How Many Solar Panels Are Needed To Power A Room?

Imagine having a room completely powered by solar panels. That is, each one of your rooms appliances rely on solar energy, instead of grid energy to operate.

Is this even possible, and if so, how many solar panels would I need to power a room?

A medium-sized room measuring 224 square feet consisting of smart television, sound system, electric fireplace, air purifier, and ceiling fan would require 5 solar panels each rated at 300 watts to power the room.

The above answer assumes you live in the sunny state of California, and used the following appliances for the specified time period:

  • Smart TV (100 watts) – 4 hours = 400 Wh
  • Sound system (100 watts) – 4 hours = 400 Wh
  • Electric fire place (1500 watts) – 4 hours = 6000 Wh
  • Air purifier (50 watts) – 12 hours = 600 Wh
  • Ceiling fan (75 watts) – 3 hours = 225 Wh

In this article, we are going to teach you how to work out how many solar panels you would need to power your own room.

We promise it’s not that complicated.

Let’s get started.

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Solar Panels For A Room (How Many Do I Need?)

When most people think of this question, they assume that the size of the room makes a difference in the number of solar panels you would need.

While this may stand true for some homes, usually, it all comes down to two things:

  1. Appliances (kWh consumption)
  2. Peak sun hours

A solar panel installation serves one purpose. Electricity production is driven by the process known as the photovoltaic effect.

Yes, the individual solar cells found in your solar panel directly convert the energy of sunlight into electrical energy through the photovoltaic effect.

Thus, figuring out how many solar panels you need to power your room, all comes down to how much electricity is being consumed by all the appliances located throughout your room.

The more electricity there is being consumed, the more solar panels you’ll need. Well, that’s the gist of it anyway.

So how do you work out the number of solar panels you’ll need to power your room?

How much kWh does a room use?

First things first, how much kWh does your room consume. Of course, your room itself consumes nothing, but what appliances do you see sitting around?

Get a piece of paper and write down all the appliances you see.

For example:

  • Desktop monitor
  • Lava lamp
  • Laptop
  • Office lamp
  • Ceiling light
  • Electronic desk

For our list, we used the exact appliances we have in one of our rooms.

Next, you want to note down how much watts each appliance consumes.

  • Desktop monitor – 22.7 watts
  • Lava lamp – 25 watts
  • Laptop – 30 watts
  • Office lamp – 6 watts
  • Ceiling light – 9 watts
  • Electronic desk – 200 watts

To do this, just look at the label that comes with each appliance, you will always see how many watts they consume.

Now, you need to estimate (more or less accurately) how long you use each appliance every day.

  • Desktop monitor – 22.7 watts (8 hours)
  • Lava lamp – 25 watts (3 hours)
  • Laptop – 30 watts (2 hours)
  • Office lamp – 6 watts (8 hours)
  • Celing light – 9 watts (8 hours)
  • Electronic desk – 200 watts (N/A)

For the next step, (unless you are a mathematics prodigy) you’ll need to take out your calculator.

To estimate your rooms kWh consumption you have to multiply your appliance’s wattage by the number of hours you use them, this number will give you their watt-hours consumption.

  • 22.7 x 8 = 181,6 Wh
  • 25 x 3 = 75 Wh
  • 30 x 2 = 60 Wh (Come on, the first calculation was tough!)
  • 6 x 8 = 48 Wh
  • 9 x 8 = 72 Wh
  • Total electricity consumption = 436,6 Wh a day, let’s round that off to 437 Wh.

To get a monthly consumption rate for your room, multiply your daily watt-hours by 31 days.

437 Wh x 31 = 13,547 Wh a month.

Lastly, convert your consumption into kilowatt-hours, we will use this number to figure out how many solar panels we will need to power a room.

Simply, divide 13,547 Wh by 1000 to get 13,547 kilowatt-hours (kWh). Let’s round that off to 14 kWh a month.

Peak sun hours

Now, of course, your monthly kWh consumption may be much higher than the amount in our example. This would be especially true if you were tabulating the appliances in your kitchen or lounge area.

This is completely fine.

You may still follow along with us. We are teaching you how to calculate the number of solar panels YOU need to power a room. This amount is unique to everyone.

The next important step is figuring out how many peak sun hours your home receives. The more sun you receive, the fewer solar panels you will need to offset your room’s electricity consumption.

This is not the sort of information anyone has just lying around, and peak sun hours don’t equal the amount of sunlight you receive each day, i.e. from sunrise to sunset.

Instead, a peak sun hour equates to 1 hour in which the sun’s solar irradiance (sunlight) produces an average of 1000W (energy) per square meter (roughly 10.5 feet). In other words: 1 peak sun hour = 1000 W/m² of sunlight per hour.

To figure out how many peak sun hours your area receives each day, feel free to use our helpful resource in the menu section of our website under the “resource” tab.

Alternatively, you can head over to Global Solar Atlas and enter your postal address or city into their search function.

By doing this a page like this will pop up:

make sure to set the site info to per day then pay close attention to the global horizontal irradiation (GHI) data (highlighted in red in our example picture).

This number: 4.982 is the peak sun hours for the city of San Fransisco. Feel free to round your number off to the nearest decimal point, in our case, it will be 4.9 peak sun hours.

Now simply times this number by 31 days to get your monthly peak sun hours.

4.9 x 31 = 151,9 (152)

Calculate how much solar panel your room needs

Now, you need to make use of the following formula:

solar panels required formula

So, putting everything together we can work out the rough amount of solar panels we would need to power a room.

14kWh divided by 152 = 0,0921

0,0921 x 1000 = 92,1 watts.

Let’s round that last amount to 100 watts.

This means based on the example we used, a 100-watt solar panel would be sufficient in powering the appliances for the desired amount of time in our room. This assumes we live in a very sunny area such as San Fransisco.

Usually, this calculation can be used to figure out a rough home solar installation, and as such your required wattage would be much more than 92,1 watts.

Probably more than 15,000 watts.

When this is the case, you can divide that large number by your desired solar panel power rating to get the specific amount of solar panels needed to power a room.

Final Thoughts

We hope this article gave you a good idea of how many solar panels you would need to power a room.

If you have any questions, please feel free to ask them in the comments section below.

Further reading:

Kyle Browning
Kyle Browning

Kyle is a researcher and content specialist at Climatebiz. He has a strong interest in green technology, particularly in photovoltaic systems. Kyle believes in a future where everyone has affordable access to renewable energy, regardless of their race, religion, or social status. This ideology led Kyle to found Climatebiz - with the goal to provide free information for anyone, anytime. You can follow Kyle on Twitter at @kylebrwng