Quick answer
Solar Panel Orientation is the compass direction a panel faces, given as an azimuth angle in degrees clockwise from true north: 90° is east, 180° is south and 270° is west.
In the US, a south-facing panel collects the most sunlight over a year. East and west faces still work, at a measurable cost in annual output.
Quick facts
The key facts about solar panel orientation, with sources:
Key takeaways
- Orientation is the compass direction your panels face. Installers write it as azimuth: 180° is due south.
- In the US, south gives the most energy over a year. Southeast and southwest lose under 4% in our Charleston model.
- East and west lose about 13%. That is often still worth doing; you may just need more panels.
- The gap is a winter problem. In May every face makes about the same; in December the east face makes about two-thirds of south.
- North faces lose about 28% at a 20° pitch, and more on steeper roofs. Most installers avoid them.
What orientation means in plain terms
Stand in your yard and look at a roof face straight on. The direction you would face if you lay on that roof, feet to the gutter, is its orientation. Solar designers turn that direction into a number called azimuth.
Azimuth counts degrees around a compass, clockwise from north. North is 0°, east is 90°, south is 180° and west is 270° 2. A roof that faces between south and west might be 200° or 225°.
Orientation and panel tilt work as a pair. Orientation is which way the panels point. Tilt is how steeply they lean. Together they decide how directly the sun hits the panels through the year.
How direction changes the sunlight your panels catch
In the northern half of the world, the sun crosses the southern part of the sky. At noon it sits due south. So a panel tilted toward the south faces the sun more squarely, for more hours, than one facing any other way.
The DOE says that for the highest yearly output, panels in the northern hemisphere should point due south and lean at an angle equal to the local latitude. Its homeowner guide adds that panels usually do best on south-facing roofs, though other roofs may suit too.
The season changes the picture. In winter the sun rises in the southeast, stays low and sets in the southwest. A north face then gets little direct light.
In late spring and summer the sun rises in the northeast and sets in the northwest, and climbs high at noon. Every face then gets plenty of light.
Each roof face, modelled in Charleston, SC
PVWatts V8 runs on 7 October 2026: 7 kW DC, 20° tilt, 14% losses, standard module, fixed roof mount, Charleston (32.78, −79.93). Only the azimuth changes 1.
| Faces | Azimuth | kWh per year | vs south |
|---|---|---|---|
| South | 180° | 10,179 | — |
| Southeast | 135° | 9,803 | −3.7% |
| Southwest | 225° | 9,792 | −3.8% |
| East | 90° | 8,883 | −12.7% |
| West | 270° | 8,869 | −12.9% |
| North | 0° | 7,325 | −28.0% |
Southeast and southwest lose under 4%, which is why installers rarely object to them. The penalty for any face grows with the roof's pitch. A north face on a steep roof loses more than this 20° example.
East and west shift production, not just reduce it
| Month | South | East | West | North |
|---|---|---|---|---|
| January | 710 | 491 | 503 | 247 |
| May | 1,038 | 1,034 | 1,011 | 1,002 |
| June | 962 | 969 | 967 | 972 |
| December | 598 | 406 | 422 | 197 |
What the monthly numbers show
In May and June, every face makes about the same. In this model the north face even edges past south in June, at 972 kWh against 962. The high summer sun lights a gentle north slope well.
The gap opens in winter, when the sun stays low in the south. In December the east face makes about two-thirds of the south face, and the north face about one-third. So orientation mostly decides how much your system helps with winter bills.
Sources: [1]
Types of orientation and what each suits
| Orientation | Azimuth range (approx.) | Best for |
|---|---|---|
| South | About 160°–200° | Most energy over a year |
| Southeast / southwest | About 120°–160° / 200°–240° | Near-south output; southwest leans later in the day |
| East | About 70°–110° | Morning output; fine where exports earn little |
| West | About 250°–290° | Late-afternoon output; may suit time-of-use rates |
| North | About 340°–20° | Only low-pitch or flat roofs, if at all |
| East-west split | Two faces, 90° and 270° | Spreads output across the day on a ridge roof |
Where orientation shows up on your quote
Proposals list azimuth for each roof face, often next to tilt and panel count. A quote might say "Array 1: 12 panels, 185° azimuth, 22° tilt". Permit drawings show the same faces on a roof plan with a north arrow.
