How to Calculate Solar Power Needs for Your Home

August 2, 2021
P4B Solar
Calculate Solar Power Adelaide

Have you considered installing a solar energy system in your home? If you’re thinking of installing solar panels on your roof, one of the first questions you’re probably asking is, “How many solar panels (also known as “solar modules”) are needed? Getting the best results with your new system will require you to provide your installer with an accurate estimate of your energy consumption.

When it comes to calculating your solar power requirements, here are a few tips to consider.

Getting an idea of your local solar subsidies is the first step in calculating your solar power needs.

Calculate Solar Power Needs

Step 1: Evaluate your local solar incentives and schemes

To get started, you’ll want to learn what kinds of solar schemes and subsidies may be available in your area. Tax credits and rebates aren’t the only incentives available; individual regions offer different incentives that can drastically affect the size of your system. We at P4B Solar, as a local Adelaide SolarEdge installer, can explain everything in detail, but below are a few concepts you might consider:

Feed-in Tariff: 

Feed-in tariffs (FiTs) are a system by which utility companies pay renewable energy producers (which includes you!) a fixed and above-retail rate for the electricity they supply. You will likely face a deployment cap that limits the size of your system to qualify.

Feed In Tariffs Graph - Residential Solar
Net Metering: 

For solar energy that you don’t use, your utility company gives you credit. The solar energy credits that you receive from the system effectively offset the cost of the grid electricity you are consuming (often during the evening).

Net Metering - Residential Solar

Step 2: What is your energy consumption?

In addition to the size of your PV system, you should consider your own energy consumption. How much energy does your home use on a typical day? The following are a few factors to consider:

  • Number of residents in a household
  • Devices used for heating and cooling
  • Appliances
  • Water Heaters
  • Lighting
  • Electric Vehicles
Home Consumption - Residential Solar

Your potential installer would like to see recent electricity bills so they can look at your consumption patterns, usually displayed in Kilowatt Hours (kWh). You should keep in mind that electricity usage may be higher during some months (for example, if you use extra lights or heating during the winter).

Installing an energy meter in your home will help you identify how much solar power you would need. You will be able to track your energy consumption habits even before you install a PV system, and therefore determine how large your PV system needs to be in order to offset your energy needs.

Energy Consumption Tracking - Residential Solar

Step 3: Designing your Solar PV system

Once your solar installer has calculated your solar power requirements, they will take the following factors into consideration:

  • Your geographic location
  • Sunlight exposure
  • The size and direction of your roof (for roof-mounted systems) or the size and shape of your yard for ground-mounted systems. For example, if you live in a location with lower sunlight exposure, a larger system might be needed to generate the same amount of power as a location with higher irradiance.

Solar energy is typically generated during the day, while energy is typically used when families use energy in the mornings or evenings. This means that you might store PV energy in a battery, as solar energy is typically produced during the day and used during the day.

When calculating how much solar power you need, another important factor is the type of PV system you plan to install. By developing inverters that utilize module-level power electronics (MLPE), it will be possible for each module to produce its maximum output without being affected by the outputs of others. You can also place more modules on your roof since they can be placed in different angles, directions, and layouts, allowing you to produce more energy for self-consumption or to feed into the grid.

Here’s a video comparing different PV inverter technologies:

Installers can calculate the size and type of your system based on both solar PV production and storage.  With a DC-coupled inverter (instead of an AC-coupled inverter), you can store excess energy over the inverter’s rated capacity. For instance, you could install a 5 kW inverter, but have solar modules that provide 7.75 kW, and then add a battery that provides 5 kW. As a result, your total PV capacity would be 12.75 kWp. 

PV System Design Tools

Installers such as P4B Solar can use SolarEdge’s web-based Designer tool to plan, build, and validate PV systems by taking all of the parameters mentioned above (and others). Based on the location and climate, a 3D simulation of the roof is created that includes the electrical design, production simulation, and everything else necessary to help future owners visualize a PV home.

Contact P4B Solar below to learn more about how much solar energy you need for your home.