How to Plan for a Home Solar System

In this blog, we’ll look at the seven most important steps to consider when installing solar panels for your home:

For most homeowners, it’s easy to understand the benefits of going solar, whether your priority is protecting the environment, reducing energy bills, increasing the value of your property, or even just reducing your reliance on utility providers.

But taking the next step and installing solar panels for your home can seem a bit more complex. How do you know that you’re working with the right installer, or using the right equipment? How many residential solar panels do you need to support your energy consumption? How often will you need to check on your solar panels or do essential maintenance?

Here, we’ve broken down the seven most important steps in planning for a home solar power system.

Step One: Assess your surroundings

Your surroundings can have a huge impact on the efficiency of your solar system, so it’s important to assess whether there are any potential problems before you invest.

Needless to say, solar panels work best when they’re exposed to direct, consistent sunlight for longer periods of time. This sounds simple, but it’s easy to overlook some of the issues that can stop any solar panels from functioning properly.

Take a walk around your house and look for anything that might block the sun from falling on the area where you want to install your panels. Are there any trees overhanging your property? Are tall surrounding buildings casting shadows on your roof?

You might also want to think about any structural limitations. Is your roof sturdy enough to support solar panels? How much maintenance does it need? Are solar panels going to stop you from conducting essential repairs?

It’s also important to think about the bigger picture: What’s the weather like in your part of the country? How many hours of sunlight can you expect each day?

It’s important to carry out checks like these before you invest in solar panels, so you can figure out which problems can be addressed, and which can’t. Roofs can be fixed and trees can be cut back, but a nearby building is a much bigger problem.

Step Two: Calculate how much energy you want to generate

The amount of energy your household uses each month will directly impact how many solar panels you install on your property, as well as the type of solar panel, their positioning, and a host of other considerations.

So it’s important to kick off your solar panel installation project with a realistic idea of how much energy you use.

The first place to look is your energy bill. Somewhere in your documentation, you should find a measurement called something like ‘Kilowatt-hours/kWh used’. This tracks how much energy you used over the last 30 days.

Can’t find ‘Kilowatt-hours’ on your bill? Just calculate the difference between your meter readings at the beginning and end of that month.

So, for example, if your previous meter reading was 40,000, and this month’s meter reading is 40,550, you’ve used 550 kWh in the last 30 days. Divide 550 by 30, and you have the number of kWh you used each day – 18.3.

At this point, you should decide how much energy you want to draw from solar panels. Do you want to shift to 100% renewable energy? Do you want to use mostly solar energy, backed up with some traditional energy sources?

Now that you’ve calculated your energy usage and how much of it you want to replace with solar energy, you can figure out how many solar panels you need to fulfill your needs.

So, now you know how much energy you need. But how much energy can you generate?

First, you need to consider whether you want to qualify for any governmental solar power incentive schemes. There are some places where you can only receive incentives — in the form of tax credits or rebates — if your installation generates less than a certain number of gigawatts. It might be more cost-effective to use a mix of solar and grid power, at least when you’re first making the switch to renewable energy.

To figure this out, you’ll need to think about two things:

• How many hours of sunlight can you expect to fall on your property each day?
• How powerful will my solar panels need to be to generate this much energy during sunlight hours?

For example, if the area where you live only gets four hours of sunlight a day, you’ll need them to generate energy much faster than the solar panels on a house that gets eight hours a day.

These might sound like complicated calculations, but you’ll usually have help from a qualified solar contractor (we’ll cover choosing the right installer further down the page). They’ll be able to make more accurate assessments and check that you haven’t left anything important out of your calculations.

Step Three: Calculate how many solar panels you need

Now that you know how many kWh of power you need each day, it’s time to figure out how many solar panels you must install to generate that much power.

Not all solar panels generate the same amount of energy — depending on the type of panel, domestic panels usually generate between 330 and 500 watts.

If you choose a panel that generates more watts, you won’t need as many of them to meet your energy needs. But panels with a higher wattage can be more expensive — it’s a trade-off between cost and efficiency, and you just need to find the right balance.

• Convert your solar panel’s wattage to kW by dividing it by 1000
• Work out how many hours of sunlight your region gets each day — there are lots of charts online that provide this information if you don’t want to calculate yourself.
• Multiply your solar panel’s wattage by the number of sunlight hours to calculate how many kilowatts one solar panel can generate per day.
• Divide your house’s daily energy consumption by the kilowattage of your solar panel to calculate how many panels you need.

So, let’s say you’ve calculated you use 124 kWh per month or 4 kWh per day.

You choose a 400 watt solar panel.

400 divided by 1000 tells us that your panel has a kilowattage of 0.4.

Your roof gets 4 effective sun hours per day, so we multiply 0.4 by 4 to discover that one panel can generate 1.6 kWh per day.

