Does this include demand charges or tiers?

No. This is a flat TOU model. If your utility charges demand or tiers, results are directional; use all-in average rates if possible.

Should I include delivery and taxes?

For best accuracy, include them in the $/kWh inputs. Otherwise, results will be a bit higher in reality.

What if rates change seasonally?

Rerun with current-season rates. If summer peak is higher, expect larger savings then; winter may be smaller.

How do I estimate shift percent?

List flexible loads (EV, laundry, dishwasher, water heating, pool pumps) and estimate what fraction you can schedule off-peak. Start conservative (20–30%) and adjust.

Can I model super off-peak vs mid-peak vs peak?

This tool is a simple two-rate model (peak/off-peak). To approximate, use peak for the higher window and off-peak for the lowest window; rerun with mid-peak as the peak rate if needed.

Will shifting usage affect demand charges?

Possibly. This calculator does not model demand charges. If you have demand fees, reducing simultaneous peak loads can help—check your utility plan for details.

How do I estimate my true all-in rate?

Add supply + delivery + riders + taxes from your bill, divide by kWh to get an all-in ¢/kWh. Use that for peak/off-peak if you want closer-to-reality savings.

energy calculator

Peak vs Off-Peak Electricity Savings

Estimate monthly savings from shifting a portion of your electricity use to off-peak rates.

Results

Peak kWh after shifting: 630.00
Off-peak kWh after shifting: 270.00
Baseline monthly cost (peak only): $252
Monthly cost after shifting: $209
Monthly savings: $43

Overview

Estimate how much you can save each month by shifting part of your electricity use from peak to off-peak rates. Great for TOU plans where running appliances at night/weekends lowers your bill.

Many utilities now offer time-of-use (TOU) pricing, where electricity is much more expensive during late-afternoon and early-evening peaks and significantly cheaper overnight or on weekends. This calculator turns that rate spread into a concrete dollar impact by comparing a "do nothing" scenario—where all of your kWh are billed at the peak rate—to a shifted scenario where a portion of your usage moves into cheaper off-peak windows. With a few numbers from your bill and a realistic guess at what you can shift, you can see whether changing habits or investing in timers, smart plugs, or EV scheduling is worth the effort.

How to use this calculator

Enter your monthly kWh usage (from bills or a monitor).
Enter your peak and off-peak rates; include riders/fees if possible for all-in cents/kWh.
Estimate what percent of usage you can shift (laundry, dishwasher, EV charging, water heating, pool pumps).
Review the baseline bill versus optimized bill and monthly savings.
Adjust shift percent and rates if your utility has seasonal or weekday/weekend differences.

Inputs explained

Monthly kWh: Total monthly consumption. Use an average from past bills or a monitor reading.
Peak rate: Your on-peak energy price ($/kWh). Add riders if you want an all-in figure.
Off-peak rate: Your off-peak price ($/kWh). For super off-peak, enter that lower rate.
Percent shifted: Portion of load you can realistically move to off-peak windows.

How it works

Base cost = all monthly kWh × peak rate (assumes no shifting).

Shifted kWh = monthly kWh × shift percent; off-peak kWh = shifted; peak kWh = monthly kWh − shifted.

Optimized cost = (peak kWh × peak rate) + (off-peak kWh × off-peak rate).

Monthly savings = base cost − optimized cost.

Formula

Base cost = monthly kWh × peak rate. Shifted kWh = monthly kWh × (shift% ÷ 100). Peak kWh = monthly kWh − shifted. Optimized cost = peak kWh × peak rate + shifted × off-peak rate. Savings = base cost − optimized cost.

When to use it

Testing savings from running laundry/dishwasher at night.
Estimating benefit of scheduling EV charging or water heating off-peak.
Comparing a TOU plan to a flat-rate plan (approximate the spread).
Justifying smart plugs/timers to move flexible loads out of peak windows.

Tips & cautions

Use an all-in rate (energy + delivery + riders) for accuracy if you know it; otherwise keep it simple with supply rates.
Start with a realistic shift percent—most homes can shift 10–40% of discretionary load with timers and schedules.
Check for seasonal/weekday/weekend TOU periods; rerun with the rates in your current season for best accuracy.
If you have demand charges or tiers, this simple model won’t capture them—treat results as directional.
For EVs, set charging to start after off-peak begins; combine with lower current settings if you only need a small daily top-up.
For water heating, dishwashers, and laundry, use built-in delay start or smart plugs to automate off-peak usage.
Large loads (dryers, ovens, HVAC setbacks) moved together can spike demand in TOU+demand plans; stagger them if demand charges apply.
Pair this with insulation/efficiency improvements—lower kWh plus off-peak shifting multiplies savings.
No tiered pricing, demand charges, or minimum bill charges; flat TOU rates only.
Ignores taxes/fees unless you embed them in the rate inputs.
Assumes your shiftable load is evenly distributed; real load shapes vary by hour/season.
Does not handle critical peak pricing, super off-peak windows, or mid-peak tiers; enter the two primary rates you want to compare.
Does not model seasonal rate changes or TOU windows explicitly; rerun with current-season numbers.

