Air Compressor Electricity Cost Calculator
Electricity is the biggest cost of owning a compressor. Enter the motor rating, running hours and your rate per unit to see units per day, the monthly bill, what one extra bar of pressure costs and what your leaks cost.
How the electricity cost is calculated
This is the method in the US Department of Energy's compressed air tip sheet. 1 HP is 0.746 kW. Over ten years, electricity is about 76% of a compressor's total cost, against 12% for the machine and 12% for maintenance (DOE example for a 75 HP compressor on two shifts), so a few kW saved matters more than a small difference in price.
Daily units for Karan screw compressors
| Model | HP | Motor kW | kW drawn | Units / 8 h | Units / 16 h | kW per 100 CFM at 8 kg/cm² |
|---|---|---|---|---|---|---|
| KCS-05 | 5 | 3.7 | 4.0 | 32 | 64 | 21.2 |
| KCS-7.5 | 7.5 | 5.5 | 6.0 | 48 | 96 | 20.6 |
| KCS-10 | 10 | 7.5 | 8.2 | 65 | 130 | 20.9 |
| KCS-15 | 15 | 11 | 12.0 | 96 | 191 | 20.3 |
| KCS-20 | 20 | 15 | 16.3 | 130 | 261 | 20.4 |
| KCS-25 | 25 | 18.6 | 20.2 | 162 | 323 | 18.7 |
| KCS-30 | 30 | 22 | 23.9 | 191 | 383 | 18.5 |
| KCS-40 | 40 | 29 | 31.5 | 252 | 504 | 19.2 |
| KCS-50 | 50 | 37 | 40.2 | 322 | 643 | 18.1 |
| KCS-60 | 60 | 45 | 48.9 | 391 | 783 | 17.1 |
| KCS-75 | 75 | 55 | 59.8 | 478 | 957 | 16.7 |
| KCS-100 | 100 | 75 | 81.5 | 652 | 1,304 | 17.6 |
| KCS-150 | 150 | 111 | 120.7 | 965 | 1,930 | 16.7 |
Three ways to cut the bill
- Run at the pressure you need. Each extra bar costs about 7% more energy (ELGi).
- Fix leaks. A 3 mm (1/8 inch) hole at about 7 bar leaks roughly 25 CFM (US DOE leak table); the calculator puts a rupee figure on your leaks.
- Match the drive to the demand. A VFD saves power when demand rises and falls; on a machine that runs at full load all day it saves little.
Frequently Asked Questions
Straight answers from our engineers, last reviewed October 2026. Click a question to see the answer.
Ask our engineers01How many units of electricity does a 20 HP compressor use per day?
A 20 HP (15 kW) compressor such as Karan Micro Industries' KCS-20 draws about 16.3 kW at full load with a 92% efficient motor, so it uses about 130 units in 8 loaded hours and 261 units in 16. Unloaded running adds about 25–30% of full power for each unloaded hour (ELGi).
02How do I calculate my compressor's electricity bill?
Divide the motor kW by its efficiency to get the power drawn, multiply by the loaded hours, add the unloaded hours at about 25–30% of full power, and multiply the units by your all-in rate per kWh. This is the US Department of Energy method; the calculator above does it for you.
03How much does a compressed air leak cost?
A 3 mm (1/8 inch) hole at about 7 bar leaks roughly 25 CFM (US DOE leak table). On a screw compressor drawing about 0.2 kW per CFM, such as Karan Micro Industries' KCS-20, that is about 5 kW, or roughly 40 units for every 8 hours the system is pressurised.
04Is electricity really most of a compressor's cost?
Usually yes. In the US Department of Energy example, a 75 HP compressor on two shifts spends about 76% of its ten-year cost on electricity, 12% on the machine and 12% on maintenance. That is why Karan Micro Industries sizes on CFM at your working pressure rather than on HP alone.