Understanding Heating or Cooling Delays
Last updated: February 20, 2026
Understanding Heating or Cooling Delays
When your heating or cooling doesn't turn on right away, it can be frustrating—but in most cases, it's completely normal. Your thermostat uses built-in protections and comfort-balancing rules to keep your system healthy and your home efficient.
This article explains the most common reasons you may see a delay.
Minimum Compressor Off Time (MCOT)
Applies to: Heat pumps and air conditioners only
After your heating or cooling turns off, the thermostat enforces a mandatory "rest" period before it can turn back on. This delay ensures the compressor stays off long enough for system pressures to equalize and components to return to safe operating conditions before restarting.
Mysa MCOT: 5 minutes
How It Causes Delays
- If the system recently turned off, it will not turn back on immediately—even if the room temperature has shifted. Once the rest period has elapsed, the compressor will automatically engage.
- You'll see the heating or cooling icon on the thermostat or in the app once the mode is selected, but the system won't engage until the delay period has elapsed.
Why It Matters
If the compressor turns on and off too quickly, pressure inside the system doesn't have time to equalize. Restarting under high pressure forces the compressor to work much harder than designed. The 5-minute delay is based on industry best practices across HVAC manufacturers, balancing safety and comfort.
Cycles Per Hour (CPH) Limits
Applies to: All HVAC systems supported by Mysa Smart Thermostat
Cycles Per Hour limits how many times your system can turn on within a single hour. This prevents short-cycling—constantly switching on and off too frequently. Mysa's CPH settings are customized to your specific system type.
System Type | CPH Limit
Electric | 12
Fuel-based (gas, oil) | 6
Heat pump or hydronic | 3
How It Causes Delays
Mysa calculates how many times per hour your system can run. Regardless of the need for heating or cooling, the thermostat may delay the next cycle until enough time has elapsed.
Example:
- System type: Heat pump
- CPH limit: 3 (one cycle every 20 minutes)
- A cycle begins at 1:00 PM and ends at 1:10 PM
- The room calls for heat again at 1:16 PM
- Only 16 minutes have passed since the last cycle began
- The system waits an additional 4 minutes before starting
Note CPH delays are ignored when you manually adjust the thermostat. This lets you bypass the delay—useful for testing, initial setup, or maintenance.
Why It Matters
Limiting cycles reduces wear and tear, prevents temperature overshooting, and keeps energy usage steady.
Temperature Differential (Swing)
Applies to: All HVAC systems supported by Mysa Smart Thermostat
The thermostat doesn't turn on heating or cooling the instant the temperature changes by 0.1°. Instead, it uses a built-in temperature differential (sometimes called swing or deadband) to avoid constant cycling.
Mysa Differential: 1°F (0.6°C)
How It Causes Delays
Your system will only turn on once the room temperature moves a certain amount away from your setpoint.
Example:
- Setpoint: 21°C
- Differential: 0.6°C
- Heating may not turn on until the room drops to 20.4°C
This can feel like a delay, especially during quick temperature changes.
Why It Matters
A small differential reduces unnecessary cycling and helps your system maintain comfort while using less energy.
Combined Effect of All Three
Sometimes all three factors overlap. For example:
- The room has moved past the differential threshold, but
- The compressor is still in its minimum off time, or
- The maximum cycles per hour hasn't elapsed yet
This combination can make delays appear longer than expected, even though the thermostat is working correctly and protecting your system.