How many solar panels does it take to run a house?

Are green living and sustainability becoming a reality for you? Maybe it’s just a dream. But the technology to make it happen is already here! Solar power is cheaper than ever, with more efficient panels and production methods making solar affordable for the average homeowner (and even renters). It’s not as difficult or expensive as you might think to ditch your reliance on fossil fuels – all you need are the right tools, education, and motivation.

In this post we’ll help get you started by showing how many solar panels are needed to run an average, 2-person household like yours.

The average household uses approximately 3500 kilowatt hours (kWh) in a month. The average solar panel generates 250 watt hours per day, which means to run an average home you will need about 90 panels. But to be fair, we’ll use the EPA’s recommended efficiency of 12%, and do the math again with 240 panels needed. One final note: you can expect some losses if your solar system is wired into the grid (to account for what goes out as well as what comes in). It’s important to get a professional opinion on sizing so you don’t get too big a system that wastes money or too small a system that doesn’t power everything you want it to. Let’s start adding up the cost now…

Why do we need to know how many solar panels are needed to run an average home?

To show you the math, so you can see how much it will cost, and so you can evaluate different systems. You may be surprised by how little money you can save by installing solar panels, and that’s why more and more people are investing in this green technology. It’s one of the fastest growing industries. 

You might ask: why should I invest in solar panels? The answer is simple – it’s not as expensive as everyone thinks! In fact, a study by the US Energy Information Administration (EIA) found that solar power will make up 1/3 of all new electricity generation across the country by 2050. 

It may sound like a lot of money upfront, but consider all the long term benefits. Solar panels will save you money in heating and cooling costs, and reduce your electricity bill drastically. Not only that, you’ll feel good knowing you’re doing your part to reduce pollution. It’s an impressive investment for your future financial well-being and to help out the environment.

But cost isn’t the only reason people want to invest in solar panels – they’re also looking for quality and efficiency upgrades. Many people are realizing that solar can improve their lives, so what’s keeping them from going “green”? The answer is very simple – lack of information.

The cost of solar energy is continuing to fall as technology improves and prices continue to drop, and thanks to smart solar power incentives, programs, and rebates available in many states, it’s never been more affordable to go solar in America. If you’re thinking about installing a photovoltaic system on your home (or business), the first thing you need to know is how many panels you’ll need.

How Much Does Solar Cost?

The cost of solar panels has fallen dramatically over the past 20 years (you can check out our infographic below for more details on why solar prices have fallen so rapidly). Solar power has seen exponential growth over the last decade as it competes with traditional fossil fuels, and finds new roles in today’s electricity market. While solar costs vary by market, national average solar costs for residential installations are around $3.50 per watt. That makes a 5 kW system (what most homeowners need to power their entire home) cost roughly between $17,500 to $22,500.

How Many Solar Panels Do I Need?

Homeowners are beginning to see the potential of solar energy and want to know how many panels they’ll need to run their homes smoothly through the day and night. On average, each household in the US consumes about 10,932 kilowatt-hours of electricity per year. Solar panels produce energy on a per-unit basis, so you need to do the math to figure out how many panels you’ll actually need.

The two main factors that determine the number of solar panels needed for your home are:

  1. How much electricity your household consumes per month (this is called your ‘load’)
  2. How efficient your solar system is at converting sunlight into usable electricity (the efficiency rating).

Using the EPA’s Solar Handbook, we can determine how many solar panels are needed to power an average home in the following manner (Note: To calculate your monthly electrical consumption, take your total annual household electricity consumption and divide it by 12):

Household annual electricity use: 10,932 kWh / 12 = 925 kWh per month

Solar Panel Conversion Efficiency

The conversion efficiency of solar panels is the amount of energy collected per unit of sunlight they are exposed to. The efficiency rating is measured on a system-wide scale, which covers all the panels installed in a system. For example, if you have 10 panels installed in your home, each panel will have a different efficiency rating – but all together their combined rating will be 100%.

How much does it cost to install solar panels?

The cost to install solar panels depends on a lot of factors. The size of the system, its location, type and quality of the system’s components, and the roof’s orientation all affect the final price. On average, it will likely cost over $10,000.00 to install a new solar energy system on your home or business. The good news is that the cost to install solar panels has dropped dramatically over the last five years. For instance, a 5 kW system installed 5-10 years ago would have run you about $25,000 (including installation). Today, you can expect to pay just under $12,000 (including installation).

Solar panels are not your only option when it comes to saving money and helping the environment. In our next section we’ll look at some of the other ways in which you can benefit from going green.

Which solar system components are the most important to look at?

