By Jonathan Marshall

Second in a two-part series.

Even in relatively temperate California, one of the leading users of energy is heating, ventilation and cooling (HVAC) systems. Yet according to one recent report by a federal laboratory, building operators in San Francisco and Los Angeles could save 40 to 50 percent of their HVAC energy costs just by retrofitting their systems with advanced controls, so they run only at the precise times and levels needed to maintain comfort.

According to PG&E energy solutions engineer Eric Noller, who spoke to a business audience at AT&T Park last week on energy-saving opportunities, three-quarters of the estimated 9 million rooftop HVAC units across the country aren’t running efficiently.

PG&E has incentives to help customers install more efficient air conditioning and heating units. (Photo by Vaughn Industries.)

In keeping with its mission to help the state save energy—and to help its customers save money—PG&E is actively engaging its business customers all across Northern and Central California to help them assess, maintain, upgrade, and in some cases replace their aging or malfunctioning HVAC systems. It’s one more way they can stay open and competitive in today’s economy.

Upgrades and retrofits of existing HVAC units can pay off handsomely. Last year, Noller helped analyze operations at one Walnut Creek office building, which cools interior spaces by circulating chilled water to air handler units on each floor. It turned out that the building’s condenser water pump was far bigger than needed for the job. Installing a relatively inexpensive variable frequency drive for the pump cut its speed 40 percent, saving 86,000 kilowatt-hours per year–about as much electricity as 14 typical homes use.

Payback time can be rapid

The net cost of the total job, after PG&E gave the customer a $7,000 check as an energy efficiency incentive, was only $7,800. The project saved the customer about $13,000 a year, resulting in a payback time of just over half a year.

Noller got involved in a much bigger job this year at a large office building in downtown Oakland. Its large chiller unit was a quarter century old, still running though near the end of its expected life. But PG&E’s energy analysis helped convince the customer to buy a new unit that was about 40 percent more energy efficient. The customer saved as much energy as 21 typical homes consume in a year, lowering its electric bill by several tens of thousands of dollar a year and pocketing an incentive payment of $28,000 from PG&E.

“The customer was very happy with the process,” Noller recalls. “The incentive they received made it possible for them to purchase the most efficient unit and complete the project this year instead of waiting for their existing chiller to degrade or fail.”

Since 2010, PG&E has helped non-residential customers save about 280 million kilowatt-hours of electricity through HVAC upgrades. That’s more than 40,000 typical homes consume in an entire year.

Maintenance can save money, too

Sometimes, system maintenance is all that’s needed to save money.  PG&E is drawing on the experience of satisfied customers who operate large buildings to address the HVAC maintenance needs of small and medium business facilities.

The HVAC Quality Maintenance program is now available to PG&E commercial customers. Robust and comprehensive services are provided by participating contractors who must meet high standards and receive advanced training. PG&E offers rebates to support creation of a three-year maintenance plan for each rooftop unit and a wide array of energy efficiency treatments to help customers lower their bills, reduce unforeseen failures, and improve occupant comfort.

“Given the impact of HVAC systems on our customers’ bills and operations, PG&E’s cost-effective maintenance program provides a substantial energy-saving opportunity to our customers and a clear win for the environment,” said Ryan Halsey, PG&E’s program manager for HVAC Quality Maintenance.

(Click here to read a NEXT100 posting on the history and impact of air conditioning.)

Email Jonathan Marshall at jonathan.marshall@pge.com.