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How much electricity do I need for my home?

July 14, 2022
How much electricity do I need for my home

Knowing the amount of electricity you need for your home is vital for two things: The first is when you’re building a new home, and the second is when you’re upgrading an older house.

It’s very easy to calculate the electrical load capacity at your property. We’ll walk you through it in a short while.

But first, let’s define what an electrical capacity load is and how it is measured.

What is an electrical load capacity?

An electrical load capacity is the total amount of power used in your house. Factored into this is everything connected to your circuit breakers, such as the air conditioning, lights, and outlets.

The unit used to measure your electrical load capacity is amperage or amps in short. Each home uses various amperage of power depending on its age and size.

Older homes use less power that’s around 30 amps, whereas newer homes use much more due to their modern appliances and automation systems, using between 200 to 400 amps.

How to Compute for Electrical Load Capacity

How to Compute for Electrical Load Capacity

In determining your power needs, you have to separate load and capacity. This way you can estimate the available load against the total capacity of your electricity provider.

So let’s move on to these units that you need to know to gauge your house’s electrical power supply.

These are amps, watts, and volts; all of which are units of power. They are related to each other, and you can compute for one of them if you have two variables.

Computing for the Power Capacity

To show you what we mean, here are each one of the formulas for power capacity:

  • Watts = volts x amps
  • Amps = watts/volts
  • Volts = amps/watts

Suppose your house has a 30-amp, 120-volt circuit breaker. The wattage will then be 120 volts x 30 amp = 3,600 watts.

As a rule of thumb, the electrical load should never be higher than 80% of the total power capacity of the house.

That would be 3,600 watts x 80% = 2,880 watts. So your lighting and plugged appliances should not go beyond 2,880 watts; otherwise, there’s a risk of circuit overload.

Thus, using your power supply safely is a matter of knowing your power capacity and balancing the electrical load of fixtures and equipment in the circuit.

Computing for the Power Load

Now you know how to get the electrical capacity, here’s how you can get your home’s electrical load.

The electrical load can be computed by adding the wattage of the different appliances and fixtures that are currently running.

Why currently running? Because it isn’t likely that you use all of your appliances at the same time.

You wouldn’t use your air conditioning and furnace at the same time, right?

That’s why compared to electrical capacity, which is pretty straightforward, getting the load is a bit trickier.

Now, electricians use this simple method to calculate the electrical load of a house. Below are the steps for this:

  1. Take the wattage capacity of your general lighting circuit breaker.
  1. Combine with this amount the wattage of all your plug-in circuits.
  1. Factor into this the wattage of your hard-wired appliances (such as water heaters, dryers, air conditioning, and range hoods).
  1. Subtract the total by 10,000.
  1. Multiply the amount by 0.40.
  1. Add 10,000.
  1. Check the wattage rating of your air conditioner and heating systems, like in-floor heating and furnace. Add the one that’s higher between them since you don’t use them both at once.
  1. Finally, divide it by 240.

You will then get the electrical load in amperage which is needed to power your home sufficiently.

And now, you can measure this against your electrical capacity to know whether you’re using the energy adequately or lower or higher than you should.

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