Solar panels in San Marcos: what they cost and what they make
A typical San Marcos home needs 22 solar panels. They would make about 13,477 kWh a year and cost $23k to $35k before incentives. At today's electricity prices they pay for themselves in about 12.6 yrs.
See panels on your own San Marcos roof
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What solar costs in San Marcos
At $3.00 a watt, the median price cash buyers pay nationally, a 9.2 kW system costs about $27,600. Quotes in San Marcos will usually fall between $23,000 and $34,500. 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 San Marcos is what your utility pays for the power you send back. Under full payback is about 12.6 yrs. Under net billing it is about 20.4 yrs, because only the ~43% 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 9.2 kW system in San Marcos
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 | $27,600 | $0 | +$161 | $36k |
| Credit-union loan 8% APR, 20 years, no dealer fee | $0 | $231 | −$70 | $8,100 |
| “1.99%” solar loan 1.99% APR, 25 years, 25% dealer fee | $0 | $146 | +$15 | $20k |
| Lease $155/mo, +2.9%/yr | $0 | $155 | +$25 | $2,300 |
| Power purchase (PPA) 13.7¢/kWh, +2.9%/yr | $0 | $154 | +$27 | $7,100 |
Under net metering, at 16.1¢/kWh rising 2.5% a year. The “1.99%” loan’s $6,900 dealer fee is included in its payments. Lease and PPA prices are typical offers, not quotes.
How much sunshine San Marcos gets
kWh per kW, 25° southAug is the best month for solar in San Marcos, and Dec the weakest: a Dec day makes 69% of a Aug day. A 6 kW system would make about 587 kWh in Dec and 852 kWh in Aug.
On June 21 the sun rises at 6:31 am and sets at 8:35 pm, 14 hours 4 minutes of daylight. On December 21 it is up from 7:23 am to 5:36 pm, just 10 hours 13 minutes.
Peak sun hours in San Marcos, month by month
| Month | Flat ground | Panels at 28° | kWh per kW |
|---|---|---|---|
| Jan | 3.1 | 4.4 | 106 |
| Feb | 3.6 | 4.6 | 100 |
| Mar | 4.5 | 5.1 | 123 |
| Apr | 5.4 | 5.5 | 126 |
| May | 5.9 | 5.5 | 129 |
| Jun | 6.7 | 5.9 | 134 |
| Jul | 6.7 | 6.1 | 140 |
| Aug | 6.4 | 6.2 | 142 |
| Sep | 5.2 | 5.6 | 126 |
| Oct | 4.4 | 5.5 | 128 |
| Nov | 3.3 | 4.6 | 106 |
| Dec | 2.8 | 4.1 | 98 |
| Year | 4.8 | 5.3 | 1,458 |
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 San Marcos
| Roof faces (6/12 pitch) | Output vs south | kWh per kW |
|---|---|---|
| South | 100% | 1,458 |
| Southeast | 97% | 1,414 |
| Southwest | 96% | 1,400 |
| East | 87% | 1,268 |
| West | 86% | 1,254 |
| North | 68% | 991 |
Face panels south and tilt them 28° for the most energy over a year. East and west roofs keep about 87% of that. A north-facing roof keeps 68%, which is rarely worth the money. Try other angles.
Where the sun goes over San Marcos
The noon sun is lower in winter, which is why the best winter tilt (54°) is steeper than the best summer tilt (2°).
San Marcos's homes
San Marcos has 28,013 households. 30.8% own their home, and 7,747 of those owners live in single-family houses, the kind of home that usually gets rooftop solar.
The median home here was built in 2001. Most roofs this young have years of life left, which makes them good candidates for solar.
70.8% of homes heat with electricity and 26.2% 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 San Marcos
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 San Marcos
How much do solar panels cost in San Marcos?
A 9.2 kW system — enough for the average Texas home — costs about $23,000 to $34,500 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 San Marcos need?
About 22 panels of 420 watts for a home using 1,096 kWh a month, the Texas average. Each kilowatt of panels here makes about 1,458 kWh a year on a south-facing roof.
Is solar worth it in San Marcos?
Over 25 years, solar power here costs about 10.6¢ per kWh, against 16.1¢ from the grid today. Payback is about 12.6 yrs if your utility credits exported power at the full retail rate, and 20.4 yrs if it pays about 30% of retail.
How many peak sun hours does San Marcos get?
5.3 a day on panels tilted to 28°, and 4.8 on flat ground. The best month is Aug; the weakest is Dec.
What is the best angle for solar panels in San Marcos?
28° for the most energy over a year, facing south. 54° is best in winter and 2° in summer. On a normal pitched roof, anything within 15° of 28° gives you about 95% of the maximum.
How long would a home battery last in a San Marcos 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 San Marcos
| City | Miles | kWh per kW | Sun hours |
|---|---|---|---|
| Kyle, TX | 9 | 1,462 | 5.3 |
| New Braunfels, TX | 16 | 1,457 | 5.3 |
| Austin, TX | 31 | 1,468 | 5.3 |
| Pflugerville, TX | 44 | 1,466 | 5.3 |
| Cedar Park, TX | 45 | 1,478 | 5.3 |
San Marcos shares a weather-data neighbourhood with New Braunfels; their sunshine numbers differ by less than our data can resolve. Housing, prices and outage figures are specific to San Marcos.
Cities with the same sunshine as San Marcos
These far-away cities get almost exactly as much solar energy per panel.
- Savannah, GA 1,460 kWh per kW
- Lincoln, NE 1,459 kWh per kW
- Deltona, FL 1,458 kWh per kW
Sources: NASA POWER 2001–2020 monthly climatology (grid cell 59 km from San Marcos'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.