Choosing the right size solar panels for your home isn’t easy. It’s essential to think about several factors, such as energy needs, voltage, upgradability, etc.
Solar panels are getting more affordable and efficient, prompting many people to install them in homes. But, which size solar system is best for my home?
Calculating Your Budget
The most significant factor is your budget, as the equipment you purchase mainly depends on how much you are willing to spend.
If you do not have the funds to buy an array that meets your consumption needs, consider alternative financing options like low-interest loans or leasing. Interest-free payments are more affordable and allow you to save the money you’d use to settle the loan.
It’s worth noting that batteries and inverters also contribute to your budget. So when calculating your budget, remember that the panels will save you money and increase the value of your home.
Your Power Needs
Here’s how to calculate your domestic power consumption needs.
- How much do you need daily?
The number of appliances you have determines your daily consumption load. For example, if you have a 100W TV, 10 3W lamps, and a 150 W refrigerator, your everyday load is 100W + 10×3W + 150 W = 280W.
- How many units does your home consume?
Electricity is measured in watt-hours, calculated by multiplying the energy consumption of an appliance by the amount of running time. Using the example above, you would need 810wH to run the devices for three hours daily. However, lights usually run longer, while equipment like fridges run for an hour or two.
- Which is the right size solar?
After calculating the number of units needed daily, multiply it by 130% to compensate for the transmission losses and other inefficiencies. Then, divide the value by the number of sun hours your area gets in winter. For example, if your home needs 1.3kwH day and receives four sun hours, you will need a (1,300wH/4H) = 325W solar panel.
Solar Panel Voltage
Solar panel voltage is also an essential consideration factor. The most common ratings are 12V, 24V and 48V, as they correspond to many appliances. That said, it’s easy to achieve the desired voltage using parallel and series arrangements.
High voltage solar panels are more efficient than lower-rated modules. For instance, a 12V panel needs more amperage to generate enough power for your equipment. However, higher amperage is only achievable using a thick cable, resulting in more power loss through resistance. Contrarily, higher voltages require thinner, less-resistant solar panels.
When choosing a solar panel, use a consistent voltage across your system. This minimises the inefficiencies and power loss caused by energy conversion. It also makes installation easier.
Solar Panel Type
Different solar panels have varying efficiency levels. The most popular types are monocrystalline and polycrystalline modules, which have efficiencies of 22% and 15%, respectively.
Monocrystalline panels are more expensive than polycrystalline modules, but they are more efficient and take up less space. They also last longer than other solar panel types.
Passivated Emitter and Rear Cell (PERC) panels are an improvement to monocrystalline modules. They boast 35% efficiency, explaining their expensiveness. However, they take up little space and can also be affixed to a particular piece of equipment.
Solar panels don’t guarantee self-sufficiency regarding your power needs. For instance, if your home requires 10kW daily, you’ll need to install a system twice as big to save the surplus in batteries for use after sunset. Otherwise, your home will go dark after dusk.
It’s wise to leave room for expansion on your solar energy system. Remember, your needs are likely to increase in the future, prompting new panels’ installation.
Besides your budget, your energy needs and panel efficiency determine the size of solar modules needed to power your home. Generally, smaller panels are pricier because they’re more efficient.
You must also consider system inefficiencies that reduce the amount of energy reaching your home. It’s best to hire a professional so that they place the panels in an optimal position for harvesting solar energy.