Worked examples

Moderate shift on typical TOU

Monthly kWh: 900. Peak rate: $0.28. Off-peak: $0.12. Shift: 30%.
Shifted kWh = 270; peak kWh = 630.
Base cost = 900 × 0.28 = $252.
Optimized = 630 × 0.28 + 270 × 0.12 = $176.4 + $32.4 = $208.8.
Savings ≈ $43.20/month.

EV charging off-peak

Monthly kWh: 1,200. Peak: $0.32. Off-peak: $0.10. Shift: 45% (EV + laundry).
Shifted kWh = 540; peak kWh = 660.
Base = 1,200 × 0.32 = $384.
Optimized = 660 × 0.32 + 540 × 0.10 = $211.2 + $54 = $265.2.
Savings ≈ $118.8/month.

Low spread, smaller benefit

Monthly kWh: 800. Peak: $0.20. Off-peak: $0.16. Shift: 25%.
Shifted = 200; peak = 600. Base = $160.
Optimized = 600 × 0.20 + 200 × 0.16 = $120 + $32 = $152.
Savings ≈ $8/month—TOU may not be worth it with a small rate spread.

Super off-peak EV charging

Monthly kWh: 1,400. Peak: $0.30. Off-peak: $0.12. Shift: 50% (EV + laundry/pool pump).
Shifted = 700; peak = 700. Base = 1,400 × $0.30 = $420.
Optimized = 700 × $0.30 + 700 × $0.12 = $210 + $84 = $294.
Savings ≈ $126/month—higher spreads and large shiftable loads drive the biggest gains.

Deep dive

Use this peak vs off-peak calculator to estimate monthly bill savings from moving flexible loads to cheaper hours.

Enter your kWh, peak/off-peak rates, and shiftable percent to see baseline vs optimized bill and savings.

Great for TOU plans: test how EV charging, laundry, and water heating shifts lower your monthly cost.

Rerun each season if your TOU rates change; plug in all-in cents/kWh for a closer real-world estimate.

If savings are small, a flat-rate plan may be better; if large, set timers to capture the off-peak discount.

Pair this with a load-shift checklist (dishwasher delay, laundry timers, EV schedule) to capture the savings shown here in real life.

Use conservative shift percentages first, then increase as you automate more loads with smart plugs and appliance schedulers.

If your utility has demand charges, stagger big appliances to avoid peak demand hits while still moving kWh off-peak.

Compare TOU vs flat-rate by plugging the flat rate into both peak and off-peak fields—if savings are minimal, staying flat could be simpler.

If your utility offers critical-peak events or super off-peak windows, re-run with those rates to see the added benefit of avoiding the highest-price hours.

Keep a seasonal note: summer peaks can be much higher—rerun before peak season to budget for the change.

FAQs

Does this include demand charges or tiers?: No. This is a flat TOU model. If your utility charges demand or tiers, results are directional; use all-in average rates if possible.
Should I include delivery and taxes?: For best accuracy, include them in the $/kWh inputs. Otherwise, results will be a bit higher in reality.
What if rates change seasonally?: Rerun with current-season rates. If summer peak is higher, expect larger savings then; winter may be smaller.
How do I estimate shift percent?: List flexible loads (EV, laundry, dishwasher, water heating, pool pumps) and estimate what fraction you can schedule off-peak. Start conservative (20–30%) and adjust.
Can I model super off-peak vs mid-peak vs peak?: This tool is a simple two-rate model (peak/off-peak). To approximate, use peak for the higher window and off-peak for the lowest window; rerun with mid-peak as the peak rate if needed.
Will shifting usage affect demand charges?: Possibly. This calculator does not model demand charges. If you have demand fees, reducing simultaneous peak loads can help—check your utility plan for details.
How do I estimate my true all-in rate?: Add supply + delivery + riders + taxes from your bill, divide by kWh to get an all-in ¢/kWh. Use that for peak/off-peak if you want closer-to-reality savings.

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This tool models simple TOU savings with flat peak/off-peak rates. It does not include demand charges, tiered pricing, minimum bills, or taxes unless you embed them in rates. Actual load shapes vary; use results as directional and confirm with your utility plan details. Re-run when rates, seasons, or TOU windows change.