diff --git a/src/channel_state.rs b/src/channel_state.rs
index 4820131..63beaf9 100644
--- a/src/channel_state.rs
+++ b/src/channel_state.rs
@@ -35,6 +35,7 @@ pub struct ChannelState {
     pub pid_engaged: bool,
     pub pid: pid::Controller,
     pub sh: sh::Parameters,
+    pub swap_tec_polarity: bool,
 }
 
 impl ChannelState {
@@ -51,6 +52,7 @@ impl ChannelState {
             pid_engaged: false,
             pid: pid::Controller::new(pid::Parameters::default()),
             sh: sh::Parameters::default(),
+            swap_tec_polarity: false,
         }
     }
 
diff --git a/src/channels.rs b/src/channels.rs
index cfec178..5bf0ee6 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -114,7 +114,11 @@ impl<'a> Channels<'a> {
 
     pub fn get_i(&mut self, channel: usize) -> ElectricCurrent {
         let i_set = self.channel_state(channel).i_set;
-        i_set
+        if self.channel_state(channel).swap_tec_polarity {
+            -i_set
+        } else {
+            i_set
+        }
     }
 
     /// i_set DAC
@@ -129,12 +133,15 @@ impl<'a> Channels<'a> {
         voltage
     }
 
-    pub fn set_i(&mut self, channel: usize, i_set: ElectricCurrent) -> ElectricCurrent {
+    pub fn set_i(&mut self, channel: usize, mut i_set: ElectricCurrent) -> ElectricCurrent {
         let vref_meas = match channel.into() {
             0 => self.channel0.vref_meas,
             1 => self.channel1.vref_meas,
             _ => unreachable!(),
         };
+        if self.channel_state(channel).swap_tec_polarity {
+            i_set = -i_set;
+        }
         let center_point = vref_meas;
         let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
         let voltage = i_set * 10.0 * r_sense + center_point;
@@ -371,7 +378,12 @@ impl<'a> Channels<'a> {
 
     // Get current passing through TEC
     pub fn get_tec_i(&mut self, channel: usize) -> ElectricCurrent {
-        (self.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4)
+        let tec_i = (self.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4);
+        if self.channel_state(channel).swap_tec_polarity {
+            -tec_i
+        } else {
+            tec_i
+        }
     }
 
     // Get voltage across TEC
diff --git a/src/command_handler.rs b/src/command_handler.rs
index efea1b8..9605279 100644
--- a/src/command_handler.rs
+++ b/src/command_handler.rs
@@ -412,6 +412,14 @@ impl Handler {
         }
     }
 
+    fn swap_tec_polarity (socket: &mut TcpSocket, channels: &mut Channels) -> Result<Handler, Error> {
+        for c in 0..CHANNELS {
+            channels.channel_state(c).swap_tec_polarity = !channels.channel_state(c).swap_tec_polarity;
+        }
+        send_line(socket, b"{}");
+        Ok(Handler::Handled)
+    }
+
     pub fn handle_command(command: Command, socket: &mut TcpSocket, channels: &mut Channels, session: &Session, store: &mut FlashStore, ipv4_config: &mut Ipv4Config, fan_ctrl: &mut FanCtrl, hwrev: HWRev) -> Result<Self, Error> {
         match command {
             Command::Quit => Ok(Handler::CloseSocket),
@@ -441,6 +449,7 @@ impl Handler {
             Command::FanCurve { k_a, k_b, k_c } => Handler::fan_curve(socket, fan_ctrl, k_a, k_b, k_c),
             Command::FanCurveDefaults => Handler::fan_defaults(socket, fan_ctrl),
             Command::ShowHWRev => Handler::show_hwrev(socket, hwrev),
+            Command::SwapTECPolarity => Handler::swap_tec_polarity(socket, channels),
         }
     }
 }
\ No newline at end of file
diff --git a/src/command_parser.rs b/src/command_parser.rs
index b9e70bb..e49a1d0 100644
--- a/src/command_parser.rs
+++ b/src/command_parser.rs
@@ -191,6 +191,7 @@ pub enum Command {
     },
     FanCurveDefaults,
     ShowHWRev,
+    SwapTECPolarity,
 }
 
 fn end(input: &[u8]) -> IResult<&[u8], ()> {
@@ -600,6 +601,7 @@ fn command(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
          fan,
          fan_curve,
          value(Ok(Command::ShowHWRev), tag("hwrev")),
+         value(Ok(Command::SwapTECPolarity), tag("swap")),
     ))(input)
 }
 
diff --git a/src/config.rs b/src/config.rs
index e7286fa..5c9d08e 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -22,6 +22,7 @@ pub struct ChannelConfig {
     pwm: PwmLimits,
     /// uses variant `PostFilter::Invalid` instead of `None` to save space
     adc_postfilter: PostFilter,
+    swap_tec_polarity: bool,
 }
 
 impl ChannelConfig {
@@ -41,6 +42,7 @@ impl ChannelConfig {
             sh: state.sh.clone(),
             pwm,
             adc_postfilter,
+            swap_tec_polarity: state.swap_tec_polarity,
         }
     }
 
@@ -51,6 +53,7 @@ impl ChannelConfig {
         state.pid.target = self.pid_target.into();
         state.pid_engaged = self.pid_engaged;
         state.sh = self.sh.clone();
+        state.swap_tec_polarity = self.swap_tec_polarity;
 
         self.pwm.apply(channels, channel);