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Electricity Rate Plan Calculator (TOU vs Flat)

Flat rate monthly

$234.00/mo

450 kWh × 0.52

TOU monthly cost

$193.95/mo

Peak 158 · shoulder 113 · off 180 kWh

Potential savings

$481.00/yr

That's about $481.00 /yr on your electricity — that's around $40.08 a month.

Time-of-use (TOU) wins · $40.05/mo · blended TOU 0.431 vs flat 0.52

Off-peak share (auto): 40% of monthly kWh

When TOU pays off

Time-of-use tariffs reward shifting flexible loads into cheap windows. If a large share of your kWh already lands off-peak—or you can move dryers, dishwashers, EV charging, and pool pumps to evenings and nights—TOU often beats a single flat ¢/kWh.

Flat rate wins when most usage stays on-peak (late afternoon AC, cooking, homework hours) and overnight rates are not much lower than your flat average.

  • Run heavy appliances after off-peak starts on your tariff
  • Pre-cool with efficient AC before peak blocks if your plan allows
  • Enter rates in any currency (₪, $, €)—math is the same per kWh
AC Efficiency & Inverter Savings — shift cooling load

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How this calculator works

How to use the Electricity Rate Plan Calculator (TOU vs Flat)

The Formula

Flat bill = total kWh × flat rate. TOU bill = peak kWh × peak rate + shoulder kWh × shoulder rate + off-peak kWh × off-peak rate. We show monthly costs and annual savings for whichever plan is cheaper at your current usage profile—before you change habits.

Practical Example

Estimate peak % from your utility dashboard or hourly chart. Shoulder is mid-tier hours; the remainder is off-peak. Shifting loads later can improve TOU results beyond this snapshot.

About Electricity Rate Plan Calculator (TOU vs Flat)

Flat vs. TOU math

Flat bill = total kWh × flat rate. TOU bill = peak kWh × peak rate + shoulder kWh × shoulder rate + off-peak kWh × off-peak rate. We show monthly costs and annual savings for whichever plan is cheaper at your current usage profile—before you change habits.

Usage split

Estimate peak % from your utility dashboard or hourly chart. Shoulder is mid-tier hours; the remainder is off-peak. Shifting loads later can improve TOU results beyond this snapshot.

Frequently asked questions

Q: Fixed charges? A: Energy-only comparison—add monthly service fees to both plans equally. Q: Super off-peak? A: Fold into off-peak rate. Q: Shift more load? A: Use Peak Shaving Potential after you pick TOU.

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