The first step toward a good solar design is not a visit to a shop; it is reading your electricity bill. The bill tells a designer how much power you use, when, and at what tariff. With a few numbers from it you can ask for a better quotation and judge whether the system offered is the right size.
Key takeaways
- Monthly units (kWh) tell you how much energy you need to produce.
- The tariff slab and any extra charges decide how much each unit costs you.
- Collect at least 12 months of bills, because summer and winter use differ a great deal.
- The connected load and sanctioned load matter for the size of the supply connection.
1. Units consumed
The most important number is the units (kWh) used each month. A system that produces about as many units as you use will cover most of your bill. Look at your highest and lowest months; in Pakistan, summer cooling often pushes use up sharply. Our guide on how to calculate the right solar system size shows how to turn units into kilowatts.
2. The tariff and slabs
Your tariff depends on your category and how many units you use. Households are charged in slabs, so the last units in a high-use month cost more than the first. Because solar removes the most expensive units first, savings can be larger than the average rate suggests. Taxes and other charges on the bill also change from time to time, so use the figures from your own recent bills rather than a rule of thumb.
3. Peak and off-peak, for commercial users
Some commercial and industrial connections have time-of-use meters, with different rates for peak and off-peak hours and charges based on maximum demand. For these users the shape of the load over the day matters as much as the total. See load profile and solar design.
4. Sanctioned and connected load
Your bill or connection papers show a sanctioned load in kilowatts. This is the load your connection is approved for. A larger solar system may need the connection and the meter to be reviewed, so check this before you order.
5. What to bring to the first meeting
- Twelve months of bills, or at least the last six, including a summer month.
- A list of your main loads: air conditioners, pumps, fridges, motors.
- Photographs of your roof and electrical board.
- Your plans for the future, such as a new floor or more air conditioners.
Next step
Send us your bills and a few details through the quotation form and we will explain the sizing in plain terms.
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