Does a Smart Panel Save Money on Time-of-Use Rates? Worked Bills for Ontario and California

Does a Smart Panel Save Money on Time-of-Use Rates? Worked Bills for Ontario and California

By EnergyBS Editorial Team | November 13, 2026

A household that moves 303 kWh a month of EV charging, water heating and drying out of the peak window saves $222 a year on PG&E's E-TOU-C rate, $278 on Ontario's standard time-of-use prices, $788 on SCE's TOU-D-PRIME and $1,236 on Ontario's Ultra-Low Overnight plan. A smart panel can claim only part of that, because a free car or charger schedule already moves the biggest load.

Take the EV out, and what is left for the panel to automate is worth $61 a year on E-TOU-C and $339 a year on Ultra-Low Overnight. Against SPAN's lowest list price of $2,550 before installation, that is a 42-year payback in Northern California and a 7.5-year payback in Ontario. SPAN's MAIN 32 specification sheet lists a 10-year warranty, so on most of the rates tested here the hardware runs out of warranty long before it has paid for itself on time-of-use savings alone.

The figures come from one stated household and three published rate schedules, all priced below with their jurisdiction and date. Change any input and the result moves, which is the point of showing the arithmetic: a reader with a different rate or a different car can redo it line by line.

The household and the 303 kWh it can move

Every number in this section is an assumption chosen for the illustration, not a measured average. A real household should replace each one with figures from its own interval data (the hourly readings most utilities publish in their online account).

Assumption 1, the EV. The car takes 10 kWh on each of 22 weekdays a month. Left alone, it is plugged in on arriving home around 5 p.m. and charges straight away, so all 10 kWh land in the early evening. That is 220 kWh a month.

Assumption 2, the heat pump water heater. Evening showers and dishes make the tank recover in the evening. Of its daily use, 2 kWh fall in the early evening on weekdays. That is 44 kWh a month.

Assumption 3, the electric dryer. Thirteen loads a month at 3 kWh each, run on weekday evenings after work. That is 39 kWh a month.

Assumption 4, the window. All 303 kWh (220 + 44 + 39) fall inside each utility's most expensive weekday window when nobody manages them, and all of it can be moved to that utility's cheapest window. This is the most favourable case for any shifting device. In a real house some of the evening load already runs late, and some cannot move without someone taking a cold shower.

Assumption 5, weekends. Weekend use is left out. Ontario prices weekends at off-peak all day, and SCE's summer weekend window is a lower mid-peak price, so weekend shifting is worth less there. On PG&E the peak runs every day, so leaving weekends out understates the PG&E saving slightly; the effect on the conclusions is covered later.

Over a year that is 3,636 kWh of movable energy (303 x 12): 2,640 kWh from the EV, 528 kWh from the water heater and 468 kWh from the dryer. The EV share is 2,640 / 3,636 = 72.6%, and that one ratio drives most of what follows.

Shifting does not reduce the kWh the house uses. It changes the price paid for each one. So every saving below is the movable kWh multiplied by the difference between two prices on the same schedule, and nothing else on the bill enters the calculation.

Three published rate schedules, priced per shifted kWh

The value of moving a kWh is the peak price minus the price in the hour you move it to. That spread is the only rate figure the calculation needs, and it varies by a factor of more than ten between the schedules below.

Ontario: OEB Regulated Price Plan, prices set for November 1, 2026

The Ontario Energy Board sets two time-based price plans for households on the Regulated Price Plan. Prices below are in Canadian cents per kWh, read from the OEB's rates page on November 13, 2026.

On the standard time-of-use plan, the household's early-evening load sits in on-peak only in winter. In summer the 5 p.m. to 7 p.m. slot is mid-peak. So the spread is 18.9 - 9.1 = 9.8 cents for the six winter months and 14.6 - 9.1 = 5.5 cents for the six summer months, an annual average of (6 x 9.8 + 6 x 5.5) / 12 = 7.65 cents.

On Ultra-Low Overnight the same hours apply all year, and the spread from on-peak to the overnight price is 37.7 - 3.7 = 34.0 cents every weekday. That is 4.4 times the standard plan's average spread (34.0 / 7.65).

These are the OEB's commodity prices for the electricity itself. Delivery and regulatory lines, the Ontario Electricity Rebate and HST are not part of the shift arithmetic here, because the calculation only uses the price difference between two hours.

