Sizing around the well pump
Well pumps draw a big surge when they start, so the battery’s power rating matters as much as its capacity. We look at the pump’s horsepower and voltage, and at pressure-tank size, before choosing equipment. Heat matters too: a propane or gas furnace needs only its blower on backup, while electric heat can drain a battery fast.
Shutoffs and daily value depend on your utility
The Evergreen CDP is Xcel territory, and Xcel’s December 2025 and March 2026 public-safety shutoffs reached parts of Jefferson County. For Xcel customers, a battery can also cover the 5–9 p.m. weekday on-peak window, which is priced at about 2.7 times off-peak.
For CORE members in the surrounding foothills, the daily value is different: CORE’s residential demand charge is set by your highest one-hour use between 4 and 8 p.m., and a battery that covers that window can trim it. We model whichever applies to your bill.
Costs and what stacks, as of September 2026
Powerwall 3: about $19,000 for the first 13.5 kWh, about $12,000 each additional. Enphase IQ Battery: about $17,000 for 10 kWh. SigEnergy: $15,500 for 9 kWh, +$3,500 per module. Colorado’s 10% storage credit on equipment applies through tax year 2026, and residential batteries are exempt from state sales tax.
Xcel customers may qualify for its Renewable Battery Connect program, which pays toward a battery in exchange for letting Xcel draw on it during grid events; we confirm current terms before counting it. We haven’t verified any CORE battery incentive; ask CORE, and we’ll include it if one exists.
Battery with no solar?
It’s a legitimate choice on a heavily shaded lot. The battery charges from the grid and holds a reserve for outages. Without solar it can’t recharge during a multi-day outage, so sizing and load discipline matter more.
FAQ
Questions we hear
How long will a battery run my Evergreen house in an outage?
With essentials only — well pump, furnace blower, fridge, lights, internet — one 13.5 kWh battery often lasts overnight to a day or more, depending on season and usage. Our blackout calculator lets you model your loads.
Is a battery better than a generator in the mountains?
A battery is silent, automatic and fuel-free; a generator can run indefinitely on fuel. Some Evergreen homeowners keep both. We’ll lay out the trade-offs honestly.
Do you install off-grid systems in Evergreen?
No. We install grid-tied systems with battery backup. They keep power on during outages while staying connected to Xcel or CORE.