Solar panel installation cost dataset

Sized from the bill, not the floor plan

Every one of those households can live in 2,000 square feet, and the systems differ by a factor of four. ⚠️ Sizing works backwards from consumption: annual kilowatt-hours divided by the yield of the region, which the model takes as 1350 kWh per installed kilowatt per year in the middle of the country, multiplied by 0.86 for wiring, inverter, dirt and temperature losses, and by 0.82 again where there is partial shade. Panels are 410 W each and the array rounds up to a whole number of them. All of those are declared model figures rather than published ones — the honest place to check yours is your own bill and a site survey.

Whether it fits the panel — the 120% rule

The allowance is 1.2 × the busbar rating minus the main breaker, and the inverter that fits is that current at 240 volts. ⚠️ This array wants 39.3 amps. Notice that the cost is identical at 100, 125 and 150 amps: below the threshold the fix is the same fix — a connection made ahead of the main breaker instead of into the busbar — and it does not get more expensive because the panel is smaller. The other route is a new panel, priced on our electrical panel upgrade dataset. No other solar calculator asks the question at all.

A third of the price is not the installation

$8,487 of the reference total — 34% — is neither hardware nor the crew on the roof: it is advertising, purchased leads, sales commission, design staff and company overhead. It is a named line here rather than spread across the others because that is the honest presentation and because it is where two quotes for the same array actually differ. ⚠️ This is also the reason a model built only from hardware and labour comes out at about $1.72 a watt when residential solar sells at nearer $2.62. Leaving the gap out would have made every other figure on this page wrong. The practical consequence: get three quotes for the same system size with the same equipment, and read the spread as this line rather than as a difference in quality.

Roof, sun and inverters

Sun region changes the size of the array rather than the price per watt: less sun means more panels for the same output. ⚠️ The two bottom rows on the right are the comparison no solar quote contains — a solar array lasts twenty-five years and an asphalt roof does not, so if the roof has under a decade left somebody pays the roofing and electrical hours twice. The remove-and-reinstall figure is not a separate estimate: it is those same two labour lines from this dataset, with the design and permit excluded because the array is already designed and bought. On standing seam metal the problem does not arise at all, which is part of why it is the cheapest roof here to mount on.

Line items

85% of the reference total comes from estimated rather than official figures. The reference job is a 9.43 kW array — 23 panels at 410 W — sized to cover 10,800 kWh a year in the middle of the country, on asphalt shingle with microinverters, into a 200 amp panel: 64.6 trade hours and 10,948 kWh of production a year. ⚠️ This dataset prices work, not tax positions: the IRS says the residential clean energy credit covers property installed through December 31, 2025 and is not available afterwards — IRS, Residential Clean Energy Credit, retrieved 2026-08-24.

The reasoning behind each figure

Design, permit and the interconnection applicationestimated, ±58%

• Layout and string design, a structural check that the roof carries the load, the building and electrical permits, and the application to the utility to connect a generator to their grid.
• ⚠️ The interconnection application is the one people have not heard of and the one that sets the timetable. The utility decides whether and on what terms your system may export, and in some territories the queue is measured in months. It is also where net metering terms are set, and those have been getting worse across the country rather than better.
• The band is a simple approval at the bottom and a jurisdiction with a structural review and a slow utility at the top.

Panelsestimated, ±32%

• Priced per watt of installed capacity, which is how the whole industry quotes and the only unit that lets two quotes be compared.
• ⚠️ Panels are the part of a solar quote everybody focuses on and they are a minority of the price. Two systems with identical panels can differ by half, and the difference is in the racking, the inverter choice, the electrical work and whose crew is on the roof.
• The band is a mainstream panel at the bottom and a high-efficiency one at the top. Higher efficiency buys the same output in less roof area, which matters only when roof area is the constraint.

String inverter and rapid shutdown devicesestimated, ±31%

• One inverter for the array, plus the module-level shutdown devices that let a fire crew de-energise the roof.
• ⚠️ Budget for replacing it once. A string inverter is the component most likely to fail within the life of the panels, and its replacement is not usually covered by the panel warranty.

Microinverters, one per panelestimated, ±26%

• One inverter behind each panel, so each works independently and shade on one does not drag down the others.
• It also satisfies the rapid-shutdown requirement inherently, which removes a separate line.
• ⚠️ The trade is where the electronics live: on the roof, under a panel, for twenty-five years. When one fails the fix involves a ladder rather than a garage wall.

Racking, flashings and roof attachmentsestimated, ±41%

• Rails, clamps, and the attachment to the roof — which on a shingle roof is a lagged mount with a flashing that tucks under the course above it.
• ⚠️ Multiplied by the roof type, and the spread is wide: standing seam metal is cheaper because the clamps grip the seam and nothing penetrates, and tile is the most expensive on this page because tiles are lifted, hooks are flashed in, and some tiles break on the way.
• Every penetration on a shingle roof is a deliberate hole in the thing keeping water out of your house. This is the line where the crew matters more than the brand.

