How to Calculate Electrical Load In a House?

electrical load calculation

According to the Energy Information Administration (EIA), an average home in the United States consumes 10632 kilowatts-per-hour (kWh) of electricity each year. Are you moving into a new home? Or want to remodel your old home? No matter what the case, you certainly want to know the electric load of your home to take control of your electricity bill.

Electric load is the total power consumption by all the devices that are connected to an electric system. These devices include all your home’s appliances, light bulbs, and outlets. Calculating the electric load is essential to ensure that your electric system meets your house’s electricity needs.

Moreover, this information is crucial if you want to make any changes to your electric system, especially in case of moving to a new home. In this blog, we will help you to calculate your total home load calculation. Let’s get started.

Understanding Electrical Capacity And Its Terms

To understand the electrical capacity consider a simple example. Say you have a Christmas tree shop. During the Christmas holidays, you have to hire more staff to manage the large number of shoppers. To find out how many people you should hire and for how many hours, you see the data from the previous year. This is the best way, but what if fewer buyers would come to your shop? You can do nothing, just have to pay the new employees for their time.

The same idea behind the electric capacity, electrical capacity is the total amount of electricity that a facility needs to operate but not the actual commodity.

To get to know the total power your home requires, you have to calculate the total electrical (amps) load of all your appliances and devices with the safety margin. In general, the electrical load never exceeds 80% of the total electrical capacity.

In America, in an old structure home where you find knob-and-tube wiring, you would discover electrical capacity with 30 amps. After that, this range increased from  90-120 amps electrical capacity. The new minimum electrical capacity range is 200 amps and the maximum is 400 amps.

For a better understanding of electrical capacity, you have to know the terms volts, amps, and watts and their relationship as well. So start with the volt.

  • Volts

Volt is the potential difference between two points. A wire that carries 1-ampere current with a power dissipation of 1 watt has a potential difference of 1 volt. In the United States, the power is delivered from the electric grid at two different electrical potentials of 120 volts and 240 volts.

  • Amps

Amperage is the rate at which current flows through the wire. The larger the amperage the more current is flowing through the circuit. Larger appliances like air conditioners or dryers use 30-amp circuits, while most of the outlets in a home use 20-amps or 15-amps.

  • Watts

Have you ever observed why a 60-watt bulb is brighter than a 40-watt bulb? The reason behind this brightness is higher wattage. Wattage is the total amount of power that an electric device consumes. You can easily calculate wattage by multiplying amperage with the volts.

The mathematical relationship between all three terms can be expressed in the following ways:

Watts = Amps * Volts

Amps = Watts/Volts

Volts = Watts/Amps

By using these formulas, you can determine the electrical capacity of a circuit or the entire electric service. For instance, a 30 amp, 120-volt circuit has a total capacity of 3600 watts.

Tools Used For Electrical Load Analysis

Analyzing the electric load is crucial to selecting the right electric system for your home. Furthermore, this information will help you to evaluate the exact current amount that your electric system can handle without malfunctioning. Have a look at some of the tools that are used for electrical load analysis.

  • Multimeter

A multimeter is the most used device to analyze the electric load in any circuit. This measures the current, voltage, and resistance in an electric system. The electrician connects the multimeter across the various components in an electrical system and determines the total electric load comprehensively.

  • Oscilloscope

This is the top choice of every electrical engineer due to its reliability and easy-to-use method. This device measures the voltage over time and displays the signal on the screen. If there is any abnormality in the waveform then the analyzers would identify it and take the necessary measures to avoid any potential damage.

  • Power Quality Analyzer

As its name shows, this tool tests the quality of power that is running throughout the circuit and its feasibility to drive an electric device that is connected with it. This analyzer is particularly used for identifying power surges, voltage fluctuations, and current overloads. If your home electric system has some damage then the quality analyzer will spot the problem.

  • Load Flow Software

This is the most advanced tool for monitoring the electric load flow in a circuit. Load flow software calculates the bus voltage, power factors, currents, and total power flows through an electric circuit. This software offers built-in features like equipment evaluation, making warning reports, and load flow result analyzer which make this software the best choice for electricians and electrical engineers to analyze the load.

Also Check Out: Importance of accurate electrical estimating

These are just a few electric load analysis tools that are popular choices for electrical engineers. Each of them allows engineers to identify problems and take necessary steps to resolve them. After analyzing the electric load, now it is time to calculate electrical load of a home.

How to Calculate the Electrical Load?

Do you want to install a new electrical system that meets your house’s energy demands? For this, you have to do residential load calculation and get the exact electrical load of your home without flaws and errors, because a minor miscalculation or mistake can bring huge damage to your home functionality. So, read this blog to get to know how you can calculate the electrical load.

  • Identify All Electrical Devices

Imagine you want to construct your home. For this, you would first make a list of all necessary materials that are required for your home construction like concrete, drywall, steel, lumber, stone, brick, etc. Identifying the electrical devices for calculating the electric load is like that material list.

Make a list of all the appliances and devices that are part of your electrical load. Add everything to this list from lighting to home appliances to HVAC systems. Make sure that you don’t skip any appliances in your home.

  • Note the Wattage of Each Device

Now it is time to get the power rating rating of reach appliances in watts or kilowatts (kW). You can easily find the wattage on the label or nameplate of the appliances or you can also find power ratings by searching the device model name with company name on the internet. Check out the most basic appliances with their power ratings.


