The Best Times to Run Energy-Intensive Appliances for Cost Savings (Time-of-Use Optimized)

It's 2 PM on a sweltering July afternoon in Chicago. Your air conditioner is working overtime, your teenager is running the dryer, and you've just started the dishwasher. Unknown to you, you're paying premium electricity rates—potentially 2-3 times higher than you'd pay at 10 PM. If you're on a time-of-use rate plan, that single afternoon of poor timing could add $20-$30 to your monthly bill.

Time-of-use (TOU) rates are becoming increasingly common in Illinois and across the United States. These rate structures charge different prices for electricity depending on when you use it—reflecting the real cost of generating and delivering power during high-demand periods. Understanding TOU rates and optimizing your appliance usage accordingly can reduce your electricity costs by 20-40% without reducing your actual consumption.

This comprehensive guide will explain how time-of-use rates work in Illinois, provide a detailed cheat sheet of ComEd peak hours and off-peak electricity hours, identify the best times to run your most energy-intensive appliances, and explore smart home technology that can automate the process.

Time-of-Use Rates Guide: Understanding How You're Charged

Before you can optimize your appliance usage, you need to understand what time-of-use rates are and how they differ from traditional flat-rate pricing.

What Are Time-of-Use Rates?

Traditional electricity rates charge a flat price per kilowatt-hour (kWh) regardless of when you consume power. Whether you run your dryer at 3 PM or 3 AM, you pay the same rate—perhaps 12 cents per kWh.

Time-of-use rates, by contrast, vary the price based on the time of day, day of the week, and sometimes the season. These rates typically include:

• Peak hours: The most expensive period, typically afternoon and early evening when demand is highest. Rates might be 20-35 cents per kWh.
• Off-peak hours: The least expensive period, typically overnight and early morning. Rates might be 5-8 cents per kWh.
• Mid-peak or shoulder hours: An intermediate rate period in some plans, typically morning and late evening. Rates might be 10-15 cents per kWh.

The price difference between peak and off-peak can be dramatic—sometimes 300-400%. This creates substantial incentive to shift energy usage to off-peak hours.

Why Do TOU Rates Exist?

TOU rates reflect the real economics of electricity generation and delivery:

Generation costs vary by hour: When demand is low (overnight), efficient baseload power plants meet all needs at low cost. When demand peaks (hot summer afternoons), utilities must run expensive "peaker" plants that cost much more per kWh to operate.

Grid stress during peak periods: High demand strains transmission and distribution infrastructure, requiring investment in capacity that sits idle most hours. TOU rates encourage customers to reduce peak usage, potentially avoiding costly infrastructure upgrades.

Renewable energy integration: Solar generation peaks midday; wind often peaks overnight. TOU rates can be designed to encourage consumption when renewable generation is abundant.

According to the U.S. Energy Information Administration, utilities in deregulated states are increasingly offering time-varying rate options to residential and commercial customers as smart meter deployment expands.

TOU Rate Options in Illinois

Illinois customers have several options for time-of-use pricing:

ComEd Hourly Pricing Program: ComEd offers residential customers the option to pay hourly market prices for electricity supply. This isn't exactly TOU (prices change every hour based on market conditions), but the pattern is similar—prices are typically lowest overnight and highest on hot summer afternoons.

ComEd Time-of-Use Rate: ComEd's Rate BESH offers time-of-use pricing for residential customers with electric space heating or large electric vehicle charging needs.

Retail Supplier TOU Plans: Some retail electricity suppliers in Illinois offer TOU rate structures as an alternative to flat-rate plans.

Ameren Illinois Time-of-Use Options: Ameren offers Power Smart Pricing (real-time hourly rates) for residential customers seeking to benefit from off-peak pricing.

Even if you're not currently on a TOU plan, understanding peak and off-peak patterns helps you avoid demand charges (for commercial customers) and positions you to benefit when TOU options become more widespread.

