What size Generator do you need for house – Calculative Guide

Generators are lifesaving machines during load shedding or voltage fluctuation. The most important and foremost step while buying a generator is to assess the size of the generator. By size of the generator, we mean the electric power it can provide and not the physical dimensions.

In this article, we will walk you through all the steps you need to consider before concluding your generator’s size and a couple of examples to help you understand how to calculate it. The following steps will assist you in deciding the size of the generator.

Step 1: Identifying the appliances you want to power with your generator

Make a list of all the appliances you want to power with your generator during load shedding. You can add the devices you wish to run 24/7 like your refrigerator, lights, security system, cooling/heating systems, washing machines, desktop, and laptop chargers, or any other device you want to be up and running during a blackout.

Step 2: Calculating the wattage

The second and most critical step is to calculate the wattage of the appliances you have selected in step 1. You need to consider two types of wattage for this purpose. First is the starting wattage; starting wattage is the amount of electrical power a switched off appliance or machine needs to start. The second is calculating the running wattage; it is the wattage your device needs to keep running without fluctuation and full power.

Running wattage for appliances like washing machines, cooling/heating systems is less than the starting wattage because they need more power to start up. Once they are up and running, they require less energy to function at an optimum level. You must add all these wattages together.

Remember to make separate columns for starting and running wattage. If you are not aware of any appliance’s wattage, it is usually mentioned in the user guide or brochure that comes with the application. If you have lost your devices’ information manual, you can Google it, or you can use this wattage guide for an estimate.

Step 3: Using the calculated wattage to get the generator

After you are done with calculations, it is always better to recheck your calculations. One helpful way is to check the generator’s details you are planning to buy or call the customer service to confirm your calculations. Please keep in mind to buy a generator with more than your calculations. It has a couple of benefits. Firstly your generator will not get heated up while working as it will not overwork itself.

Secondly, your appliances will get a full power supply and perform well. It will not only ensure your generator’s long life but will also keep your devices safe.

The following examples will help you understand how to calculate the wattage of your appliances. Please note that these figures are just an illustration; your devices will not have the same wattage.

Example 1
Appliances Starting Wattage Running Wattage
Lights (2) 200 200
Refrigerator 3000 900
Central AC -2 tons 8800 4000
Microwave Oven 1300 1300
Electric Range 2200 2200
Total 15500 8600

Example 2

Appliances Starting Wattage Running Wattage
Lights (4) 200 200
Refrigerator 3000 900
Central AC -2 tons 8800 4000
Microwave Oven 1300 1300
Electric Range 2200 2200
TV 380 380
Security System 600 600
Washing Machine 1200 1200
Laptop 250 250
Desktop Computer 200 200
Total 18130 11230

You are now ready to pick your desired generator according to wattage, check out the below options:

  1. Best 2000 Watt Generators
  2. Best 3000 Watt Generators
  3. Best 4000 Watt Generators
  4. Best 5000 Watt Generators
  5. Best 7500 Watt Generators
  6. Best 10000 Watt Generators

It would be best if you buy a generator with more power than the total starting wattage of your appliances. It is better to buy a generator with some additional capacity so you can accommodate any other appliances in the long run.

Secondly, if you live in an area where power outages are more frequent, a larger generator is recommended. You can power your entire house with it and avoid the hassle of load shedding.

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1 thought on “What size Generator do you need for house – Calculative Guide”

  1. Wow, I had no clue that home generators come in different sizes which also reflects the amount of electricity they can provide. My uncle recently moved off the grid, but he notices that he’s having frequent episodes of power outages around the area. I’ll be sure to share this with him so he’d consider getting an automatic generator.

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