Appliance Power Ratings
LED Bulb 4W – 25 W
Incandescent Lamp 40W – 150W
Table Fan 30W – 70W
Fluorescent Tube Light 18W – 60W
Cooler 100W – 500W
Computer 100W – 250W
Washing Machine 300W – 500W
AC (1 ton) 3.517KW
Induction Motor Ceiling Fan 60W – 80W
TV 60W – 120W
Refrigerator 150W – 400W
Smartphone Charger 4W – 7W
Microwave 600W – 1700W


Now, assume that you are using the following appliances in your home.

  • 4 LED Bulbs
  • 1 Refrigerator
  • 1 AC
  • 2 Ceiling Fans
  • 1 Microwave
  • 1 Washing Machine
  • 1 Computer
  • 2 Smartphone Chargers
  • 1 TV

Now calculate the total wattages.

  • Calculate Total Wattage

To do the electrical load calculation, find out how many hours your home appliances consume electricity, and then multiply wattages with time, you would get total wattages.


No. of Appliances Power Ratings Daily Use Load Calculation
4 LED Bulbs 9W each 10h 4*9W*10h = 360Wh
1 Refrigerator 300W 12h 1*300W*12h = 3600Wh
1 AC 3517W 6h 1*3517W*6h = 21102 Wh
2 Ceiling Fans 70W each 9h 2*70W*9h = 1260Wh
1 Microwave 1000W 0.5h 1*1000W*0.5h = 500Wh
1 Washing Machine 350W 1h 1*350W*1h = 350Wh
1 Computer 175W 2h 1*175W*2h = 350Wh
1 TV 95W 4h 1*95W*4h = 380Wh
2 Smartphone Chargers 6W each 3h 2*6W*3h = 36Wh
So, the total working electric load will be 27938Wh


  • Convert Watts to Amps if Necessary

You can also convert watts to amps if you want by dividing wattages by the voltages as

Amp= Watts/Voltage

suppose, the total voltage of your home is 240 volts. Divide total wattages by this voltage and get the total current your home is receiving from the electric grid.

Current = 27.938 Wh/ 240 Volts = 116.40 amps


How Many AMPS Does a House Use?

According to electrical engineers, a house needs 100-200 amps on average. Today, 100 amps are enough for the smaller home. But this amp range can exceed if large electricity-drawn appliances are used like swimming pools, complex HVAC systems, electric dryers, hot tubs, and more.

You can find out your house amperage by calculating your total wattages and dividing them by voltages, just like we elaborated above. So, let’s move to our last section which is safety measurements for your home.

Electrical Safety Tips For the Future

Lastly, let’s talk about the most essential aspect of an electric system which is electrical safety. But sadly, most of the time this aspect is overlooked and brings unfortunate events. Are you thinking about what electrical safety is? Electrical safety is a set of precautions and measurements that must be followed to avoid the potential risks and hazards associated with the electrical system.

According to a survey, in the USA there are 24200 fires due to electric system malfunctions which resulted in 295 deaths and 9000 injuries. Below, we will mention some of the important electrical measurements one by one.

  • Hire Licensed Electrician

Doing electrical maintenance and services by yourself is dangerous and may comply with the building regulations. Make sure that you get Electrical Estimating Services from some licensed and trained workers. A licensed electrical worker has the expertise and training to ensure that all the installation and maintenance will be done professionally.

  • Regularly Inspect Electrical Cords and Outlets

Regularly inspect the electrical cords and outlets to identify the wear and tear damage. Look for broken outlets and frayed cords and replace the broken cords to avoid any potential electrical hazards. Furthermore, don’t overload outlets by plugging too many cords at a time.

  • Keep Appliances Away From Water

Water and electricity can never be mixed. Keep the electrical appliances, outlets, cords, and fixtures away from wet areas. Moreover, don’t touch electric appliances with wet hands.

  • Install Fuses and Circuit Breakers

These two are the most crucial electric safety devices. In case of any electricity surge or voltage fluctuation, these devices save the electric appliances from damage and malfunctioning. But the important thing is that you should know how to manage these devices otherwise, these may bring damage rather than protection.

  • Unplug Appliance When not Used

Whether you use appliances for warming your room, making your coffee, or styling your hair, in every case they make your life easier. But if you use them improperly then they can become a cause of hazards. Always unplug the appliances after you use them. This not only saves electricity but also avoids electrical accidents like fires or short circuits. Also, never use these appliances near a watery area like a tube or sink.

  • Use Electrical Bulb With the Proper Wattage

Use the electrical bulb with the proper wattage for lamps and fixtures. Using a bulb with higher wattage can cause overheating or fires. Consult manufacturers or some expert electrician to get know the wattage of the bulb, if you don’t know the correct wattage. In addition to this, to save money and enhance safety use retrofit LED bulbs.


Whether it is handling your electric load or changing the existing electrical system of your house, understanding an electric load calculation leads to an efficient, safe, and reliable home setup.

Moreover, calculating the electric load empowers you to optimize the home’s electric capacity, make plans for upgrades, and streamline the electric system of your house. You can calculate this load by yourself or by taking some electrical estimating services from some well-known estimating firm.

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