How do you calculate furnace energy cost?

Multiply furnace load in kW by runtime in hours to get kWh, then multiply by the blended energy rate. With 650 kW over 6 hours at $0.11/kWh, total energy cost is $429 for 3,900 kWh.

What is the energy cost per casting?

Divide total energy cost by the number of castings processed. In the example, $429 across 180 units is $2.38 per processed unit — the figure to fold into a per-part quote.

Should I use connected load or metered load?

Use metered load when you have it, because induction furnaces draw full power on the melt ramp but far less while holding. The 650 kW here is treated as the effective draw; if the furnace holds at low power for part of the runtime, metered kWh will be lower than 3,900.

What is a typical melt energy figure for a foundry?

Iron melting in efficient induction furnaces runs roughly 500-600 kWh per ton; aluminum is lower per ton but melts at lower throughput. Convert the 3,900 kWh here by your charge weight to benchmark against those figures.

Why does blended energy rate matter?

It captures demand charges and time-of-use pricing, not just the energy rate on the bill's headline. If your real blended rate is $0.14 rather than $0.11/kWh, the same heat costs $546 instead of $429 — a 27% swing straight into part cost.

How can I reduce furnace energy cost per unit?

Cut hold time, keep lids closed, maintain lining for good coupling, and batch heats to avoid reheating. Increasing units processed per heat also lowers the per-unit cost: melting the same 3,900 kWh for 220 units instead of 180 drops cost per unit from $2.38 to about $1.95.

Foundry & Forging calculator

Furnace Energy Cost Calculator

Furnace energy cost is the electricity bill attributable to melting and holding metal, expressed both as a total and as a cost per casting processed. Foundry cost engineers and energy managers use it because melt energy is typically the single largest variable cost in an electric foundry — often rivaling labor — and small efficiency gains compound across every heat. It matters for quoting, since under-costing melt energy quietly erodes margin on every part, and for capital decisions like upgrading induction power supplies or improving lining and lid practice. This calculator turns connected load, runtime, and a blended energy rate into the per-unit number you can put into a quote or an efficiency case.

What this calculator does

Estimate furnace energy cost for melting, holding, heat treatment, or preheat operations.
Use it when electricity, gas, induction power, or holding time is material to casting or forging cost.
It computes total furnace energy cost, total kWh consumed, the hourly energy cost, and the energy cost allocated per casting or forging processed.

Formula used

Total furnace energy cost = furnace connected or metered load × furnace runtime × blended energy rate
Furnace Energy Cost cost per processed unit = total energy cost ÷ castings or forgings processed

Inputs explained

Furnace connected or metered load:
Furnace runtime:
Blended energy rate:
Castings or forgings processed:

How to use the result

Use it when quoting energy-intensive parts, benchmarking melt efficiency across heats, or building the business case for a power-supply or lining upgrade.
Using connected load assumes the furnace draws near its rated kW for the full runtime; if the unit spends time at reduced hold power, metered kWh will be lower than this estimate and you should enter metered load instead.

Current U.S. benchmarks

As of Apr 2026, industrial electricity averages 8.7 cents per kWh across the U.S. (EIA), up 5.5% from a year earlier. State averages range widely, so plants should confirm against their own tariff.
The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 3,569 primary metal manufacturing establishments employing about 354,911 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate furnace energy cost? Multiply furnace load in kW by runtime in hours to get kWh, then multiply by the blended energy rate. With 650 kW over 6 hours at $0.11/kWh, total energy cost is $429 for 3,900 kWh.
What is the energy cost per casting? Divide total energy cost by the number of castings processed. In the example, $429 across 180 units is $2.38 per processed unit — the figure to fold into a per-part quote.
Should I use connected load or metered load? Use metered load when you have it, because induction furnaces draw full power on the melt ramp but far less while holding. The 650 kW here is treated as the effective draw; if the furnace holds at low power for part of the runtime, metered kWh will be lower than 3,900.
What is a typical melt energy figure for a foundry? Iron melting in efficient induction furnaces runs roughly 500-600 kWh per ton; aluminum is lower per ton but melts at lower throughput. Convert the 3,900 kWh here by your charge weight to benchmark against those figures.
Why does blended energy rate matter? It captures demand charges and time-of-use pricing, not just the energy rate on the bill's headline. If your real blended rate is $0.14 rather than $0.11/kWh, the same heat costs $546 instead of $429 — a 27% swing straight into part cost.

Last reviewed 2026-05-12.