Power-User · Level 3 of 3
This assumes Home Assistant is already running on your network — a Raspberry Pi, a mini PC, or a Home Assistant Green — with your smart plugs, thermostat, and water heater switch already added as devices. If you haven’t set that up yet, start with 20 Home Assistant Automations Worth Setting Up First and come back here once the basics are running.
Five automations move the needle on an electric bill: catching standby and vampire loads, setting back HVAC on a schedule, scheduling the water heater instead of running it around the clock, shifting flexible loads to off-peak hours, and tracking all of it against your actual utility rate instead of a guess. Each one below ships with the YAML and the rough math, so you can see whether it’s worth your time before you copy anything.
What do you need before setting any of this up?
None of the automations below need anything exotic, but each one assumes a specific piece of hardware is already added as an entity in Home Assistant:
- Home Assistant itself, running and reachable from the dashboard you normally use
- At least one metered smart plug (reports live wattage, not just on/off) for the standby-load automation
- A thermostat exposed as a
climateentity — most Nest, Ecobee, and Honeywell models qualify through their official integration - A smart switch rated for your water heater’s amperage, if you’re automating that one
- Your utility’s time-of-use rate schedule, if you’re on a TOU plan (check your account portal or a recent bill)
Skip whichever automation doesn’t match your setup — there’s no reason to buy a smart switch just to automate a water heater you rent with the apartment, for instance. Pick the one or two that fit your house first.
What actually moves the needle on your electric bill?
The average U.S. residential electricity rate was 18.83 cents per kWh as of April 2026, according to the U.S. Energy Information Administration — up sharply from a few years ago, which is exactly why automations that used to save a few dollars a month now save more. The table below uses that national average; swap in your own rate from a recent bill for a more accurate number, since rates vary widely by state and utility.
| Automation | What it targets | Rough monthly savings* |
|---|---|---|
| Standby/vampire load cutoff | Devices drawing power while “off” (TVs, consoles, chargers) | $3–$8 |
| HVAC setback schedule | Heating/cooling while nobody’s home or asleep | $10–$25 |
| Water heater scheduling | Keeping a tank hot 24/7 instead of on-demand | $5–$15 |
| Time-of-use load shifting | Running flexible loads during peak-rate hours | $5–$20 |
How do you catch standby and vampire loads with a smart plug?
A metered smart plug — one that reports live wattage, not just on/off state — is the cheapest way to find out which devices are quietly drawing power around the clock. Brands like Shelly and Emporia make plugs and whole-home monitors with native Home Assistant integrations; neither is in Automate My Life’s tool catalog yet, so treat these as plain pointers rather than an endorsement of one over the other. Check the box before buying: you specifically need a plug that exposes a power sensor, not just a switch entity.
Once the plug is added and its power sensor shows up as an entity, this automation cuts power to a device once it’s been idle below a threshold for a set time — useful for a TV/soundbar/console cluster that draws 15–20 watts “off” but never fully powers down:
alias: Cut standby power to TV cluster
trigger:
- platform: numeric_state
entity_id: sensor.tv_plug_power
below: 5
for:
hours: 1
condition:
- condition: state
entity_id: input_boolean.standby_cutoff_enabled
state: "on"
action:
- service: switch.turn_off
target:
entity_id: switch.tv_plug
The input_boolean guard matters — add a helper toggle so you can pause the automation from the dashboard on movie night without editing YAML. Start with one plug on your worst offender, watch the power sensor’s history for a week, then decide if it’s worth repeating elsewhere. For more ideas on what else is worth plugging in this way, see Smart Plug Automation Ideas: 12 Useful Ways to Use Them.
How do you set back HVAC on a schedule instead of running it constantly?
Heating and cooling is usually the single biggest line item on a bill, and it’s also the easiest to automate badly — a setback that’s too aggressive means a cold house at 6am and a thermostat fighting to catch up, which can erase the savings. A gentler setback while everyone’s asleep or away, timed to recover 30–45 minutes before people are up or home, tends to hold the savings without the discomfort:
alias: Overnight HVAC setback
trigger:
- platform: time
at: "22:30:00"
action:
- service: climate.set_temperature
target:
entity_id: climate.living_room
data:
temperature: 62
---
alias: Morning HVAC recovery
trigger:
- platform: time
at: "05:45:00"
condition:
- condition: time
weekday:
- mon
- tue
- wed
- thu
- fri
action:
- service: climate.set_temperature
target:
entity_id: climate.living_room
data:
temperature: 68
Adjust the setpoints and the weekday condition to your own schedule — the point is the pattern, not the exact numbers. If your thermostat already has its own scheduling built in (a Nest or Ecobee, for instance), it’s fair to ask whether you need Home Assistant in the loop at all here; the honest answer is that it’s most useful when you want the setback tied to other conditions, like an away-mode sensor or a door left open, rather than a fixed clock alone.
