However, the vital question in 2023 is how many solar panels one requires to power a household. The answer hinges on various factors, from energy consumption to geographical location, roof orientation, roof dimension, and solar panel specifications.
Yes, those may seem like a lot of factors to consider, but not to worry, in this article, we look at estimating the requisite number of solar panels for your home based on everyday scenarios and assumptions.
Crunching the Numbers: How to Estimate Your Energy Consumption
The primary step in gauging your solar panel needs involves determining your average monthly or annual electricity consumption. You can find this information in your utility bill or using an online energy calculator. Alternatively, in your calculations, you can use the national average of 2,900 kilowatt-hours (kWh) per annum or 237 kWh per month, typical for a standard UK household.
Afterward, you’ll need to divide your yearly or monthly electricity consumption by the average number of peak sun hours in your vicinity. What are peak sun hours? Peak sun hours are the hours of the day when the sun shines at its brightest and produces the most solar energy. For instance, in London, the daily average peak sun hours hovers around 2.8 hours throughout the year.
With these figures in hand, you can deduce the number of solar panels required to generate sufficient power per hour to meet your energy needs. For instance, if your yearly consumption amounts to 4,000 kWh and your locale enjoys 2.8 peak sun hours daily, you’ll require about 3.9 kilowatts (kW) of solar power per hour.
4,000 kWh ÷ 365 days ÷ 2.8 kW = 3.9 kW.
Estimating Your Roof Size and Orientation
The subsequent step involves estimating your roof’s size and orientation. This essential data determines the amount of space at your disposal for solar panel installation. Ideally, you want a large, south-facing roof, untouched by the shadow cast by trees or neighboring buildings.
To define your roof’s length and width, you can use a tape measure or opt for a satellite imaging tool such as Google Maps. You can then multiply these dimensions to give you the total square footage of your roof.
Consider a case in point where your roof stretches 40 feet in length and 30 feet in width; this equates to a total surface area of 1,200 square feet. To gauge the percentage of your roof open to solar panel installation, you’ll need to consider factors such as pitch, shape, roof direction, or any obstructions and shading issues detracting from your solar panel’s efficacy. Generally, approximately 75% of your roof is deemed suitable for solar panels, though this may vary depending on your unique circumstances.
With this percentage in mind, you can calculate the usable roof space for solar panels. For instance, in a scenario where your roof sprawls over 1,200 square feet, you can harness a usable roof space of 900 square feet (1,200 x 75%).
How to Estimate the Number of Solar Panels You Need
The final step involves dividing the amount of solar power you need to generate per hour by the power rating of each solar panel you are considering. This gives you an estimate of how many solar panels you’ll need to install on your roof.
The power rating of a solar panel denotes the quantity of electricity it can generate under standard test conditions. This power rating is not just influential in electricity production but also factors into the solar panel’s dimensions and cost.
As of 2023, the typical power rating of a residential solar panel spans a range from approximately 250 W to 400 W, with the precise figure contingent on the brand and model. Using these benchmarks, one can calculate the required solar panels.
For example, you’ll need about 12 solar panels to generate 3 kW of solar power using panels with a 250 W power rating. The arithmetic goes thus:
3 kW * 1,000 = 3,000 W.
You then divide this by the power rating of your chosen solar panel. 3000 ÷ 250 = 12.
Of course, these are only rough estimates and may vary depending on your energy consumption, roof orientation, weather, and solar battery performance. Therefore, you should consider engaging a professional solar installer for a more precise quote. A great choice installer in the UK is The Solar Co, which specialises in everything from solar panels to solar batteries and EV charging.
Solar energy has come to stay. In 2023 and beyond, it will remain an exemplary conduit for energising many homes across the globe. Though deciphering the perfect number of solar panels for your abode may seem daunting, adhering to the steps outlined in this article can help you figure it out.