How to Read a Solar Quote

Every solar quote contains the same dozen line items, and each one is a place where money quietly changes hands. Once you know what each line means and what a fair value looks like, you can spot an inflated proposal in about ten minutes. This is that walkthrough.

Line 1: System size (kW DC)

The quote should state the system size in kilowatts DC, for example 7.6 kW DC. This is the total rated capacity of the panels, and it is the denominator for every price comparison you will make. Two things to check. First, that the size matches your usage: divide your annual kWh by roughly 1,200 to 1,700 (your region’s production factor) to see if the proposed size is in the right neighborhood. Our cost guide for typical homes shows what common sizes look like.

Second, watch for the AC/DC sleight of hand. Some quotes emphasize the inverter’s AC rating, which is always lower than the DC panel rating. A “7.6 kW system” with a 6 kW inverter is normal (inverters are routinely undersized relative to panels, a practice called clipping design). But the price per watt should always be calculated on the DC panel rating. If a quote blurs which number it uses, ask directly.

Lines 2-4: Panels, inverter, racking

This is where vague quotes reveal themselves. A proper equipment section lists the panel manufacturer and exact model (for example, REC Alpha Pure-RX 430W, not “430W Tier 1 panel”), the inverter or microinverter model (for example, Enphase IQ8HC, not “microinverters”), and the racking system. With model numbers you can look up datasheets, verify efficiency and warranty terms, and confirm the gear matches what gets installed.

Why it matters beyond comparison shopping: equipment determines your warranty reality. A 25-year panel warranty from a manufacturer with a shaky balance sheet is worth less than a 25-year warranty from an established one, which is part of why which brands installers actually recommend matters. It also determines monitoring: Enphase and SolarEdge systems include panel-level monitoring, while basic string inverters show only whole-system output. If the quote says “monitoring included,” check whether it is panel-level or system-level.

Line 5: Total price and price per watt

Find the total contract price, then divide by the DC system size to get price per watt. A $23,560 quote for 7.6 kW is $3.10 per watt. Do this for every quote and the mysterious 40 percent spread between installers becomes concrete: you will see $2.70, $3.10, and $3.90 per watt for the same roof, and the differences are mostly sales cost and margin, not equipment.

Critical: make sure you are dividing the cash price. If the quote only shows a financed total, you are looking at a number inflated by dealer fees, and the gap between quoted and real price can be thousands. Ask for the cash price in writing. An installer who will not provide one is telling you the financing markup is load-bearing for their business model.

Line 6: Production estimate

The quote should state estimated first-year production in kWh, ideally with a month-by-month breakdown and a shading analysis. Divide annual kWh by system kW to get the specific yield. In the Southeast and Southwest, 1,500 to 1,700 is realistic. In the Northeast and Pacific Northwest, 1,200 to 1,400. If the number looks heroic for your region, the savings math downstream is fiction.

Also check the degradation assumption, usually around 0.5% per year. That is honest for modern panels. If a proposal assumes zero degradation over 25 years, its lifetime savings are overstated by roughly 6 to 8 percent. Small fudge, but it reveals the proposal’s relationship with accuracy. Cross-check any estimate with NREL PVWatts, which takes five minutes and your address.

Line 7: Savings and payback claims

Savings figures are built from three assumptions: your current rate, the annual rate increase, and the production estimate. The rate increase assumption is the one most often juiced. Proposals commonly assume 4 to 6 percent annual increases; the EIA’s long-run residential average is closer to 2 to 3 percent. Every extra point of assumed increase adds thousands to the 25-year savings headline.

Ask for the assumptions in writing, then rerun the math at 2.5% rate growth. If the payback still looks acceptable, the deal is real. Also confirm whether the savings figure nets out loan interest. Some proposals show “savings” against the electric bill while quietly ignoring $15,000 in loan interest over 25 years. Real savings subtract everything you pay, including financing. This matters more than ever: with no federal credit cushioning the numbers, as our 2026 solar economics guide explains, an inflated savings claim can make a marginal deal look like a great one.

Lines 8-10: The three warranties

Solar has three separate warranties and salespeople love to blur them into one reassuring “25-year warranty.” Separate them:

• Equipment warranty (10 to 25 years): covers defects and premature failure. This is the manufacturer’s promise, and its value depends on the manufacturer surviving.
• Performance warranty (25 to 30 years): guarantees output, typically 85 to 92% of original capacity at year 25. This is the warranty that actually governs what your panels produce in old age.
• Workmanship warranty (5 to 25 years): covers the installation itself, leaks, wiring, roof penetrations. This comes from the installer, not the manufacturer, which is why installer longevity matters. A 25-year workmanship warranty from a two-year-old company is a hope, not a guarantee.

Read who backs each warranty and what voids it. Common exclusions include unauthorized modifications, failure to maintain access for service, and damage from extreme weather beyond rated specs.

Lines 11-12: Payment schedule and fine print

Standard residential terms: a deposit of 10 to 25 percent at signing, a progress payment at installation, and the balance at permission to operate or final inspection. Be cautious of any contract demanding more than a third upfront. Also read the timeline commitments and cancellation terms. Many states give you a multi-day right to cancel a door-to-door sale, and reputable contracts state it plainly.

The fine print also holds the escalator clause if you are being quoted a lease or PPA rather than a purchase: annual payment increases, often 2.9 to 3.5 percent, compounding for 25 years. A lease that starts below your electric bill can end up above it. And check who handles warranty claims, monitoring setup, and the interconnection application with your utility. “Homeowner responsible for utility paperwork” on a $25,000 project is a bad sign.