Where to Put Plug-in Solar Panels: Sun, Shade, and the Best Placement

How to assess your property for solar placement: sun exposure by region, latitude, shade analysis, and optimal angles for US locations.

The Golden Rule: South Facing, Full Sun

Solar panels generate power proportional to sunlight.

The single biggest factor in whether your system is worth it: does your installation spot get 4+ hours of direct sunlight daily?

If yes, you're golden. If no, reconsider.

Understanding Your Latitude

The US spans roughly 25°N (southern Florida) to 48°N (northern Washington state).

Your latitude determines:

How high the sun is in the sky (and thus the optimal panel tilt angle)
How much sun you get daily (varies seasonally)
How seasonal variation affects generation

Sun Path by Latitude

Southern US (25–30°N: Florida, southern Texas, Hawaii)

Summer: Sun reaches nearly overhead (80–90° angle)
Winter: Sun stays lower (40–50° angle)
Daily variation is significant (much more sun in summer)
Optimal panel tilt: 25–30°
Winter generation: 60–70% of summer (significant drop)

Central US (35–40°N: California, Arizona, Tennessee, North Carolina)

Summer: Sun reaches 65–75° above horizon
Winter: Sun at 25–35° angle
Seasonal variation: moderate (25–40% difference summer vs. winter)
Optimal panel tilt: 35–40°
Winter generation: 70–80% of summer (manageable)

Northern US (43–48°N: New York, Great Lakes, Washington, Pacific Northwest)

Summer: Sun reaches 55–65° above horizon
Winter: Sun at 15–25° angle
Seasonal variation: severe (winter is 30–50% of summer)
Optimal panel tilt: 43–48°
Winter generation: 50–70% of summer (significant drop)

Implication: The farther north you are, the more seasonal your solar generation. Summer is fantastic; winter is weak.

This is why Southern California has better solar economics than upstate New York: more consistent year-round sun.

Which Direction Is "South"?

True south, in the Northern Hemisphere, is the direction where the sun is highest at midday.

Use your phone's compass app and note which direction reads "180°" (or "S").

That's true south.

OK directions (also generate well):

SSW (slightly south of southwest): 200°
SSE (slightly south of southeast): 160°
South: 180° (perfect)

Mediocre directions:

SW (southwest): 225° — You'll lose 5–10% generation vs. south
SE (southeast): 135° — You'll lose 5–10% generation vs. south

Bad directions:

East: 90° — You lose 20–30% generation
West: 270° — You lose 20–30% generation
North: 360° — You lose 50%+ generation; don't bother

Why South Matters

In summer (June–July), the sun is nearly overhead. South-facing panels are perpendicular to the sun's rays, capturing maximum power.

East and west-facing panels catch the sun at a 45° angle, so they capture less power.

In winter, south-facing panels tilt toward the lower winter sun and capture it efficiently.

East and west panels? The sun is too low on the horizon (especially in winter), so they capture even less.

Real numbers: An east-facing system might generate 20–30% less annual power than an identical south-facing system in the same location. Over 25 years, that's thousands of dollars in lost savings.

Don't compromise on direction if you can avoid it.

Shade Assessment: The Payback Killer

Shade is the enemy of solar.

Even partial shade—just one corner of a panel blocked—can reduce that panel's output by 20–40% or more.

How to Assess Your Site

Step 1: Walk your property at different times of day

Morning (6–9 AM): Where is the sun? What casts shadows?
Midday (11 AM–1 PM): Is your south-facing spot in sun or shade?
Afternoon (3–5 PM): Still sunny, or is shadow encroaching?

Note: you care mostly about 9 AM–3 PM. This is when the sun is strong and your system generates most power.

Step 2: Check for obstructions

Trees, buildings, fences, and structures block sun.

A large oak tree to the south? It will shade your panels, especially in late afternoon.
A two-story building to the south? It might shade your panels by midday in winter (when the sun is low).
A neighbor's fence? Probably not a big deal unless it's tall and directly south.

Step 3: Assess seasonal shade

The sun's angle changes throughout the year.

In winter, the sun is lower on the horizon. A tree that doesn't shade your panels in summer will shade them in winter.

This is especially problematic if you're in a northern state where winter is already weak for solar. Adding shade to winter makes it worse.

Step 4: Use a solar calculator

PVGIS (EU JRC's Photovoltaic Geographical Information System) lets you upload a photo of your sky and assess shade impact.

Go to pvgis.com. Use the "Sky view" tool:

Take a panoramic photo of your site facing south
Upload it to PVGIS
PVGIS maps the shade and calculates impact

This is more accurate than eyeballing it.