Check which north is used. PVWatts and most design tools use true north. A phone compass reads magnetic north.
NOAA explains that the angle between the two, called magnetic declination, changes with place and time, so a compass reading must be corrected to get true north 7.
A few degrees off barely changes output, but large gaps on a quote deserve a question.
Benefits and limits of non-south roofs
Why other faces can still work
- Southeast and southwest lose under 4% in our model.
- East and west still make about 87% of south over a year.
- West faces push output later in the afternoon.
- Using two faces can fit more panels on a small roof.
What you give up
- More panels are needed for the same yearly kWh.
- Winter output drops much more than summer output.
- Mixed faces need separate strings or panel-level electronics.
- North faces rarely pay back on pitched roofs.
Limits: the roof decides, not the installer
On a roof mount, the panels lie flush with the roof, so they face wherever the roof faces. You cannot turn them. A ground mount is the only common way to pick your own direction. Our ground vs roof comparison covers the trade-offs.
When panels sit on more than one face, they should not share one string on a single string inverter. Each face makes power at a different time. Microinverters or optimizers let each panel work on its own 5.
How orientation affects cost and payback
We do not quote dollar prices here. Orientation changes the kWh you get for the money. See cost per watt for current figures.
- More panels for the same kWh. An east or west roof needs roughly 15% more kW to match a south roof, from our Charleston runs.
- Slower payback. The same price buys fewer kWh, so payback stretches. Test it with the payback calculator.
- Extra electronics. Mixed faces may need panel-level electronics, which add parts at each panel 5.
- Lifespan is the same. Direction does not shorten panel life. DOE guidance says systems should produce for at least 30 years 6.
How an installer chooses which faces to use
A licensed installer makes these choices during design. Do not go on the roof to measure it yourself.
- Measure the azimuth and pitch of every roof face, using true north.
- Map shade on each face through the year.
- Model yearly kWh for each face with PVWatts or design software.
- Fill the best faces first, usually south, then southwest and southeast.
- Add east or west faces only if more kWh is needed and the cost per kWh still makes sense.
- Choose string or panel-level electronics to suit the mix of faces.
Maintenance: direction does not change upkeep
Orientation has no effect on routine care. DOE guidance says a roof system has no moving parts and should need no routine maintenance. Rain usually keeps panels clean enough.
One thing to know: north-facing and low-pitch panels may hold snow longer, since they get less winter sun. DOE says you may clear snow from the ground with a long-handled snow rake. Never climb onto the roof.
Sources: [6]
Warning signs on a quote or in your app
Ask your installer about any of these:
- A north-facing array on a pitched roof, with no modelled output shown.
- East and west panels on the same string with a single string inverter.
- Azimuths on the quote that do not match your roof plan.
- Winter output far below the model for your roof faces.
Rules that touch orientation
No building code tells you which way panels must face. Codes and fire rules set walkways and setbacks on each roof face, which can limit how many panels fit on the face you want. Your local building department enforces the codes it has adopted.
Homeowner associations may have rules about panels on street-facing roofs. The DOE notes that many states have solar access laws that stop HOAs from banning or unreasonably restricting solar 3. See our guide to solar access rights by state.
Orientation and peak hours in SC, GA and VA
Where a time-of-use rate prices late-day power higher, a west face shifts some output toward those hours. In South Carolina, Duke Energy Carolinas' Schedule R-STOU sets on-peak hours of 6–9 p.m. on weekdays outside winter 8.
Dominion Energy South Carolina's Rate 5 sets on-peak hours of 4–8 p.m. in summer 9. Most solar output still comes before those hours, so ask for a model of your own bill. In Georgia and Virginia, check your utility's current rates.
Orientation compared with related terms
| Term | What it describes | Unit |
|---|---|---|
| Orientation (azimuth) | Which way the panels face | Degrees from north |
| Tilt | How steeply the panels lean | Degrees from flat |
| Shading | What blocks sunlight from the panels | % loss |
| Irradiance | How strong the sunlight is | W/m² |
| Peak sun hours | Daily sunlight in full-sun hours | hours/day |
Common misconceptions
- Myth Only a south roof is worth covering.
- Reality East and west faces lost about 13% in the Charleston runs. That can still be a good investment; the price per kWh produced is what matters.
- Myth Azimuth on a quote uses magnetic north.
