When you want to add items from a previous order to an order you are building, select Order Tracking on the left navigation bar. 1  On the Order History page, select the order number you want to view. The Order Detail page appears. 2  Select the Reorder Items button to add all products on this order to your shopping cart.
Using 4 hours of full sun, gives you this equation: 250 watts x 4 hours. Thatâs 1 kWh (1,000 watts) in a day per 250-watt panel. If you multiply 1kWh per panel by 30 days in a month, youâll find that each 250 watt rated panel will produce about 30 kWh in an average month.
In contrast, SunPower panels are known to be the most efficient solar panels on the market. To figure out how many solar panels you need, divide your homeâs hourly wattage requirement (see question No. 3) by the solar panelsâ wattage to calculate the total number of panels you need. So that average U.S. home in Dallas, Texas, would need about 25 conventional (250W) solar panels or 17 SunPower (370W) panels. 5.