Cycles per hour explained
The cycles per hour (CPH) setting is the most times a thermostat will start your heating or cooling in one hour. Honeywell measures it at a 50% load, so 3 CPH means at most three runs of about 10 minutes, each followed by 10 minutes off. A higher number holds the temperature tighter with shorter, more frequent runs.
What does cycles per hour mean?
It is a ceiling on how often the thermostat may start the heating or cooling in an hour. Honeywell's installation guides put it this way: cycle rate limits the maximum number of times the system can cycle in a 1 hour period, measured at a 50% load.
The 50% load part matters. It describes a day when the system needs to run about half the time to hold the temperature. Honeywell's own example: at 3 CPH and a 50% load, the most the system will cycle is three times per hour, 10 minutes on and 10 minutes off. On milder or harsher days the system cycles less often than that, because each run is either shorter with long gaps, or long enough that there are fewer starts.
So cycles per hour does not set a timer. It sets how eagerly the thermostat reacts to small changes in room temperature, and that in turn decides how long each run lasts.
What happens when you raise or lower it?
A higher number means the thermostat starts the system sooner when the room drifts from the setpoint. Runs are shorter and more frequent, and the temperature stays closer to what you set. A lower number lets the room drift a little further before the system starts, so runs are longer and less frequent.
Sensi describes the same tradeoff in its support pages: a faster cycle rate provides tighter temperature control and shorter on and off cycles, while a slower one allows a slightly wider temperature swing. Honeywell says its thermostats are designed to control temperature to within about 1°F either way, and that a typical mid-efficiency forced air system cycles about five times an hour under typical conditions.
Honeywell's support page for a system that turns on and off too fast points to this setting and notes that the installer can adjust it. Our page on house temperature swings between cycles covers the opposite complaint.
What are the recommended settings?
Honeywell sets the default by equipment type. These are the values in its T4 Pro and T6 Pro Smart installation guides:
| Equipment | Recommended cycle rate(cycles per hour) |
|---|---|
| Cooling (air conditioner or heat pump), stages 1 and 2 | 3 |
| Standard efficiency gas forced air | 5 |
| High efficiency gas forced air | 3 |
| Oil forced air | 5 |
| Electric forced air | 9 |
| Fan coil | 3 |
| Hot water radiant heat | 3 |
| Steam | 1 |
The pattern is clear in the table: Honeywell gives the slowest heat sources, steam and hot water, the lowest numbers, and electric forced air the highest.
What is it called on each brand?
The name and the place differ a lot:
| Brand | Setting | Where it lives |
|---|---|---|
| Honeywell Home (T4 Pro, T6 Pro) | Cycle rate, in cycles per hour. Options 365 and 366 (cooling), 370 and 371 (heating), 375 (auxiliary heat) | Installer setup on the thermostat |
| Emerson Sensi | "Cycle Rate": Fast, Medium or Slow | Sensi app, thermostat settings, System settings, set per mode |
| ecobee | No cycles per hour setting. Heat and Cool Differential Temperature and the compressor minimum on and off times do the job | On the thermostat only: Installation Settings > Thresholds |
| Google Nest | No cycles per hour setting. Nest uses a maintenance band that it adjusts automatically | Learning Thermostat (4th gen): Google Home app, Equipment, Advanced configuration |
Sensi recommends Medium for most homes with ducted heating and cooling, and Slow for hot water boilers or steam. On ecobee and Nest, the closest equivalent is the temperature differential: how far the room may drift before the system starts.
Should you change it?
Usually not. The factory value is matched to the equipment type chosen during setup, and Honeywell treats it as an installer setting. If the equipment type was set wrong, the cycle rate will be wrong too, which is worth asking the installer about.
Cycles per hour also works alongside compressor protection, which adds a minimum rest after each compressor cycle. Even with a high cycle rate, the thermostat will not restart the compressor until that rest is over.
Frequently asked questions
- What is a good cycles per hour setting?
- The one that matches your equipment. Honeywell recommends 3 CPH for cooling and, for heat, values from 1 CPH for steam up to 9 CPH for electric forced air. Sensi recommends Medium for most ducted systems. These are the factory starting points for a reason.
- Does a higher cycles per hour setting save energy?
- None of the manufacturers we checked says so. A higher setting gives tighter temperature control with shorter runs. A lower setting allows a wider swing with longer runs. Pick the value recommended for your equipment rather than tuning for savings.
- Can I change cycles per hour myself?
- On Honeywell Home thermostats it is an installer setting, and Honeywell says the installer can adjust it. On Sensi it is in the app under System settings. On ecobee and Google Nest there is no cycles per hour setting; they use other controls.
- Is cycles per hour the same as compressor protection?
- No. Cycles per hour caps how often the system runs in normal use. Compressor protection is a separate minimum off time after each cooling or heat pump cycle. Honeywell keeps them as separate installer options.