Short, practical answers from an engineering point of view. Every number here can be checked with our free planning tools.
Sizing and cost
What size solar system do I need?
Divide your monthly units by 30.4 to get daily kWh, then divide by about 3.9. For example, 600 units a month is about 19.7 kWh a day, so you need roughly a 5 kW system. The 3.9 comes from about 5 peak sun hours a day in the Islamabad and Rawalpindi region multiplied by a 78% performance factor for real-world losses. Use 12 months of bills, not one, because summer use can be double winter use.
How much does a solar system cost in Pakistan?
It depends on system size, panel and inverter brands, whether you add batteries, and your roof structure. Batteries are usually the biggest extra cost. For an itemised, indicative price in PKR for your own consumption, use the solar cost estimator. A confirmed price comes after a site assessment.
How many solar panels do I need for a 10 kW system?
With 585 W panels you need 18 panels (10,000 ÷ 585 = 17.1, rounded up). With 550 W panels you need 19. The exact count also depends on how the panels are wired into strings for your inverter.
How much roof space does a 10 kW system need?
About 60 m² (roughly 650 sq ft) of usable roof for 18 panels, allowing space between rows and for maintenance. Elevated structures can keep the roof below usable. Our sizing tool checks a 10 kW layout, or any other size, against your roof area.
Is an online estimate the same as a quotation?
No. Online results are indicative estimates based on stated assumptions. A formal quotation follows a site assessment that checks the roof, cable runs, distribution board and earthing.
System types and load-shedding
What is the difference between on-grid, hybrid and off-grid solar?
On-grid systems feed your home and the grid and have no batteries, so they cost the least per unit. Hybrid systems add a battery, so essential loads keep running during outages. Off-grid systems are not connected to the grid at all and depend fully on batteries.
Does solar work during load-shedding?
An on-grid system switches off during load-shedding. This is a safety rule so it does not feed power into lines being repaired. A hybrid or off-grid system keeps your chosen loads running from its battery and from the panels during the day.
Do solar panels work in winter and on cloudy days?
Yes, but output is lower. Expect noticeably less generation on cloudy monsoon days and short winter days, and more in spring and summer. Size the system on your yearly usage, not on a single sunny month.
Batteries
How long will a solar battery run my house?
Divide the battery's usable energy by your average load. A 5.12 kWh LiFePO4 battery delivers about 4 kWh after depth of discharge and inverter losses. That runs a 500 W average load (fans, lights, router, fridge) for about 8 hours. Use the battery backup calculator with your own appliances.
Lithium or sodium-ion: which battery is better for solar?
LiFePO4 lithium is compact, efficient and widely supported. Sodium-ion is newer and bulkier, but tolerates temperature extremes well and avoids lithium. Both work for home backup. Choose on inverter compatibility, warranty and support. Read our lithium vs sodium-ion guide.
Can I add more batteries later?
Usually yes, if the battery model supports parallel expansion and your inverter supports the larger bank. Ask for the maximum number of units in parallel before you buy.
Grid, bills and maintenance
Can I sell solar electricity back to IESCO?
Exporting surplus power requires an approved net-metering or net-billing connection from your distribution company. In Islamabad and Rawalpindi that is IESCO. The rules and the rate paid for exported units have been revised over time, so confirm the current terms before counting on export income. Our estimator leaves export credit out unless a verified rate is configured.
Will solar make my electricity bill zero?
Rarely. Fixed charges and taxes usually remain, and not every unit you generate replaces a unit you would have bought. Solar can still cut a large share of your purchased units. Read how to read your bill before going solar.
How long do solar panels last?
Quality panels are commonly sold with 25 to 30 year performance warranties. Inverters and batteries have shorter warranties, so check each datasheet.
How often should solar panels be cleaned?
Clean them whenever dust visibly builds up. In dusty months that can be every one to two weeks. Use plain water and a soft brush, early morning or evening, and never stand on the panels. Have the wiring and connections checked once a year.
About us
Which areas does Engr Ahsan Solar serve?
Rawalpindi, Islamabad, DHA and Bahria Town. See our Islamabad, Rawalpindi and DHA and Bahria Town pages, or message us on WhatsApp at +92 317 5635464.