Formula & worked example
Annual useful heat=Qrec·utilization·hours; avoided purchased energy=useful heat/η; payback=project cost/annual savings.
Recovering 50 kW for 4,000 h/year at 70% utilization yields 140 MWh/year of useful recovered heat.
HVAC & plant engineering calculator · Updated Sep 17, 2026
Heat Recovery Payback Calculator — Annual Savings, CO₂ & Simple Payback
Convert recoverable heat, utilization, operating hours, displaced-system efficiency, energy tariff and project cost into annual useful heat, purchased-energy savings, money savings, CO₂ reduction and simple payback.
Inputs
Live engineering result
Useful recovered heat 140 MWh/year
Avoided purchased energy 164.70588 MWh/year
Annual money saving 16,470.588
CO₂ reduction 32.941176 t/year
Simple payback 1.5178571 years
Assumptions & limits
- Simple payback excludes financing, maintenance escalation, degradation and tax effects.
- Tariff and carbon factor must match the displaced energy source.
Frequently asked questions
What does this Heat Recovery Payback Calculator calculate?
Convert recoverable heat, utilization, operating hours, displaced-system efficiency, energy tariff and project cost into annual useful heat, purchased-energy savings, money savings, CO₂ reduction and simple payback.
Can I use this for final design?
Use it as an auditable engineering sizing cross-check. Final equipment and piping selections should use project design conditions, manufacturer data, applicable standards and local code.
Why are the engineering assumptions shown?
Plant calculations are sensitive to fluid properties, pressure, temperature and operating hours. Exposing assumptions makes the result easier to verify instead of hiding them behind a single answer.