How Much Solar Do I Need and Why?

It is predicted that the world will add 70,000 solar panels every hour in the next 5 years.

When you think that the earth absorbs approximately 3,850 billion terajoules of solar energy every year, it is not hard to see why. 

The question is, how much solar will your home need and why.

Being able to predict how much solar you will need first means understanding your goals. 

Do you want to save as much money as possible? Minimize your carbon footprint? Maximize your return on investment?

This article assumes you are like the vast majority of the population who want to save money, while minimizing their environmental footprint at the same time.

Understanding the cost of solar 

In 1954 Bell Laboratories invented the first solar cell which became available to the public in 1956. 

The cost was astronomically high at about $300 for a one-watt solar cell. By 2019, the average cost per watt was $3.05 in the United States. 

$300 in the 1950's is the equivalent of $1,865 in 2019 (This means a common 320-Watt Solar Panel would of cost you $596,800 back in the 1950's).

Taking all these metrics into account means the price per solar watt has decreased by over 600 times. 

In fact, Our World In Data shows that utility-scale solar systems are now the least costly option for us to build and operate. 

Just take a look at this infographic below. 

how much solar do i need

Solar energy greenhouse gas emissions comparison

All energy produced by solar reduces greenhouse gas emissions by up to 95% compared to coal!

Energy source

Greenhouse gas emissions (Life cycle CO2 equivalent in gigatons (gCO2eq/kWh)

Coal

820

Gas

490

Biomass

230

Solar Power

41

Geothermal

38

Hydropower

24

Wind

12

How much solar do I need? 

Unfortunately, there is no base amount to how much solar you will need. Instead, the process requires a little bit of individual calculation in order to figure out. 

In most grid tied homes, this is not something you ever have to consider. That is, there is no limit to how much energy you consume. You simply settle the utility bill at the end of the month, and you are good to go. 

When relying on solar technology, you need to know roughly how much energy you consume every month in order to implement the right solar system into your home. 

(If you are interested in how many solar panels you need to take your home off-grid, take a look at this article

How to calculate your solar needs

In order to know how much solar you will need, you first need to learn how to calculate for your specific needs.

Step 1 – Calculate your energy consumption

In order to know how much solar you will need, you first need to know what your average energy consumption is every month.

Homes

For households, it is pretty easy to figure out your energy consumption. All you need to do is take a look at your utility bill.

Most utility bills display the kWh used at the bottom of the document with the total cost of electricity multiplied by that. 

Homes use much more electricity than boats and campervans so the energy reading will usually be calculated in kWh which stands for kilo-watt hour.

Cabins & Campervans

For those of you living in a cabin or campervan, figuring out your energy consumption can be somewhat of a tedious task.

To do this, you need to go through each appliance and calculate the overall monthly kWh used. 

Most appliances will likely show their watts.

In order to figure out what your total kWh is, use the following formula:

Watts times hours divided by 1,000 equals kWh

Here's an example how much kWh a coffee machine uses each day. 

1425 Watts x 2 hours ÷ by 1000 = 2,85 kWh per day. 

Now, do this for each and every one of your appliances to figure out what your overall kWh consumption is per month.

Step 2 - Work out how many direct sunlight hours your area receives

Peak hours of sunlight equal the amount of time the sun reaches an average of 1000 Watts per square meter. 

Of course, a solar panel only works when there is sun shining down on it, so knowing how long direct sun shines on average in your area is very important information. 

The most accurate way to determine the peak hours of sunlight your area receives is by using an insolation meter

However, if you want to get a rough estimate for your area you can use this world insolation map below: 

insolation map

Step 3 - Calculate your solar system size

Now the fun part, you need to calculate what size solar system you will need. 

To start you need to figure out how much direct hours of sunglight your area gets every month. 

Simply times your daily amount by 30.

So for example: Colorado - 5,3 X 30 = 159 hours of direct sunlight a year. 

Next to figure out how much solar you will need we have to divide your monthly electricity usage by your monthly sunlight hours.

Example: I use 500 kWh per month divided by 159 hours = 3,1 kW. 

This means a 3,1 kW system will be sufficient to meet my monthly energy demands.

I hope you now understand all the calculations involved.