Peak vs. Off-Peak Cheat Sheet: Know Your Time Windows

The specific hours that qualify as peak, off-peak, and mid-peak vary by utility, rate plan, and season. Here's a detailed breakdown for Illinois customers.

ComEd Peak Hours and Off-Peak Hours

Summer (June - September):

• Peak hours: 2 PM - 7 PM, weekdays (highest prices, avoid running major appliances)
• Mid-peak hours: 7 AM - 2 PM and 7 PM - 10 PM, weekdays
• Off-peak hours: 10 PM - 7 AM, weekdays; all day Saturday and Sunday

Winter (October - May):

• Peak hours: 6 AM - 10 AM and 5 PM - 9 PM, weekdays
• Mid-peak hours: 10 AM - 5 PM, weekdays
• Off-peak hours: 9 PM - 6 AM, weekdays; all day Saturday and Sunday

Holidays: Most TOU plans treat holidays as off-peak days, similar to weekends.

Ameren Illinois Peak Hours

Ameren's Power Smart Pricing program uses real-time hourly rates rather than fixed TOU periods, but typical patterns show:

• Highest prices: Summer weekday afternoons (1 PM - 6 PM), especially during heat waves
• Elevated prices: Winter mornings (6 AM - 10 AM) and evenings (5 PM - 9 PM)
• Lowest prices: Overnight hours (10 PM - 6 AM) year-round; weekends typically lower than weekdays

Understanding Price Differentials

The savings opportunity depends on the difference between peak and off-peak rates. Here are typical differentials:

Running that dryer at 11 PM instead of 3 PM during summer can save $1.00-$1.35 per load. Run four loads per week, and you're saving $16-$22 monthly on laundry alone.

Best Times for HVAC, Dryer, Dishwasher, and Other Appliances

Not all appliances are equally easy to reschedule. Here's a practical guide to optimizing your major energy consumers for TOU rates.

HVAC and Air Conditioning

Your HVAC system is likely your largest electricity consumer, accounting for 40-60% of summer electricity bills. While you can't simply turn off AC during peak hours, you can optimize its operation.

Pre-Cooling Strategy:

• Lower your thermostat to 68-70°F during off-peak morning hours (before 2 PM in summer)
• Allow temperature to rise to 76-78°F during peak hours (2-7 PM)
• The thermal mass of your home maintains comfort even as AC runs less
• Resume normal cooling after 7 PM when rates drop

Smart Thermostat Programming:

• Program setback during peak hours automatically
• Enable "eco" mode that reduces runtime during high-demand periods
• Use "away" settings that maximize savings when no one is home

Estimated Savings: 15-25% reduction in cooling costs during summer peak season, or $30-$75 per month for typical Illinois homes.

Clothes Dryer

Electric dryers consume 2-5 kWh per load, making them one of the easiest appliances to shift for savings.

Best times to run your dryer:

• Weekdays: Before 7 AM or after 10 PM
• Weekends: Anytime (off-peak all day)
• Avoid: 2-7 PM on summer weekdays (highest rates)

Practical tips:

• Run laundry loads in evening and dry before bed
• Use delayed start feature if available to start drying at 10 PM
• Consider line drying or drying racks during summer to avoid peak-hour use entirely
• Run full loads only to maximize efficiency

Estimated Savings: $1.00-$1.50 per load by shifting from peak to off-peak. At 5 loads per week, that's $20-$30 monthly.

Dishwasher

Dishwashers use 1.5-2.5 kWh per cycle, with much of that going to heat water and run the drying cycle.

Best times to run your dishwasher:

• Run after dinner dishes are loaded, but delay start until 10 PM or later
• Morning runs before 7 AM work well if you load the night before
• Weekend runs anytime

Practical tips:

• Use delay start feature (most dishwashers have this) to begin at off-peak times
• Skip the heated dry cycle—open door and air dry to save additional energy
• Run only full loads

Estimated Savings: $0.35-$0.50 per cycle by shifting to off-peak. Running once daily saves $10-$15 monthly.