Alternatively, use a simple shadow measurement:

In winter, at midday, does shadow fall on your proposed panel location?

Yes? Shade is a problem; consider a different location.
No? You're good; shade won't be an issue.

Shade Impact Numbers

No shade: 100% output (baseline)
Dappled shade (light tree cover): 80–90% output
Partial shade (1/3 of panel blocked): 60–75% output
Heavy shade (>50% blocked): 30–50% output; consider skipping

A 20% shade impact (e.g., morning shade for 2 hours) might reduce annual output by 10–15%, which extends payback from 5 years to 6 years. Manageable.

A 50% shade impact? That's a deal-breaker. Your payback extends 2+ years. Not worth it.

Roof vs. Balcony vs. Ground

Roof Mounting

Best if:

Roof faces south and has no shade
Roof is structurally sound and not at end-of-life (won't need replacement for 15+ years)
You own the property (not a renter)

Pros:

Maximum sun exposure (nothing blocks you)
Aesthetically clean (not visible from ground)
Occupies no living space

Cons:

Requires roof access and safety equipment
Permanent (can't take it when you move)
Roof damage risk (if not installed carefully)
Older roofs might not be suitable

For homeowners with south-facing roofs, roof mounting is excellent.

Balcony Mounting

Best if:

Balcony faces south
You're a renter or want portability
Balcony gets 4+ hours of direct sun

Pros:

Fully removable
Easy installation (just clamps)
No roof or structural risk

Cons:

Limited space (usually 200–400W max)
Visible and somewhat exposed
Generates less power than roof (smaller system)

For apartment dwellers, balcony mounting is the best option.

Ground Mounting

Best if:

You have a large yard with south-facing space
Ground is level and stable
You want maximum system size

Pros:

Optimal angle adjustment
Easy access for maintenance
Can scale up (add more panels)

Cons:

Takes up yard space
Weather exposure (snow accumulation, wind)
Visible from property

For homeowners with good yards, ground mounting is ideal for larger systems.

Optimal Tilt Angle for Your Latitude

The optimal tilt angle is roughly equal to your latitude.

But don't obsess: anywhere from 25° to 45° is fine. The difference between perfect and slightly off is only 5–10% output.

Quick reference:

Region	Latitude	Optimal Tilt
Florida, Southern Texas	25–30°	25–30°
Southern California, Arizona, New Mexico	32–37°	32–37°
Central US, Texas, Oklahoma	35–40°	35–40°
New York, Pennsylvania, Colorado	40–43°	40–43°
Great Lakes, Minnesota, Washington	43–48°	43–48°

If you're in a state's range, use that angle. If you're between two ranges, split the difference.

Most residential systems use a fixed angle year-round. Some use a steeper angle in winter (for weak winter sun) and shallower in summer, but this requires manual adjustment and adds complexity. Not common for DIY systems.

Special Cases

Very Hot Climates (Arizona, Southern California)

In extreme heat, panels are less efficient. Leave airflow around panels so they can cool.

Don't mount them flush against a roof with no air gap. That traps heat and reduces output.

Very Cold / Snowy Climates (Northern US, Mountain West)

Use steeper angles (40–50°) so snow slides off.

A horizontal or shallow-angle panel in winter accumulates snow, blocking sun entirely.

Keep a snow brush nearby. A quick 5-minute brush-off after heavy snow yields 20–30% output gains for that day.

Coastal Areas (High Wind)

Over-engineer your mounting. Wind can gust, and panels can flex or tip.

Use additional bracing, tie-downs, or ballast.

Checking Your Spot: Checklist

Before finalizing your installation location:

✓ South-facing (within 30° of true south)
✓ 4+ hours of direct sunlight daily (9 AM–3 PM focus)
✓ No shade from trees, buildings, or structures (now or seasonally)
✓ Level, stable ground (if ground-mounted)
✓ Accessible for maintenance and cleaning
✓ Far from foot traffic (won't be bumped or blocked)
✓ Proper tilt angle for your latitude (~equal to your latitude)

If all checked, your site is good.

If one or more fail, reconsider the location or skip solar.

The 80/20 Rule

You don't need perfect placement. You need good placement.

The difference between perfect and pretty-good is small. The difference between pretty-good and bad is huge.

A south-facing spot with 2 hours of afternoon shade? That's 80% of perfect. Still worth doing.

A west-facing balcony with full afternoon sun? That's 70% of perfect. Worth trying.

A north-facing window? That's 30% of perfect. Skip it.

Aim for south-facing, full sun, and you'll be happy.

Next Steps

Found a good spot? See how to install it, or explore balcony or backyard installation guides.