How Many Solar Panels Are Needed To Power A House

how many solar panels to power a house

How many solar panels are needed to power a house? You’re going to want to speak with an expert but the simple answer would be that an average home needs between 20 and 25 solar panels to be fully powered by solar.

However, not every house is average. Each home has a different amount of energy consumption and electricity needs. As a result, not every home needs the same amount of panels and same solar solution.

Let’s break down the many factors that come into play when trying to figure out how many solar panels it takes to run a house.

The formula we’ll use to determine how many solar panels to power a house is:

Number of panels = annual energy usage / production ratio / panel wattage.

First Factor: Annual Energy Usage

Every homeowner’s annual home energy usage is different. In the United States, the monthly power consumption of an average household is 893 kilowatt hours. Factors include: the number of people you have in your home, the appliances you use, the size of your home – all of these things come into play. An obvious factor is that the bigger the family, the more energy consumption through electricity usage. A bigger home means more energy to power everything, including more lights, a larger HVAC, and the list goes on. But are you aware of the amount of energy the appliances in your home use?

How Many Solar Panels Do I Need To Run My Appliances?

What uses the most energy in your home? If you guessed heating and cooling your home, you are correct! Space heating and cooling can be blamed for 30% of why your monthly electricity bill is so high. And as the planet heats up, the weather is getting more extreme, leading to bigger heating and cooling needs to stay comfortable.

A deeper dive into how households consume energy shows the following breakdown:

chart showing the average household energy consumption

Don’t worry if this seems like a lot of information. Our sister company, Energypro, is made up of energy efficiency experts. They provide tips on how to lower usage in each category and save money on your utility bills.

How To Read Your Electric Bill

If you’d like to know your monthly energy consumption, pull out your latest electric bill. It will show how many kilowatt-hours of electricity your household uses. We know electricity bills contain lots of information and numbers that can be a little confusing to read at first, so we’ve explained that for you in detail here.

What is Solar Panel Wattage?

A solar panel’s power rating, otherwise known as a solar panel’s power wattage, is important to know when trying to determine how many solar panels you need. This number is the electricity output of the panel in perfect conditions. Most quality residential solar panels are around 250-400 Watts.

All About Solar Panel Production Ratios

What does a solar panel’s production ratio mean? A production ratio is the estimated energy output of a system over time in kilowatt-hours, to the size of the system in Watts.

For example, a 10 kW system that produces 15 kWh of electricity in a year has a production ratio of 1.5. (15/10 = 1.5)
In the U.S., production ratios typically fall between 1.3 and 1.6.

Production ratios can be finicky though. A particular system’s production ratio can be affected by how much sunlight your system gets (which varies based on your geographical location and what time of year it is.) Even if your area has fewer sunny days and hours of sunlight, you can still achieve an energy offset. You just need a greater number of panels to do so. Many people don’t know this but solar panels still work even on cloudy days.

Is My Area Right For Solar Panels? Ask an expert!

How Do I Calculate How Many Solar Panels I Need?

A solar energy specialist can help to calculate the actual total number of solar panels you need and help you create a customized plan for your home.

A way to estimate this is with this formula that ends up looking something like this:

Number of panels = system size / production ratio / panel wattage

How Many Solar Panels For A 1800 Sq Ft House

Let’s work with an example. If you wanted to calculate how many solar panels for your 1800 square foot house:

First– find out what a typical 1800 sq. ft. house average energy consumption is per year.

Let’s say your typical energy consumption a month is 1,300 kwh for a family of four with moderate energy usage. That would make your yearly total around 15,600 kwh a year.

The equation to find the number of solar panels would be:

(15,600) / 1.5 / 355 = number of solar panels.

In this situational example, the home may need 25-30 panels, depending on your home energy usage.

how many solar panels to power a 1800 sq.ft house

How Many Solar Panels Are Needed To Fully Power A House?

If you want to fully offset your energy consumption, it’s best to plan for a buffer in the number of panels you get. Best practice for this is to have about 25% more solar panels than you think you need. Your solar panels won’t always operate at full efficiency and produce at top capacity. This will allow for energy offset even during those lower producing days and times of year. Between April showers or winter snowstorms, you never know what might come your way and it’s best to be prepared instead of planning your operation only on best-case-scenario. We definitely recommend speaking with a solar specialist and planning for these scenarios by adding some buffer panels to your home solar system.

How Much Do Solar Panels Cost?

The cost of your solar system will depend on the number of panels and type of panels you decide to go for.  After this is determined, our solar energy experts can help you navigate the federal and any local incentives that are available to you to lower your costs. The most popular of these is the Federal Solar Tax Credit, or ITC, which can provide a 30% credit on your federal taxes of the value of your whole home solar system (battery storage included!)* Incentives that are just available to your area may include state tax rebates, financial incentives from your utility company for going solar, property tax exemptions and more.

The Solar Energy Experts

Sure, you could try and collect this data and do the calculations yourself and guess that you need x amount of solar panels. Or, you can let the experts handle it for you! They are trained in evaluating your home’s specific characteristics and energy consumption habits. Solar Energy Specialists also know what kind of panels and their wattage that will work best for your needs. We can design the perfect solar panel system for your home and walk you through the process from start to finish. If you’re ready for a free solar panel estimate, contact us today. There’s no obligation to move forward but we’d love to share with you how you can meet your solar power goals.

Free Solar Quote


*Tax and credits or incentives including those provided by federal, state, or local governments may change or end. This can impact the amount of money you might save. Consult a tax professional to understand any tax liability or eligibility for any tax credits that may result from the purchase of your solar system.
**If you have taxable income and own the system, you may qualify for the federal investment tax credit (ITC). It is your responsibility to determine your eligibility and to apply. Consult a qualified tax professional for assistance and details.

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