Energy Consumption Calculator

Calculate energy consumption step by step: E = P_rated × load factor × hours/day × days/year.

In short

Formula: E = P_rated × load factor × hours/day × days/year.

Complete the required fields to see the result.

What this calculator does

Calculate energy consumption step by step: E = P_rated × load factor × hours/day × days/year. Worked example, questions and limitations included.

Use it to turn Rated power, Average load factor, Operating hours per day, Operating days per year into a checked result you can compare, copy, or rerun with different assumptions.

The page shows the formula, a numeric worked example, and the assumptions that affect this thermal & hvac calculation.

Inputs and what they mean

Rated power: — number value.
Average load factor: — Share of rated power actually drawn on average.
Operating hours per day: — number value.
Operating days per year: — number value.

How to use it

Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
Check the breakdown to see every intermediate step.
Read the limitations before relying on the result.

Formula

Load factor is entered by you — no typical value is assumed.

Hours ≤ 24 and days ≤ 366.

For HVAC, compressors cycle, so use a measured or estimated average.

E = P_rated × load factor × hours/day × days/year.

Inputs used: Rated power, Average load factor, Operating hours per day, Operating days per year.

Worked example

3.5 kW unit at 60% load, 8 h × 250 days

Daily = 3.5 × 0.6 × 8 = 16.8 kWh.
Annual = 16.8 × 250 = 4,200 kWh.

Reading the result

The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.

Limitations and assumptions

Single average load factor.
Standby consumption excluded unless included in load factor.
No seasonal variation.
Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
The result depends on the values you enter for this energy consumption calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

Common questions

What is load factor?

The average power drawn as a share of rated power. A compressor running half the time at full power has about a 50% load factor.

How is this different from the energy calculator?

This one works per year with a load factor for equipment; the energy calculator uses a direct average power over days. Check the formula, example, and limitations on this page before using the result for a real thermal & hvac decision.

How do I get cost?

Use the equipment energy cost calculator with your own tariff. Check the formula, example, and limitations on this page before using the result for a real thermal & hvac decision.

How do I use the Energy Consumption Calculator?

Enter the required values for Rated power, Average load factor, Operating hours per day, Operating days per year. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

What formula does the Energy Consumption Calculator use?

E = P_rated × load factor × hours/day × days/year. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

Can the Energy Consumption Calculator be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.