How Many Do You Need to Power Your Home

How Many Do You Need to Power Your Home

The energy usage of yours in kilowatt-hours (kWh) dictates the dimensions of the system. Panels have an extensive range of wattages 275W-360W is typical as of first 2019, along with other aspects like mount orientation, local exposure to the sun, and also the existence of a battery bank additionally play a part. Read this article and work with our solar price calculator for assistance finding an accurate estimation.

How Many Do You Need to Power Your Home?

The solution is fairly complex, and frankly, many people use it from the wrong angle when they begin to look into solar. We are usually asked to quote a method to power a three (3) bedroom home or maybe support a family of four (4). It is not possible to offer a precise estimation until we understand far more about the household’s electricity requirements. The greatest place to begin is evaluating your present power consumption based on past energy bills. The past use information is a good baseline to determine exactly how many panels you’ll require. Lifestyle, climate as well as panel effectiveness all play a job in finding out the dimensions of the solar system. 

How many panel sections for grid-tied systems?

Let’s find out how many panels, you will gather up to six (6) a few months to a year’s worth of electric powered costs. And if you are living in a region with perhaps blistering hot summers or snowy winters, the bigger sample of costs to figure out when you use spikes. Take peak periods into consideration because you calculate exactly how many panels you will have to cover the energy usage of yours. Several companies offer a (12) month summary of just how much energy you make use of on every bill. Based on your utility provider, you might simply have one bill to locate an estimate for the season. Got the paperwork of yours in order? Great? you need to look for the number of kilowatt several hours (kWh) of electrical energy you make use of per year.

What is a kilowatt-hour?

A kilowatt-hour (kWh) is a measurement of power. If a machine rated for one kilowatt (1000W) runs for one (1) hour, then 1 kWh of electrical power has been used. The power company measures total power use in kilowatt-hours. The total usage of yours in kilowatt-hours determines exactly how much is your bill each month.

Example one: A fridge ranked from 250 watts runs for four (4)  working hours per day. 250W x four (4) = 1000W, or maybe one (1) kW. This fridge uses one (1) kWh of power over one day.

Example two: An oven is ranked at 2000 watts (two (2) kW). Cooking in this particular oven for 30 minutes would consume one (1) kWh of power (2kw x 0.5 several hours = 1kWh).


Find exactly how much kWh of power you consume per year. That can provide you with an excellent jumping-off use for estimating your energy required? though you are not there yet.

Divide that quantity by 365 to have the daily energy usage of yours in kWh.


When you have your daily energy usage, use this method to calculate your total system size:

Daily Usage (kWh) Sun Hours 0.9 inefficiency factor = Minimum Solar Array Output

Sun-hours refers to how much sun you receive each day where you reside. You can see that information on our US sun-hours map. More on this a little later. The inefficiency element just accounts for conditions which would help to make your program run below its equipment inefficiencies, voltage drop, extreme temperatures, like shade, and optimal output. Take your everyday use and also divide it by these 2 numbers to get an estimation of the general output of the system of yours.

For example:

Based on the U.S. Energy Information Administration, the typical American home used 10,766 kWh of electrical energy annually in 2016. That is approximately 29.5 kWh each day.


Suppose you are living in Arizona, that gets 5.5 sun hours each day.

29.5 kWh each day 5.5 sun hours 0.9 = 5.9595 kW capability process.

That would provide you with an estimated system dimension of 5.96 kW, or perhaps 5959W, one kilowatt = thousand watts.


From there, the previous step is divided by the electricity rating of each person board. Solar panels are graded by the amount of power they use. The sections you will use in a residential environment usually vary from 275 to 350 watts each panel.


Let us say we wish to make use of Astronergy 335W panels. Get your system size, besides, to divide by the board wattage to determine exactly how many solar panels you want in your system:

5959W 335W = 17.78 panels


Round up the last number, since you cannot buy partial panels. With this situation, we will have eighteen panels (18) rated from 335 watts apiece to recoup the energy needs.

