitive sectors to continue to product and program development.
Additionally the solicitation addresses the energy goals inherent in the California Energy Code (Title 24 Part 6 of California Code of Regulations), which requires that its energy savings do no harm to the environment. This project creates strategies for continuing to provide acceptable indoor air quality (and thus do no harm) while saving energy.