• Benchmark and track energy use (2.4–7% of energy spend): More than 35,000 buildings that benchmarked consistently from 2008 to 2011 cut energy use 2.4% a year on average, 7.0% over three years. The owners chose to benchmark, so this shows an association, not proof. ENERGY STAR, 2012.
• Retro-commission heating, cooling and controls (3.4–12% of energy spend): In Lawrence Berkeley National Laboratory's database of 446 existing-building projects, median whole-building energy savings were 6.4%, and the middle half of projects saved 3.4% to 12.4%. This replaces the lab's older, often-quoted 16% median. Berkeley Lab, Crowe et al. 2020.
• Upgrade lighting to LED (3.9–7.9% of energy spend): Lighting is about 15% of a commercial energy bill. Swapping fluorescent tubes for LED tubes cut lighting energy 27% to 29% in a federal test; full fixture retrofits in DOE's Interior Lighting Campaign saved a median 54%. EIA, CBECS 2018, PNNL for GSA, 2016, PNNL for DOE, 2019.
• Add lighting controls (3.5–5.6% of energy spend): A Berkeley Lab review of 88 studies found controls cut lighting energy 24% (occupancy sensors) to 38% (several strategies together), applied here to lighting's share of the bill. EIA, CBECS 2018, Berkeley Lab, Williams et al. 2012.
• Fit efficient restroom fixtures (9.5–13% of water and sewer spend): Restrooms use 37% of a typical office's water: toilets 56% of that, urinals 29%, faucets 11%. WaterSense toilets use 20% less than the federal standard and urinals at least 50% less; public-restroom faucets at 0.5 gallons a minute use 77% less than the 2.2 standard (the high end). Fixtures older than the standard save more. EPA WaterSense, 2023, EPA, commercial toilets, EPA, urinals, EPA, faucets, DOE FEMP and PNNL, 2015.
• Install smart irrigation controllers (3.3–6.6% of water and sewer spend): Landscaping uses 22% of a typical office's water, and EPA says properly installed WaterSense-labeled controllers cut irrigation water 15% to 30%. Irrigation meters often carry no sewer charge, so the dollar savings can be smaller. EPA WaterSense, 2023, EPA, irrigation, DOE FEMP and PNNL, 2015.
• Tune cooling tower water treatment (2.8–5.6% of water and sewer spend): Cooling and heating use 28% of a typical office's water. Raising a cooling tower from 4 to 6 cycles of concentration cuts its make-up water 10%; from 3 to 6, 20% (DOE and EPA). Not all of that 28% is tower make-up, so the high end assumes most of it is. EPA WaterSense, 2023, DOE FEMP, EPA, cooling towers, DOE FEMP and PNNL, 2015.
• Measure and cut kitchen food waste (2–4% of food purchasing spend): Champions 12.3 followed restaurants, hotels and caterers that measured and cut kitchen food waste. Over three years the median site's food-waste cost fell 2 points of food spend at restaurants and hotels, and more than 4 points at caterers. Savings build to that level by year three. Champions 12.3, restaurants (2019), Champions 12.3, hotels (2018), Champions 12.3, catering (2018).
• Measures in the same category overlap, so the calculator compounds them: each one saves its share of what the others leave. The total is less than the sum of the measures.
• Five-year figures are five times the annual savings, at today's prices, before up-front costs. Paybacks are as the studies report them.
• Why there's no line for waste hauling: no government or academic study gives a savings rate that holds across hauling contracts, which bill by the pickup, the container or the ton. EPA's method is to price the pickups you'd avoid from your own bill, which is how we size it in a waste audit.

This is a screening estimate from published averages, not an audit. Savings depend on your buildings, systems, rates and what you've already done.