How do you schedule the water heater instead of keeping a tank hot all day?
A tank water heater on a smart switch — most installs use a relay rated for the heater’s amperage, not a plug-in device — can run on a schedule that matches when hot water actually gets used, instead of holding temperature 24 hours a day. This works best for a second water heater (a garage or workshop unit) or a household with a predictable routine; it’s a poor fit if hot water demand is unpredictable, since recovery time on some tanks runs 30–60 minutes.
alias: Water heater on for morning and evening use
trigger:
- platform: time
at: "05:30:00"
- platform: time
at: "16:30:00"
action:
- service: switch.turn_on
target:
entity_id: switch.water_heater
---
alias: Water heater off after use window
trigger:
- platform: time
at: "08:00:00"
- platform: time
at: "21:00:00"
action:
- service: switch.turn_off
target:
entity_id: switch.water_heater
Confirm the switch is rated for your heater’s load before wiring anything — this is one of the setups where getting it wrong is a safety issue, not just an inconvenience, so if you’re not confident reading the heater’s nameplate amperage, have an electrician handle the switch install and just automate the Home Assistant side.
How do you shift flexible loads to off-peak time-of-use hours?
If your utility bills on a time-of-use (TOU) rate plan, the same kWh can cost two or three times more during a peak window — usually weekday afternoons and early evenings — than overnight. Check your utility’s rate schedule (it’s on your bill or account portal) before building this, since the exact peak hours vary by provider and season. Once you know your window, an input_boolean helper tied to a time condition lets you gate any flexible load — a dishwasher, EV charger, or pool pump — to off-peak hours:
alias: Block dishwasher during peak TOU window
trigger:
- platform: time
at: "16:00:00"
action:
- service: input_boolean.turn_on
target:
entity_id: input_boolean.peak_hours_active
---
alias: Clear peak TOU window
trigger:
- platform: time
at: "21:00:00"
action:
- service: input_boolean.turn_off
target:
entity_id: input_boolean.peak_hours_active
From there, reference input_boolean.peak_hours_active as a condition on any automation or smart plug you don’t want firing during the peak window — a dishwasher’s start button already has a delay-start feature on most modern models, so this is often more about the automation nudging you (a notification: “peak rates end at 9pm, want to start the dishwasher then?”) than force-stopping a running appliance.
How much of this is realistic to expect?
Treat every number above as a scenario estimate, not a guarantee. The honest range for a household running all four automations is somewhere between $20 and $60 off a monthly bill, weighted heavily toward the HVAC setback since that’s usually the largest single load in the house. A one-bedroom apartment with a small window unit and no TOU plan will see far less than a four-bedroom house on a peak/off-peak rate in a hot climate. Measure your own baseline for two weeks before you automate anything, then compare against two weeks after — that’s the only number that actually tells you whether it worked.
Where the numbers above come from: the 18.83¢/kWh figure is the U.S. Energy Information Administration’s national average residential rate as of April 2026. The per-automation dollar ranges are scenario estimates built from typical device wattage and runtime, not a lab measurement of any specific house — your utility’s actual rate schedule will move these numbers up or down. Recheck your own rate at least once a year, since it has been climbing faster than usual the past couple of years.
A few signs an automation on this list isn’t worth building yet: your thermostat already has smart scheduling that does the same job, your utility doesn’t offer a time-of-use plan so there’s no peak-rate penalty to dodge, or the device you’d be metering already draws under a few watts at idle. Automating a load that’s already small just adds a maintenance burden with no real payoff — the standby-load check with a smart plug is the fastest way to find out which of your own devices are actually worth the effort.
None of this requires a whole-home energy monitor to start — a single metered smart plug on your worst-offending device is enough to prove the concept before you spend more. Once you’ve got the standby cutoff and HVAC setback running, the beginner automation list and the smart plug ideas post cover the rest of what’s worth setting up next.