How to Assess Your Home for Solar 2026: Roof, Shade, and Energy Guide

Before you request a single solar quote, the smartest thing you can do is a 30-minute self-assessment of your home's solar potential. Installers who know you've done your homework quote more accurately — and homeowners who understand their own site avoid the most common sizing mistakes.

This guide walks you through five dimensions of a residential solar assessment: roof condition and geometry, shade exposure, electricity usage, electrical system readiness, and net metering eligibility. At the end, you'll know whether your home is a strong, marginal, or weak solar candidate — and exactly what to tell installers when they arrive.

---

Part 1: Roof Assessment

Orientation

In the continental United States, south-facing roofs produce the most solar energy — typically 15–25% more than east- or west-facing roofs, and 35–40% more than north-facing roofs. The sun tracks an arc from east to west across the southern sky, making true south the sweet spot.

How to check your orientation: Google Maps' satellite view shows your roof in relation to compass directions. Alternatively, a compass app on your phone placed flat on the roof surface gives a precise reading. Look for roof faces with azimuths between 135° and 225° (true south = 180°). Southwest (135°–180°) and southeast (180°–225°) faces are both workable; a 10° deviation from true south reduces annual production by roughly 1–2%.

East/west split systems: If your best roof faces are east and west, installers can put panels on both sides. You lose some efficiency vs. south, but the production curve becomes more useful: east panels peak in the morning, west panels in the afternoon, which aligns better with peak electricity pricing in many states.

North-facing roofs: Generally not viable unless your electricity rate is extremely high and you have no other option. A north-facing 6 kW system in Atlanta might produce what a 4 kW south-facing system produces, making the math unfavorable in most markets.

Pitch (Tilt Angle)

Solar panels produce best at a tilt equal to your latitude — roughly 25°–45° for most U.S. locations. Typical U.S. residential roofs range from 4:12 to 8:12 pitch (18°–34°), which falls comfortably within the productive range.

• Flat roofs (0°–5° pitch): Possible but require ballasted racking to tilt panels to at least 10°; ground-water pooling on flat-mounted panels accelerates soiling.
• Steep roofs (>45°): Production is somewhat reduced but more self-cleaning; installation is harder and more expensive (up to 20% labor premium).
• Standard roofs (15°–35°): No tilt adjustment needed; direct mount to the existing pitch.

Roof Age and Condition

Solar panels are designed to last 25–30 years and are installed with mounts that penetrate the roofing membrane. If your roof is more than 10 years old, get a roofing inspection before or during the solar quote process. Installing solar on a roof that needs replacement within 5 years means paying $3,000–$8,000 to remove and reinstall the solar array when the roof is replaced.

Signs you should replace the roof first:

• Missing, curling, or cracking shingles
• Visible water damage, dark stains, or moss on shingles
• Daylight visible in the attic
• Granule loss visible in gutters (sign of advanced shingle wear)
• Roof age > 15 years with asphalt shingles (typical lifespan: 20–25 years)

If you're replacing the roof anyway, do it before your solar installation — many installers offer a bundled roof + solar discount, and you avoid the future removal/reinstall cost. Some states (CA, NY, MA) allow you to add the roof repair cost to the ITC basis if the work is directly required for the solar installation. The federal solar tax credit guide explains what's eligible.

Roof Material

Most roof materials work fine for solar installation. A few exceptions:

Roof Type	Solar Compatibility	Notes
Asphalt shingles	Excellent	Standard mount, least expensive installation
Metal standing seam	Excellent	Clamp mounts with no penetrations; best for hail areas
Metal corrugated	Good	Penetrating mounts needed; still common
Concrete tile	Good	L-foot mounts work; some tiles must be replaced during install
Clay/ceramic tile	Moderate	Brittle; higher labor cost; skilled installers needed
Slate	Difficult	Extremely fragile; steep labor premium; few installers qualified
Flat membrane (TPO/EPDM)	Good	Ballasted racking required; usually for ground-floor flat roofs
Wood shingles/shake	Poor	Fire risk; many local codes prohibit penetrating mounts

The best roof types for solar guide has a full breakdown of installation compatibility, structural load ratings, and cost implications by roof type.

Available Roof Area

A rough rule of thumb: each kW of solar capacity requires approximately 65–80 square feet of unobstructed roof space (accounting for panel size + spacing between rows). A standard 8 kW residential system needs 520–640 square feet.

What to exclude from your measurement:

• HVAC equipment, satellite dishes, and vents (panels can't be installed within 3 feet of these under NEC 2023)
• Skylights and dormer windows
• Chimney setback (typically 2 feet clearance required)
• Ridge setback (typically 18–24 inches from ridge under most codes)
• Fire access pathways (code typically requires 3-foot clear paths on hip roofs; 18-inch clear ridge on gable roofs)

If your usable roof area is below 400 square feet after all exclusions, talk to your installer about high-efficiency panel options (HJT or IBC panels at 21–23% efficiency produce more per square foot) or consider a ground-mount system. The solar panels for small roofs guide covers both angles in detail.

