How much could you save on demand charges?
Enter your ZIP to pull your plan's real demand rates, then add your battery and the loads that tend to run at peak. You'll see what an unmanaged peak, a full Powerwall discharge and DemandGuard would each cost you in a month.
Peak Summer Inputs
Find your rate plan, describe your battery, and pick the big loads that might overlap during peak hours.
Until you search, you're looking at example plans from SRP and APS in Phoenix. We send only your ZIP code.
Usage helps estimate the baseline household demand and time-of-use energy cost around your summer peak window.
Battery
Defaults match a single Powerwall 2-style estimate. Adjust if your usable capacity or continuous output differs.
Peak-Time Loads
Check or count anything that may overlap during the billed demand window. The calculator assumes those loads can coincide to set your demand peak.
* Illustrative estimate only, not a savings guarantee or utility bill quote. Summer demand outcomes depend heavily on exact interval timing, appliance overlap, solar production, weather, battery health, and utility billing rules. DemandGuard results assume a sustainable target across the full summer peak window; real solar conditions can improve or worsen the outcome.
How the demand charge calculator works
Three steps to start saving on your energy bill
Find Your Plan And Set Your Inputs
Enter your ZIP and pick your plan, add your battery details, and check which high-demand appliances can overlap during your billed peak window.
Compare Three Peak Scenarios
See the estimated monthly impact of unmanaged peak use, full Powerwall discharge, and a DemandGuard-style demand ceiling built around the plan’s reset interval.
Use The Strategy That Lasts
The key question is not just “Can the battery help?” It’s whether it can hold through the whole summer peak window without handing a later demand interval back to the grid.
Demand charge calculator FAQ
How accurate is this calculator?
This calculator is illustrative only. It uses published tariff data plus simplified assumptions about overlapping loads, battery discharge, and summer demand timing. Actual savings depend on your specific tariff details, appliance overlap, solar production, weather, and battery behavior, so these numbers are not a guarantee or billing quote.
What if I don't know my energy plan?
Check your most recent utility bill — your plan name or code is usually near the top. SRP solar customers often see E-27 or E-15. APS customers commonly see R-3 for the 4–7 PM demand plan. If you’re not sure, your utility can confirm it. To see whether your plan has a demand charge, check by ZIP code.
Does Grid Getter work with my utility?
Grid Getter works with any Tesla Powerwall. In the app you can search by ZIP code for your rate plan from 3,700+ US utilities, and Grid Getter fills in the rates, peak windows and demand charges. This calculator uses the same ZIP search for demand rates. For SRP and APS it also has energy rates, so those totals include both.
Why can DemandGuard outperform full discharge?
Naively draining the battery early can still leave you exposed later in the same peak window, which means a late interval can still set your monthly demand charge. DemandGuard works differently: it targets the lowest sustainable grid ceiling that your battery can hold across the full window instead of spending all your battery energy up front.
Swap the estimate for your real numbers
The free report reads your own battery data, read-only, and shows your biggest demand peak of the past 12 months and what it cost.
Get your free reportFree. Our Tesla access is deleted after 24 hours.