Solar panels in Kailua-Kona, HI
Roofs in Kailua-Kona get about 1,253 hours of usable sunlight a year — less than 96% 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 Kailua-Kona → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Kailua-Kona solar system costs
A 26-panel system (10.4 kW) is about right for an average Kailua-Kona home using 10,800 kWh a year. It would produce roughly 11,077 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 3,408 | $6,384 | $1,435 | 4.4 yrs |
| 12 panels | 4.8 kW | 5,112 | $9,576 | $2,152 | 4.4 yrs |
| 16 panels | 6.4 kW | 6,816 | $12,768 | $2,870 | 4.4 yrs |
| 20 panels | 8 kW | 8,520 | $15,960 | $3,587 | 4.4 yrs |
| 26 panels | 10.4 kW | 11,077 | $20,748 | $4,576 | 4.5 yrs |
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 Kailua-Kona gets 1,253 sun hours
That figure comes from Google's analysis of real rooftops across Kailua-Kona — 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 Kailua-Kona reaches about 1,525 hours, roughly 22% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,253 hrs/yr |
|---|---|
| Unshaded roof | 1,525 hrs/yr |
| Electricity rate (Hawaii avg) | 42.1¢/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 | 6 |
| Google imagery from | 2013 |
When Kailua-Kona actually produces
Annual totals hide the thing that catches people out: 29% of Kailua-Kona's yearly sunlight arrives in May–July, and just 20% across November–January.
| Month | Sun hrs | Share of year |
|---|---|---|
| Jan | 83 | |
| Feb | 95 | |
| Mar | 107 | |
| Apr | 116 | |
| May | 120 | |
| Jun | 121 | |
| Jul | 120 | |
| Aug | 117 | |
| Sep | 110 | |
| Oct | 98 | |
| Nov | 86 | |
| Dec | 80 |
Output is unusually steady — only about 1.5× between Jun and Dec. Kailua-Kona 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 Kailua-Kona's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.
How Kailua-Kona compares to the other 673 cities
| Measure | Kailua-Kona | Rank of 673 |
|---|---|---|
| Usable sunlight | 1,253 hrs | 649th |
| Sunlight lost to shade | 18% | 5th most |
| Median roof size | 330 m² | 82nd largest |
| Electricity rate | 42.1¢ | 5th highest |
| Payback | 4.5 yrs | 5th fastest |
| Grid carbon | 699 kg/MWh | 209th dirtiest |
What actually stands out about Kailua-Kona:
- Shading is a real problem here. Kailua-Kona loses 18% of its potential sunlight to trees, chimneys and neighbouring buildings — the 5th-worst of the 673 cities measured. Panel placement matters more here than in most places, and a roof survey is worth more than a phone quote.
- Plenty of roof to work with. Typical roofs here fit around 137 panels — roughly 5× what an average home needs. Roof size will not be what limits your system in Kailua-Kona.
- Dimmer than the rest of Hawaii. Kailua-Kona roofs get 23% less usable sunlight than the typical Hawaii city we've measured — statewide averages will overstate what you can expect here.
- Expensive electricity works in your favour. At 42.1¢/kWh, Hawaii is among the priciest places to buy power — which is exactly what makes generating your own pay back faster.
- Older imagery. Google's aerial capture of Kailua-Kona dates from 2013. Tree growth and new construction since then are not reflected.
Cities with almost the same sunlight
These are the closest matches to Kailua-Kona's 1,253 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 |
|---|---|---|---|
| Grande Prairie, AB | 1,250 | 18.1¢ | 15.1 yrs |
| Gresham, OR | 1,257 | 12.4¢ | 15.4 yrs |
| Federal Way, WA | 1,249 | 11.3¢ | 16.9 yrs |
| Portland, OR | 1,258 | 12.4¢ | 15.4 yrs |
Nearby cities
See all of Hawaii → statewide sunlight, rates, incentives and every city we've measured.
Kailua-Kona solar questions
How many solar panels do I need in Kailua-Kona?
About 26 panels for an average home using 10,800 kWh a year. Kailua-Kona roofs get 1,253 usable sun hours, so each 400W panel produces roughly 426 kWh annually. A typical Kailua-Kona roof fits about 137 panels, so roof space is unlikely to be your limit.
Is solar worth it in Kailua-Kona?
At 42.1¢/kWh and 1,253 sun hours, a typical system pays for itself in about 4.5 years and returns roughly $93,650 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 Kailua-Kona?
A 10.4 kW system costs about $29,640 before incentives and $20,748 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 Hawaii 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.