calculate power consumption

How to Calculate Power Consumption of a Commercial Building?

calculate power consumption

Are you an owner of a commercial building? Then the cost of the power consumption for your commercial building will always be one of your main concerns because this energy cost makes up your largest operating expenses.

According to the US Department of Energy, commercial buildings in the US account for 18% of energy consumption. This energy consumption is worth $180 billion each year. And this impact isn’t just economic, the CO2 emissions of the commercial buildings account for approximately 826 million metric annually.

Optimizing energy consumption in your building not only provides you with opportunities for cost savings but also helps you minimize your environmental impact. Before knowing how to reduce energy consumption, you should first learn how to calculate the power consumption of a commercial building.

In this article, we’ll explore factors that affect the power consumption in a commercial building, calculate the power consumption of the building, and tips for reducing costs.

What is the Difference Between Power Consumption and Electricity?

Mobile chargers and power banks are two different devices although they are used for the same purpose. Likewise, power consumption and electricity are two different things but most of the time we use them interchangeably. To get a better understanding of power consumption and electricity, read this blog.

  • Electricity and its Units

Power is the rate of electricity used while electricity is the actual energy consumption. Imagine a 100-feet pipe, filled with water. When you open a valve on one end, the water immediately flows out the other end. The pressure wave has traveled to 100 feet of pipe. Likewise, electricity is the flow of electrons through a conductor.

Electricity (Energy) = Power * Time

The unit of electricity is kilowatt hour or kWH. This is the actual amount of energy used in one hour. Suppose you use 1000W power in 1 hour then you consume 1 unit or 1 kWH of electricity. So, if a 100W bulb lit up for 5 hours then the total electricity it consumes:

Electricity = 100W * 5h = 500WH = 0.5 kWH or 0.5 unit

  • Power Consumption and its Units

Power consumption is the amount of energy used per unit of time to operate something. Consider an office building, it needs 4-watt power energy to function and the availability of the power is always required to work properly.

Power is always measured in watts (W) or kilowatt (kW). There are 1000 watts in 1 kilowatt. Let’s say, your washing machine has a power rate of 1.5kW which means it consumes electricity at the rate of 1500 watts. Similarly, if you buy a 100W bulb, it does not mean it consumes 100 watts of electricity. It means it consumes at the rate of 100W.

But the thing is power is not free and faces fluctuation in its prices, so it’s crucial to understand power usage now more than ever. Here’s a quick review of factors that affect power consumption.

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Factors Affecting Power Consumption

Every business is unique and has a different working environment from others. So, there is a lot that goes inside the walls of a company that can affect its power consumption. Numerous factors are affecting power consumption and understanding these factors can help optimize the performance of devices and systems. Here is a brief review of all the appliances and equipment that use electricity.

  • Lighting Systems:

There are various light fixtures in a commercial building, which consume a significant amount of electricity. These light fixtures are the primary source of electric loads in commercial buildings. The most common light fixtures are tubular fluorescent, compact fluorescent, and LED lights.

  • HVAC (heating, ventilation, and air conditioning) Systems:

In a commercial building, there are complex HVAC systems that use electricity to heat, cool, and ventilate the building. Generally, these systems maintain temperature in the range of 72 degrees, humidity between 30% to 50%, and CO2 levels below 1000 PPM. These systems are a major source of power consumption in commercial buildings.

  • Type of Appliances:

Commercial buildings also have kitchen appliances such as dishwashers, dryers, refrigerators, and ovens. These electric appliances also affect the commercial electrical load of a building. Therefore, it is important to include them in your power consumption calculations.

  • Office Equipment and Motors:

Different office equipment like computers, telephone systems, and printers consume a large amount of electricity in a commercial building. This equipment contributes to a significant electric load in commercial buildings.

Additionally, There is a wide range of electric machinery used in a commercial building like elevators, escalators, and others. Like other appliances and equipment, they affect the electric load of your commercial building.

  • Building Design and Layout:

The commercial building design and layout play a key role in its energy efficiency capabilities. A well-structured and thoughtful building design plays a key role in minimizing the power consumption of the building. So, if your commercial building is designed in such a way that it fully harnesses natural resources like sunlight, airflow, etc. then it will help in reducing your electricity bill.

  • Operating Hours and Occupants Behaviors

Occupants’ behaviors and operating hours of a commercial building also impact power consumption. Consider the active hours of your commercial building are between 6:00 pm – 3:00 am. That means you need more electricity to light up the building.

Same as if your occupants are unaware of the sustainable goals and don’t turn off the lights or appliances while leaving the building, then eventually your power consumption increases.


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Thus, there are many different types of electric loads, which vary according to the specific needs of the building. Understanding these electric loads and their characteristics is crucial for maintaining the electrical system in a commercial building.

Gather Data on Power Consumption of a Commercial Building

We know you are the building owner, not an electric load calculator. So, it is difficult for you to calculate the power consumption of your commercial building. The first thing that will come to your mind is where you can get data on your power consumption. In this section, we will elaborate on how you can get power data.

  • Reviewing Utility Bills

The electric bill is likely to deal with watts or kilowatts. Don’t panic when seeing numbers in 1000s. We have given a brief overview of both of these terms in the above section, so you know 1000 watts = 1kW = 1 unit.

So, get your building electricity bill, and review what total units your building is consuming. When you know the total units that your building is consumed then you know how to calculate the electric load.

  • Using Smart Meters and Monitoring Systems

You can use smart meters and monitoring systems to gather data on your power consumption. With these advanced meters, you will calculate the electric load for each of your appliances then you calculate the total power consumption. However, this method needs expertise in using these digital tools.

