Thermostat Modes

Every Mysa Smart Thermostat has at least two modes: either Heat and Off, or Cool and Off. Depending on how your thermostat was configured during setup, you may also see additional options like Heat and Cool together, Auto, Fan Only, or Aux.

Changing Modes

From the device control screen, tap the mode icon to open the mode menu. Tap the mode you want and it sends immediately—a blue status bar confirms the command was sent. The hold type defaults to "until next scheduled event." To choose a different hold type, tap the hold button.

You can also set modes in your schedule—each scheduled event can include a specific mode, so your thermostat automatically switches throughout the day.

Available Modes

Heat

In Heat mode, the thermostat calls for heating when the room temperature drops below your setpoint. Heating turns on when the temperature falls 1°F (0.6°C) below the setpoint, and turns off once the room reaches the target.

Use Heat mode during colder months or anytime you only need heating.

Cool

In Cool mode, the thermostat calls for cooling when the room temperature rises above your setpoint. Cooling turns on when the temperature rises 1°F (0.6°C) above the setpoint, and turns off once the room reaches the target.

Use Cool mode during warmer months or anytime you only need air conditioning.

Off

Off mode stops the thermostat from calling for heating or cooling. However, it doesn't disable the thermostat entirely—the device stays powered on, connected to Wi-Fi, and continues following its schedule.

If your schedule includes a mode change, the thermostat will switch out of Off mode when that event occurs. To keep the thermostat off indefinitely, set a hold to "Indefinitely" or delete the schedule.

Tip: Off mode is useful during mild weather, seasonal transitions, or when you want to air out your home without the HVAC kicking in.

Freeze Protection still works in Off mode. If the temperature drops to 7°C (45°F), the thermostat will turn on heating regardless of the mode setting to protect your pipes.

Conditional Modes

These modes only appear if your HVAC system supports them.

Auto

Auto mode lets the thermostat switch between heating and cooling automatically. Instead of a single setpoint, you set two: a "Heat To" temperature and a "Cool To" temperature.

If the room drops below the Heat To temperature, heating turns on.
If the room rises above the Cool To temperature, cooling turns on.
Between the two setpoints, the system stays idle.

Note: Auto mode must be enabled in the app before it appears on the thermostat. Go to Settings > Thermostat Preferences > Auto Mode. Requires firmware 4.4.11 or higher.

For details on deadband settings and setpoint ranges, see Auto Mode.

Fan Only

Fan Only mode runs your HVAC fan without heating or cooling. This circulates air throughout your home, which can help even out temperatures between rooms or improve air quality.

Note: Fan Only requires a G-wire (fan control wire). If your configuration code ends in "A," you don't have independent fan control and this mode won't appear.

For more on fan control options, see Fan Control.

Aux

Aux mode forces the thermostat to use auxiliary heat instead of the primary heating source. This gives you direct control over when to use your backup heating—a unique Mysa feature that most thermostats don't offer.

Auxiliary heat is typically electric resistance heating or a gas/oil furnace that supplements a heat pump. Since heat pumps lose efficiency in extremely cold weather, aux heat provides supplemental warmth when needed.

When you might choose Aux mode:

Extreme cold — On very cold days, you may want to run gas or electric resistance heat instead of your heat pump, which loses efficiency in low temperatures.
Time-of-use rates — If electricity is cheaper during certain hours, you can switch to Aux during those windows to save money.
Faster heating — Aux heat typically heats faster than a heat pump, useful when you need to warm up quickly.

Note: Aux mode only appears if your HVAC configuration supports auxiliary heat.

Automatic Aux Heat: If you enable Staged Auxiliary Heat, the thermostat can automatically bring in aux heat when the room temperature falls too far below the setpoint and the heat pump can't close the gap. You can configure the temperature delta and delay thresholds in Settings > Thermostat Configuration > Staged Auxiliary Heat.

For full details, see Staged Auxiliary Heat.

Understanding Staged Heating and Cooling

If your HVAC system has multiple stages (Heat 1/Heat 2 or Cool 1/Cool 2), the thermostat automatically decides when to bring in the second stage. You can customize this behavior in Settings > Thermostat Configuration > Multi Stage Heating or Multi Stage Cooling.

Two settings control when the second stage kicks in:

Difference — If the room is further than this value from the setpoint, the second stage activates immediately. For example, with a difference of 4°C (7°F), if your setpoint is 21°C (70°F) and the room is 16°C (61°F), the second stage kicks in right away.
Stage Duration — If stage 1 has been running for this long but the room still hasn't reached the setpoint, the second stage kicks in. For example, with a duration of 10 minutes, if Heat 1 runs for 10 minutes and the room is still below setpoint, Heat 2 activates.

You'll see which stage is active in the runtime status indicator on both the home screen tile and the device control screen (e.g., "Heat 1" or "Heat 2").

FAQs

Why don't I see Auto mode on my thermostat? Auto mode must be enabled in the app first. Go to Settings > Thermostat Preferences > Auto Mode and toggle it on. Your thermostat also needs firmware version 4.4.11 or higher.

Why don't I see Fan Only mode? Fan Only requires a G-wire for independent fan control. If your HVAC system doesn't have a G-wire connected, this mode won't be available.

Why don't I see Aux mode? Aux mode only appears if your HVAC system has auxiliary heat configured. This is typically found on heat pump systems with electric or gas/oil backup heating.

Does Off mode save energy? Yes, since the system won't heat or cool. But remember that Freeze Protection will still activate if temperatures drop too low.

Can I schedule different modes throughout the day? Yes. Each scheduled event can include a mode, so you could run Heat in the morning, Off during the day, and Heat again in the evening.

What's the difference between Aux mode and Staged Auxiliary Heat? Aux mode lets you manually force auxiliary heat on. Staged Auxiliary Heat is an automatic feature that brings in aux heat when the heat pump can't keep up—you configure the thresholds and the thermostat handles it automatically.