We cannot strain this enough: this computation is an extremely rough estimate. It must simply be applied to ballpark method size and make premature pricing estimates. But do not take the estimate as gospel. There are too many elements which could alter the dimensions of the system of yours in practice. Additional considerations for off-grid systems Calculating power consumption requirements for an off-grid system is a tad a lot more complex. Individuals that live off-grid want to concentrate on everyday power use instead of annual or monthly consumption. You are not starting down by a power cost each month. You are responsible and independent for covering your daily energy. The process has to have the ability to create adequately and shop enough to preserve things running smoothly. Without power bills being a starting point, it is better to begin by listing out your major devices and estimating just how much you make use of them on a daily schedule.  Living off the grid, you are going to need a large battery process that is Big enough to save power that is sufficient for the day and next use solar energy to charge them on time. It is typical to lean holding a backup power generator during the wintertime when there will be no plenty of sunlight to completely power the solar system of yours. When you understand how much power you utilize in kWh each day, a sun design technician can figure out the least battery size required with a formula which accounts for items as inefficiencies as well as temperature coefficients.

The fundamental formulas we use sizing off-grid systems

Minimum Battery capability (for lead-acid batteries)

Daily use (kWh) x two (2) for a fifty (50) percent discharge depth x 1.2 inefficiency aspect = Minimum Battery Capacity


Minimum Solar Array Size

Daily usage kWh/Sun hours/.9 inefficiency factor = Minimum Solar Array Output

Ensure solar energy array meets battery charge specifications, usually around ten recharging amps per 100ah battery capacity/power. You might require a larger array or maybe battery bank based on the location, ambient temperature, the usage patterns along with other elements. 


Factoring in Sun Hours Depending on your Area 

Sun hours refers to just how much solar power hits a specified location over a specific amount of time. The local climate determines exactly how many peak sun hours you receive every day. This amount can change drastically based on the place you live in. Remember that the phrase sun hours does not simply relate to the hours of sunlight that your location receives. The peak hours occur once the sun is actually at its top in the sky, which could change depending on the season and just how close you’re to the equator. In the winter season, typically sun hours in the location might reduce by twenty-five (25) percent to fifty (50) percent.  So just how do sun hours impact the number of sections on your solar energy system? Living in a region with fewer sun hours, you will have more panels to shoot what you have to cover a hundred (100) percent of the energy usage. Nevertheless, in case you live in a location that gets five (5)- six (6) sun hours each day, you may have the ability to manage with a smaller phone system.


Quality versus Quantity: Panel effectiveness is not everything

Another thing which affects the dimensions of your process is the effectiveness of the solar power panels themselves. Most residential sections vary from 275Watts to 360Watts. Should you go having a 275Watts choice, you will need several additional panels to establish the array.

When it comes to sun, effectiveness is not often the most crucial aspect to consider when you develop the system. It truly depends on what the specific goals of yours are.

Several ideas on this matter. Probably the most common mistakes people do is they buy into ultra-efficient, high quality, and technically complex structures, and it may not be well worth it? particularly if ROI is the biggest concern of yours.

The best deal of the proprietary systems that way have very great equipment, and the essential to check out the price per watt. The customers urge us to think about this. “How much will you currently pay for the complete wattage/production?”

It does not matter how effective a panel is whether it costs a great deal more. If a board is fifty(50) percent much more effective but costs hundred (100) percent more, you are better off having to pay for a much larger system of less effective panels.

But there are a few situations where creating a smaller but more effective solar energy system makes sense. For instance, in case the roof space of yours is restricted, you may need a far more effective phone system to cover your energy requirements within that given place.

Astronergy 280Watts panels versus Mission Solar 360Watts panels

Considering other variables when developing a solar system 

This breakdown just serves as an extremely rough estimate and a kick-off point for planning the system of yours. It is good to help you better a ballpark figure on the price of panels. It is going to help as a benchmark whenever you calculate the roof of yours to find out if you can install a method up there. But if you get deeper into planning the system of yours, unexpected hurdles often come up and the method size is likely to change. Let’s say you choose to opt for 275Watts panels rather than 350Watts sections because the cost-per-watt is lower? What if shade covers the system, or maybe your roof does not directly confront the sun? What if harsh environmental causes the equipment to do below its rated effectiveness? Let’s say you begin using much more power as compared to what you did before? You will need a lot more panels.

Even though this breakdown can provide you with an estimation of the number of solar power panels you will need in the array, after the day it is simply an estimation. There are many different variables which can figure out the size of the solar system, though this method is still essential as it offers you a perception of what to search for before you need out quotes on solar energy systems.

In case you are keen on going solar, the greatest thing you can do is talk with a sun design technician that will help you find the perfect program for the unique situation. Bring the estimate as being a place to start. We will go over any possible issues and alter the layout to suit your lifestyle and location.