A reduction in operating costs. A decline in wear and tear on equipment. Longer equipment life. A better working environment. Does this sound like your wish list? If so, here’s a good way to actually achieve these aspirations: conduct an HVAC audit.
“Next to lighting, HVAC is the largest energy user in a building, so improvements in system performance can significantly lower the total energy bill – by up to 40 percent,” says Mark Price, energy business unit manager at Everett, WA-based Fluke. As he points out, without an audit that tells you how equipment performs, you don’t know how much energy your system consumes. “Once consumption is known, you can compare against upgrade options, get ROI estimates, and make informed decisions,” says Price.
Equipment performance can be greatly improved with an audit. “Routine maintenance functions commonly fall off the map,” says Price. He explains that things as easy as changing filters on time can save electricity and save an air-handler from premature failure.
The four biggest savings in terms of HVAC audits, according to Price, come in terms of:
- Adding variable speed drives to chillers and other big loads.
- Right-sizing fans.
- Adjusting controls (changing setpoints and daily/seasonal cycles) or upgrading them.
- Optimizing ventilation (not including significant upgrades or retrofits).
Other things you might find during an audit include worn motors, leaky valves, inefficient compressors, ineffective heat exchangers, and inefficiencies in the fuel/energy process, according to Jerry Pindus, CEO at Fresh Meadows, NY-based US Energy Group.
In addition to helping you identify less-than-optimal equipment, another goal for an HVAC audit is to keep the system up to speed. “The building environment is constantly changing: seasonal temperatures, building upgrades, office space use, number of occupants, etc. An audit will quickly identify if your system is updated and tracking to all of these changes,” says Price.
A routine audit should be done at least once every 12 months, according to Pindus; however, he recommends performing audits whenever you can to look for inefficiencies on a daily or weekly basis (long boiler runtimes, water loss, steam leaks, high stack temperatures, etc.). An energy-management system will look at these areas, triggering alerts to crucial issues, documenting results, and maintaining useful historical records.
Price recommends that basic checks be done at least quarterly to ensure that any energy savings are sticking (monitoring energy use of key components, such as chillers, boilers, air-handlers, etc.; ensuring the correct operation of dampers, condition of filters, and ventilation rates; etc.).
You’ll benefit most from an audit if you take time to do the necessary pre-work. Creating an inventory of information – equipment age and size, make/model, maintenance schedule, dates of any upgrades, and location – will help prioritize where the audit team will spend time. Price says that benchmarking energy usage across 2 or 3 weeks will help establish the baseline needed to measure improvements. Finding and examining utility bills will also be key, especially in establishing ROI.
HVAC audits can be conducted in isolation, but there are advantages to incorporating an HVAC audit into a larger, facility-wide audit. The rule, according to Pindus, is to “audit what you can, when you can, as part of a consistent, practical, cost-effective program.”
Leah B. Garris ([email protected]) is managing editor at Buildings magazine.