California: PG&E Electric Schedule E-TOU-C, effective June 1, 2026

PG&E's E-TOU-C tariff sheet lists total bundled energy rates effective June 1, 2026 under Advice Letter 7921-E. The peak runs 4 p.m. to 9 p.m. every day; all other hours are off-peak. Summer is June 1 through September 30.

The baseline credit of $0.08140 per kWh applies to baseline usage at either time of day, so it does not change the spread. The annual average spread for the household is (4 x 0.12300 + 8 x 0.03000) / 12 = $0.06100 per kWh.

That winter spread of 3.0 cents is the most important number on this page for a PG&E customer. For eight months of the year, moving a kWh from 6 p.m. to midnight on E-TOU-C saves three cents.

California: SCE TOU-D-PRIME, prices as listed November 13, 2026

Southern California Edison offers TOU-D-PRIME to customers with an electric vehicle, a home battery or an electric heat pump. The household's EV makes it eligible. SCE's time-of-use plans page lists prices in whole cents for customers who take both delivery and generation from SCE. The page did not show an effective date for these prices when read on November 13, 2026, so treat them as the prices displayed that day.

TOU-D-PRIME also has a winter super off-peak price of 24 cents from 8 a.m. to 4 p.m. The calculation uses the 30-cent overnight price instead, because a car that is away at work during the day cannot charge then, and a water heater recovering after evening showers needs to run that night. A dryer could use the daytime window on a weekend, which would be worth a few more dollars than shown. The annual average spread is (4 x 35 + 8 x 15) / 12 = 21.67 cents.

The worked bills: what moving 303 kWh a month is worth

Multiplying the household's movable kWh by each spread gives the annual saving from shifting, split by load. Each cell is the load's annual kWh times the average spread; the totals add across.

Ontario figures are Canadian dollars; California figures are US dollars.

Two of the monthly bills, written out so the method is easy to follow:

PG&E, a July bill. Unmanaged, 303 kWh at the summer peak price cost 303 x $0.52240 = $158.29. Shifted to off-peak, the same 303 kWh cost 303 x $0.39940 = $121.02. The saving is $37.27 for the month, which is 303 x $0.12300. The rest of the household's use is billed the same either way, so it cancels.

PG&E, a January bill. The same 303 kWh cost 303 x $0.39757 = $120.46 at peak and 303 x $0.36757 = $111.37 off-peak. The saving is $9.09. Four summer months at $37.27 and eight winter months at $9.09 give $149.08 + $72.72 = $221.80 a year.

Ontario Ultra-Low Overnight, any weekday-heavy month. Unmanaged, 303 kWh at 37.7 cents cost $114.23. Moved past 11 p.m., they cost 303 x 3.7 cents = $11.21. The monthly saving is $103.02, and twelve months give $1,236.24. The ULO saving does not change by season, because the OEB's ULO hours and prices are the same all year.

SCE TOU-D-PRIME, an August bill. 303 kWh at 61 cents cost $184.83; at 26 cents they cost $78.78. The saving is $106.05. In a winter month it is 303 x 15 cents = $45.45. Four summer months and eight winter months give $424.20 + $363.60 = $787.80.

The spread between the best and worst case is large. The same household, moving the same 303 kWh, saves 5.6 times as much on Ontario ULO as on PG&E E-TOU-C ($1,236.24 / $221.80). Any claim about what "a smart panel saves" without naming the rate is close to meaningless.

Which device actually moves each load

A saving belongs to whatever causes the shift. If the EV would charge after 9 p.m. anyway because the car's own scheduler is set, a smart panel installed the same week cannot claim that saving. This is the step most "smart panel savings" estimates skip.

The EV. Most of the movable energy (72.6% here) sits in the one appliance most likely to have a timer already. Setting a start time of 9 p.m. on E-TOU-C or TOU-D-PRIME, or 11 p.m. on Ontario ULO, captures the full EV column of the table above with no new hardware. The advanced EV charging guide covers departure-time settings, preconditioning and what happens when two schedules (car and charger) disagree. A smart panel earns EV credit only with an older charger and a car that cannot schedule, and even then a new charger with a timer is a cheaper fix than a panel.

