Solar · Service

Solar panel installation, starting with your roof

Before anyone talks to you about panels, two questions decide whether this is a good deal: how old is your roof, and who is going to own the system. We match you with vetted local installers and help you get both answers straight.

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In short

What is solar panel installation?

A residential solar installation puts a grid-tied array on your roof and ties it into your electrical service through an inverter and a new AC disconnect. The physical work is usually one to three days; the permitting, utility interconnection approval and final inspection around it typically take considerably longer than the install itself. Two decisions made before any of that determine whether the project is worth doing: the remaining life of your roof, and whether you buy the system or sign a long-term contract for the power it makes.

Triggers

Signs you need solar panel installation

Your roof is newly replaced, or has well over a decade of life left — this is the ideal moment to go solar, and the reason people who wait end up paying twice
You have a large, mostly unshaded south, west or east-facing roof plane with few vents, chimneys or dormers breaking it up
Your electricity bill is consistently high and driven by usage you cannot easily reduce — a pool pump, a well, electric heat, an EV, a home office running all day
You already have or are planning electric appliances, a heat pump or an EV, so your consumption is going up rather than down
You plan to stay in the house long enough for a 20-to-25-year asset to make sense
Your utility has been raising rates and you want to fix part of your energy cost rather than ride the increases
You are already replacing the roof, so the mounting work and the roofing work can be sequenced together instead of fighting each other

Seeing something not on this list? Browse solar problems by symptom →

The job

How solar panel installation actually works

Roof condition and remaining life — the first conversation, not the last

A solar array is a 20-to-25-year commitment bolted to a roof covering that may not last that long. If your roof has fewer than roughly ten good years left, the honest sequence is roof first, panels second. Removing and re-setting an existing array so a roofer can work underneath is a real, separately quoted cost, and it is money you spend for nothing but access.

Watch for: A salesperson who declares your roof "fine for solar" from a satellite image or a walk around the outside. Get an independent opinion from a roofer who is not being paid by the solar sale. Also ask, in writing, who removes and re-installs the array if the roof needs work later, and at whose expense.
Shading, orientation and a real production estimate

The site assessment measures how much sun each roof plane actually gets across the year, allowing for trees, neighbouring buildings, chimneys and the way the array will self-shade in winter. The output is an annual production estimate in kilowatt-hours, which is the number every financial claim in the proposal rests on.

Watch for: A production estimate with no shade measurement behind it, or one that quietly assumes trees will be removed. Ask which software produced it, what shading data went in, and whether the estimate is guaranteed. If a proposal promises savings, the production number under it should be contractually backed, not aspirational.
System design and sizing against your actual usage

Sizing works backwards from twelve months of your own utility bills, not from your roof area. An array much larger than your consumption may produce power you export for far less than you pay to import it, depending entirely on what your utility does with exported energy.

Watch for: Being sized to fill the roof rather than to match your bill. Ask directly what your utility currently pays for exported power and how long that arrangement is guaranteed for new systems — net-metering and buyback terms vary by state and by utility, and several have changed them. Get the answer from the utility, not only from the installer.
Ownership structure — cash, loan, lease or PPA

Buying outright with cash or a loan means you own the equipment and you are the party who claims any tax credit you qualify for. A lease or a power purchase agreement means a third party owns the hardware on your roof; they take the incentives, and you pay them monthly for the system or for the power it produces, usually for twenty years or more.

Watch for: The escalator clause. Many lease and PPA contracts raise your payment by a fixed percentage every year for the life of the agreement, on the assumption that utility rates will rise faster. If they do not, the deal inverts. Find the escalator, read what it does in year fifteen, and price the total contract, not the first monthly payment.
Permitting, interconnection and utility approval

Your installer files a building and electrical permit with the local authority and an interconnection application with your utility. The utility reviews whether your service and the local circuit can accept the export, and issues permission to operate. The array cannot legally be switched on before that permission arrives.

Watch for: Timelines quoted as though permitting were instant. Ask who files, who pays the fees, what happens to your deposit if the utility rejects or delays the application, and whether the contract lets you walk away if approval takes beyond a stated date.
Mounting, flashing and roof penetrations

Racking is lagged into the rafters and each penetration is flashed and sealed. This is roofing work performed by an electrical contractor, and it is where the long-term risk on your house lives — dozens of new holes in a weatherproof surface.

Watch for: Sealant-only penetrations with no metal flashing worked into the shingle courses. Sealant is a maintenance item; flashing is a roof detail. Ask what flashing system is used, and confirm your roof warranty survives the installation — some manufacturer warranties are affected by third-party penetrations.
Electrical work, inverters and the interconnection point

Panels are wired into strings or fitted with microinverters or optimisers, then connected through a new disconnect into your service panel. Older or fully loaded panels sometimes need a main-breaker change or a service upgrade to accept the backfeed.

Watch for: A panel upgrade appearing as a change order on install day. A competent installer opens your service panel during the site visit and tells you then. Also ask where the rapid-shutdown device is and whether the design uses string inverters, optimisers or microinverters, because that choice decides how future repairs and expansions work.
Inspection, permission to operate, and monitoring handover

The local inspector signs off the electrical and structural work, the utility swaps or reprograms the meter if needed, and permission to operate is granted. You should be handed monitoring access, a wiring and layout diagram, the equipment serial numbers and every warranty document.

Watch for: Being left without monitoring logins or without knowing what normal production looks like for your system in each season. Without a baseline you will not notice a failed string or a dead microinverter for months, and quiet underproduction is the most common way owners lose money on a working-looking array.

Money

What does solar panel installation cost?

Residential solar is priced per watt, so the total tracks system size, roof complexity, equipment tier and any electrical upgrades. Incentives, financing structure and what your utility pays for exported power change the real number enormously — confirm the current federal and state position before you sign anything.