  • Conducting Energy Audits

Energy audits are the assessments that are carried out to evaluate how energy-efficient your building is. These audits are greatly beneficial for getting to know the energy usage of your building. You can hire some registered energy auditors that make your energy consumption calculation seamless.

You can gather data from any way that we mentioned above, now it is time to calculate the commercial power consumption of your building. Let’s start.

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How to Calculate Commercial Power Consumption?

Estimating power consumption of your commercial building can be done easily by following a simple method. It is based on the basic formula

P = VI

Where P is power, V is voltage, and I is current.

To calculate power consumption, you’d need to determine the current and voltage of each electric load in the commercial building and then use the formula P = VI to calculate the power consumption of each load. Once you have the power consumption of each electric load, you can simply add them up to find the total electric load.

For instance, let’s suppose you have four electric loads in your commercial building with the following current and voltage measurements:

  • Electric load 1: 4 amps at 120 volts
  • Electric load 2: 5 amps at 240 volts
  • Electric load 3: 2 amps at 120 volts
  • Electric load 4: 1 amp at 240 volts

To determine the electric load of your commercial building, you would first use the formula P = VI to calculate each electric load.

For electric load 1, power consumption would be 4 amps* 120 volts = 480 watts.

For electric load 2, 5 amps * 240 volts = 1200 watts

For electric load 3, 2 amps * 120 volts = 240 watts

For electric load 4, 1 amp * 240 volts = 240 watts

Then, you would simply add up the power consumption of each electric load to get the commercial electric load.

In the above case, the total power consumption of your commercial building would be

Total Power Consumption =  480 watts + 1200 watts + 240 watts + 240 watts

Total power consumption = 2160 watts

Thus, you can calculate the total power consumption of your building by the above mentioned method. Likewise, you can calculate the cost of your power consumption by yourself or hire some expert for commercial electrical estimating services for your electric load.

In the USA, the average cost is about $0.17 kWh which increased by about 16% between 2021 and 2023. You can do the math on what your facility is spending. Consider an example, your home refrigerator uses 500W running for a year and will consume 500W x 8760 hours = 4380000 Wh = 4380 kWh. If you’re paying $0.17, the cost to run the server is 4380 x $0.17 = $ 745 per year.


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Tips to Reduce Power Consumption of a Commercial Building

In today’s modern world, where energy consumption has a significant impact on both the environment and business efficiency. That’s why finding ways to reduce energy consumption is crucial.

According to the report, over 50% of the energy consumption in commercial buildings can be attributed to heating and cooling systems. This not only puts a burden on natural resources but also leads to higher energy costs for businesses.

Luckily, there are several strategies and technologies available to reduce the electric load of commercial buildings that we’re going to mention here.

  • Regular HVAC Maintenance

In a commercial building, HVAC systems contribute greatly to power consumption. According to the US Small Business Administration, 40% of energy consumption in a commercial building is due to the HVAC systems.

Regular and proper maintenance is essential to reduce power consumption and save on your electricity bills. By maintenance of HVAC systems, you can minimize your building energy consumption, increase energy efficiency, and get better performance of the HVAC systems.

You can hire some HVAC technicians to get their services for the maintenance of HVAC systems. Besides this, you can get electrical estimating services from some professionals even before HVAC maintenance services, so you know where to invest.

  • Educate Employees on Energy-Savings

Educating your employees and building occupants about the importance of energy saving is one of the most important factors. As the lion’s share of a country’s energy usage comes from commercial buildings, it is vital to follow energy-saving practices within the building.

If your staff knows the importance of energy-saving and aligns with the sustainable goals then the power consumption of your commercial building will eventually reduce. You must train and educate your staff about how to turn off the appliances or lights when they leave, how to use natural light when possible, and the importance of avoiding excessive energy consumption for the environment.

  • Ensure that the Building is Properly Insulated

According to the EPA, the proper insulation can save up to 10% of your electricity bills. Proper insulation and sealing of your commercial building can prevent heat from coming into the building during summer or store heat inside the building during winter.

Insulation is not only limited to your building’s doors or windows, but your building roof, HVAC ducts, electrical outlets, etc. all need proper insulation. Insulation of your commercial building helps you to save more electricity which eventually reduces your power consumption by preventing heat transfer.

  • Install Advance Building Technology

No doubt, we are living in the digital advancement era, where everything is shifting to automation. The installation of smart building technologies into your commercial premises significantly reduces the power consumption of your building.

For instance, there are programmable thermostats available in the market that are designed with such technology that if the building is not in use they turn off the lights, HVAC systems, and other electric appliances. The installation of these technologies not only saves energy but also increases the comfort level of your building occupants.

  • Switch to LED Lighting

According to the research, the lighting of the commercial building consumes 17% of the total energy consumption. The best option to reduce energy consumption due to lighting is to upgrade your lighting with LED lighting, as these lights are 90% more energy efficient as compared to traditional bulbs.

LED lightings not only help you to minimize your building power consumption, but they also give your building a modern and aesthetic look. Additionally, LED lights have a 15% longer life span as compared to incandescent lights and require frequent replacement which further saves more cost.


Before jumping on the calculator, you need to know the factors that affect your commercial building energy consumption and how to overcome the effects of these factors. That is all we have discussed in this blog.

So, after knowing all the factors, you calculate the total energy consumption of your commercial building by following the easy method that we mentioned above. You can review your bill data, conduct an energy audit, or use smart monitoring systems to get a better understanding of commercial electricity load. Moreover, you can hire some experts to get an accurate calculation of your building load.