There are many components that go into a solar energy system, but your battery is one of them. Batteries have evolved because of the way they store and release electricity and they are now being used in many clean energy applications. In this section we’ll talk about what you need when installing a new solar energy system and what batteries to pick. We’ll explain how you need a battery bank (or multiple batteries), size requirements, how to charge up your batteries, how long it will take for your batteries to be charged before you can use them, and more. Let’s take a look at some of the major components of your solar electrical system.

What is a solar battery system?

A solar battery system includes a group of batteries that store energy generated by the solar panels during the day. A battery will store the electricity generated from that day’s sun and deliver it to your home or business in the evening. In the morning, you can use this stored electricity to start your car battery, to power electronics and appliances, or run electric water heaters. Some batteries can even be used in conjunction with a wind turbine as part of an energy storage system (ESS). If there is no sunlight (because it is cloudy or overcast), then your house’s solar energy panels will not generate any electricity. The battery bank will be used to store electricity instead.

There can be other benefits of having a solar battery system, including:

  1. Avoiding having to install additional power lines and electrical meters if the area has a limited number of electrical outlets (or no outlet at all). In this case, you can use the energy generated by your solar panels and use it just as easily as you would if it was running off the grid.
  2. Eliminating expensive electricity bills from things you’re not using, like lights that are on all night or appliances that are only turned on when they are absolutely necessary.
  3. Storing excess clean energy to be used later when electricity is more expensive or doesn’t come from clean sources.

There are other types of batteries, but the most common types used in a solar battery system include:

  1. Lead acid batteries – These are the oldest type of battery and they can last for about 5 to 10 years. Unfortunately, this is the only type that is not rechargeable. Because of this, lead acid batteries are very heavy and have a shorter lifespan than other types. These batteries can be fairly inexpensive to buy and install but you will need to monitor them closely because they can leak if not looked after properly over time.
  2. Sealed Lead Acid Battery

A sealed lead acid battery is very similar in appearance to a maintenance free battery. They are compact and typically have no vents or vents just on the bottom of them so they can be installed in certain areas where there is no wiring or electrical required for the battery. They are lighter and more economical to buy than a maintenance free battery but they do not last very long compared to other types of batteries.

These batteries can be fairly affordable but can leak if not looked after properly over time.

  1. Gel Cell Battery

Gel cell batteries are usually used in forklift trucks, golf carts, and other small vehicles that require a quick start when needed or heavy use once a day. These batteries are lighter and can supply more power than a sealed lead acid battery, but they do not last nearly as long. Gel cell batteries also have a shelf life of three to five years so you must store them properly.

  1. AGM Battery

AGM batteries have the same characteristics as gel cell batteries but are sealed in such a way that they can put out more power over longer periods of time. These are one of the most common types of rechargeable batteries available today and typically last for about 10 to 15 years (which is twice as long as other types of rechargeable batteries).

These are usually used in backup systems for smartphones, laptops, electric vehicles and more. They are extremely lightweight and are quite expensive. If you use them in an emergency, however, you will have power on demand and no need to worry about recharging since they can be charged up quickly.

Solar Battery Storage Capacity

The third most important factor to understand when choosing a solar battery system is the number of watts per hour (W/Hr) required. This will tell you how much energy a solar battery can hold, measured in watt-hours or simply watt-hours (Wh). Traditionally, batteries were rated in amp-hours but this is changing as technology advances. Today, you need to look at the W/Hr capacity of a battery when you are considering a solar energy system.

Why do I need a battery in my solar system?

There are two main reasons why your solar battery system will need to have a battery:

  1. To store electricity during the day when it is not being used. This can be used for things like starting your car, powering electronic devices, running appliances and many other uses. You can also use your vehicle’s engine batteries and auxiliary lighting when the sun doesn’t shine or won’t shine all day long because of clouds or overcast weather.
  2. To store excess energy generated during the day. You can use this stored energy for the following:
  • Using your solar system at night (for example, if you have a generator but don’t have electricity after the sun goes down).
  • Using your solar panels during cloudy, overcast or rainy days. This is because your solar system generates its own electricity (which will take longer to recharge) and does not need to be powered by the grid.

What does it take to calculate how much a solar panel system will cost?

Once you have discussed with your solar contractor or solar salesman what size and number of panels that you desire, you will be given a variety of details on how many watts they can generate for your home, as well as what type of financial support these will receive after installation. Solar panels produce a specific amount of energy, or wattage, and in order to determine how much they will cost you need to figure out the amount of watts that will be produced. Many factors play into this cost:

  1. The amount of electricity your household consumes per month
  2. The efficiency rating of the panels
  3. National average solar system cost
  4. The location of the installation (The further north or south your home is from the equator, the longer it will take for sunlight to get to it and vice versa)

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