See the full solar panel installation cost guide — by material, size and region →

Solar tools and calculators → Size a system against your own usage before you look at any proposal.

Straight answer

When solar panel installation is the wrong call

Everyone else ranking for this is paid when you say yes. Here's when you shouldn't.

Your roof has under about ten years left. Replace it first. Otherwise you will pay a crew to remove the array, pay the roofer, then pay to re-set and re-commission it — a cost that buys you no extra electricity at all.
Your best roof planes are shaded for a meaningful part of the day. Optimisers and microinverters reduce the damage from partial shade; they do not create sun. If the honest production estimate is weak, a smaller system or no system beats a large one that underperforms its projection.
You are likely to sell within a few years and you are being offered a lease or PPA. A third-party contract attached to the roof has to be assumed by your buyer or bought out at closing, and it can narrow your buyer pool or complicate the appraisal. If a long stay is not likely, ownership is the safer structure — or wait.
You have no tax liability and the deal is sold to you on a tax credit. A credit you cannot use is not a discount. Work out what your position actually is with someone qualified before it is priced into your savings projection.
Your bill is low, or high for a reason you could fix cheaper. Air sealing, insulation, an old resistance water heater or a failing HVAC system can be worth more per dollar than an array, and they shrink the system you need if you do go ahead.
The only thing making the numbers work is an escalating lease payment compared against an assumed rate of utility inflation. That is a forecast, not a saving. Ask to see the same comparison with a flat utility rate and decide again.

Your options

Types of solar panel installation

Add a battery

Backup power and storing your own production instead of exporting it.

Equipment and inverter choices

String, optimiser and microinverter designs, and what each means for repairs later.

Financing and ownership structures

Cash, loan, lease and PPA compared before you sign a 20-year document.

Solar shingles and roof-integrated systems

When the roof itself is the array — usually a roofing decision first.

Compare solar options side by side →

Before you sign

What to check when hiring for solar panel installation

How many years of roof life does an independent roofer say I have left?

The single most consequential question on this page, and the one your solar salesperson is least motivated to chase. Ask a roofer who is not part of the solar sale.
Who removes and re-installs this array when the roof is replaced, and what does that cost today?

Get a figure and a named responsible party in writing now. Twelve years from now the company that sold you the system may not exist.
Is this a cash sale, a loan, a lease or a PPA — and who claims the incentives?

If a third party owns the hardware, they own the incentive value. Any savings pitch that implies otherwise is misleading, and the difference compounds over twenty years.
If this contract escalates, what is my payment in the final year?

Ask for the whole payment schedule, not the first-year figure. An escalator that looks small annually is a large number by year twenty.
What does my utility pay for exported power today, and for how long is that locked for new systems?

This is the assumption every savings projection depends on. Terms vary by state and by utility and have been revised in several markets — verify with the utility directly.
What is the workmanship warranty, who honours it, and is the installer the same company as the salesperson?

Solar sales are heavily subcontracted. Equipment warranties come from manufacturers; roof penetrations and wiring are covered by the installer, and only if the installer is still trading.
What flashing system is used at each penetration, and does my roof warranty survive it?

Leaks show up years later, at which point the argument is between your roofer and your solar company. Settle it before the holes are drilled.

All solar hiring checklists →

Local pros

Solar Panel Installation near you

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Related work

Often done at the same time

Solar Battery Installation

Backup power and self-consumption

Solar System Expansion

Adding panels to an array you already have

Solar Maintenance

Monitoring, inverters and production drop-off

Solar Panel Repair

When the system stops producing

All solar services →

FAQ

Solar Panel Installation — questions people ask

Still have a question? Talk to our team →

Should I replace my roof before installing solar?

If the roof has fewer than roughly ten years of life left, yes — almost always. Re-roofing under an existing array means paying to remove it, store it, and re-install and re-commission it, plus new penetrations and flashings. That spend produces no additional electricity. Doing the roof first also lets the roofer and the installer coordinate penetration details rather than working around each other.

How long does the whole process take from signing to switch-on?

The physical installation on a typical house is one to three days. The surrounding process — site survey, engineering, permit approval, installation, local inspection, then utility interconnection and permission to operate — is what stretches the calendar, and it varies enormously by jurisdiction and utility. Ask your installer for the recent real-world timeline in your specific city and utility territory, not a national average.

What is the difference between a solar lease, a PPA and buying?

Buying, with cash or a loan, makes you the owner: you keep the equipment and you are the party who claims any incentive you qualify for. A lease means you rent the hardware for a monthly payment. A PPA means you buy the electricity the system produces at an agreed rate. Under both third-party structures, the company owns the panels and takes the incentive value, and the agreement typically runs twenty years or more with an annual escalator.

What happens to a solar lease when I sell the house?

The agreement does not simply disappear at closing. Typically your buyer must qualify and formally assume it, or you buy the contract out — and buyout figures early in a term can be substantial. It also has to be disclosed, and lenders and appraisers treat a leased system differently from an owned one. If you might move, read the transfer and buyout clauses before you sign, not when you list.

Do I still have power in an outage?

Not with a standard grid-tied array. For safety, the inverter shuts down when the grid goes down so it cannot backfeed the lines that utility crews are working on. Backup during an outage requires a battery and the correct switching hardware, and even then it usually powers a selected subset of circuits rather than the whole house.

Will solar panels damage my roof?

A properly flashed installation should not, and the covered area is somewhat sheltered from weather and UV. The risk sits in workmanship: dozens of new fastener penetrations sealed by an electrical contractor rather than a roofer. Ask what flashing is used, get the workmanship warranty in writing with a stated term, and confirm your existing roof warranty is not voided by third-party penetrations.