How do you calculate boiler blowdown loss cost?

Multiply blowdown volume by the fuel-and-water value per klb by the unrecovered heat share, then add the testing and treatment adder. With 420 klb at $5.60/klb, 100 percent unrecovered, plus a $150 adder, the total is $2,502, or $5.96 per klb.

What is a good boiler blowdown rate?

Blowdown is best expressed as a percent of feedwater, typically 4 to 8 percent, driven by cycles of concentration. The cost calculator shows why minimizing it matters: at $5.96 per klb, trimming excess blowdown drops straight to the bottom line.

What does unrecovered heat share mean?

It is the fraction of blowdown heat that is not captured by a flash tank or heat exchanger. At 100 percent, all the heat in the 420 klb of blowdown is lost; installing heat recovery might cut that to 40 percent, roughly halving the variable loss below its current $2,352.

How much can blowdown heat recovery save?

Flash steam and blowdown heat exchangers commonly recover 60 to 80 percent of blowdown heat. Applied to the example's $2,352 variable loss, recovering 70 percent would save about $1,646 per period before the fixed $150 adder.

Why include a testing and treatment adder?

Because blowdown is not just wasted heat and water — you also pay to test conductivity and dose treatment chemicals. The $150 fixed adder captures that overhead, which is why total cost ($2,502) exceeds the pure variable loss ($2,352).

How is cost per klb calculated here?

Total cost is divided by blowdown volume: $2,502 divided by 420 klb equals $5.96 per klb. That per-unit figure lets you benchmark blowdown cost across boilers of different sizes.

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Boiler Blowdown Loss Calculator

Boiler Blowdown Loss puts a dollar figure on the energy, water, and chemicals thrown away every time a boiler blows down to control dissolved solids. Steam plant engineers and utility managers use it because blowdown is a necessary evil — too little fouls the boiler, too much wastes hot, treated water straight down the drain. The metric captures the fuel value of the heat lost, the treated-water cost, and the treatment overhead so you can see what excess blowdown really costs. It is the number that justifies conductivity-based automatic blowdown control and heat-recovery flash tanks.

What this calculator does

Estimate boiler blowdown loss from hot water, chemicals, heat, and makeup water that leave the boiler system.
Use it when reviewing boiler blowdown loss for a utility budget, maintenance priority, capacity check, energy project, or production support plan.
It computes the total cost of boiler blowdown by combining the value lost per klb, the share of heat not recovered, and a fixed testing and treatment adder, then divides by volume for cost per klb.

Formula used

Total boiler blowdown loss cost = boiler blowdown volume × fuel and water value lost × unrecovered heat share + testing and treatment adder
Cost per item or period = total cost ÷ boiler blowdown volume

Inputs explained

Boiler blowdown volume:
Fuel and water value per klb:
Unrecovered heat share:
Testing and treatment adder:

How to use the result

Use it when evaluating automatic blowdown control, sizing a blowdown heat recovery system, or auditing steam plant losses against the fuel bill.
It uses a single blended value per klb; actual fuel and makeup-water costs vary with load and season, so recompute when energy prices or cycles of concentration change.

Current U.S. benchmarks

Industrial electricity averages 8.66 cents per kWh across the U.S. (EIA, Apr 2026), up 5.5% from a year earlier. Energy-intensive steps carry this directly into unit cost.

Common questions

How do you calculate boiler blowdown loss cost? Multiply blowdown volume by the fuel-and-water value per klb by the unrecovered heat share, then add the testing and treatment adder. With 420 klb at $5.60/klb, 100 percent unrecovered, plus a $150 adder, the total is $2,502, or $5.96 per klb.
What is a good boiler blowdown rate? Blowdown is best expressed as a percent of feedwater, typically 4 to 8 percent, driven by cycles of concentration. The cost calculator shows why minimizing it matters: at $5.96 per klb, trimming excess blowdown drops straight to the bottom line.
What does unrecovered heat share mean? It is the fraction of blowdown heat that is not captured by a flash tank or heat exchanger. At 100 percent, all the heat in the 420 klb of blowdown is lost; installing heat recovery might cut that to 40 percent, roughly halving the variable loss below its current $2,352.
How much can blowdown heat recovery save? Flash steam and blowdown heat exchangers commonly recover 60 to 80 percent of blowdown heat. Applied to the example's $2,352 variable loss, recovering 70 percent would save about $1,646 per period before the fixed $150 adder.
Why include a testing and treatment adder? Because blowdown is not just wasted heat and water — you also pay to test conductivity and dose treatment chemicals. The $150 fixed adder captures that overhead, which is why total cost ($2,502) exceeds the pure variable loss ($2,352).

Last reviewed 2026-05-12.