How many solar panels do I need for the house?

We estimate that a typical house needs between20 and 24 solar panelsto cover 100% of the electricity consumption. The actual formula to find out how many solar panels you need can be found by the system size divided by the production ratio, divided by the power of the panel.

The actual number you will need to install depends on factors such as geographic location, panel efficiency, panel power rating, and your personal energy consumption habits. The important thing is that the number of solar panels you need for your home directly influences the price you pay for solar. Although the answer is not always simple, we have collected some case examples to help you understand, at a high level, how many solar panels you need to install an efficient solar network.

How to calculate how many solar panels you need

To calculate how many solar panels you need, you need to divide the total size of the system by the ratio of production to the power of the panel. Calculating how many solar panels you will need to meet all your energy needs depends on several factors. The easiest way to find out how many panels you will need is to use our Solar Calculator. By entering your address and the estimated monthly energy bill, we do all the calculations for you, so that you can make an informed decision. If you want to do these calculations for yourself, we have explained our formula below to help you.

You can calculate how many solar panels you need taking into account three main factors:

• Annual electricity consumption
• Solar panel power
• Production rates

The formula we used to estimate the number of solar panels you need to power your home depends on these key factors. Here are the assumptions we made and how we did our calculations:

Annual electricity consumption

The annual electricity consumption is the amount of energy and electricity you use in your home during an entire year. Measured in kilowatt-hours (kWh), this number is influenced by the appliances in your home that use electricity and how often you use them. Refrigerators, air conditioning units, small kitchen appliances, lights, chargers, and many others use electricity.

A household uses an average of 10,715 kWh of electricity per year, so we’ll use this number as the ideal solar panel system or solar grid size, which would mean you could offset 100% of your electricity consumption and utility bill with panels solar (in practice, it’s not so neat, but bear with us here). If you’re interested in getting a more accurate number based on your personal energy consumption, check your utility bills from last year to find out how much electricity you used. Once you have this number, feel free to plug it into the equations below.

Solar panel power

Also known as the nominal power of a solar panel, the power of the panel is the electrical energy production of a certain solar panel under ideal conditions. Power is measured in watts (W), and most solar panels fall within the power range of 250 – 450 W.

Production rates

The production ratio of a solar panel system is the ratio between the estimated energy production of a system over time (in kWh) and the actual size of the system (in W). These numbers are rarely 1:1 – depending on how much sunlight your system will receive (which is mainly based on your geographic location), the output ratio will change accordingly.

For example, a 10 kW system producing 14 kWh of electricity in a year has a production ratio of 1.4 (14/10 = 1.4) – this is a completely realistic production ratio to see in the world real. solar

We have our three main assumptions (energy usage, solar panel power, and production reports) – now how do those numbers translate into an estimated number of solar panels for your home? The formula looks like this:

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

Entering our numbers from above, we get:

Number of panels = 10,715 kW / 1.3 or 1.6 / 340 W

…which gives us between 20 and 24 panels in a solar matrix, depending on the production ratio we use (20 for a ratio of 1.6 and 24 for a ratio of 1.3). So, 20 panels at 340 W each result in a total system size of approximately6.8 kW!

The main considerations to determine how many solar photovoltaic panels you need

Calculating how many solar panels you need can be done with the three inputs above, but digging deeper, there are many more factors at play in determining your ideal solar panel system size. Understanding production rates, the relationship between system size and number of panels, and the impact of home size can all be important when designing your ideal solar panel configuration.

How many kWh can solar panels produce?

The amount of power (kWh) your solar power system can produce depends on how much sun exposure your roof receives, which in turn creates the output ratio. The amount of sunlight you receive in a year depends both on where you are in the country and on what time of year it is. And in any location, you will be able to produce enough energy to cover your energy needs and say goodbye to your utility bills – if you live in an area that receives fewer peak hours of sunlight, you will only need to have a bigger solar. array system installed at your home. Thus, production ratios differ by geographic location, and a lower production ratio (due to less sunlight) means you will need more solar panels to get the amount of energy you need.

