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Energy waste is endemic in commercial buildings in the U.S. In fact, the average commercial building in the U.S. wastes 30% of the energy it consumes,¹ leading to unnecessarily high utility bills and maintenance and equipment replacement costs.

To overcome such business issues, new applications in heating, ventilation and air conditioning (HVAC), such as occupancy sensors, are becoming energy-efficiency staples in commercial buildings across the country.

Complementary HVAC occupancy sensors and technologies
Attributable largely to systems or appliances left running when not in use, commercial energy waste can be prevented through the many kinds of HVAC occupancy sensors available to businesses today.

• Demand-controlled ventilation. Commonly used with an HVAC system, DCV implementation is one of the most effective ways businesses can reduce energy waste. DCV systems read the number of occupants in a room (often using CO₂ sensors, which use carbon dioxide levels resulting from human exhalation to determine occupancy) and adjust outside ventilation air based on the demands of the room or space.
• Exact reading occupancy sensors. Some occupancy sensors use exact measurements of the number of people in a space to determine cooling, ventilation and heating needs. Businesses that use ticket sales, turnstiles, security swipes or even video recognition can use the exact number of people in a space to regulate HVAC.
• Temperature and humidity sensors. These operate in one of two ways. They use occupancy readings to increase or decrease heating, air conditioning or ventilation to indoor spaces. They also read room temperatures and make automatic adjustments based on settings such as time of day and preferred climate. Through a variety of applications, including wall mounts, the humidity sensors can identify when environments become moist or muggy. Humidity sensors can be used in tandem with the temperature sensor or as an optional feature.
• Programmable thermostats. To demonstrate the effectiveness of these devices, the Standard School District of Bakersfield, Calif., worked with PG&E to install thermostats for added energy efficiency. These thermostats not only controlled temperature better but came with a built-in, preprogrammed 365-day calendar software that operated according to the school's schedule. In combination with installed door switches, the results included consistent temperatures and carbon dioxide levels, projected reductions of 4% in electrical consumption and more than 12% of natural gas consumption for the two campuses.² Saved expenses were also a result because of PG&E's Customized Retrofit program, which covered nearly 34% of the District's project costs.

Integrative approaches cut costs
While most HVAC systems are designed to operate at set levels, switching to HVAC control systems with built-in occupancy sensors ensures that heating or cooling are supplied to the places that need it most.

To gain the most energy efficiency, businesses must also be mindful of which technologies play best together. It's even possible to tie HVAC occupancy sensors to lighting occupancy sensors so that all indoor systems are responsive to the number of people in a room. To demonstrate this, PG&E helped one biotech company install occupancy sensors for lighting as part of its commercial savings plan, resulting in annual calculated energy savings of $234,000 and a return on investment in less than 10 months.³

Businesses with heavy ventilation needs can also integrate their exhaust systems with their building's overall HVAC system, using occupancy sensors to control all facets of the airflow process in every space.

HVAC occupancy sensor savings
Most suitable for commercial applications, occupancy sensors enable businesses to reduce waste and operational cost. By implementing such energy-efficiency measures, especially for spaces where occupancy is at varying levels, building managers may also lower maintenance expenses and provide a comfortable atmosphere for employees and customers.

Download "The Complete Guide to Working with a Lighting or HVAC Contractor" eBook from PG&E and learn how working with an HVAC contractor can help you better optimize HVAC occupancy sensor use. Find out more about cost-effective occupancy sensor installation from PG&E that will better differentiate your business for optimal success.

Referenced in article:

1. ENERGY STAR
2. Pacific Gas and Electric Company
3. Pacific Gas and Electric Company