diff --git a/src/thermostat/max1968.rs b/src/thermostat/max1968.rs
index 9cf02ef..8d05ffb 100644
--- a/src/thermostat/max1968.rs
+++ b/src/thermostat/max1968.rs
@@ -218,7 +218,7 @@ impl MAX1968 {
     }
 
     pub fn is_powered_on(&mut self) -> bool {
-        self.phy.shdn.is_set_low()
+        self.phy.shdn.is_set_high()
     }
 
     pub fn power_down(&mut self) {