Guide Addresses Residential Commissioning

Houses are complex systems of interacting components that don't always perform properly. Even when built or retrofitted using formal design procedures, houses often fail to meet health, safety, comfort, and energy-use expectations. A major reason for this generally poor performance is the lack of consistent procedures to ensure that a home is built and operated in the way it was intended.

Residential commissioning combines components and system testing with changes to improve home energy efficiency and comfort. Many good commissioning elements are already practiced in some fashion, but they don't deal with the house as a system, and therefore don't fully consider parallel issues of energy consumption, peak power, thermal comfort, and pollutant control.

"Guidelines for Residential Commissioning," a report prepared by Lawrence Berkeley National Laboratory for the California Energy Commission, was created to integrate as many available procedures into a comprehensive process that considers the house as a whole system. The guide also provides examples that demonstrate the benefits of whole-house commissioning.

The Three Phases

The guide explains the commissioning process and suggests how to structure a commissioning program. It recommends three phases of commissioning:

1. Audit - Evaluating the current conditions and performance of the house.

2. Tuning - Making minor adjustments and repairs to systems and materials to improve efficiency and performance.

3. Opportunity identification - Providing information to the client about additional energy-efficiency measures, such as improved insulation, that could be installed and implemented.

Procedures that take place during the commissioning phase include air tightening, duct sealing, refrigerant and air handler airflow corrections, and improving insulation installation quality in new homes.

A list of 16 recommended audit procedures is included in the guide, along with references that describe how to conduct each procedure, an inventory of the equipment required, an estimate of the time required, and an indication of the energy-savings potential.

The guide also describes the benefits of residential commissioning, which include:

Reduced electricity and gas consumption. In the guide, there are tables to show substantial energy savings, as they are a principal benefit of commissioning houses. Savings typically come from such measures as sealing leaky ducts or correcting a refrigerant-charge deficiency in a central air conditioner.

Improved occupant comfort and indoor air quality (IAQ). The commissioning process can help to identify places where contractors can reduce uncontrolled air infiltration, provide appropriate ventilation capacity, and achieve more consistent surface temperatures through better-installed insulation. Commissioning can also help ensure that the HVAC system actually does deliver the expected amount of space conditioning.

Greater envelope durability and longer HVAC equipment life. Improving the building and its systems will reduce callbacks and warranty costs, which will provide the business community with increased profits.

If widely practiced, residential commissioning can also lead to significant decreases in electrical demand that will provide greater system reliability for utilities.

Cost, and an industry emphasis on reducing first costs, is a barrier to widespread use of commissioning. The guide can help overcome the barrier by providing an integrated set of simple, rapid, inexpensive, and reliable commissioning methods and by qualifying the potential benefits.

Applications

All new and existing homes are eligible for commissioning. The biggest savings potential lies with existing houses that are performing poorly. Well-engineered new homes may still benefit from commissioning, but offer the lowest potential for energy and comfort benefits.

California's Title 24 energy code mandates that components of new homes comply with performance standards such as minimum efficiencies for space conditioning and water heating equipment.

With the implementation of residential commissioning programs, code authorities and officials will see improved compliance with building codes as the commissioning process identifies and corrects elements that do not meet code requirements. Whole-house commissioning also has the potential to take houses to a level of performance beyond that resulting from Title 24.

To get a copy of "Guidelines for Residential Commissioning," go to www.energy.ca.gov/reports/500-04-012/2004-04-07_500-04-012_A1.PDF. Contact at Lawrence Berkeley National Laboratory is Max Sherman, 510-486-4022, mhsherman@lbl.gov. Contact at the California Energy Commission is Chris Scruton, cscruton@energy-stste.ca.us, www.energy.ca.gov/pier/buildings.

Publication date: 07/18/2005

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