If we divide your energy usage (4 kWh) by 1.6, we’ll find that you need just 2.5 solar panels to generate the energy you need. Since you can’t get 0.5 of a solar panel, it’s your choice whether you round up to 3 or down to 12.

And, of course, this calculation changes depending on the power of your solar panel. If you choose a 330 watt solar panel, you’ll need between 3 and 4 panels to generate all of the energy you need.

Step Four: Choose where to place your solar panels

It goes without saying that you’ll want to place your solar panels in a position where they’ll get as much light as possible, for as much of the day as possible.

If you’re in the Northern Hemisphere, this usually means your solar panels should face south. If you live in the Southern Hemisphere, they’ll get most light if they face north.

Next, consider the tilt of your solar panels. Again, you’ll want to aim for an angle that catches the most sunlight for the longest period of time. This means that the closer you are to the equator, the more horizontal your solar panels should be. It’s also a good idea to consider cleaning and drainage. If you live in a region that gets lots of rain, placing your solar panels on a slight incline will allow rainfall to clean off dirt and debris that can build up on solar panels and reduce their effectiveness.

While most domestic solar panel installations sit on the roof of the house, you might also want to consider placing them somewhere else on your property – particularly if your roof isn’t pitched in a direction that gets a lot of sunlight. If you have lots of flat ground with good drainage available, you might find that ground-mounted panels are a better option.

Step Five: Find a microinverter that converts your energy efficiently 

Solar panels might be the most visible part of the solar system, but there’s another component that’s just as important: the microinverter.

Microinverters turn the raw direct current (DC) energy collected by your solar panels into safe, usable alternating current (AC) energy. There are other types of inverters available, but microinverters are generally the most reliable for home use because they convert energy from each panel individually. This means that if one panel falls into the shade or develops a fault, the rest of the panels can keep operating at full capacity – and therefore keep the lights on.

But not all microinverters are created equal; if you want to avoid wasting energy during the conversion process, you’ll need to look for microinverters that:

• Have high efficiency ratings (CEC and MPPT are good ones to look at)
• Have an extended warranty and come with technical support, so you can get help quickly if your microinverters need maintenance
• Have built-in monitoring, so you can keep an eye on whether your solar system is converting energy efficiently, troubleshoot any issues, and see how much energy you’re using (we’ll go into more detail on measurement below)

Step Six: Find a solar panel contractor to help with your installation

It’s possible to install solar panels yourself, but it’s usually safer and more efficient to work with a qualified contractor. While you might want to try steps 1-5 by yourself to understand whether solar panels are right for you, a contractor can carry out a more thorough assessment to confirm how much energy you need, whether your property can benefit from solar power, and which equipment is best for you.

So how do you find the right solar panel installer? You’ll want to assess them from several angles:

• Are they accredited? In the US, for example, installers should be accredited with the North American Board of Certified Energy Practitioners (NABCEP). Spend some time researching any nationally or internationally recognized accreditations.
• Are they experienced in installing home solar systems? An experienced installer will be excellent at anticipating problems, sourcing the best equipment at the best price, and finding ways to make your solar system more reliable and efficient.
• Are they licensed and insured to install a home solar system? The licenses required will vary from country to country, but they’ll usually need at least a general electrician’s license.
• What do their previous customers say about them? If you can, find some reviews online or get a recommendation from a friend. They’ll be able to tell you if the installer did a thorough job, delivered everything on time, and was able to provide long-term, reliable energy.

Step Seven: Think about how you’re going to measure your home solar system

Once your solar panel system is up and running, you’ll want to be certain that you’re not wasting any energy or missing opportunities to generate more power. With that in mind, it’s a good idea to talk to your installer about where and how you can collect data on how your solar system is performing.

If your solar system is hooked up to the grid, your electricity bill can give you some insight into how well your panels and inverters are performing. You’ll be able to see how much money you’ve received for your solar energy, and whether your solar power had to be supplemented with energy from the grid, though you won’t get any granular insight.

A better idea is to look for microinverters that come with a tracking and monitoring app where you can see how much energy you produce each month, how individual panels are performing, and if any of the panels need your attention. Then you can compare your readings against the estimated power outputs you’ll find in the manuals of your solar panels and microinverters.

By keeping track of your actual output compared to your expected output on a monthly basis, you’ll find it much easier to identify any problems with your solar panels early on. 

What comes next?

Installing solar panels at home can feel intimidating at first, but it’s much easier to successfully generate your own renewable energy if you set yourself up for success from the start.

If you plan carefully and work with a skilled installer, you can often find unexpected ways to increase the amount of energy you generate – and also avoid lots of the pitfalls that can come with installing solar panels incorrectly. With the right equipment, the right support, and the right expectations in place, you’ll be on your way to generating solar power at home in no time.