Solar panels in Castle Rock: what they cost and what they make
A typical Castle Rock home needs 12 solar panels. They would make about 8,209 kWh a year and cost $13k to $19k before incentives. At today's electricity prices they pay for themselves in about 10.9 yrs.
See panels on your own Castle Rock roof
Type your address. You get your roof from above, the panels that fit, a month-by-month forecast and a battery test. No phone number.
What solar costs in Castle Rock
At $3.00 a watt, the median price cash buyers pay nationally, a 5.0 kW system costs about $15,000. Quotes in Castle Rock will usually fall between $12,500 and $18,750. 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 Castle Rock is what your utility pays for the power you send back. Under full payback is about 10.9 yrs. Under net billing it is about 17.9 yrs, because only the ~42% 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 5.0 kW system in Castle Rock
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 | $15,000 | $0 | +$104 | $26k |
| Credit-union loan 8% APR, 20 years, no dealer fee | $0 | $125 | −$22 | $11k |
| “1.99%” solar loan 1.99% APR, 25 years, 25% dealer fee | $0 | $79 | +$25 | $17k |
| Lease $95/mo, +2.9%/yr | $0 | $95 | +$19 | $2,900 |
| Power purchase (PPA) 14.2¢/kWh, +2.9%/yr | $0 | $97 | +$17 | $4,700 |
Under net metering, at 16.7¢/kWh rising 2.5% a year. The “1.99%” loan’s $3,750 dealer fee is included in its payments. Lease and PPA prices are typical offers, not quotes.
How much sunshine Castle Rock gets
kWh per kW, 25° southJun is the best month for solar in Castle Rock, and Dec the weakest: a Dec day makes 65% of a Jun day. A 6 kW system would make about 604 kWh in Dec and 931 kWh in Jun.
On June 21 the sun rises at 5:32 am and sets at 8:29 pm, 14 hours 57 minutes of daylight. On December 21 it is up from 7:16 am to 4:39 pm, just 9 hours 23 minutes.
Peak sun hours in Castle Rock, month by month
| Month | Flat ground | Panels at 39° | kWh per kW |
|---|---|---|---|
| Jan | 2.7 | 4.9 | 109 |
| Feb | 3.7 | 5.6 | 119 |
| Mar | 4.8 | 6.2 | 149 |
| Apr | 5.8 | 6.1 | 150 |
| May | 6.4 | 6.0 | 154 |
| Jun | 7.2 | 6.2 | 155 |
| Jul | 6.8 | 6.1 | 153 |
| Aug | 6.1 | 6.2 | 150 |
| Sep | 5.3 | 6.4 | 145 |
| Oct | 4.0 | 5.9 | 134 |
| Nov | 2.9 | 5.2 | 111 |
| Dec | 2.3 | 4.5 | 101 |
| Year | 4.8 | 5.8 | 1,629 |
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 Castle Rock
| Roof faces (6/12 pitch) | Output vs south | kWh per kW |
|---|---|---|
| South | 100% | 1,629 |
| Southeast | 95% | 1,548 |
| Southwest | 94% | 1,531 |
| East | 81% | 1,319 |
| West | 81% | 1,319 |
| North | 57% | 929 |
Face panels south and tilt them 39° for the most energy over a year. East and west roofs keep about 81% of that. A north-facing roof keeps 57%, which is rarely worth the money. Try other angles.
Where the sun goes over Castle Rock
The noon sun is lower in winter, which is why the best winter tilt (64°) is steeper than the best summer tilt (10°).
Castle Rock's homes
Castle Rock has 28,219 households. 78.8% own their home, and 21,484 of those owners live in single-family houses, the kind of home that usually gets rooftop solar.
The median home here was built in 2007. Most roofs this young have years of life left, which makes them good candidates for solar.
22% of homes heat with electricity and 76.3% with gas. If you switch to a heat pump or an electric car, plan for more panels or leave room on the roof.
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates.
If the power goes out in Castle Rock
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 Castle Rock
How much do solar panels cost in Castle Rock?
A 5.0 kW system — enough for the average Colorado home — costs about $12,500 to $18,750 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 Castle Rock need?
About 12 panels of 420 watts for a home using 674 kWh a month, the Colorado average. Each kilowatt of panels here makes about 1,629 kWh a year on a south-facing roof.
Is solar worth it in Castle Rock?
Over 25 years, solar power here costs about 9.4¢ per kWh, against 16.7¢ from the grid today. Payback is about 10.9 yrs if your utility credits exported power at the full retail rate, and 17.9 yrs if it pays about 30% of retail.
How many peak sun hours does Castle Rock get?
5.8 a day on panels tilted to 39°, and 4.8 on flat ground. The best month is Sep; the weakest is Dec.
What is the best angle for solar panels in Castle Rock?
39° for the most energy over a year, facing south. 64° is best in winter and 10° in summer. On a normal pitched roof, anything within 15° of 39° gives you about 95% of the maximum.
How long would a home battery last in a Castle Rock 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 Castle Rock
| City | Miles | kWh per kW | Sun hours |
|---|---|---|---|
| Parker, CO | 10 | 1,660 | 5.8 |
| Centennial, CO | 15 | 1,654 | 5.7 |
| Aurora, CO | 24 | 1,648 | 5.7 |
| Lakewood, CO | 26 | 1,643 | 5.7 |
| Denver, CO | 27 | 1,642 | 5.7 |
Castle Rock shares a weather-data neighbourhood with Denver; their sunshine numbers differ by less than our data can resolve. Housing, prices and outage figures are specific to Castle Rock.
Cities with the same sunshine as Castle Rock
These far-away cities get almost exactly as much solar energy per panel.
- San Jose, CA 1,667 kWh per kW
- Sacramento, CA 1,662 kWh per kW
- Honolulu, HI 1,676 kWh per kW
Snow: NASA records about 17 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 33 km from Castle Rock'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.