Temperature Linear

Purpose

The Temperature Linear module provides a simple three-zone mapping from temperature to fan speed. Define your temperature thresholds and fan speed percentages, and the controller handles the rest — no complex tuning required.

When to Use

Choose Linear when you want straightforward temperature-based fan control without the complexity of PID tuning or multi-point curves. It works well for most home and office setups where you just need fans to ramp up as temperature rises.

For more precise temperature targeting, consider Temperature PID. For finer control over the speed curve shape, see Temperature Curve. The modules overview has a comparison table.

Configuration

Variable	Default	Description
`friendly_name`	`"Fancontroller"`	Device name prefix for all entities
`t_off`	`"25.0"`	Temperature below which fans turn off (C)
`t1`	`"30.0"`	Lower temperature setpoint (C)
`t2`	`"50.0"`	Upper temperature setpoint (C)
`fanpercent1`	`"30.0"`	Fan speed at t1 (%)
`fanpercent2`	`"100.0"`	Fan speed at t2 and above (%)

Zone Behavior

The module divides temperature into four zones:

Zone	Temperature Range	Fan Speed	Behavior
Off	Below `t_off`	0%	Fans completely off
Constant low	`t_off` to `t1`	`fanpercent1`	Fans run at a fixed low speed
Ramp	`t1` to `t2`	`fanpercent1` to `fanpercent2`	Linear ramp between the two speeds
Constant high	Above `t2`	`fanpercent2`	Fans run at maximum configured speed

With the defaults (t_off=25, t1=30, t2=50, fanpercent1=30%, fanpercent2=100%):

Below 25 C: fans off
25-30 C: fans at 30%
30-50 C: fans ramp linearly from 30% to 100%
Above 50 C: fans at 100%

Home Assistant Entities

Number Entities

Entity	Range	Step	Unit	Default	Description
Linear Off Temperature	20 — 50	0.5	C	25.0	Temperature below which fans stop
Linear T1	20 — 50	0.5	C	30.0	Lower temperature setpoint
Linear T2	20 — 50	0.5	C	50.0	Upper temperature setpoint
Linear Fan Percent 1	0 — 100	1	%	30	Fan speed at T1
Linear Fan Percent 2	0 — 100	1	%	100	Fan speed at T2 and above

Sensor Entities

Entity	Unit	Description
Linear Output	%	Current calculated fan speed (updated every 10s)

Switch Entities

Entity	Default	Description
Auto Control Fan 1	ON	Enable linear control for fan 1
Auto Control Fan 2	ON	Enable linear control for fan 2
Auto Control Fan 3	ON	Enable linear control for fan 3
Auto Control Fan 4	ON	Enable linear control for fan 4

YAML Examples

Basic Usage (Default Settings)

packages:
  temperature_linear:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_linear.yaml
        vars:
          friendly_name: "My Fan Controller"

Quiet Desktop Profile

packages:
  temperature_linear:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_linear.yaml
        vars:
          friendly_name: "Desktop Cooler"
          t_off: "28.0"
          t1: "32.0"
          t2: "45.0"
          fanpercent1: "20.0"
          fanpercent2: "80.0"

This profile keeps fans off until 28 C, starts at a quiet 20%, and caps at 80% for reduced noise.

Tuning Tips

Adjust t_off based on ambient temperature — if your room is normally 24 C, setting t_off to 25 C means fans only spin when something is actively generating heat
Set fanpercent1 to your fans’ minimum reliable speed — most fans need at least 20-30% PWM to start spinning consistently. Check the troubleshooting guide if fans stutter at low speeds.
Use the HA number entities to fine-tune — all five parameters can be adjusted live from Home Assistant without reflashing
Watch the Linear Output sensor — it shows the current calculated fan speed percentage, helpful for verifying your thresholds behave as expected