More and more households today are considering installing solar panels on their home, and one of the most compelling reasons is to ease, at least a little, the burden of high bills and make use of what the sun offers us free of charge, every single day.
When we decide to step into the world of solar energy, the first question we ask is how many panels we need for our household for everything to work properly. The answer doesn't come off the cuff, because it isn't the same if you have a 70 m² house with one air conditioner, or a 200+ m² house with 4 televisions, 2 water heaters running non-stop, 2 freezers, and electric heating on top of that.
Nor is it the same if you live in the mountains with many cloudy days, or on a plain where the sun shines on many more days of the year.
That's why in this article we'll clarify roughly how many panels you need depending on the size of the house, the average consumption, and the number of sunny days, so you don't install too few or too many, but just right.
What determines the number of solar panels a household needs?
Before getting into any calculations, you should know what actually affects the number of panels you really need. The point is not for the roof to look modern, but for it to produce enough electricity for your needs.
Factors that affect the calculation:
- How much electricity do you use per month?
This is the most important factor. If your monthly electricity bill says you use, say, 400 kWh, that's the baseline. Some use less, some more, it depends on whether you have electric heating, how many people live in the house, how many freezers and fridges you have, whether you wash and dry clothes in machines every day, and so on.
- Where is the house, and how many sunny hours does it get per year?
Serbia has quite a lot of sun, on average, around 1,600 to 2,000 sunny hours per year. But again, it's not the same whether your house is in Senta, Valjevo, or up on Zlatibor. The geographic position and altitude can shift the calculation.
- How much room do you have on the roof?
You may want 15 panels, but if your roof is small, they won't all fit. That's why we also look at the roof area and whether it's suitable for installation. South-facing roofs with a moderate tilt are best.
- Which panels are used?
Today the most common panels are 350W to 450W. The more powerful the panels, the fewer you need for the same output. You'll discuss this with the installation company, but it's good to know that not every panel is the same, and not every panel on the market is equally high quality. Choose proven partners for solar panel installation.
How many solar panels do you need based on house size?
When discussing solar panel installation, people most often ask: "If I have a 100 m² house, how many panels do I need?"
We have to stress one big truth here, square metres are only a rough indicator. What's much more important is how much electricity you use. Two houses of the same size usually have different consumption, sometimes by a factor of two.
Still, we'll give you a rough estimate for houses with average consumption that use standard household appliances and live a moderate lifestyle, in other words, we'll stick to average consumption.
A 50 m² house
– Consumption: about 250–300 kWh per month
– Required: 6–8 panels (if they are 400W)
A 100 m² house
– Consumption: about 400–500 kWh per month
– Required: 10–12 panels
A 150 m² house
– Consumption: about 600–700 kWh per month
– Required: 14–16 panels
A 200 m² house
– Consumption: about 800–900 kWh per month
– Required: 18–20 panels
This can, of course, vary. If you heat the whole house with electricity, your consumption will be higher and you'll need more panels. If you have a solar water heater, a gas cooker, or a combined system, the number of panels can be smaller.
Our advice is to first look at your electricity bills for the past year. Then, based on that, calculate the average monthly and annual consumption. That will be the proper basis for an accurate calculation.
How to calculate how many panels you really need on your own
Before contacting specialists, you can run a simple, rough calculation. You need three pieces of information for it:
- How much electricity you use per year
- How much electricity one panel produces on average per year
- The capacity of the panels you plan to install
Step by step:
-
Check your annual consumption from electricity bills, Take 12 monthly bills and add up the consumed kWh. For example: 400 kWh per month × 12 months = 4,800 kWh per year.
-
Estimate how much one panel can produce per year, In Serbia, an average 400W panel produces about 400–500 kWh per year. That depends on location and sunlight. Let's take an average of 450 kWh per panel.
-
Divide total consumption by the production of a single panel, For example: 4,800 kWh per year ÷ 450 kWh per panel = 10.6. We'll round up to 11 panels.
And that's it. If you have higher consumption, you'll need more panels. If you plan to be more frugal or have lower consumption, you'll get by with fewer.
This is just a basic calculation. In practice, we also look at whether you have space for that many panels, what their efficiency is, whether you're building a system with or without batteries, and so on. But as an initial orientation, this is more than enough to know what to expect.
If you've reached this part of the article, you already have a clearer picture of how many solar panels a household needs, how to roughly calculate it yourself, and why the number depends on your habits, location, and house size.
The good news is that today you no longer have to guess or worry about getting it wrong. The experts at MySolar can produce an exact calculation, look at your roof, assess consumption, and propose the optimal solution tailored to your needs. Rest assured, there will be no surplus, no shortage, just the right amount.
Investing in solar panels is a long-term decision, but with the right information it becomes simple.