Next, we will display average solar system requirements for different applications used in areas. 

(Before we head on to the next section, take a look at the data below. This map shows the average kWh consumption per person annually):

 

How much solar do I need for my home?

Let's assume that you live in the United states in a home with two people.

Based on Our World in Data you would use on average a total of 2040 kWh every month in your household.

The amount of solar you will need will look something like this. 

State

Average Daily Sun Peak Hours

Average Monthly Sun Peak Hours

Solar System Size

Arizona

6.5

195

10,4 kW

California

5.82

175

11,6 kW

Colorado

5.37

161

12,6 kW

How much solar do I need for my cabin?

Small homes or cabins are known to use much less electricity than conventional homes, for the simple reason that they often have much less appliances around to draw on energy. 

Of course we would like you to work out your own average, but to give you a basic idea on how much solar a small home or cabin would need, we have made the table below. 

This table assumes you use a total of 800 kWh per month. 

State

Average Daily Sun Peak Hours

Average Monthly Sun Peak Hours

Solar System Size

Arizona

6.5

195

4,1 kW

California

5.82

175

4, 5 kW

Colorado

5.37

161

5 kW

How much solar do I need for my campervan? 

On average, a high end campervan will use about 10 kWh per day, that comes up to roughly 300 kWh per month (this assumes you are travelling during summer and do not require any heating). 

State

Average Daily Sun Peak Hours

Average Monthly Sun Peak Hours

Solar System Size

Arizona

6.5

195

1,5 kW

California

5.82

175

1,7 kW

Colorado

5.37

161

1,8 kW

 

Now of course it would be very hard or close to impossible to install a 1,5 kw solar system onto the roof of a campervan. 1,5 kW = 1500 watts. 

If you were to find yourself a 320 watt solar panel, you would need to install 4 of them to reach your energy requirements. If you have an average sized campervan this is going to prove pretty difficult, but perhaps a larger RV may be able to handle this many solar panels. 

To make up for this lack of space, you may want to consider installing a battery storage system. 

For example, let's say your energy demand is 300 kWh a month or 10 kWh a day. 

Your campervan is located in Arizona and requires a 1,5 kW solar system to off set your energy usage. 

However, your campervan can only fit a 1 kW solar system onto its roof. 

In order to make up for this lack of solar, you could think of adding a solar power station with extra storage to your system. 

For example our AC50S could make up for the lack of kW (located on your roof) in the form of stored energy. 

This way, your energy demand focuses on your storage system, and your storage system then relies on your solar system to replenish its batteries. 

How much can solar save you? 

Below is the estimated solar savings per state, data has been provided by Energy Sage.

2018 Solar panel savings estimates by state table

State

Average Price
(6 kW Solar System)

Average Electricity Rate
Per State ($/kWh)

20-Year Savings

This is a solar panel savings table found on EnergySage.com

Arizona

$11,214

0.1226

$16,866

California

$13,566

0.1877

$49,424

Colorado

$13,314

0.1202

$14,216

Florida

$10,584

0.1247

$17,976

Massachusetts

$13,818

0.1936

$30,523

Maryland

$11,550

0.1335

$19,026

New Jersey

$13,188

0.1534

$19,655

New York

$14,154

0.1781

$26,637

Texas

$12,390

0.1140

$13,720

Washington

$11,802

0.0973

$10,483

 

How does solar energy save you money?

It may be worthwhile investing in solar energy and solar power station if your monthly electricity bill is still very high. Especially now while you can still make use of the 26 percent tax break.

Besides the financial rewards, investing in solar is also good for the environment, here are a couple more reasons why it’s a smart choice:

  • Price of coal and nuclear is not dropping
  • Solar installation costs have improved, and prices dropped dramatically
  • Installing a solar system provides long term subsidy benefits
  • Save money for your pension by reducing your monthly electricity bill
  • Solar panels can last you up to 30 years and require little upkeep

Conclusion 

Overall, solar technology is definitely one of the smartest investments you can make in the 20th century. 

Now that you have the tools to figure out how much solar you need and how much it will cost you, we believe you are well on your way to leading a more sustainable/affordable lifestyle. 

Please feel free to reach out to us should you have any questions regarding our latest solar power technology. 

 

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