Solar panels in Key West, FL
Roofs in Key West get about 1,919 hours of usable sunlight a year — more than 90% of the cities we've measured. Here's what that means in cost, savings and payback, using real rooftop data rather than a national average.
Check your specific roof in Key West → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Key West solar system costs
A 17-panel system (6.8 kW) is about right for an average Key West home using 10,800 kWh a year. It would produce roughly 11,092 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 5,220 | $6,384 | $799 | 8 yrs |
| 12 panels | 4.8 kW | 7,830 | $9,576 | $1,198 | 8 yrs |
| 16 panels | 6.4 kW | 10,439 | $12,768 | $1,597 | 8 yrs |
| 20 panels | 8 kW | 13,049 | $15,960 | $1,738 | 9.2 yrs |
| 26 panels | 10.4 kW | 16,964 | $20,748 | $1,888 | 11 yrs |
How we worked this out for Key West
Every number on this page comes from these seven steps. Nothing is a national average — the sunlight figure is measured from Key West rooftops.
| # | Step | Result |
|---|---|---|
| 1 | What one panel makes here 400W ÷ 1000 × 1,919 sun hrs × 0.85 system losses |
652 kWh/yr |
| 2 | Panels needed to cover typical usage 10,800 kWh ÷ 652 kWh per panel |
17 panels |
| 3 | System size 17 panels × 400W |
6.80 kW |
| 4 | Annual production 6.80 kW × 1,919 hrs × 0.85 |
11,092 kWh/yr |
| 5 | Installed cost 6,800 W × $2.85 per watt, then −30% federal credit |
$13,566 |
| 6 | Annual saving 3,780 kWh used as generated × 15.3¢ + 7,312 kWh exported × 15.3¢ |
$1,664/yr |
| 7 | Payback $13,566 ÷ $1,664 per year |
8.2 years |
Step 6 matters more than it looks. Only 34% of what a system this size produces in Key West is used the moment it is generated; the other 7,312 kWh is exported and credited one-for-one under net metering. Because exports here are credited at or near retail, that split changes the payback very little — 8.0 years against the 8.2 we show. In places where exports pay a fraction of retail the same split moves payback by years, which is why we model it explicitly rather than assuming.
Assumptions: 400W panels, 15% system losses (inverter, wiring, heat, soiling), $2.85/W installed, 10,800 kWh typical annual household use, 15.3¢/kWh electricity. Change any of those and every figure above moves — which is exactly why a single national "solar costs X" number is misleading.
Notice that payback barely improves as systems get bigger, and eventually gets worse. That's because you can only save money on electricity you were going to buy anyway. Once a system covers your usage, extra panels mostly generate exports at a much lower rate.
Why Key West gets 1,919 sun hours
That figure comes from Google's analysis of real rooftops across Key West — it already accounts for shading from trees, chimneys and neighbouring buildings, which is why it's lower than the raw "hours of daylight" figures you'll see elsewhere. An unusually open, unshaded roof in Key West reaches about 1,957 hours, roughly 2% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,919 hrs/yr |
|---|---|
| Unshaded roof | 1,957 hrs/yr |
| Electricity rate (Florida avg) | 15.3¢/kWh |
| Installed cost assumed | $2.85/W |
| Panel size assumed | 400 W |
| Federal tax credit | 30% |
| Typical household usage | 10,800 kWh/yr |
| Power used as generated | 34% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 10 |
| Google imagery from | 2018 |
When Key West actually produces
Annual totals hide the thing that catches people out: 30% of Key West's yearly sunlight arrives in May–July, and just 18% across November–January.
| Month | Sun hrs | Share of year |
|---|---|---|
| Jan | 118 | |
| Feb | 139 | |
| Mar | 162 | |
| Apr | 182 | |
| May | 193 | |
| Jun | 196 | |
| Jul | 194 | |
| Aug | 186 | |
| Sep | 169 | |
| Oct | 145 | |
| Nov | 123 | |
| Dec | 112 |
Output is unusually steady — only about 1.7× between Jun and Dec. Key West is close enough to the equator that seasonal variation is mild, which makes sizing a system considerably more predictable.
The annual total is measured from Google's rooftop imagery. Its split across months is calculated from solar geometry at Key West's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.
How Key West compares to the other 788 cities
| Measure | Key West | Rank of 788 |
|---|---|---|
| Usable sunlight | 1,919 hrs | 77th |
| Sunlight lost to shade | 2% | 722nd most |
| Median roof size | 337 m² | 70th largest |
| Electricity rate | 15.3¢ | 401st highest |
| Payback | 8.2 yrs | 116th fastest |
| Grid carbon | 541 kg/MWh | 476th dirtiest |
What actually stands out about Key West:
- Unusually open roofs. Only 2% of available sunlight is lost to obstruction in Key West — better than all but 66 of the 788 cities measured. Most roofs here get close to their theoretical maximum.
- Plenty of roof to work with. Typical roofs here fit around 102 panels — roughly 6× what an average home needs. Roof size will not be what limits your system in Key West.
- Large roofs. At a median of 337 m², Key West has the 70th-largest typical roof footprint we've measured.
- Sunnier than the rest of Florida. Key West roofs get 8% more usable sunlight than the typical Florida city we've measured — statewide averages will understate what you can expect here.
- Older imagery. Google's aerial capture of Key West dates from 2018. Tree growth and new construction since then are not reflected.
Cities with almost the same sunlight
These are the closest matches to Key West's 1,919 usable sun hours from other states and provinces. Same sunlight, different electricity prices — which is usually what decides whether solar is worth it.
| City | Sun hrs | Rate | Payback |
|---|---|---|---|
| Jurupa Valley, CA | 1,920 | 31.2¢ | 8.3 yrs |
| Fairfield, CA | 1,917 | 31.2¢ | 8.3 yrs |
| Irvine, CA | 1,924 | 31.2¢ | 8.3 yrs |
| Glendale, CA | 1,914 | 31.2¢ | 8.3 yrs |
Nearby cities
See all of Florida → statewide sunlight, rates, incentives and every city we've measured.
Key West solar questions
How many solar panels do I need in Key West?
About 17 panels for an average home using 10,800 kWh a year. Key West roofs get 1,919 usable sun hours, so each 400W panel produces roughly 652 kWh annually. A typical Key West roof fits about 102 panels, so roof space is unlikely to be your limit.
Is solar worth it in Key West?
At 15.3¢/kWh and 1,919 sun hours, a typical system pays for itself in about 8.2 years and returns roughly $28,023 over a 25-year panel life. That is a solid return, and it improves further if electricity prices rise. Exported power earns full retail credit here.
How much do solar panels cost in Key West?
A 6.8 kW system costs about $19,380 before incentives and $13,566 after the 30% federal tax credit. That works out near $2.85 per watt installed. Roof pitch, shading, electrical panel upgrades and equipment choice move the price most, which is why quotes for the same house can differ by thousands.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Florida electricity rates. Not a quote and not financial advice. Your roof, usage, utility plan and local incentives will change these numbers — get real quotes before buying.