Solar Site Assessment: What Happens and How Long It Takes

TL;DR: A solar site assessment takes 1 to 2 hours and covers roof condition, orientation, shading, and electrical panel capacity. It is the single most important step before signing a solar contract. Remote assessments using satellite imagery can handle initial screening, but an in-person visit catches problems that aerial photos miss. After the assessment, expect a detailed proposal within 1 to 2 weeks. Any installer who skips this step or rushes through it is not worth hiring.

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What a Solar Site Assessment Actually Covers

A solar site assessment is a physical evaluation of a property to determine whether solar panels will work there, how many panels will fit, and how much energy the system will produce. It is not a sales pitch. It is an engineering exercise.

The assessor looks at five core areas during the visit, and each one affects the final system design and cost estimate.

Roof Condition and Structural Integrity

Solar panels add 2.5 to 4 pounds per square foot to a roof. The assessor checks the roof's age, material, and structural condition to confirm it can handle that load for 25+ years. Asphalt shingle roofs less than 10 years old are ideal candidates. A roof with 15+ years of wear may need replacement before panels go up, which changes the project timeline and budget.

The assessor also checks for soft spots, sagging, water damage, and the condition of the decking underneath. If the attic is accessible, they will inspect the rafters and trusses for signs of stress or rot.

Roof Orientation and Tilt Angle

South-facing roofs produce the most solar energy in the Hudson Valley. Southwest and southeast orientations work well too, producing about 80% to 90% of a south-facing roof's output. East or west-facing roofs are still viable but generate less energy, which affects the system's payback period.

Roof pitch matters as well. The ideal tilt for New York's latitude (roughly 41 degrees north) falls between 30 and 35 degrees. Flat roofs need tilted racking systems, which adds cost but allows panels to face the optimal direction.

Shading Analysis

Shade is the biggest performance killer for solar panels. The assessor uses a tool called a Solar Pathfinder or a digital shade analysis device (like a Solmetric SunEye) to measure shade exposure throughout the day and across seasons.

Trees are the most common shade source in the Hudson Valley. A tree that causes no shade in July may block significant sunlight in December when the sun sits lower in the sky. The assessor maps shade patterns for the full year to calculate actual production estimates, not best-case numbers.

Electrical Panel and Service Evaluation

The home's electrical panel needs enough capacity to handle a solar system's output. Most modern homes have a 200-amp service panel, which is sufficient for a standard residential solar installation. Older homes with 100-amp or 150-amp panels may require a panel upgrade, adding $1,500 to $3,000 to the project cost.

The assessor checks the panel's available breaker slots, the main breaker rating, and the condition of the wiring. They also verify the utility meter type and note whether a new net meter will be needed.

Available Roof Space and Obstructions

Vents, chimneys, skylights, dormers, and satellite dishes all reduce usable roof space. The assessor measures the available area and maps out where panels can go while maintaining required setbacks from roof edges (building code requires 18 inches to 3 feet depending on the municipality).

Ground-mount systems need a different evaluation: soil type, terrain slope, distance from the electrical panel, and potential trenching routes for conduit.

How Long Does a Solar Site Assessment Take?

A thorough in-person assessment runs 1 to 2 hours for a standard residential property. Larger homes, properties with multiple roof sections, or ground-mount evaluations can take closer to 3 hours.

Solar Site Assessment Time Breakdown

The assessor spends roughly half the time on the roof and exterior, and the other half inside examining the electrical panel, reviewing utility bills, and discussing the homeowner's energy goals.

Remote vs. In-Person Assessments

Many installers now offer a remote assessment as a first step. Using satellite imagery from Google Earth or EagleView, combined with utility bill data, they can estimate system size and production without visiting the property.

What Remote Assessments Can Do

Remote assessments work well for initial screening. They can determine roof orientation, approximate square footage, and general shade patterns from aerial views. An installer can produce a ballpark quote within a day or two using remote tools. This saves time for homeowners who want to know if solar is even feasible before scheduling a visit.

What Remote Assessments Miss

Satellite images do not show roof condition, rafter spacing, electrical panel capacity, or attic access. They cannot detect soft spots, water damage, or structural concerns. Tree shade patterns change with seasons, and a single aerial photo captures only one moment in time. For these reasons, a reputable installer always follows up a remote assessment with an in-person visit before finalizing the system design.