---

Part 2: Shade Analysis

Shading is the most significant factor that separates a strong solar site from a marginal one. Even partial shading — one branch crossing a corner of one panel — can reduce the output of an entire string inverter circuit by 30% or more.

Self-Assessment: Walk Your Roof Line

Stand in your yard and look at your roof at different times of day:

• Early morning (7–9 AM): Note what's casting shadows across the roof face.
• Solar noon (roughly 12–1 PM): This is peak production time — shadows here are most costly.
• Late afternoon (3–5 PM): Note if western trees shadow panels as the sun shifts west.

In winter, the sun is lower in the sky — shadows are 2–3× longer. What barely grazes the roof edge in July may cover large roof sections in December. If you have tall trees to the south or southwest that lose their leaves, you may have a "winter shading problem" that doesn't show up in summer assessments.

The 20% Rule

A rough industry guideline: if more than 20% of your available roof area is shaded for more than 2 hours during peak sun hours (roughly 10 AM–3 PM), your system economics will be meaningfully impacted and you should discuss shade mitigation strategies with your installer.

Shade Mitigation Tools

Microinverters and power optimizers: The single most effective solution to shade problems. By giving each panel its own power conversion (microinverters) or maximum power point tracking (power optimizers), you prevent one shaded panel from dragging down the rest of the array. A 10–20% shading loss with a string inverter may drop to 2–5% with microinverters. See the microinverters vs. string inverters guide for cost and performance analysis.

Tree trimming: If the shading source is trees on your property, get an arborist assessment before your solar quote. Trimming costs $200–$800 per tree; removal costs $500–$2,500 depending on size. Some of this cost may be includable in the solar project cost for ITC purposes if the shade prevents viable installation.

System repositioning: Sometimes moving the array from a shaded south face to a less-ideal but less-shaded west face produces more energy overall. Your installer will run production estimates for multiple configurations.

Professional Shade Analysis Tools

Installers typically use one or more of the following tools to quantify shade:

PVWatts (NREL): A free tool that models annual production based on system size, tilt, azimuth, and location. Does not model shade directly, but allows you to input a derate factor for shading losses (industry standard: 0.97 for minimal shade, 0.85–0.90 for moderate shade).

Solargraf / Aurora Solar: Professional software that imports satellite roof models and runs shading simulations by hour throughout the year. Outputs a "shade report" showing annual production loss from shade by panel location. Ask your installer to share this report with you.

SunEye / Solar Pathfinder: Physical devices placed on the roof that photograph the horizon and overlay the sun's path throughout the year. A shade factor of 0.90+ (≥90% of available sunlight) is generally considered a good solar site; 0.80–0.89 is workable; below 0.80 produces unfavorable economics.

LiDAR mapping: Some installers use aerial LiDAR data to build precise 3D models of nearby trees and structures for accurate shade simulation without sending a technician to the roof.

---

Part 3: Electricity Usage Baseline

Understanding your actual electricity usage is essential for sizing your solar system correctly. There are three common sizing mistakes caused by insufficient usage data:

1. Over-sizing by using peak summer bills (especially in AC-heavy climates) — results in a system that produces more than you can use in winter, with surplus lost at avoided-cost rates.
2. Under-sizing by using winter bills (in heating-dominant homes) — results in a system that covers less of your annual usage than expected.
3. Ignoring planned future loads — adding an EV, heat pump, or pool in the next 2–3 years will change your usage significantly.

How to Read Your Electricity Bill for Solar Sizing

Find your annual kWh consumption — not your monthly bill amount, but the actual kilowatt-hour usage. Your bill should show:

• Monthly kWh used (often on the billing summary page)
• 12-month rolling average or total (many utilities display this; otherwise add up 12 monthly bills)
• Rate schedule (flat, tiered, time-of-use — affects net metering value significantly)
• Distribution and supply charges (only the supply/energy portion is offset by solar; fixed distribution fees continue)

Most U.S. homes use 10,000–15,000 kWh per year. High-usage homes (large square footage, electric heat, pool, or EV) may exceed 20,000 kWh.

The Self-Sizing Formula

Once you have annual kWh:

System size (kW) = Annual kWh ÷ (Peak sun hours/day × 365 × 0.80)

The 0.80 factor accounts for inverter efficiency, wiring losses, and temperature derating. Peak sun hours by state range from 3.5–4.5 in the Pacific Northwest to 5.5–6.5 in the Desert Southwest. The how many solar panels do I need calculator guide walks through this step-by-step with regional sun hour tables.