The water heater. This is where switching hardware can genuinely earn money, because a hard-wired 240-volt appliance has no plug for a cheap timer. If the heater's own controls or app offer a schedule, use it first. If not, a SPAN panel, Leviton 2nd Gen smart breakers (which Leviton says need its LWHEM hub and a Leviton load center to switch and schedule), or a dedicated timer on the circuit can hold it off through the peak. One caution: holding off a tank for five hours each evening means it recovers later, possibly when someone needs hot water, and a hybrid unit recovering quickly may fall back on its resistance elements. That can erase part of the saving. Check the heat pump water heater cost and payback guide for how these units use energy in each mode.

The dryer. A smart panel can turn off the dryer circuit at 4 p.m. That does not move 3 kWh to midnight. It stops the drum, leaves damp clothes, and the load happens whenever someone restarts it. Whether a given dryer resumes on its own after power returns depends on the model, so check the manual before relying on it. The dryer's share of the saving belongs to the habit of starting it later or the delay-start button, not to the panel. The heat pump dryer comparison shows the other way to cut that column: use fewer kWh per load in the first place.

So the honest credit for a smart panel in this household is the water heater column, plus the dryer column if you are generous, plus the EV column only where nothing else can schedule the car.

Payback years when the panel gets credit for everything, and when it doesn't

The table below divides list prices by annual savings. List prices come from the manufacturer pages read on November 13, 2026, in US dollars, before installation, taxes and shipping. Installation is a real extra cost that would lengthen every payback here; this page does not quote an installed price because none was read from a primary source for these markets.

Case A: the device gets credit for all 3,636 kWh. This is the most generous reading and fits only a house where nothing else can schedule any of the three loads.

Case B: the EV is scheduled for free, so the device gets credit for the water heater and dryer only (996 kWh a year). Annual savings are $338.64 on ULO, $215.80 on TOU-D-PRIME, $76.19 on Ontario TOU and $60.76 on E-TOU-C.

Case C: the device gets credit for the water heater only (528 kWh a year), the realistic reading if the dryer moves by habit. Savings are $179.52, $114.40, $40.39 and $32.21. The MLO 24 then takes 14.2 years on ULO, 22.3 years on TOU-D-PRIME, 63.1 years on Ontario TOU and 79.2 years on E-TOU-C.

Ontario rows divide US-dollar list prices by Canadian-dollar savings without converting, because SPAN's page lists US prices and no Canadian list price was read. Convert at the day's exchange rate before using those rows for a decision; the conclusion for the ULO row is the one most sensitive to that conversion.

Read against SPAN's stated 10-year warranty on the MAIN 32, the rows that pay back inside ten years are every Case A row on ULO and TOU-D-PRIME, the MLO 24 on Ontario TOU in Case A (9.2 years), and in Case B only the MLO 24 on ULO (7.5 years). Case A assumes the house has no other way to schedule the EV, which few households with a recent car or Level 2 charger face.

The weekend effect on PG&E deserves one line. Adding eight weekend days a month to the PG&E calculation raises every PG&E saving by about 8/22, or 36%, because E-TOU-C's peak covers all days. That shortens the Case B MLO 24 payback from 42.0 to about 31 years. It does not change the conclusion.

The cheaper alternatives, priced the same way

A clamp-on monitor cannot switch anything, so it cannot claim any shifting saving on its own. Its value is showing whether the schedules you set are working, and what the rest of the house draws between 4 p.m. and 9 p.m. A more useful way to price it is the number of kWh it has to move, by catching a schedule that failed or a habit worth changing, before it has paid for itself.

Each figure is the list price divided by the average spread for that schedule. On Ontario ULO, a $39.99 whole-home reader pays for itself if it shows you one EV schedule that silently failed for 12 weekday evenings (118 kWh at 10 kWh a night). The SPAN panel would have to move 7,500 kWh that nothing else could move, which is more than two years of this household's entire movable load.

Emporia also lists Smart Scheduling and peak demand management for "connected devices". A clamp-on monitor has no switch of its own, so any scheduling runs through separate connected devices such as smart plugs or a smart charger, not through the breakers in your panel. SPAN Drive, at $750, is an EV charger sold only as an accessory to a SPAN panel, so it is not a stand-alone alternative. For a full comparison of what each class of hardware can switch, see smart panel vs smart breakers vs energy monitor.