- Reality PVWatts and most design software use true north. A phone compass reads magnetic north; the difference varies by location 7.
- Myth North faces make nothing.
- Reality In our model a north face at 20° made about 72% of south over a year, and slightly more than south in June. Winter is where it falls short.
- Myth West is always better than east.
- Reality Yearly kWh were nearly equal. West only wins where late-day power is worth more on your rate.
When orientation matters to you
Use these rules:
- If you have a south face with little shade, fill it first.
- If your best face is east or west, plan roughly 15% more kW and check the payback.
- If your utility uses time-of-use rates, ask whether a west face fits your bill better.
- If the only free face is north on a pitched roof, consider a ground mount or community solar.
- Next step: size the system with the system size calculator, then read about solar production.
Questions about solar panel orientation
Is east or west better for solar panels?
For total kWh they are close. In our Charleston runs, east made 8,883 kWh a year and west 8,869 kWh. West produces later in the day, which can help if your utility prices late-afternoon power higher. Otherwise, pick the face with less shade and more room.
Can solar panels face north?
They can, but output drops. In our 20° Charleston example, a north face made about 28% less than south over a year, and the loss grows on steeper roofs. Many installers avoid north faces unless the roof is nearly flat, because each panel there pays back slowly.
What azimuth is south for solar panels?
South is 180°, measured clockwise from north. East is 90° and west is 270°. Design tools like PVWatts use true north. If you check with a phone compass, correct for magnetic declination, the gap between magnetic and true north at your location.
Do I need more panels on an east or west roof?
To make the same kWh, yes. In the Charleston example each kW on an east or west face made about 13% less than on a south face. So you would need roughly 15% more capacity to match. Check that the roof has room and your utility's size cap allows it.
Is southwest better than south for solar?
Over a year, south still wins by a little. In our Charleston model, southwest made 9,792 kWh against 10,179 kWh for south, under 4% less. Southwest shifts some output later in the day, which may suit a time-of-use rate. Ask for a model of your own bill.
Should I split panels between east and west roofs?
It can make sense on a ridge roof with no south face. Each face then makes power at a different time of day, spreading output from morning to late afternoon. Use separate strings or panel-level electronics so one face does not hold back the other.
Does orientation matter more in winter?
Yes. In our Charleston model, all faces made about the same in May and June. In December, east made about two-thirds of south and north about one-third. If winter bills matter most to you, a south face matters most.
How do I find my roof's orientation?
Use an online map to see which way each roof face points, or ask the installer's site survey. Design tools measure azimuth from true north. If you use a phone compass, NOAA's calculator gives the magnetic declination to correct the reading. Do not climb on the roof to check.
Can I change the direction of panels on my roof?
Not on a normal flush roof mount. The panels follow the roof's own direction. Tilted racks on flat roofs and ground mounts are the exceptions, since the installer can aim them. Our ground mount guide covers when that is worth it.
Sources
- PVWatts V8 API runs by HyreSolar, 7 October 2026 (Charleston SC, 7 kW, standard module, roof mount, tilt 20°, azimuth varied, losses 14%, NSRDB PSM V3 TMY), retrieved .
- NLR (formerly NREL), PVWatts V8 API documentation, retrieved .
- U.S. DOE Solar Energy Technologies Office, Homeowner's Guide to Going Solar, retrieved .
- US DOE Solar Energy Technologies Office, Solar Photovoltaic System Design Basics, retrieved .
- US DOE Solar Energy Technologies Office, Solar Integration: Inverters and Grid Services Basics, retrieved .
- US DOE Weatherization Assistance Program, Solar Frequently Asked Questions, retrieved .
- NOAA National Centers for Environmental Information, Magnetic Declination, retrieved .
- Duke Energy Carolinas (SC), Schedule R-STOU, retrieved .
- Dominion Energy South Carolina, Rate 5 Time-of-Use Residential, retrieved .
Expert review
Written by the HyreSolar Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Every output figure is a PVWatts V8 result for the stated inputs; percentages are computed from them.
Azimuth convention from the PVWatts documentation; due-south and latitude guidance from DOE; declination from NOAA. Time-of-use hours are from the Duke and Dominion tariffs held in sc-local/facts.js. The azimuth ranges in the types table are our own grouping.
Suggest a correction. We fix errors and say what changed.