December 01, 2025

Start thermostat when windows and doors are closed

Once all windows and doors are closed, it’s time to resume climate control. This automation restores your HVAC system to continue heating or cooling your home.

Use cases

Automatic Comfort

After Airing Out - All windows and doors have been closed after bringing in fresh air
Resume Normal Comfort - Restore temperature control automatically
Seamless Experience - Climate control adapts without manual intervention

Efficiency

Energy Optimization - Don't waste time with HVAC off when windows are closed
Return from Nice Weather - Automatically resume when outdoor conditions change

Products needed

Essential Equipment

Smart Thermostat

Popular brands: Nest, Ecobee, Honeywell, Sensi
WiFi or Zigbee enabled • API control • Mode restoration capability

Contact Sensors

Popular brands: Aqara, Wyze, SmartThings, Ring
Must match sensors used in "stop thermostat" automation • Cover all monitored windows/doors

Optional Enhancements

Temperature Sensor

Verify indoor temp before resuming (safety check)

Variable/Helper

Store previous thermostat state for accurate restoration

Basic automation setup

IF all windows closed THEN restore thermostat to previous mode AND send notification "Climate control resumed"

Triggers

Any window or door closes

Conditions

ALL windows and doors are closed: Critical condition
Thermostat is currently off
Optional: Indoor temperature outside comfortable range

Actions

Turn on thermostat
Restore previous mode (heat/cool/auto)
Optional: Restore previous temperature setpoint
Optional: Send notification "Climate control resumed"

Platform-specific examples

Home Assistant

Trigger Any window or door closes

Condition ALL windows/doors closed AND thermostat is "off"

Action Restore thermostat to saved previous mode

Tip: Use group sensor for simplified "all closed" check

SmartThings

IF Living room window closes

AND ALL windows/doors closed AND Thermostat is "Off"

THEN Set thermostat mode to "Auto"

Hubitat

Trigger Any contact sensor closes

Condition All contacts closed AND thermostat is "off"

Action Restore thermostat to previous saved mode

Setup: Use Rule Machine with contact group

Apple HomeKit

When Any window or door closes

Condition All windows/doors closed, Thermostat is off

Do Turn on thermostat to Auto mode

Alexa

When Smart Home sensor closes

Condition All windows/doors closed, Thermostat "Off"

Action Set thermostat to Auto mode

Google Home

Starter Window sensor closes

Condition All windows and doors are closed

Action Set thermostat to Heat-Cool mode

Advanced features

Save and restore complete state

Store not just mode, but complete thermostat state using scene creation:

When stopping thermostat:

Create scene snapshot of thermostat (saves mode, temperature, fan, all settings)
Turn off thermostat

When resuming:

Activate saved scene
Restores: HVAC mode, temperature setpoint, fan mode, all custom settings

Delay before resuming

Wait a few minutes before resuming to ensure windows stay closed:

Add “for 2 minutes” delay to trigger - ensures windows remain closed before resuming

Temperature-based resume

Only resume if indoor temperature needs adjustment:

Winter: Resume heating if temperature drops below 68°F
Summer: Resume cooling if temperature rises above 75°F

Use conditional logic checking indoor temperature and thermostat mode.

Smart scheduling

Don’t resume during times when HVAC would normally be off:

Add time condition: Only resume between 6 AM and 11 PM (not during sleep hours when thermostat would be in eco mode)

Troubleshooting

Issue: Thermostat doesn’t resume

Causes:

Not all windows/doors actually closed
Missing sensor in condition check
Previous state not saved correctly
Automation disabled or has errors
Platform limitation on “all closed” detection

Solutions: ✅ Verify ALL sensors report closed state in app ✅ Check automation conditions - ensure every window/door sensor is listed ✅ Review automation logs - see which condition is failing ✅ Test state restoration - manually turn off thermostat and trigger automation ✅ Use group sensor (Home Assistant) or virtual sensor to simplify “all closed” check ✅ Add notification showing which sensors prevented trigger

Issue: Wrong mode restored

Causes:

Previous state not saved when shutting down
State variable not created or misconfigured
Default mode used instead of saved mode
Seasonal mode change (heat vs cool) not accounted for

Check:

✅ Verify “stop thermostat” automation saves state before turning off
✅ Check helper/variable entity exists and updates correctly
✅ Review saved state value in automation logs
✅ Test full cycle: open window → close window → verify correct mode

Fix:

Create input_text helper to store previous mode
Save complete thermostat scene instead of just mode
Add fallback: If no saved state, use “auto” mode
Consider seasonal logic: Default to “heat” in winter, “cool” in summer

Issue: Thermostat resumes too quickly

Causes:

Trigger fires immediately when any window closes
Don’t account for someone closing/reopening windows
No delay to verify windows stay closed
False triggers from sensor fluctuations

Solutions: ✅ Add “for: 2 minutes” delay to trigger - ensure windows stay closed ✅ Increase delay to 5 minutes during nice weather (encourage natural ventilation) ✅ Don’t resume if another window opened within 5 minutes ✅ Add temperature check: Only resume if temp outside comfortable range ✅ Consider time of day: Longer delays during pleasant weather hours

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