Is Home Solar Worth It? Check Your Electricity Bill

The value of home solar does not depend on the size of your electricity bill alone. It depends on how much electricity your home uses during the day, because solar panels only generate power when the sun is out. This article explains how to read your electricity bill and make your own rough estimate of savings before an engineer surveys your site.

What to look for on your electricity bill

• Units of electricity used (kWh) per month. This is the most important figure, more useful than the amount in THB alone.
• Base tariff, Ft charge and VAT are used to work out how much each unit you save is worth.
• Customer type and meter size tell you whether your home has single-phase or three-phase power, which affects the system size you can install.
• Several months of past bills: hot-season bills are usually higher than the rest of the year, so look at the annual average rather than a single month.

Separate daytime and night-time use

Your bill does not split usage by time of day, so you need to estimate it from your household’s habits: is someone home during the day, do you run air conditioning, work from home, or use water pumps and appliances a lot in the daytime? The electricity you use during the day is the part an on-grid solar system reduces directly. Night-time electricity is still paid as usual unless you add a battery.

How to estimate your savings

1. Work out the average monthly units used from several months of bills.
2. Estimate the share of your home’s electricity used during the day.
3. Multiply the daytime units by your average cost per unit to get the maximum monthly amount solar can save.
4. Choose a system size that generates close to your daytime use. You do not need the largest system.

Try the home electricity calculator to see a recommended system size. The result is a rough estimate; actual figures depend on the site survey.

What makes it more or less worthwhile

• Roof orientation and shading: a roof that gets sun all day without shade generates more power.
• A system sized to your usage: a system larger than your daytime use produces surplus power, which is worth less than power you use yourself.
• Equipment quality and warranty: panels and inverters that meet standards help the system last.
• Care after installation: clean panels and a regularly checked system generate at full capacity. Read more in how to care for solar panels after installation.

Let an engineer assess your actual bill

Send a photo of your electricity bill to the SCAN EARTH POWER team on LINE @SEPSOLAR or fill in the form below. An engineer will assess the right system size and book a free roof survey.