4 Reasons Picking the Right Size Generator Matters!

The power’s out. Again. 

You and your family are sitting in darkness, unable to charge your electronics, run your air conditioner (a must in southwest Florida in the summer!), use your stove, and, oh yes— your refrigerator full of food is about to spoil. You’ve had enough! It’s time to invest in a backup generator.

The catch? You don’t know which size of generator would be best for your house. Getting too large of a generator has its drawbacks, but so does getting one too small, and in this post, we’re here to talk about both!

Here are four reasons finding the right size home generator is important:

1. An undersized generator may provide insufficient or unreliable power.

When we’re talking about generator size, we’re more concerned about size in terms of “wattage” versus size in terms of physical “dimension.”

You see, generators are available in watts (W) or kilowatts (kW), which are measurements of electricity or the electrical power the generator supplies. When your home appliances need more power than your generator is rated to provide, it can cause a few issues.

For one, you may experience what is referred to as a “voltage drop.” In an effort to provide all the voltage you’re asking it to maintain, your generator may slow down— throttling the current to your appliances. 

When we’re asking our generator to do too much, this is when you may experience flickering or dimming lights, AC units pumping slower or other symptoms as a result of your appliances not having enough power to run properly.

Looking for a clear explanation of how a permanently-installed backup generator functions, as opposed to a portable generator? Read How a Standby Generator Works. 

2. The wrong size home generator can cause damage to your electronics and appliances.

In some cases, your generator could overwork itself and experience overheating and other problems that we’ll go over in our next point. 

An overworked generator could malfunction and cause surging or other damage to connected appliances. This could either completely fry your appliances or devices connected to the generator, or it could significantly shorten their lifespan.

3. Too small/low wattage of a unit can cause damage to the generator itself.

A low-wattage generator that’s being asked to power more than it can handle will try really hard to do what you ask of it. While it may throttle down and drop its voltage, it will also be pumping harder than it should and as a result, may show telltale signs of overload

If your generator is too small for the electronic demands, it could start to run loudly, emit excessive heat, overrun its fans to try and cool the unit down, etc. If you notice soot appearing in the exhaust of your generator, this is usually a clear sign you’re overworking your generator. It means your generator is struggling to filter or that clogging is occurring inside the unit.

Overheating like this could lead to fire— or even an explosion! That’s right, we said explosion. If there’s a gas tank near the unit and a spark leads to a fire, this is a major hazard. 

Excessive overuse like this can also significantly cut down the lifespan of your generator by burning out your alternator, stator and other expensive generator parts that when shot, aren’t worth it to replace compared to getting a new unit (kind of like an engine going on a car!).


Did you know that generators are either powered by liquid propane or natural gas? Compare the pros and cons of each generator fuel type here.

4. Purchasing an overly big/high-wattage generator can mean wasted money.

Depending on the brand, wattage, fuel type and installer you choose, generators can be expensive. 

We’ll choose Generac as an example. At the time of writing this, prices for small to large-sized Generac generators start at $3,459 for an 11 kW generator, $4,219 for a 16 kW and $4,949 for the 20 kW Guardian Series models. Factor in that initial price difference. Why pay almost $1,500 more for a 20 kW when you really only need the 11 kW?

Realize too that if you get a generator that produces more than you need, you need not only be concerned about the initial cost of the generator, but also the operating costs. If you have a liquid propane generator, this will mean paying more for fuel to fill a larger tank and potentially more in maintenance costs to service a bigger unit. 

Curious as to how much a new generator will really run you? See how much a home standby generator typically costs.


Compare Sizes, Side-By-Side, in Our Pricing Guide

In our Battle of the Home Standby Generator guide, we stack comparisons against three major generator brands Generac, Cummins, and Kohler, for three different generator sizes. Download our free resource today to save time and research shopping.  

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