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Ideal solar inverter size for your home

A solar inverter is an essential component of your solar energy system. They convert the direct current (DC) energy of your solar panels to alternating current (AC) that powers your home and appliances. When configuring a solar energy system for your home, your inverter choice and setup will be important when considering your system’s energy output and efficiency. With that in mind, we’ll explain what goes into deciding the best inverter size and capacity for your home.

How to figure out the best inverter size for your system

There are different kinds of solar inverters, each varying in terms of their capacity, physical size, and additional features such as islanding and battery monitoring. Although in particular, we will be focusing on their size which is rated in watts (W). This is mainly discussed for a solar energy system with a single, central inverter that converts all of the incoming DC to AC. Different factors will determine the size of your central inverter.

How large is your solar array?

Your geographical location is an important factor in general for solar energy systems. It is also an important consideration when choosing an appropriate inverter, as it directly impacts the production of your solar energy system. Solar energy systems in different locations around the country vary in their power production.

For example, a system that is close to the equator will produce more power than a system that is operating much further north. This is due to the differences in climate and sunlight hours. Areas with moderate temperatures and more peak sunlight hours will push solar energy systems closer to their maximum power output. Compared to areas up north, which may experience lower temperatures, but inconsistent peak sunlight hours and weather conditions.

If your location is closer to the equator, has consistent weather, and has plenty of sunlight ideal for solar energy. You will want an inverter unit that can properly handle your solar array’s maximum power output. So your system makes the most of the energy being produced by your solar panels. On the other hand, if the conditions of your location are affecting the efficiency of solar panels, with higher temperatures and lower sunlight hours.

You may be able to use an undersized inverter unit. Since your system is unlikely to reach its maximum power output consistently. Generally, these conditions will fall below the standard testing conditions (STC) for solar panels to reach their peak output. Solar panels perform their best with strong sunlight and cooler temperatures, hotter temperatures negatively impact the efficiency of solar panels. Shading from clouds also drastically impacts the performance of solar panels.

Your Location

Your geographical location is an important factor in general for solar energy systems. It is also an important consideration when choosing an appropriate inverter, as it directly impacts the production of your solar energy system. Solar energy systems in different locations around the country vary in their power production. For example, a system that is close to the equator will produce more power than a system that is operating much further north. This is due to the differences in climate and sunlight hours. Areas with moderate temperatures and more peak sunlight hours will push solar energy systems closer to their maximum power output. Compared to areas up north, which may experience lower temperatures, but inconsistent peak sunlight hours and weather conditions.

If your location is closer to the equator, has consistent weather, and has plenty of sunlight ideal for solar energy. You will want an inverter unit that can properly handle your solar array’s maximum power output. So your system makes the most of the energy being produced by your solar panels. On the other hand, if the conditions of your location are affecting the efficiency of solar panels, with higher temperatures and lower sunlight hours. You may be able to use an undersized inverter unit. Since your system is unlikely to reach its maximum power output consistently. Generally, these conditions will fall below the standard testing conditions (STC) for solar panels to reach their peak output. Solar panels perform their best with strong sunlight and cooler temperatures, hotter temperatures negatively impact the efficiency of solar panels. Shading from clouds also drastically impacts the performance of solar panels.

Factors specific to your property

Your property and how your solar panel array is designed will also play a part in your inverter choice. In regards to your property’s location, it will determine the tilt and azimuth of your solar panels. These are important when aligning your solar panels to optimally capture the sun’s light, which directly affects the power production of your solar panels. The environment around your property will also be considered. For example, if there is shading from nearby trees or structures, the amount of dust or grime that builds up on your solar panels. As any shading negatively affects the energy production of your panels.

When configuring a solar energy system, we will account for these factors when we conduct an initial inspection of your property. These factors will go into the planning for your solar energy system, along with the equipment and overall energy production of your system. Generally, these factors will go into the derating factors of your solar energy system. This determines the realistic performance of your solar energy system compared to the STC specifications which are lab testing results. If your home and system design will be affected, by shading, can’t reach the optimal amount of tilt, and isn’t facing south. Your solar energy system will have a higher derating factor and won’t reach your system’s maximum energy output. This means that you will be able to run an inverter with a smaller capacity to match the realistic power output of your solar array.

How to calculate solar inverter sizing

To get an idea of the ideal solar inverter to match your solar array, you will need to consider the array-to-inverter ratio of your solar panel system. As your solar inverter’s DC rating may be higher or lower than your solar panel array. To calculate the array-to-inverter ratio, you will need the DC rating of your solar array, by the maximum AC output of your inverter.

For example, if your array is 8 kW and your inverter is 8000 W, then the ratio is 1. If you install it with a 6000 w inverter, the ratio will be 1.3. Most solar energy systems will have a ratio between 1.15 to 1.25, as inverter manufacturers and system designs don’t recommend a ratio higher than 1.55.

A higher ratio could work if your solar energy system doesn’t reach its maximum power output. This could be to any of the factors we have mentioned previously. Although oversizing your solar array while keeping your inverter capacity lower can be done to save on cost. Although this can be an issue, an oversized array can run into clipping issues. Clipping is when solar panels are producing too much energy for the inverter to handle. When this happens, the inverter will limit the amount of energy it’s converting, which results in power losses. On the opposite end of the scale, having an inverter that’s too large compared to your array will reduce the amount of electricity. This is because inverters are most efficient when they are running close to their overall capacity.

Microinverters

Microinverters are small inverters that are mounted on or near each solar panel in an array. They directly convert the DC electricity that the solar panel produces into AC electricity. The size of the microinverter will depend on the energy output of the individual solar panel, rather than the whole array. Like a centralized inverter, they also have guidelines for the DC rating of a tied solar panel. Clipping can also happen if the solar panel has a higher wattage than the specifications of the inverter. It is also important to make sure the microinverters are suitable for solar panels.

If you’re still unsure about which inverter is suitable for your home. Our team is here to answer any questions you have. Our Project Managers and Solar Energy Consultants will help design a solar energy system that suits your home and needs.

Get started with solar energy today

If you are looking to start your transition to solar energy, we are here to help. Our website also has a free online estimate tool that generates a personalized report for you from a simplified questionnaire. That report will contain the potential savings you can net, and the cost of a solar energy system installed on your property. You can also contact us directly via phone at +1 (602) 363-8919 or via email at Scott@elitesolarenergy.org for more information regarding solar energy for your property.