Washing Machine

Washing machines themselves use modest electricity (0.3-0.5 kWh per load), but if you use hot water, the water heater adds significantly more.

Best times to run your washer:

• Evening hours after 7 PM (when you can follow with off-peak drying)
• Early morning before 7 AM
• Weekends anytime

Practical tips:

• Wash with cold water when possible—90% of washing machine energy goes to heating water
• Run full loads only
• Coordinate with dryer timing for greatest overall savings

Electric Vehicle Charging

EVs are one of the largest new loads in many households, and timing is crucial for cost optimization.

Best times to charge your EV:

• Ideal: 10 PM - 6 AM (lowest rates, grid demand minimal)
• Acceptable: 6 AM - 7 AM or 9 PM - 10 PM
• Avoid: 2-7 PM on summer weekdays (peak rates can make charging 3-4x more expensive)

Practical tips:

• Use your EV's built-in charging scheduler to start charging at midnight
• Install a Wi-Fi enabled charger for remote scheduling control
• Consider a dedicated EV TOU rate if available (some utilities offer special EV rates)
• Charge to 80% for daily driving—full charges only when needed for longer trips

Estimated Savings: For an EV using 300 kWh monthly, shifting from peak to off-peak charging can save $45-$75 per month.

Water Heater

Electric water heaters can be optimized for TOU rates, though this requires some planning.

Strategies for water heater optimization:

• Timer installation: Install a timer that heats water during off-peak hours only (early morning and late night)
• Higher off-peak temperature: Heat water to a higher temperature during off-peak and rely on stored hot water during peak
• Shift usage: Take showers before 7 AM or after 10 PM when possible

Heat pump water heaters: These use 50-70% less electricity than standard electric water heaters and can be scheduled to run during off-peak hours only.

Pool Pumps

Pool pumps are major electricity consumers that run several hours daily.

Best times to run pool equipment:

• Overnight hours (10 PM - 7 AM) are ideal
• Split into two off-peak sessions if continuous operation is preferred
• Avoid afternoon peak hours entirely

Estimated Savings: A 1.5 HP pool pump running 8 hours daily can cost $60-$90 monthly at peak rates vs. $20-$30 at off-peak rates.

Smart Home Tech for Automation: Set It and Save

Manually shifting every appliance to off-peak hours is tedious and easy to forget. Smart home technology can automate the process, ensuring you capture savings consistently.

Smart Thermostats

A smart thermostat is typically the highest-impact single investment for TOU optimization.

Key features for TOU optimization:

• Time-of-use awareness: Some thermostats (like Nest and Ecobee) can learn your utility's TOU schedule and automatically pre-cool before peak periods
• Occupancy detection: Reduce heating/cooling when no one is home
• Remote control: Adjust settings from your phone when plans change
• Learning algorithms: Automatically optimize based on your habits and preferences
• Utility program integration: Connect with ComEd or Ameren demand response programs for additional savings

Top picks:

• Google Nest Learning Thermostat: Learns your schedule, integrates with utility programs, Energy Star certified
• Ecobee Smart Thermostat Premium: Room sensors for multi-zone optimization, built-in Alexa, utility program compatible
• Honeywell Home T6 Pro: Budget-friendly option with solid scheduling and geofencing

ComEd and Ameren rebates: Both utilities offer $25-$100 rebates on qualifying smart thermostats. Check current offers before purchasing.

Smart Plugs and Outlets

Smart plugs provide scheduling control for any plug-in appliance.

Best uses for smart plugs:

• Window AC units (schedule to pre-cool before peak hours)
• Space heaters (schedule for off-peak morning warm-up)
• Pool pump timers (replace mechanical timers with smartphone-controlled scheduling)
• Holiday lighting (schedule for off-peak hours only)
• Charging stations (schedule to charge devices overnight)

Top picks:

• TP-Link Kasa Smart Plug: Reliable, affordable, works with Alexa and Google Home
• Wemo Smart Plug: Energy monitoring built-in, Apple HomeKit compatible
• Amazon Smart Plug: Seamless Alexa integration, competitive price

Smart EV Chargers

If you have an EV, a smart charger provides the most control over this significant load.