A ten-year test you can run on your own rate

The household on this page is only one case. A quick test turns the method into a rule you can apply with your own bill and rate sheet.

1. Find your spread: the price in your most expensive window minus the price in the cheapest window you can realistically use. Use a seasonal average if the spread changes by season, as in the PG&E and SCE examples.
2. List the loads that have no schedule of their own and would run in the peak window today. Leave out the EV if the car or charger can schedule, and leave out anything you will move by habit anyway.
3. Estimate those loads' peak kWh a year from interval data.
4. Divide the device's list price, plus installation, by 10 (years of warranty), then by your spread. The result is the kWh a year the device has to move on its own to pay back within ten years.

For a $2,550 list price before installation, the threshold is 750 kWh a year on Ontario ULO, 1,177 kWh on SCE TOU-D-PRIME, 3,333 kWh on Ontario TOU and 4,180 kWh on PG&E E-TOU-C. For a $4,100 MAIN 40 it is 1,206, 1,892, 5,359 and 6,721 kWh.

Compare those thresholds with the household here. Its water heater and dryer together move 996 kWh a year, enough to clear the MLO 24 threshold on ULO and nowhere else. If your list from step 2 is shorter than the threshold, a smart panel is not a time-of-use purchase for you; it may still be the right purchase for another reason, covered below.

The test also works in reverse. If your utility moves you to a steeper rate, the threshold falls in proportion to the new spread. A household on a flat rate today has a spread of zero, and no switching device saves anything on shifting alone until the rate changes.

Ontario's Ultra-Low Overnight plan is where the math gets close

ULO is the one schedule here where a smart panel's time-of-use case is real for a household with several hard-wired loads. The 34.0-cent spread means each kWh moved is worth more than three times what it is worth on Ontario's standard plan in winter, and more than eleven times the PG&E winter spread.

The same steepness works against the household for anything it cannot move. Every kWh that still runs between 4 p.m. and 9 p.m. on a weekday costs 37.7 cents on ULO against 18.9 cents (winter) or 14.6 cents (summer) on standard TOU. Cooking dinner, lighting and a heat pump running on a cold evening all land there. Whether ULO is the cheaper plan overall depends on the full load profile, not just the shiftable part; the Ontario electricity rates guide walks through that plan choice. The figures on this page assume the household is already on the plan it is testing.

For a household that does choose ULO, the order of purchases matters:

• Set the EV to start after 11 p.m. This alone is $897.60 a year in the table above, at no cost.
• Check whether the water heater has a schedule. If it does, set it to recover after 11 p.m. and accept some hot-water planning.
• Only then price a switching device for whatever hard-wired load is left. On ULO, a load of about 750 kWh a year justifies a $2,550 panel on time-of-use savings alone, before installation.

Outside Ontario, start by checking whether your utility offers a time-varying residential rate at all. On a flat rate the spread is zero, and the shifting case for any device disappears until the rate changes.

When the panel's other jobs change the answer

A smart panel is rarely bought for time-of-use savings alone, and the payback tables above deliberately ignore its other jobs. Three of them can change the decision.

A battery on a time-of-use rate. A home battery that charges in the cheap window and discharges in the peak moves much more energy than the three loads here, and a panel that coordinates which circuits draw from it in an outage adds a separate kind of value. That is a battery decision first; the home battery sizing guide covers which loads a battery can carry and for how long. Battery arbitrage also has round-trip losses that shrink the spread, which this page's arithmetic does not include.

Avoiding a service upgrade. If a smart panel lets a house add an EV charger and a heat pump without replacing a 100-amp service, the avoided upgrade can be worth far more than any time-of-use saving. That is a code and load-calculation question, worked through in the panel capacity electrification guide. The time-of-use saving is then a side benefit on top of a purchase made for capacity.

Seeing the bill in dollars. SPAN's page says its app shows energy use in dollars based on the rate plan you enter. That is useful on a rate as steep as ULO, where a forgotten load between 4 p.m. and 9 p.m. is expensive, but a $39.99 whole-home monitor that shows the evening spike gives much of the same warning.

