Retro-commissioning existing buildings
Most existing buildings drift away from how they were meant to run. Retro-commissioning finds the problems, ranks the fixes by cost and payback, and verifies the savings.
When you need it
- Energy bills are rising and you don’t know why.
- Tenants complain about comfort even though the equipment seems fine.
- Equipment runs at night and on weekends when the building is empty.
- You’re planning capital upgrades and want to fix how the building runs first.
What we do
Collect data
We review utility bills, drawings, control sequences and maintenance records, and talk with the operators.
Investigate
We walk the building, test equipment and trend the control system to find out what runs when, and why.
Prioritize
We list each problem with its estimated cost to fix and its energy or comfort benefit, so you can decide what to do first.
Fix and verify
Once the measures are in place, we verify that they work and that the savings show up.
What you receive
- A findings report with each issue, its cause and its fix
- Measures ranked by cost, savings and payback
- Verification results after implementation
- Recommendations to keep the building on track
Questions
How much can retro-commissioning save?
In a Lawrence Berkeley National Laboratory study of 643 U.S. buildings, commissioning existing buildings produced median whole-building energy savings of 16%, with a median payback of 1.1 years. Results vary by building, but the fixes are often low-cost changes to controls and schedules.
What kinds of problems do you find?
Typical findings include equipment running when the building is empty, heating and cooling fighting each other, outdoor air dampers stuck open or shut, failed sensors, and setpoints that were changed and never put back.
Do we need new equipment?
Usually not to start. Retro-commissioning gets existing equipment running properly. It also shows which equipment really does need replacing.
Further reading
- Part-load performance: why buildings rarely run at design
Learn why design conditions occur only a few hours a year, how part-load efficiency differs from full-load ratings, and how to select equipment and controls that perform well across the whole year.
- Rules of thumb in HVAC sizing and why they fail
Learn where common HVAC sizing rules of thumb come from, why they fail for modern buildings, the real costs of oversizing, and the proper role of benchmarks in design review.
- Sensible and latent heat: why the ratio matters
Learn the difference between sensible and latent heat, how to calculate the sensible heat ratio, and why matching equipment to that ratio is the key to humidity control.
- Thermal comfort and ASHRAE Standard 55
Learn what ASHRAE Standard 55 requires, how comfort depends on more than air temperature, and how to use the standard to design, commission and troubleshoot commercial spaces.
- Constant volume vs variable air volume systems
Learn how constant volume and VAV systems control temperature, how they differ in energy use, comfort and complexity, and how to decide which suits a building or a retrofit.
- Duct static pressure and how to reduce it
Learn what static, velocity and total pressure mean in a duct system, how to diagnose high static pressure, and which fixes deliver real reductions in fan energy and noise.
Related services
Also in commissioning: Building commissioning, Infrared thermography.
Get a quote for retro-commissioning
Tell us about the building and what you need. We’ll be in touch within one hour.