What to Prepare Before the Assessor Visits

A little preparation makes the assessment faster and more accurate. Here is what to have ready before the visit:

• 12 months of utility bills (or a login to the utility's online portal so the assessor can pull usage data directly)
• Clear access to the electrical panel (move stored items away from the panel box)
• Attic access (if applicable, clear a path to the attic hatch)
• Roof access (let the assessor know if there are locked gates, aggressive dogs, or tricky ladder placement spots)
• A list of planned changes (if an EV purchase, pool heater, or home addition is planned, mention it because these affect system sizing)
• Any HOA restrictions or deed covenants (some HOAs have panel placement rules, and New York's Solar Access Law limits but does not eliminate HOA authority)

What the Proposal Includes After the Assessment

After the site visit, the installer produces a detailed proposal. This document is the foundation of the entire project and should include specific numbers, not vague estimates.

• System size in kilowatts (kW) based on roof space and energy needs
• Panel count and model with specifications (wattage, efficiency, warranty)
• Inverter type (string inverter, microinverters, or optimizers) and brand
• Estimated annual production in kilowatt-hours (kWh) based on the shading analysis
• Total cost before incentives (equipment, labor, permitting, interconnection)
• Net cost after incentives (federal 30% tax credit, NY-Sun incentive, and any local rebates)
• Projected savings over 10, 15, and 25 years with assumed utility rate increases
• Payback period (the point where cumulative savings exceed the system cost)
• Warranty details for panels, inverter, racking, and workmanship

If the proposal does not include all of these elements, ask for them. A missing item is a missing answer, and missing answers lead to surprises after signing.

Timeline from Assessment to Installation

The assessment itself is just the starting point. Here is a realistic timeline for a residential solar project in the Hudson Valley:

Solar Project Timeline: Assessment to Installation

The total timeline from first assessment to flipping the switch runs 2 to 4 months for most Hudson Valley installations. Permit delays from local building departments are the most common cause of extended timelines.

Red Flags: When an Installer Skips the Assessment

A proper site assessment protects the homeowner. Any installer who cuts corners during this step will likely cut corners during installation. Watch for these warning signs:

• No in-person visit at all. A remote-only assessment followed by a contract is not enough. If the installer has never seen the roof, they cannot guarantee the design will work.
• Assessment under 30 minutes. Spending less than half an hour means the assessor skipped something. Roof condition checks alone take 20 to 30 minutes on a standard home.
• No shade analysis tool. Eyeballing shade is guesswork. A real assessment uses a Pathfinder, SunEye, or equivalent device.
• No electrical panel inspection. If the assessor does not open the panel box and check capacity, the proposal's accuracy is questionable.
• Pressure to sign before the proposal. Some companies send a salesperson instead of an assessor. If the person on the roof spends more time on pricing than measuring, that is a sales call, not an assessment.
• Generic proposal without site-specific data. A proposal should reflect the actual property, not a template with estimated numbers plugged in.

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Frequently Asked Questions

Q: How long does a solar site assessment take?

A: A standard residential solar site assessment takes 1 to 2 hours. The assessor spends time on the roof checking condition and orientation, performing a shade analysis, inspecting the electrical panel, and discussing energy goals with the homeowner. Larger properties or ground-mount evaluations may take up to 3 hours.

Q: Is a solar site assessment free?

A: Most reputable solar installers in New York offer free site assessments with no obligation. The assessment is part of the sales process, and the installer covers the cost. Be cautious of companies that charge for an assessment, as this is uncommon in the residential solar market.

Q: Can a solar assessment be done remotely?

A: An initial screening can be done remotely using satellite imagery and utility bill data. Remote assessments provide a rough estimate of system size and cost. An in-person visit is still necessary before finalizing any system design because satellite photos cannot reveal roof condition, electrical panel capacity, or accurate year-round shade patterns.

Q: What should homeowners prepare before a solar assessment?

A: Have 12 months of utility bills ready, clear access to the electrical panel and attic, and note any planned changes like EV purchases or home additions. Let the assessor know about any HOA restrictions or access challenges on the property.

Q: What happens after the solar site assessment?

A: The installer uses the assessment data to design a system and prepare a proposal. The proposal includes system size, panel and inverter models, estimated production, total cost before and after incentives, projected savings, and payback period. Expect to receive the proposal within 1 to 2 weeks of the site visit.

Q: Should homeowners worry if an installer does not do a site assessment?

A: Yes. An installer who skips the in-person site assessment cannot accurately design a system or guarantee performance. Without checking roof condition, structural integrity, shade patterns, and electrical capacity, the proposal is based on assumptions rather than facts. This is one of the clearest red flags when choosing a solar installer.

Last updated: March 2026