Here is an example: two households of comparable size in 2 cities consume the average amount of electricity for a household, which is 10,715 kWh annually, as mentioned above. The household needs a system of approximately 6.8 kW to cover 100% of the energy needs. By comparison, the comparable household in another city needs a system of approximately 8.2 kW to cover its energy needs. Solar panel systems are smaller than solar panel systems in other cities but can produce the same amount of energy because they are exposed to more peak hours of sunlight each year. Homeowners in less sunny areas can make up for this difference simply by using more efficient panels or by increasing the size of their solar power system, resulting in slightly more solar panels on their roofs.

How many solar panels do you need for certain system sizes?

In our long example at the beginning of this piece, we determined that a 6.8 kW system would probably cover the average energy consumption for a household if you live in an area with a production ratio of 1.6, which could be a realistic number for houses. in most parts.

Let’s expand this a little further and look at some examples. In the table below, we have compiled some estimates of solar panels for the common dimensions of the systems. Again, the big caveat here is that we use 1.6 as our chosen production ratio. For buyers, this might actually be realistic, but for people in the northeast or areas with less sun, these estimates might be a little high in terms of production and low in terms of the number of panels needed.

The number of solar panels required for certain system sizes

System size, Number of photovoltaic panels required, Estimated annual production

Power: 3 kW = 7 photovoltaic panels / area required for installation 15 square meters, annual production 3800 kWh

Square match of solar panel systems of different sizes

System Size Panels 300W, 340W, 360W, 400W, 450W

Perhaps one of the most difficult aspects of sizing a solar panel is estimating the annual amount of energy consumed by your household. A series of larger consumer products or add-ons can significantly change your annual kWh requirements and greatly affect how many panels you will need. For example, if you use central air conditioning or power a heated pool in your yard, the size of the solar panel could be changed drastically. To understand the size you will need, you should evaluate the energy impact of the various products you own or are considering for your home.

If your house is small or has an unusual roof shape, the size of the solar panels can be very important to consider. While those with a large roof could sacrifice some efficiency and buy larger panels to get the ideal energy, homeowners with a smaller roof should be able to use fewer small high-efficiency panels – such as those from SunPower, LG, or REC – to get an optimal output. For those atypical roofs, you might end up with a system design like this:

How does the size of my house affect the number of solar panels I need?

While the size of solar panels has remained more or less stable over the past few years, the production power in the same area has increased dramatically. In fact, many manufacturers like SunPower have reduced the size of the gaps between the panels and use invisible framing and mounting hardware to keep the panels tight, efficient, and aesthetically pleasing. Consult the table for a general estimate of how many solar panels your house would need depending on its surface area.

The surface of the house in square meters compared to the number of solar panels needed

House size Annual electricity requirement Number of solar panels required:
92 sq m – 4,710 kWh
180 sq m – 9,420 kWh
230 sq m – 11,775 kWh
280no ​​– 14.13 kWh

How many solar panels do I need for common appliances?

By reviewing the various kWh requirements for everyday household appliances and products, one thing is clear: certain add-ons will dramatically change your monthly energy consumption and can have a huge impact on the size of your solar panel system that you should- install it. For example, pairing your electric vehicle with solar panels is an excellent way to reduce carbon emissions and improve energy efficiency; however, it should be planned accordingly as it could double the size of your PV system.

While it is certainly possible to install a solar system and then have a solar installer add more panels later to meet increased energy needs, the most pragmatic option is to size your system as accurately as possible based on expected purchases, such as an electric vehicle. , swimming pool, or centralized air system. Asking yourself, “How many solar panels will I need for my refrigerator, hot tub, etc.” it’s a great habit for any new solar homeowner.

Solar panel requirements for individual appliances

Product Average annual electricity requirement Number of solar panels required:
Refrigerator 600 kWh2
Window air conditioning 215 kWh
Central air conditioning 1,000 kWh
Electric vehicle 3,000 kWh
Heated swimming pool 2,500 kWh
Hot tub (outdoor) 3,300 kWh

Frequently asked questions