Key features:

• TOU scheduling: Automatically delay charging until off-peak rates begin
• Utility rate integration: Some chargers connect to your utility account and optimize automatically
• Load management: Reduce charging rate if home demand approaches limits
• Energy monitoring: Track exactly how much you're spending on EV charging
• Solar integration: Prioritize charging when solar production is high

Top picks:

• ChargePoint Home Flex: Adjustable amperage, WiFi connected, excellent app
• Emporia EV Charger: Budget-friendly with good smart features
• Wallbox Pulsar Plus: Compact, powerful, Apple/Android compatible

Smart Appliances with Built-In Scheduling

Many modern appliances include delay-start or smart scheduling features.

Dishwashers: Most dishwashers from major brands (Bosch, LG, Samsung, Whirlpool) include delay-start features allowing scheduling up to 24 hours ahead. Wi-Fi connected models allow scheduling via smartphone.

Washing Machines: Similar delay-start features are common. Some LG and Samsung models offer "Smart ThinQ" connectivity that can integrate with utility programs for automatic off-peak scheduling.

Dryers: Delay-start dryers are less common but available. Look for "steam refresh" features that can dewrinkle clothes if you can't transfer them immediately when the cycle ends overnight.

Whole-Home Energy Monitoring

To truly optimize your energy usage, you need visibility into what's consuming power and when.

Energy monitoring options:

• Sense Energy Monitor: Clips to your electrical panel and uses machine learning to identify individual appliance consumption. See real-time usage and get alerts when appliances turn on during peak hours.
• Emporia Vue: Budget-friendly whole-home monitoring with optional circuit-level sensors.
• Utility smart meter data: ComEd and Ameren provide hourly usage data through their online portals—less granular but free.

According to National Renewable Energy Laboratory research, households with real-time energy feedback reduce consumption by 5-15% on average, simply by becoming more aware of their usage patterns.

Home Automation Hubs and Routines

For comprehensive automation, a home automation hub can coordinate multiple devices based on time, occupancy, or other triggers.

Popular platforms:

• Amazon Alexa: Routines can trigger multiple devices at scheduled times ("At 10 PM, start the dishwasher, begin EV charging, and set thermostat to 72°F")
• Google Home: Similar routine capabilities with integration across Google ecosystem
• Apple HomeKit: Automation scenes for iOS users
• SmartThings: More advanced automation logic for tech-savvy users

Example TOU-optimized routine:

"Off-Peak Start" (10 PM trigger):

• Start dishwasher
• Begin EV charging
• Set water heater to "boost" mode
• Set thermostat to pre-cool/pre-heat for morning

Creating Your Personal TOU Optimization Plan

Here's a step-by-step process to maximize your savings with time-of-use rates:

Step 1: Understand Your Rate Structure

• Log into your ComEd or Ameren account
• Review your current rate plan (flat rate, TOU, or real-time pricing)
• If on flat rate, evaluate whether TOU would save money based on your usage patterns
• Note exact peak, mid-peak, and off-peak hours for your plan

Step 2: Audit Your Major Energy Consumers

• Identify your 5-10 largest electricity-using appliances
• Note when each typically operates
• Calculate which can be shifted to off-peak hours

Step 3: Implement Easy Shifts First

• Set dishwasher delay to run after 10 PM
• Shift laundry to evenings and weekends
• Schedule EV charging for overnight
• Adjust pool pump timer for off-peak hours

Step 4: Invest in Smart Technology

• Install a smart thermostat as your first investment
• Add smart plugs for appliances that need scheduling control
• Consider energy monitoring to track your optimization progress

Step 5: Monitor and Adjust

• Review monthly bills to confirm savings
• Adjust strategies seasonally as peak hours change
• Look for additional optimization opportunities