Strategic Solar Sizing to Maximize Efficiency and Profitability

Solar panel installation for home use is a powerful way to cut energy costs and increase your property's value. But did you know that properly sizing your photovoltaic (PV) system is key to maximizing those benefits?

Several factors determine the ideal solar energy system setup, from the size of your Coquitlam home to available roof space, sunlight exposure, and budget. It may sound overwhelming, but an installation company will make it easy for you to understand.

Key Takeaways:

• Correctly measuring your solar panel systems will generate sufficient power to meet your needs.
• South-facing roofs in Coquitlam offer better module performance throughout the year.
• Coquitlam enjoys peak sun production from mid-June to late September, with August offering the most sunlight. This abundance of months is best for electricity generation.

Why Sizing Matters in Solar Energy Systems?

Correct sizing guarantees you generate enough current to meet your needs. This prevents higher bills and maximizes your investment.

A well-sized solar power system operates efficiently by reducing wear and tear on components and extending its lifespan. Proper computation allows you to reduce or eliminate reliance on the grid.

One Reddit commenter said, "If you undersize your system you will have months where you still have a utility bill if there is a lot of cloudy weather."

Another Redditor recommended, "Off grid people should correctly size to meet their needs in bad winter conditions. If you based on summer production, you won't have enough to cover your winter needs."

Categories in Sizing Options For Solar Panel Installation for Home

Knowing the measure and configuration requires considering several factors. Your installer will assess how much energy you need and conduct a thorough site evaluation before providing you with an accurate cost estimate.

Home Extent and Electricity Needs

Understanding how much power your house consumes is important to choosing the right size. The amount of current used varies by home, family habits, and appliance demands.

• Smaller homes might need around 4,000 kWh per year.
• Larger residences surpass 10,000 kWh annually.

For instance, a residence in Coquitlam might average about 7,000 kilowatt-hours per year. To meet most of this demand, you'd generally look at a power amount between 5-6 kW to cover 80-90% of that usage.

In contrast, a larger home would likely need an 8-10 kW system to achieve similar coverage. With the specific home measure, you can better control costs and reduce dependence on traditional sources.

Roof Space

Proper positioning of each module in a designated area maximizes sunlight exposure. For homeowners in Coquitlam, a south-facing roof is ideal, as it allows for the best production throughout the year. Factors like partial shading from nearby trees or buildings can impact the setup.

• Orientation Matters: South-facing roofs mostly yield the highest production. If your roof faces east or west, installers will adjust the number of modules or their placement to get optimal sun exposure.
• Type: The choice between monocrystalline and polycrystalline can affect efficiency. Monocrystallines, while more expensive, are space-efficient. This type is an excellent choice for roofs with limited area. Let's say your roof can hold about 16 panels, which translates to approximately 5 kW. 

Note: If you opt for high-efficiency monocrystalline, you could generate more than standard polycrystalline within the same space. This decision can lead to better output and a higher return on investment (ROI).

Sunlight Hours (Hrs) /Climate

Sunlight exposure affects output. While July shines the brightest with around 289 hours of sunshine, December is much dimmer, just 56 hours. Annually, Coquitlam gets about 1,940 hours of sun, ideal for converting sunlight into electricity by installing solar panels or modules.

• Sunny Season (Mid-June to Late September): Coquitlam's clearest period stretches from mid-June to late September, with August as the clearest month. Expect a clear sky or partly cloudy, about 65%, during this time. This period is ideal for producing renewables, and longer days generate excess energy for battery storage or grid tie-ins.
• Cloudy Season (Late September to Mid-June): Cloud cover increases from late September, with January being the cloudiest month—75% of the time is overcast. This can reduce output by up to 30% in winter months. Factor in a size that compensates for lower winter production.

Budget Constraints

Solar panels cost a few thousand dollars, but the type of equipment chosen mostly determines their cost. You can start with fewer panels to fit a smaller budget and expand their panel systems as needed.

Options like loans, leases, power purchase agreements (PPAs), and other financing options with federal tax credits make any renewable source more accessible by spreading costs over time. This helps you achieve savings without heavy upfront expenses.

Family Sizes

This can greatly influence a home's electric demands, which impacts systems' sizing.

Multi-Houses

Homeowners with multiple properties or investment rentals can maximize savings by measuring systems for each location. Strategies could include smaller systems for each property or a shared, larger option if they're close together.

This approach allows for consistent current production, lower overall costs, and the potential for excess generation that can offset other utility bills.

Solar Panel System Sizing 

You can start by estimating your electricity usage. Your installer will conduct a thorough assessment, including a detailed electric consumption analysis, to determine the most suitable solar system for your needs.

Determining Consumption Demands

Start by calculating the daily power and energy needed for all your appliances.

• Find the daily watt-hour (Wh) for each appliance, then add them up to get the overall watt-hour needed each day.
• Adjust for loss by multiplying this total by 1.3. This gives the watt-hour per day home panels must supply.

For example:

• Total appliance use = (20 W x 3 hours) + (50 W x 2.5 hours) + (80 W x 24 x 0.4 hours) = 1,028 Wh/day
• Total Photovoltaic energy needed = 1,028 x 1.3 = 1,336.4 Wh/day

The Photovoltaic Modules

Photovoltaic module sizes affect the amount of current generated based on the module dimensions and the site's climate. To determine the necessary photovoltaic module size, consider the panel generation factor, which varies by location. In Canada, the generation factor is 6.

Note that this result is the minimum number of modules required. Adding more panels can boost performance and battery life.

For example:

• Total Wp of PV panel capacity needed: 1,336.46 / 6 = 222.7 Wp
• Number of PV modules needed: 222.74 / 10 =2.02 modules
• Actual requirement: Since partial modules aren't practical, round up to 3 modules.

At least three 110 Wp modules should power this system for sufficient coverage.

Inverter

When you use an AC output, you'll need an inverter. Its input rating must meet or exceed the entire wattage of your appliances and match your battery's nominal voltage. For stand-alone solar power systems, the inverter must handle the full wattage you'll use at once and be sized 25–30% above this total.

• If your setup includes motorized appliances like compressors, choose an inverter rated at least three times the appliance capacity to handle startup surges.
• For a grid-tied, the inverter's input rating should match the photovoltaic array rating for safe, efficient operation.

Here's a sample computation:

1. Absolute Watt of all appliances: 20 + 50 + 80 = 150 Watts
2. Inverter size with a 25–30% safety margin:

• 25% increase: 150 × 1.25 = 187.5 Watts
• 30% increase: 150 × 1.3 = 195 Watts

The inverter size must be between 187.5 and 195 Watts or greater for a safe margin.

Battery

You'll need a deep-cycle battery for photovoltaic systems because systems frequently charges and discharges. It must be large enough to store solar power for nighttime and cloudy days.

Here's the formula to calculate the ideal battery size:

Battery Capacity (aH) = Entire watt hours per day used by appliances x Days of Autonomy / (0.85 x 0.6 x nominal battery voltage)

Photovoltaic Charge Controller

The Amperage and Voltage capacities rate a photovoltaic charge controller. Choose one that matches the voltage of your photovoltaic array and batteries and check if it can handle the current from the array.

Sizing for a series charge controller depends on the photovoltaic input current and the panel configuration (series or parallel). The standard method is to take the PV array's short circuit current (Isc) and multiply it by 1.3.



Formula:

Charge controller rating = Total short circuit current of PV array x 1.3

Frequently Asked Questions