For a quick automated calculation, the Solar System Designer takes your monthly usage and state and outputs a recommended system size, panel count, and bill-of-materials estimate.

Accounting for Future Loads

If you plan to add any of the following within 5 years, estimate the additional kWh demand and include it in your system sizing:

Addition	Typical Annual kWh Impact
Electric vehicle (15,000 mi/year)	+3,000–5,000 kWh
Air-source heat pump (replaces gas furnace)	+2,000–5,000 kWh (offset by gas savings)
Heat pump water heater (replaces electric resistance)	−900–1,200 kWh (more efficient)
Pool pump (gas → variable speed electric)	+2,000–4,000 kWh
Home addition (500 sq ft)	+1,500–2,500 kWh
EV + heat pump (combined)	+4,000–9,000 kWh

The solar panels and EV charging guide covers the combined sizing strategy and IRA credit stacking for adding solar and an EV simultaneously.

---

Part 4: Electrical System Readiness

Your home's electrical system must be able to accommodate solar without a full rewire, though upgrades may be needed. Understanding this before getting quotes helps you budget correctly and avoid sticker shock.

Main Electrical Panel

Solar inverters connect to your main electrical panel. Two requirements must be met:

1. Sufficient breaker capacity under the 120% rule: NEC 690.64 limits the total amperage of all breakers (including the new solar breaker) to 120% of the main panel's rated capacity. Practically:

Maximum solar breaker = (Panel rating × 120%) − Main breaker rating

Example: A 200A panel with a 200A main breaker can accommodate up to a 40A solar breaker (200 × 1.20 − 200 = 40A), which supports roughly a 9–10 kW solar system.

If your panel is maxed out (or close), you have options:

• Main breaker downsizing: Many utilities allow reducing the main breaker to 175A, which frees up capacity without a panel upgrade.
• Load-side connection at lower amperage: Some solar inverters can connect below the main breaker.
• Panel upgrade: A 100A → 200A panel upgrade costs $1,500–$3,000 and resolves all capacity issues.

2. Panel age and condition: Panels older than 25 years may not accept new breakers (discontinued bus systems), may have known safety issues (Federal Pacific Stab-Lok, Zinsco — these should be replaced regardless of solar plans), or may fail inspection. If your main panel is pre-1990 vintage, budget for a possible panel replacement.

Grounding

Modern solar installations require proper grounding equipment and, in some jurisdictions, an updated grounding electrode system. If your home has aluminum wiring (common in homes built 1965–1973), mention this to your installer — it affects hardware choices and may require additional work.

Sub-panel Needs

Homes with detached garages, workshops, or outbuildings may need to run conduit to enable whole-home coverage, or may want a dedicated circuit for battery storage or EV charging. Discuss your full energy layout with installers and ask what conduit/sub-panel work is included in the quote vs. billed separately.

The hidden solar installation costs guide covers the full range of electrical upgrade costs you might encounter in a solar project, with cost tables by type of upgrade.

---

Part 5: Net Metering Eligibility Check

The financial value of solar depends heavily on whether you have access to retail-rate net metering — the policy that credits you at the full retail electricity rate for every excess kWh you send back to the grid. Without retail-rate net metering, your self-consumption optimization strategy changes, and system sizing rules shift.

How to Check Your Net Metering Status

Step 1: Identify your utility company from your electricity bill. Note whether it's an investor-owned utility (IOU), a municipal utility, or a rural electric cooperative (co-op).

Step 2: Check your state's net metering status:

• Most states have retail-rate net metering for IOUs by law.
• Several states (California, Indiana, Tennessee/TVA territory, Mississippi/Alabama) have moved to avoided-cost export rates ($0.03–$0.07/kWh vs. retail $0.12–$0.28/kWh) — this changes the system design significantly.
• Rural co-ops are often exempt from state net metering mandates — always call your co-op directly to confirm their buyback rate.

Step 3: Ask your installer for the specific form and process to register for net metering at your utility. Registration sometimes has a wait list (Xcel Energy in CO and MN have historically had queues), and the application must be submitted before the system can be energized.

The net metering guide explains retail-rate vs. avoided-cost credits, how annual true-up works, and what net metering policy risk means for your state. For state-specific net metering rules, the all 50 state solar incentives hub links to each state's dedicated guide.

System Sizing Under Different Net Metering Structures

Retail-rate net metering (most states): Size to 100–105% of annual usage. Excess production earns near-retail value at year-end true-up.

Avoided-cost export (CA NEM 3.0, IN, TN TVA, AL, MS): Size to 85–90% of annual usage and pair with battery storage to maximize self-consumption. Sending excess to the grid earns $0.03–$0.05/kWh — not worth oversizing for.

