Solar panels in Knoxville: what they cost and what they make
A typical Knoxville home needs 25 solar panels. They would make about 13,852 kWh a year and cost $26k to $39k before incentives. At today's electricity prices they pay for themselves in about 16.0 yrs.
See panels on your own Knoxville roof
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What solar costs in Knoxville
At $3.00 a watt, the median price cash buyers pay nationally, a 10.5 kW system costs about $31,500. Quotes in Knoxville will usually fall between $26,250 and $39,375. Complex roofs, main-panel upgrades and financing push prices up.
The 30% federal tax credit no longer applies to systems homeowners buy. This estimate includes no state or utility incentives; check with your utility before you buy.
The number that decides whether solar pays in Knoxville is what your utility pays for the power you send back. Under full payback is about 16.0 yrs. Under net billing it is about 25+ yrs, because only the ~44% of solar a typical home uses as it is made saves the full retail price.
Cash purchase, prices rising 2.5% a year, panels losing 0.5% a year, $25/kW a year for upkeep. No federal credit for homeowner-owned systems.
Every way to pay for a 10.5 kW system in Knoxville
Change any number →| Way to pay | Day one | Monthly payment | Monthly net, year 1 | Ahead after 25 years |
|---|---|---|---|---|
| Pay cash Full price on install day | $31,500 | $0 | +$138 | $23k |
| Credit-union loan 8% APR, 20 years, no dealer fee | $0 | $263 | −$125 | −$8,400 |
| “1.99%” solar loan 1.99% APR, 25 years, 25% dealer fee | $0 | $167 | −$28 | $4,900 |
| Lease $135/mo, +2.9%/yr | $0 | $135 | +$25 | $3,100 |
| Power purchase (PPA) 11.8¢/kWh, +2.9%/yr | $0 | $136 | +$24 | $6,400 |
Under net metering, at 13.9¢/kWh rising 2.5% a year. The “1.99%” loan’s $7,875 dealer fee is included in its payments. Lease and PPA prices are typical offers, not quotes.
How much sunshine Knoxville gets
kWh per kW, 25° southMay is the best month for solar in Knoxville, and Dec the weakest: a Dec day makes 58% of a May day. A 6 kW system would make about 454 kWh in Dec and 783 kWh in May.
On June 21 the sun rises at 6:19 am and sets at 8:55 pm, 14 hours 36 minutes of daylight. On December 21 it is up from 7:42 am to 5:25 pm, just 9 hours 43 minutes.
Peak sun hours in Knoxville, month by month
| Month | Flat ground | Panels at 33° | kWh per kW |
|---|---|---|---|
| Jan | 2.3 | 3.6 | 84 |
| Feb | 2.9 | 3.9 | 84 |
| Mar | 4.0 | 4.8 | 113 |
| Apr | 5.3 | 5.5 | 126 |
| May | 5.8 | 5.5 | 131 |
| Jun | 6.2 | 5.6 | 128 |
| Jul | 5.9 | 5.4 | 127 |
| Aug | 5.5 | 5.5 | 126 |
| Sep | 4.7 | 5.4 | 118 |
| Oct | 3.7 | 5.0 | 113 |
| Nov | 2.8 | 4.4 | 95 |
| Dec | 2.0 | 3.3 | 76 |
| Year | 4.3 | 4.8 | 1,319 |
A peak sun hour is one hour of sunlight at 1,000 W per m². Why sites disagree.
The best angle and direction for panels in Knoxville
| Roof faces (6/12 pitch) | Output vs south | kWh per kW |
|---|---|---|
| South | 100% | 1,319 |
| Southeast | 96% | 1,266 |
| Southwest | 95% | 1,253 |
| East | 85% | 1,121 |
| West | 84% | 1,108 |
| North | 64% | 844 |
Face panels south and tilt them 33° for the most energy over a year. East and west roofs keep about 85% of that. A north-facing roof keeps 64%, which is rarely worth the money. Try other angles.
Where the sun goes over Knoxville
The noon sun is lower in winter, which is why the best winter tilt (58°) is steeper than the best summer tilt (7°).
Knoxville's homes
Knoxville has 86,263 households. 46.6% own their home, and 38,155 of those owners live in single-family houses, the kind of home that usually gets rooftop solar.
The median home here was built in 1974. Many roofs that age are due for replacement. Replace the roof first, then add solar: taking panels off and putting them back later costs thousands.
74.9% of homes heat with electricity and 23.7% with gas. Electric heat raises winter use, so size solar to your own bills rather than the state average.
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates.
If the power goes out in Knoxville
Solar panels alone shut off in a blackout. Add a battery and they keep going. One Tesla Powerwall 3 (13.5 kWh) running a fridge, freezer, furnace fan, lights, Wi-Fi, TV and microwave (6.9 kWh a day):
Change the appliances, the battery and the weather in the battery calculator.
Questions people ask about solar in Knoxville
How much do solar panels cost in Knoxville?
A 10.5 kW system — enough for the average Tennessee home — costs about $26,250 to $39,375 before incentives, based on $2.50–$3.75 per watt. The 30% federal credit no longer applies to systems homeowners buy.
How many solar panels does a house in Knoxville need?
About 25 panels of 420 watts for a home using 1,154 kWh a month, the Tennessee average. Each kilowatt of panels here makes about 1,319 kWh a year on a south-facing roof.
Is solar worth it in Knoxville?
Over 25 years, solar power here costs about 11.7¢ per kWh, against 13.9¢ from the grid today. Payback is about 16.0 yrs if your utility credits exported power at the full retail rate, and 25+ yrs if it pays about 30% of retail.
How many peak sun hours does Knoxville get?
4.8 a day on panels tilted to 33°, and 4.3 on flat ground. The best month is Jun; the weakest is Dec.
What is the best angle for solar panels in Knoxville?
33° for the most energy over a year, facing south. 58° is best in winter and 7° in summer. On a normal pitched roof, anything within 15° of 33° gives you about 95% of the maximum.
How long would a home battery last in a Knoxville power outage?
A Tesla Powerwall 3 running a fridge, freezer, furnace fan, lights, Wi-Fi, TV and microwave (6.9 kWh a day) lasts about 43 hours with no sun. With 7 kW of solar to recharge it, it gets through a three-day outage even in overcast January.
Solar near Knoxville
| City | Miles | kWh per kW | Sun hours |
|---|---|---|---|
| Cleveland, TN | 75 | 1,342 | 4.9 |
| Asheville, NC | 83 | 1,383 | 5.0 |
| Kingsport, TN | 87 | 1,326 | 4.8 |
| Johnson City, TN | 91 | 1,340 | 4.8 |
| Chattanooga, TN | 96 | 1,342 | 4.9 |
Cities with the same sunshine as Knoxville
These far-away cities get almost exactly as much solar energy per panel.
- Madison, WI 1,331 kWh per kW
- Rockford, IL 1,326 kWh per kW
- Janesville, WI 1,326 kWh per kW
Snow: NASA records about 8 cm of snow on the ground here in an average January. Covered panels make little until it slides off, and these figures (like PVWatts') don't subtract that.
Sources: NASA POWER 2001–2020 monthly climatology (grid cell 66 km from Knoxville's Census point), our PV model (within 1.6% of NLR PVWatts® on average), U.S. EIA prices and use, U.S. Census 2025 population estimates and ACS 2020–2024. Estimates for an average home, not a site survey. How we calculate.