Wiring, conduit, disconnects and the production meterestimated, ±37%

• DC and AC wiring, conduit from the roof to the equipment, the disconnects the utility requires and where applicable a production meter.
• It scales with system size and with how far the panels are from the electrical panel, which the model does not ask separately — a longer run sits at the top of the band.

On the roof: mounting, flashing and laying the array

• Modelled at 3.4 hours per kilowatt, multiplied by the roof factor: setting out, flashing every attachment, running rail and laying panels.
• Roofers carry this line because the part that decides whether the roof still works in ten years is the flashing, not the electricity.

Electrical: conduit, terminations, disconnects and commissioning

• Modelled at 2.6 hours per kilowatt plus a fixed 8 hours, which is the part that does not scale: the connection at the panel, the disconnects, the labelling and the commissioning happen once whatever the array size.

Supply-side connection, when the panel cannot take the backfeedestimated, ±51%

• ⚠️ This line appears when the existing electrical panel physically cannot accept the solar backfeed, and it is the item no solar calculator asks about. A panel has a limit on how much current can be pushed into it from one end while the main breaker feeds it from the other: the two together cannot exceed 120% of what the busbar is rated for.
• On a 200 A panel with a 200 A busbar that leaves about 40 A of backfeed — around 9.6 kW of inverter at 240 volts. A 10 kilowatt system already does not fit. On a 100 A panel it is about 4.8 kW.
• When it does not fit there are two ways out. This one connects the solar ahead of the main breaker instead of into the busbar, which sidesteps the limit entirely; the other is a new panel, which is a separate job priced on our electrical panel page and usually costs more.
• The band is a straightforward tap in an accessible meter position at the bottom, and one needing the utility to disconnect and a new meter main at the top.

Supply-side connection — labour

• Modelled at 9 hours. Work ahead of the main breaker is work on conductors that the main breaker does not protect, which is why it is done by somebody who does it often and usually with the utility involved.

Customer acquisition, sales and company overheadestimated, ±39%

• ⚠️ This line exists because leaving it out would make every other number on the page a lie. In American residential solar the hardware and the crew are roughly two thirds of what a homeowner pays; the rest is what it cost the company to find you — advertising, lead purchase, the salesperson’s commission, design staff, financing partners and general overhead.
• It is not padding and it is not a scandal: somebody has to pay for the appointment that ended in a signature. It is put on its own line because **this is where two quotes for the same array differ**, far more than the panels do, and a homeowner comparing quotes needs to know that the variable part is not the equipment.
• The practical consequence is the most useful advice on this page: get three quotes for the same system size and the same equipment. The spread you see is mostly this line.
• The band is deliberately wide — from a small local installer who does not buy leads to a national company with a call centre — and it is a modelled estimate rather than a published figure, because no such figure is published per installation.

Monitoring, commissioning and the utility sign-offestimated, ±59%

• Monitoring hardware and its setup, commissioning the system, and the paperwork that ends with permission to operate from the utility.
• ⚠️ Permission to operate is a real gate, not a formality: a finished array is not allowed to run until the utility says so, and the wait after the panels are on the roof is measured in weeks in many territories.

Not included in this dataset

Anything about your tax position

⚠️ This page prices work and is not tax advice. The federal residential clean energy credit is set out by the IRS, and its own page — read on 2026-08-24 — says the credit covers property installed through 31 December 2025 and is not available for anything placed in service after that. Much of the solar industry is still advertising 30% as though it were current. Check the IRS page and a tax professional for your own position; state and utility incentives are separate again and are not modelled here.

What the electricity is worth to you

Whether solar pays depends on what you would otherwise be charged and on what your utility pays for exports, and net metering terms have been getting worse across the country rather than better. This page prices the installation; it does not compute a payback, because the number that would decide it is set by a tariff we cannot read from a form.

A roof that cannot take it

The model assumes a structurally sound roof. An array adds load and, more to the point, needs solid rafters to fix to — an old or damaged roof deck is a repair before it is a solar job, and it is not modelled here.

Replacing the roof underneath, later

⚠️ Panels outlast an asphalt roof. If the roof has under a decade left, somebody will remove and reinstall the array to replace it, and that is real money that appears on no solar quote. This page computes it separately so it can be seen before it is committed to, not after.

Batteries

Storage is a separate decision with separate economics, priced on our solar battery page. Solar without a battery does not keep the lights on in a power cut — the inverter shuts down so it cannot backfeed a line somebody is working on — and that surprises people.

Tree removal and trimming

Shade is the single biggest thing that ruins a solar system, and the fix is sometimes a tree. Our tree removal and tree trimming pages price that side of it.

A service upgrade if the panel is full or too small

Where the backfeed does not fit, this dataset prices the supply-side connection. Replacing the panel instead is the other route and it is priced on our electrical panel page — usually dearer, and worth doing anyway if the panel is old.