How Many Solar Panels Do You Need To Power Your House?

Oct 08 2021
How Many Solar Panels Do You Need To Power Your House?

Installing a photovoltaic (PV) panel on your home bears promising opportunities, such as saving money while doing good. Since the inception of modern day solar energy, this motivation has moved over 16.4 million households to go solar in the U.S alone. 

While more people are keen on joining the home solar installation trend to save the environment, often, one of the biggest questions everyone seems to ask is "how many solar panels do I actually need to power my house?"

If you are wondering just how many panels are needed to run the house, then hang on,  this article is for you. We'll give you a brief lesson to answer this question.

What are the benefits of installing a solar system for the home?

Below are several advantages you may enjoy.

  • Saving on utility bills

Using renewable energy actually helps you reduce your electric bill. You only need to install a PV system once to enjoy energy for decades to come. 

  • Lower costs of maintenance

Solar panels are durable and easy to maintain. All you have to do is to clean a few times annually, or you may even hire a professional to do it for you.

  • Incentives 

In the U.S.A and countries like it, the government provides financial incentives, rebates and tax credits to promote the installation of solar systems. 

  • Reliable energy source

You minimize your dependence on traditional power sources. This means you are not as often affected by power outages, if at all, depending upon your system.

  • Clean, green energy.

By using this clean energy, you are promoting a sustainable environment. About 85% of the electricity from the grid comes from non-renewable resources which may cause environmental damage.

Do solar panels save you money?

Yes, of course! They can save you a lot of money.  You can find out just how much by calculating your average annual spending on electricity and comparing that to the cost of purchasing and maintaining a solar system. Innovate Solar offers a calculator to do just this for you, showing how much you could save on a month-to-month basis. It's also important to keep in mind that nowadays, while the expenses of solar installation are going down, the cost of electricity is skyrocketing. 

Factors that determine how many solar panels you need

If you’re asking yourself questions such as, “How many solar panels do I need?” and, “How much solar do I need?”, it’s actually fairly simple, (phew, right?). 

The average number needed per house ranges from 20 to 25 panels. That's it! This number will typically fit well on just one side of your roof, and houses with smaller roofs will typically require less energy anyways, so space is hardly ever an issue. To get a more accurate figure, however, you need to consider the following factors;

Your energy usage

Even if you’re not a first time homeowner, one question that gets brought up early in this process is, how many watts does an average house use? Well, the truth is that every household’s energy usage varies a fair amount. The average energy usage per household is estimated to be around 1400 kW every month. This figure, however, also depends on the exact energy requirements of the system, and what sort of things your system powers. If you’re powering an electric vehicle, you would of course see increased electrical usage, and would thus need more panels. Or, a 25 foot RV will need less power than 4 rooms, meaning in that case you’d be using less than 360 KW per month. If you need to power a small house, you will need much fewer panels. It all depends.

Knowing the power output of the panels you’d like to use allows you to plan a bit more accurately. Again, Innovate Solar’s technical library has the specs on just about any consumer-grade panel you could hope to purchase, so for specific power output, that’s a great place to start. 

Wattage of the solar panels/ Photovoltaic (PV) modules

Different panels are manufactured with different specifications. This does have some effect on the ultimate quantity one will decide on. If the PV modules are of the highest domestic wattage, then less of them will be needed, and vice versa. Usually, all domestic grade PV modules produce an estimated 250 to 400 Watts per hour. 

Sunlight in your area

PV modules are useless without the proper exposure to sunlight. As such, one should always be conscious of the area of their installation. Intense sunlight is needed for them to function at their maximum. This is why experts always conduct surveying operations to provide solar system size recommendations for maximum sunlight absorption. 

In areas with large trees, foliage, and towering skyscrapers, a larger system is needed to cover a wider surface area. This allows your solar system to receive sunlight from multiple angles.

How to calculate solar panel costs for your home?

Individual installations attract different costs. For example, a house with multiple stories may be more expensive to install into than the average cabin or house, even if they’re using the same amount of energy. This cost is mainly in terms of cabling. The best way to make a somewhat accurate estimation of the cost of PV modules required is to employ a surveyor for a quote.

The average installation cost is around $18,,000 for a low-tier solar system and up to $40,000 for a higher value system. Additionally, the cost for ongoing maintenance ranges around $150/year, where the average user maintains their system after a year or two of usage. A large chunk of this cost goes to the clean the array and check on the inverter system which should be of the power range from 1 kW to 5 kW. Most households generally run on a 3 kW system or greater. 2 kW systems are not very common, as they are smaller and are unable to supply a standard 3 bedroom house.

Determine your average monthly electricity usage 

If you are looking to go completely off the grid, but still run a house 24 hours a day, you need to know average monthly usage and incorporate energy storage. This is a factor that should be considered from the very start as it influences the size of the solar system needed, and is often provided by your current electric company. 

To be self-sufficient, a 2,000 sq ft house may need a range of 750 kWh per month to 1400 kWh per month. An 800 kWh per month use is common with 1200-1500 square foot house. A larger, 3,000 sq ft home may consume up to 2,500 kWh per month, more so in summer when air conditioner and pool units will be active most of the time. Managing a smaller residence e.g. a 700 sq ft or 1 500 sq ft home may be a lot cheaper. However, in any case, there is a need for proper power management as well.

Calculate your daily kWh usage

Most household power systems come with meters. A meter is the most reliable wattage calculator for determining daily usage. To make an accurate estimation of your daily usage, use the battery capacity, your system wattage, and inverter size. 

Calculating your daily power usage is a crucial step given the need to map out the exact requirements for installing the most suitable solar system. 

For example, to see the daily watt usage for a 1000 square foot house before going off the grid, simply use the bill total on any given day. Take the total and divide it by 1,000, since 1 kilowatt is equal to 1,000 watts. This gives the daily watt usage, as per usage billing dictated in kWh. 

