If you’ve requested solar quotes and received two or three proposals back, you’ve probably noticed they don’t all look the same. System sizes vary, pricing structures differ, and the payback projections can be hard to compare directly. Here’s how to read what’s actually in front of you.
System Size and Production Estimates
The first number to focus on is system size, measured in kilowatts (kW). A larger system produces more electricity, but size alone doesn’t tell you whether it’s right for your home. The right system size depends on your actual annual electricity usage, not a round number.
Ask each installer what your current annual kilowatt-hour consumption is and how they sized the system to match it. A reputable installer will show you this math. One that can’t explain why they chose a specific size is a flag.
Production estimates are typically given as annual kilowatt-hours. Compare these across quotes, not just system size, since panel efficiency and roof orientation affect output independently of how many panels are installed.
Price Per Watt
The most useful number for comparing quotes is price per watt, calculated by dividing the total system cost by the system size in watts. For a 10 kW system priced at $30,000, that’s $3.00 per watt.
In Pennsylvania in 2026, installed residential solar typically ranges from $2.50–$3.50 per watt before incentives. Quotes significantly above that range warrant a question. Quotes significantly below it warrant a harder look at what’s been left out.
Payback Period and ROI
Most quotes will include a payback period, typically 7–12 years for Pennsylvania homeowners depending on system size, usage, and current utility rates. The key variable is the electricity rate assumption built into that projection.
Ask what rate per kilowatt-hour each installer used in their payback calculation. If the number seems frozen at a historical rate rather than reflecting current pricing, the real payback period may be shorter than projected. As rates rise, solar savings per kilowatt-hour rise with them.
Also ask how they’re treating net metering credits in the projection. Pennsylvania’s net metering policy allows you to send excess generation back to the grid for credit, and that credit value should be reflected in the long-term savings estimate.
Equipment Quality
Not all panels and inverters are the same. Ask for the specific make and model of panels, inverters, and racking in each quote. Tier 1 panel manufacturers carry stronger production warranties and have better long-term bankability than off-brand alternatives.
String inverters are less expensive but mean the whole system underperforms if one panel is shaded. Microinverters or power optimizers handle shading better and provide panel-level monitoring, at a higher upfront cost.
What to Ask Before You Sign
Before committing to any quote, confirm the installer is NABCEP-certified, check that the quote includes permitting and interconnection costs, and ask for references from installations in your county. Interconnection timelines with PPL or Met-Ed can vary, and an experienced local installer will have a realistic picture of what to expect.
For background on Pennsylvania incentives, our 2026 solar overview covers current federal and state programs.
At Topp Home, we provide transparent solar quotes for homeowners throughout South Central PA and walk through every line item before you decide. Schedule a free inspection and price quote today.
