How to Use the Steam Condensate Load Calculator
Steam gives up its latent heat as it condenses inside a heat exchanger or heating unit, and that latent heat is exactly the heat load being delivered. So Condensate Load (lb/hr) = Heat Load (BTU/hr) ÷ Latent Heat of Vaporization (BTU/lb). Enter your heat load and select the steam pressure in use to get the hourly condensate rate instantly.
Latent heat depends on steam pressure — at 0 psig (212°F) it's about 970 BTU/lb, but as pressure rises, saturation temperature goes up while latent heat actually goes down, dropping to about 857 BTU/lb at 150 psig (366°F). That means higher-pressure steam needs more condensate flow to deliver the same heat load than lower-pressure steam does.
This result is the theoretical condensate load under steady, normal operating conditions. In practice, steam traps and condensate piping are typically sized with a safety margin (often 2-3x normal load) to handle startup overload, so final trap sizing and pipe sizing should follow the manufacturer's selection criteria and be reviewed by a mechanical engineer.
Frequently Asked Questions
Yes. As steam pressure rises, saturation temperature increases but latent heat actually decreases. To deliver the same heat load, higher-pressure steam requires more condensate flow than lower-pressure steam.
This is the theoretical condensate load under normal running conditions. Actual steam traps are typically sized with a safety factor (often 2-3x) to handle startup overload, so final trap sizing should follow the manufacturer's selection guide and be reviewed by a mechanical engineer.