What actually changed on your bill
Under the plan in effect since late 2025, every weekday evening from 5 to 9 pm is on-peak, including winter, and summer months (June through September) carry their own higher pricing. Weekends and holidays are off-peak. Time-of-use is the default for residential customers with smart meters, which is why many households found themselves on it without asking.
We deliberately don’t print the cents-per-kWh here: the exact rates change with rate cases and seasons, and your bill’s rate-schedule line is the authoritative number. The ratio — roughly 2.7 to 1 — is what drives the decision.
Why solar alone doesn’t fix a time-of-use bill
Rooftop panels in Colorado produce most between late morning and mid-afternoon. By 5 pm in winter the sun is setting; even in June, production is tapering during the peak window. Net metering still credits your daytime surplus, but the evening kWh you pull at on-peak prices are exactly the ones solar doesn’t cover well.
A battery changes that. It fills from solar (or off-peak grid power) and discharges from 5 to 9 pm, so the house draws little or nothing from Xcel at on-peak prices. That’s the same equipment that keeps your lights on in an outage, which is why many Colorado buyers justify it on both counts.
Cheaper things to try first
Move the dishwasher, dryer, and EV charging outside 5–9 pm on weekdays; most modern appliances and cars have delay-start timers. Pre-cool the house in summer before 5 pm. If your usage simply can’t move and you don’t want equipment, you can opt out of time-of-use back to a flat rate — sometimes that’s the right answer.
If you’ve done all that and evening usage is still heavy, a battery pencils out better. As of September 2026, Colorado offers a 10% state income-tax credit on home battery purchases for tax years through 2026, and batteries are exempt from state sales tax. Xcel has also run a battery incentive program (Renewable Battery Connect) in exchange for limited utility use of the battery; amounts and deadlines change, so verify before counting on it.
What we install for peak shifting
We install Tesla Powerwall 3 (13.5 kWh usable; about $19k installed for the first unit), Enphase IQ Batteries (about $17k for the first 10 kWh), and SigEnergy (about $15.5k for the first 9 kWh, with 9 kWh modules at about $3.5k each). For pure peak shifting, a single battery usually covers a typical household’s 5–9 pm load; the peak-shift calculator shows how much of yours it would cover.
What to do next
- 1Find your on-peak kWh on your last few Xcel bills — it’s broken out if you’re on time-of-use.
- 2Try shifting laundry, dishwasher, and EV charging out of 5–9 pm on weekdays for one billing cycle.
- 3Run the peak-shift calculator with your on-peak kWh to see what share a battery would cover.
- 4Compare the result to simply opting out to Xcel’s flat rate.
- 5If a battery still wins, ask us to size one with or without new solar, and to show the state battery credit timing for your tax year.
FAQ
Questions we hear
What hours are on-peak on Xcel’s Colorado time-of-use plan?
As of September 2026, 5 to 9 pm on non-holiday weekdays, year-round, per the plan effective November 1, 2025. Weekends and holidays are off-peak. Check your rate schedule for current details.
How much more expensive is on-peak power?
About 2.7 times the off-peak rate, based on the plan structure we researched. We don’t list exact cents per kWh because they change; your bill shows your current rates.
Can a battery work without solar panels?
It can charge from the grid during off-peak hours and discharge on-peak, which captures the price gap. Paired with solar, it charges from your own daytime surplus instead, which usually improves the economics and gives you outage backup that can recharge.
Does a battery make sense if I’m home only on weekends?
Less so. On-peak pricing applies only on weekdays, so if your house is nearly empty from 5 to 9 pm Monday through Friday, the time-of-use savings are small. Outage backup might still justify it, but not peak pricing alone.
Is the Colorado battery tax credit still available?
As of September 2026, the 10% state credit (C.R.S. 39-22-546) applies to tax years 2023 through 2026. It’s nonrefundable unless assigned to the seller. Confirm timing with your tax preparer.