Occupancy Sensor Savings Calculator

Turn idle spaces into measurable utility bill reductions. Model upfront sensor costs and ongoing maintenance. Plan upgrades confidently with clear savings projections for teams.

Adjust assumptions to match your site, tariff, and operating patterns.

Energy • Cost • Payback • ROI

Enter your details

Use the fields below to estimate annual savings and investment returns.
Values are kept after you calculate.
Downloads reflect your latest calculation.
Energy inputs
Example: 28% means lights run 28% fewer hours.
HVAC and pricing
Useful when sensors trigger set-backs in unoccupied zones.
If you have tiered tariffs, use an average rate.
Optional, for carbon impact estimates.
Costs and assumptions
Higher rates make future savings worth less today.
Reset

Formula used

Lighting baseline energy (kWh/yr)
baseline_lighting_kWh = (fixtures × watts × hours_per_day × days_per_year) ÷ 1000
Energy saved (kWh/yr)
saved_kWh = baseline_lighting_kWh × lighting_reduction% 
          + baseline_HVAC_kWh × HVAC_reduction%
Money saved and investment metrics
gross_savings = saved_kWh × rate_per_kWh
net_savings   = gross_savings − annual_maintenance
upfront_cost  = sensors × (unit_cost + install_cost)
payback_years = upfront_cost ÷ net_savings

NPV = Σ[ net_savings_year_t ÷ (1 + discount_rate)^t ] − upfront_cost

How to use this calculator

  1. Enter fixture count, wattage, and operating schedule.
  2. Set the expected runtime reduction from sensors.
  3. Optionally add HVAC energy and its reduction rate.
  4. Fill in your electricity rate and carbon factor.
  5. Enter sensor quantities, costs, and annual maintenance.
  6. Review payback, ROI, NPV, then export CSV or PDF.
Practical note: If you are unsure about reduction %, start with 15–30% for lighting and 5–15% for HVAC, then refine using meter data or a pilot zone.

Example data table

Sample scenarios to help you sanity‑check inputs. Replace with your site values.
Scenario Fixtures Watts Hours/day Days/yr Light reduction Sensors Rate
Small office floor 45 18 9 250 22% 12 0.16
Training center 120 24 11 300 30% 28 0.19
Warehouse aisles 200 40 12 310 35% 40 0.14
Disclaimer: This tool provides an estimate. Actual savings depend on space usage patterns, sensor placement, commissioning, and how existing controls are configured.

Related Calculators

Energy Bill Savings CalculatorHome Retrofit ROI CalculatorWhole House ROI CalculatorMonthly Utility Savings CalculatorAnnual Energy Savings CalculatorEnergy Cost Reduction CalculatorEnergy Price Increase SavingsGas Rate Savings CalculatorDual Fuel Savings CalculatorNet Energy Savings Calculator

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.