Time-of-use rates: If your utility has TOU pricing, the value of exported solar depends heavily on what time of day you're producing vs. consuming. Battery storage to shift solar production into peak-rate hours (typically 4–9 PM) dramatically improves economics. See the TOU rates and solar guide for a full optimization strategy.

---

Your Solar Self-Assessment Scorecard

Use this quick scoring system to summarize your home's solar suitability:

Factor	Strong (2 pts)	Workable (1 pt)	Challenging (0 pts)
Roof orientation	South-facing	SE or SW	East or West
Roof condition	≤ 10 years old	10–17 years	> 17 years
Shade at solar noon	< 5% coverage	5–20% coverage	> 20% coverage
Annual kWh usage	8,000–18,000	> 18,000 or < 6,000	Unable to determine
Electrical panel	200A, < 25 yrs	100A or upgrades needed	Fuse box / known issue
Net metering access	Retail-rate	Avoided cost, battery viable	No NEM, no battery

Scoring:

• 10–12 points: Excellent solar site. Expect a straightforward installation and strong economics.
• 7–9 points: Good site with addressable challenges. Get 3 quotes and discuss specific concerns.
• 4–6 points: Marginal site. Request detailed shade analysis and panel-by-panel production estimates before committing.
• 0–3 points: Challenging site. Community solar or portable solar may be better options.

---

What to Tell Your Installer Before the Site Visit

Once you've completed this self-assessment, you can give installers the information they need to quote accurately — without waiting for their site visit. A well-prepared homeowner gets faster, more accurate quotes.

Share with installers:

1. Your roof orientation(s), pitch, and age (from the Part 1 assessment)
2. Any shading sources (trees, adjacent structures, HVAC equipment)
3. 12 months of electricity bills or your annual kWh total
4. Your main panel amperage and age
5. Any planned additions: EV, heat pump, pool
6. Whether your utility offers retail-rate net metering (and what rate schedule you're on)
7. The state solar incentives you're interested in claiming (especially SREC, SMART, or RSIP programs that require installer certification)

Providing this information upfront filters out installers who don't read it (a red flag) and lets the ones who do come prepared with accurate sizing proposals.

---

Tools and Next Steps

Free tools to supplement your self-assessment:

• Solar ROI Calculator: Input your state, monthly bill, and roof quality to get a personalized payback period and 25-year savings estimate.
• Solar System Designer: Generate a complete bill-of-materials for a DIY or informed-buyer system estimate based on your usage and state.
• Solar Financing Calculator: Compare cash, loan, and lease total costs over 25 years to find your optimal financing path.

Next steps in the buyer journey:

1. Complete this self-assessment → know your solar potential before calling anyone
2. Find and vet local installers → 3 quotes minimum from NABCEP-certified installers
3. Learn how to read a solar quote → decode every line before signing
4. Compare quotes side-by-side → $4,000+ savings potential
5. Understand your financing options → cash vs. loan vs. lease 25-year math
6. File IRS Form 5695 → step-by-step walkthrough after installation

---

Frequently Asked Questions

Can I do this assessment without getting on my roof? Yes. Roof orientation can be determined from Google Maps or a compass app. Shade can be observed from the yard at different times of day. Roof condition can be estimated from the street or with binoculars. The electrical panel is in your home. Net metering status comes from your utility bill and a phone call. The only item that truly requires roof access is a professional shade analysis — which your installer will conduct during the site visit.

How accurate are the results without professional tools? Accurate enough for a go/no-go decision. Professional tools add precision but rarely change the fundamental site viability assessment. If this guide shows your home scores 10+ points, professional analysis will confirm it. If you score 2 points, professional analysis won't overcome structural site challenges.

What if my HOA might block my installation? Check your state's solar access laws before investing time in the assessment process. Most states (California, Texas, Florida, New York, Colorado, and 20+ others) void HOA prohibitions on solar panels. The HOA solar rights guide has a complete state-by-state breakdown and a template HOA request letter.

Should I get a home energy audit before going solar? It's worth considering. An energy audit ($300–$600, or free in some states through utility programs) identifies air sealing, insulation, and HVAC efficiency improvements that could reduce your annual kWh consumption by 15–25% — potentially letting you install a smaller, cheaper solar system. However, most homeowners don't do this and still get good results. If your energy bills feel high relative to your home size, an audit makes more sense before committing to solar.

Does my home need a battery to go solar? Not in most states. If you have standard retail-rate net metering, a grid-tied solar system without battery storage delivers 90–95% of the financial benefit of the same system with battery. Battery storage becomes financially compelling if you have: (1) time-of-use rates with high peak charges, (2) avoided-cost net metering (CA NEM 3.0, IN, TN, AL, MS), (3) frequent power outages, or (4) desire for whole-home backup. The battery backup vs. generator guide breaks down the economics of each resilience option.