Estimate the amount of sunlight your PV modules will receive

Before trying to measure the amount of sunlight your solar panels will receive, make sure the hardware  and batteries have matching specifications. 

An accurate estimation can be made, using the peak sunlight period and input power rates for each unit. This estimate will also govern the number of batteries to be used, the number of PV modules to be installed, as well as the most suitable inverter system to use. 

Note that the amount of sunlight you will receive can be affected if there are any obstructions over the panels. Trees, lamp posts, and multi-story buildings constructed nearby can all reduce the amount of direct sunlight your panels receive at various points throughout the day. 

The actual amount received can be acquired from individual capacity meters on the panels themselves, handy for optimizing your system. 

Determine how many solar panels you’ll need 

A very common question then is, “How many solar panels do I need to power a home?” The exact number depends on a couple of factors, such as the power output of the panels themselves, sunlight exposure, and their resistivity –where some may react to sunlight much quicker than others. 

The average number of solar panels needed basing on system size

SYSTEM SIZE

MONTHLY ENERGY PRODUCTION 

NUMBER OF PANELS 

1 kW

100 – 200 kWh

3

2 kW

200 – 300 kWh

6

3 kW

300 – 400 kWh

9

5 kW

550 – 650 kWh

15

10 kW

1200-1300 kWh

30

12 kW

1400 - 1500 kWh

33

15 kW

1800 - 1900 kWh

41

18 kW

2100-2200 kWh

50

20 kW

2350 - 2450 kWh

55

To calculate how many solar panels you need, consider the factors mentioned above, e.g. the size of your house, the amount of sun exposure, their capacity and batteries, etc. If their capacity is 240 watts, the question, “how many 240 watt solar panels do I need?” is easy to answer. Simply divide your daily energy needs by the productivity factor (approximately 3.5) and the resulting number by the number of panels.  А standard, 12 kW residential system will produce approximately 55 kWh per day. 

Example: 

A household use is 1400 kWh per month, how many 365 Watt Panels will it need? 

1400 kWh / 30.4 (average days in the month) = 46 kWh/Day

46 kWh per day / Average Daily Peak Hours (say, 4 hours in Florida) = 11.5 kW system is needed

11.5 kW system will consist of (11,500 Watts / 365 Watts in a single panel) = 32 panels.

32 panels will take approximately (32 X 15 sq. ft) = 480 sq. ft of roof space.

Answer: This house will need 32 panels, and ~500  square feet of usable roof space. 

While smaller households can need only about  2,000 watts, others that are bigger could need  4,000 watts, hence more panels. In monthly terms, medium to big houses can consume up to  1,500 watts kWh per month and the smaller an average of 1,000 kWh per month. 

It's possible to set up smaller solar systems that can generate 10 kW. Such a system may be sustained by several 100-watt solar panels, allowing it to charge efficiently. In the event of large-scale installations, several dozens of solar panels can be used, where the required wattage is massive , like 1 megawatt. 

The average number of solar panels needed basing on house size 

SYSTEM SIZE

LOW PANELS (50 FEET) 

AVERAGE POWER PANELS (50 FEET)

HIGH POWER PANELS (50 FEET)

1 kW

185

205

120

2 kW

210

250

145

3 kW

240

280

170

5 kW

270

310

200

The most probable answer to, “How many watts do I need for my solar panels,” lies in the number of units to be installed. Some houses are larger than others, physically and in terms of electricity usage. The largest houses can run 1,000 watts continuously. These are the ones that need a larger number, where a tiny house may be seen to need just one or two PV modules to power up. So, if you are looking to run a house on solar panels, the installations would be affected if the house is larger. For most households, the number of solar panels installed caps out at 25 panels. Even though they can use more than 135 kW per day, just a handful of panels will be utilized, which is nothing equivalent to those in high-end solar systems. 

How much roof space is needed for solar panels

Mathematically, each square foot on a house’s roof has the potential to generate up to 15 watts on its own. This, coupled with the household usage, shows that the roof space for installing panels varies directly with the house’s average usage over a specified time. Using this a small house will only need about 200 sq ft of the roof, while the larger one can be enough to provide power for a 1,400 sq ft house.  

How can Innovate Solar help?

Innovate Solar is a revolutionary name in this industry. Seeking to fundamentally change the way we go solar, the company has been coming up with the best ideas for solar installation since its inception. With its solar energy partnership program and easy-to-use solar power calculator system, the company is more than ready to set you up in any way. The organization is dedicated to assisting customers in any way possible, with 24-hour availability. It ensures the availability of nearly all products that have to do with solar systems, both residential and commercial, therefore, be sure that we can get your powered up in no time. Our platform is decentralized, allowing access to purchases from all over the world. 

How much will it cost to install solar panels at your home?

The installation on bigger properties e.g. a 4000 sq ft house can seem quite expensive, but rest assured that this is an investment. This is because of the amount of components needed to be installed. That said, the gap of installation ranges widely from $5,000 to a whopping $40,000, all varying from home to home depending on size and energy usage. 

Key points to keep in mind

  • Batteries and wires need to be serviced, as they are most vulnerable to operational damage. 

  • There are two phases to using renewable energy, one where you can choose to stay on the electrical grid as backup and the other one where you make a complete switch.

  • The largest inverter systems allow users to use almost any appliances they like.

Conclusion

Renewable energy is the future of energy—it is clean, and very cost-effective. With more people becoming empowered on the benefits of moving from non-renewable energy, it's believed that we may have a chance to save the planet. Already, the movement has begun and you cannot be the only one to be left behind.

Go ahead and join the solar movement to save big on both cash and the environment. Get your solar power for home from Innovate Solar today!

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