How would you like to cut your commercial building energy costs by 40 percent? You can, with retro-commissioning.
First, let’s get our terms straight. There are three types of commissioning for commercial buildings:
- Commissioning—when a new building comes online, all systems are measured to ensure they operate as deigned.
- Retro-commissioning—when you review the systems of an existing building for the first time, some years after it’s built.
- Recommissioning—when you review the systems of a building for a second or third time.
Yes, it’s a little confusing. It’s the same process with a different name depending on when you conduct the review. But the ACEEE says retro-commissioning of existing buildings and recommissioning older buildings are where you stand to gain the most bang for your buck.
Buildings Eat Energy
It is no secret that commercial building operations account for 28 percent of global greenhouse gas emissions. More than half of the commercial buildings in the United States were built before 2000 and continue to rely on older, inefficient energy infrastructures. Studies by organizations like the ACEEE found that retro-commissioning can achieve 40 percent energy savings–seven times more than a typical single-measure retrofit. Yet only some property owners and managers are embracing a retro-commissioning approach.
What Systems can be Retro-commissioned?
Retro-commissioning programs typically target energy-intensive equipment and inefficiently controlled systems. A list of equipment and systems to start with from the Federal Energy Management Program includes:
- Building automation system, including controlled devices, sensors, control loops, and logic
- Cooling systems
- Central cooling plant
- Primary air-handling units
- Terminal units
- DX systems
- Heating systems
- Central boiler plant
- Primary heating systems
- Fire safety/smoke purge aspects of the HVAC system
- Lighting systems
- Hot water equipment
- Humidity control equipment
- Building pressurization controls
The Good News About Retro-Commissioning
A report by the Building Commissioning Association found that the cost of retro-commissioning commercial buildings is anywhere from $.05 to $0.50 per square foot. With up to 40 percent energy savings, payback periods range from two months to two years. That is good news. But there is even better news—many utilities offer performance-based retro-commissioning incentives paid directly to owners based on the kilowatt-hours (kWh) saved, accelerating payback, and sometimes paying for the entire project.
For example, California’s Pacific Gas and Electric (PGE) pays owners $0.09 for every kWh saved. The first payment is based on estimated energy savings, and the second payment is based on actual savings after 12 months.
The Los Angeles Department of Water and Power (LADWP) breaks down retro-commissioning incentives by retrofit category:
- $0.08/kWh for electricity saved from lighting fixture retrofits
- $0.30/kWh for savings from high-efficiency HVAC/refrigeration equipment and variable-speed drives
- Up to $750/kW for thermal energy storage
All non-lighting incentives are capped at 75 percent of the total cost, while lighting incentives may cover 100 percent.
Similar programs are offered throughout the country.
There are also soft benefits of retro-commissioning for owners and tenants:
- Increased property values
- Improved tenant comfort and retention
- Longer equipment life
- Reduced maintenance costs
Owner/tenants gain the added benefits of a 10 percent improvement in employee productivity and 40 percent fewer employees taking sick days, according to the ACEEE.
When is it Time to Retro-commission/Recommission a Building?
Any building that has never been commissioned should be retro-commissioned to ensure all systems perform as specified. After a first commissioning, second and third commissions are called recommissioning, but the process is identical to retro-commissioning a building that has never been commissioned. Should you consider another commissioning for your commercial buildings? There are a few things to keep in mind.
Do You Qualify for Incentives?
The first question to ask is whether your utility offers incentives and if you qualify for them. PGE’s incentives are available to commercial customers that:
- Receive gas or electric service from PGE.
- Pay a California public purpose programs surcharge on their utility bills.
- Own or operate a facility that has at least 100,000 square feet of conditioned space or that consumes 2,000,000 kWh or 50,000 therms per year.
- Have access to funding to implement commissioning measures within 12 months.
LADWP’s qualification criteria are more relaxed. Commercial building owners:
- Must be an LADWP non-residential electric customer in good standing.
- All projects require a pre-inspection of the existing equipment and baseline conditions.
- Any new equipment must replace existing equipment.
How Long Since Your Last Checkup?
A second question to ask about retro-commissioning is when you last went through the process. As with your dentist and your doctor, you need to schedule regular checkups for your buildings!
According to the Department of Energy, you should consider recommissioning every 3-5 years. The performance of sensors and controls inevitably decays over time, heating coils clog, and new technologies come online that offer cost-effective hardware and software upgrades.
You Are Burning More Energy
Another sign that it might be time for retro-commissioning is that your energy use and costs are rising beyond the impact of rate increases and climate-related events like cold snaps and heat waves. The Department of Energy also recommends “ongoing commissioning,” where the monitoring measures and equipment remain in place to detect and respond to changes in system performance in real-time.
Your Tenants (or Employees) are Complaining
Listening to tenants and/or employees is always a good idea. Regarding energy performance, it is better to hear from them sooner rather than later. If building occupant complaints or service requests sharply increase, it is a sign of system performance change. It is important to get regular “boots-on-the-ground” feedback because if sensors or equipment are malfunctioning, monitoring or reporting systems might not see it.
A Remodel has Changed Building Configurations
When a building undergoes structural, operational, or occupancy changes that require reconfiguration of the systems like lighting, HVAC, or air quality, you will need to verify that the new configuration is operating with the same efficiency as originally designed. You should also verify that maintenance personnel are adequately trained and have documentation to operate the building efficiently and achieve optimum performance.
Finding a Retro-commissioning Service Provider
Most commercial building owners outsource commissioning to third-party experts with the experience and tools to audit and test system performance, recommend, and implement solutions, and measure results. Few property owners or managers have the in-house expertise to design and execute a retro-commissioning project. And, if you are looking to take advantage of utility incentives, most retro-commissioning service providers will tackle the “paperwork” of applying for the benefits, allowing owners, in some cases, to pay only the project’s net cost upfront. In the case of the LADWP’s lighting incentives that pay up to 100 percent of project costs, the upfront fees could be zero.
Service providers can also be invaluable after completing a retro-commissioning project, as implementation is not the end of a project. “Without training for facility staff and an operations and maintenance program, the benefits that accrue will not last,” the Department of Energy said.
At the project’s end, a retro-commissioning service provider should conduct thorough training for facility employees and provide documentation for future staff. Training should include a combination of group workshops and hands-on demonstrations specific to the building’s equipment.