When comparing smart panels as products, including how SPAN, Lumin, Leviton and Schneider differ in circuit count and blackout behaviour, the best smart electrical panel comparison is the place to start. This page answers a narrower point: whether time-of-use savings alone carry the price. Other panel topics, from upgrade costs to rebates, sit in the electrical panels hub.

What changes the numbers most

Four inputs move the result more than the brand of panel does.

The rate. The PG&E E-TOU-C winter spread of 3.0 cents and the Ontario ULO spread of 34.0 cents differ by a factor of 11.3. Rates change: PG&E's E-TOU-C sheet carries a rate table effective June 1, 2026, and the OEB's current Ontario prices were set for November 1, 2026. Re-run the arithmetic whenever the rate sheet changes. For a general method of modelling a plan from your own interval data, see the time-of-use strategy guide; for the structure of California's investor-owned utility rates, the California electricity rates guide.

How much load is truly unscheduled. Case A and Case C differ by a factor of almost seven in annual savings (3,636 / 528 = 6.9). The single most useful thing a homeowner can do before buying switching hardware is to check which appliances already have a schedule.

Seasons. On PG&E E-TOU-C and SCE TOU-D-PRIME, summer is worth much more per kWh than winter. A household whose movable load is mostly winter heating, such as a water heater in a cold garage, earns mostly the low winter spread.

Comfort and hot water. Every saving here assumes the shift costs the household nothing in comfort. Holding a water heater off for five hours, or delaying a dryer until midnight, has a cost that does not appear on the bill. If the household overrides the schedule twice a week, the saving falls in proportion.

The common error in published smart panel savings claims is a version of Case A: crediting the panel with every kWh that moves, including the EV kWh that a free timer already moves. On the rates read for this page, that error makes the panel look three to four times more valuable than it is in a typical house with a schedulable car.

Frequently Asked Questions

Does a smart panel save money on a time-of-use rate?

Only through the loads it moves that nothing else would move. In the household on this page, with the EV scheduled for free, a SPAN MLO 24 at $2,550 list price paid back in 7.5 years on Ontario's Ultra-Low Overnight plan and in 42 years on PG&E's E-TOU-C, before installation. The rate's peak-to-cheap spread decides most of the answer.

What is the best smart panel for time-of-use rates?

For time-of-use alone, the cheapest device that switches the loads you cannot schedule in any other way. If those loads are a water heater and nothing else, that may be a timer or smart breakers rather than a whole panel. SPAN's app can show cost in dollars using the rate plan you enter, which helps on steep rates. For product-by-product differences, see our smart panel comparison linked above.

Can my EV charger do the same job as a smart panel on time-of-use?

For the EV itself, yes. A charger or car with a start-time setting moves the EV's charging out of the peak at no extra cost, and in the household here the EV was 72.6% of the movable energy. A panel adds value for the EV only if neither the car nor the charger can be scheduled.

Does shifting load to off-peak reduce how much electricity I use?

No. Moving a kWh from 6 p.m. to midnight changes its price, not the quantity. A water heater held off through the evening can even use slightly more energy if it recovers in a less efficient mode. Savings come from the price difference only.

Is Ontario's Ultra-Low Overnight plan worth it with a smart panel?

ULO has the steepest spread tested here, 34.0 cents per kWh from on-peak to overnight, so it is where switching hardware comes closest to paying back. But ULO also charges 37.7 cents for anything left between 4 p.m. and 9 p.m. on weekdays, so check the whole household's evening use before switching plans.

How do I work out the payback for my own house?

Divide the device price, including installation, by your peak-to-cheap spread and by the kWh a year it would move that no existing schedule already moves. Or use the ten-year threshold above: price divided by 10, divided by your spread, is the kWh a year the device must move to pay back within ten years.

Sources

Rate figures are from the Ontario Energy Board's electricity rates page (prices set for November 1, 2026), PG&E's Electric Schedule E-TOU-C (rates effective June 1, 2026, Advice 7921-E) and Southern California Edison's time-of-use plans page (no effective date displayed), all read November 13, 2026. Device list prices are from SPAN, Emporia and Leviton product pages read the same day, in US dollars before installation, taxes and shipping. Household load figures are stated assumptions for illustration, not measurements, and every saving and payback above is arithmetic on those inputs. This page is general information about electricity rates and equipment costs, not financial or electrical advice; a licensed electrician decides what can be installed in a given panel. Full citations are listed below.