diff --git a/include/ExitAirTempSensor.hpp b/include/ExitAirTempSensor.hpp
index 44c736c..f18fd9b 100644
--- a/include/ExitAirTempSensor.hpp
+++ b/include/ExitAirTempSensor.hpp
@@ -6,23 +6,40 @@
 #include <limits>
 #include <vector>
 
-struct CFMInfo
+struct ExitAirTempSensor;
+struct CFMSensor : public Sensor
 {
-    std::vector<std::string> pwm;
+    std::vector<std::string> tachs;
     int32_t c1;
     int32_t c2;
     int32_t maxCFM;
-    double pwmMin;
-    double pwmMax;
+    double tachMinPercent;
+    double tachMaxPercent;
+
+    std::shared_ptr<ExitAirTempSensor> parent;
+
+    CFMSensor(std::shared_ptr<sdbusplus::asio::connection> &conn,
+              const std::string &name, const std::string &sensorConfiguration,
+              sdbusplus::asio::object_server &objectServer,
+              std::vector<thresholds::Threshold> &&thresholds,
+              std::shared_ptr<ExitAirTempSensor> &parent);
+    ~CFMSensor() = default;
+
+    bool calculate(double &);
+    void updateReading(void);
+    void checkThresholds(void) override;
+
+  private:
+    std::vector<sdbusplus::bus::match::match> matches;
+    boost::container::flat_map<std::string, double> tachReadings;
+    boost::container::flat_map<std::string, std::pair<double, double>>
+        tachRanges;
+    std::shared_ptr<sdbusplus::asio::connection> dbusConnection;
+    void addTachRanges(const std::string &serviceName, const std::string &path);
 };
 
 struct ExitAirTempSensor : public Sensor
 {
-    boost::container::flat_map<std::string, double> pwmReadings;
-    boost::container::flat_map<std::string, double> powerReadings;
-    std::vector<sdbusplus::bus::match::match> matches;
-
-    double inletTemp = std::numeric_limits<double>::quiet_NaN();
 
     double powerFactorMin;
     double powerFactorMax;
@@ -32,8 +49,12 @@
     double alphaF;
     double pOffset = 0;
 
-    std::vector<CFMInfo> cfmData;
+    // todo: make this private once we don't have to hack in a reading
+    boost::container::flat_map<std::string, double> powerReadings;
+
+    std::vector<std::unique_ptr<CFMSensor>> cfmSensors;
     ExitAirTempSensor(std::shared_ptr<sdbusplus::asio::connection> &conn,
+                      const std::string &name,
                       const std::string &sensorConfiguration,
                       sdbusplus::asio::object_server &objectServer,
                       std::vector<thresholds::Threshold> &&thresholds);
@@ -45,9 +66,12 @@
   private:
     double lastReading;
 
+    std::vector<sdbusplus::bus::match::match> matches;
+    double inletTemp = std::numeric_limits<double>::quiet_NaN();
+
     std::shared_ptr<sdbusplus::asio::connection> dbusConnection;
     std::chrono::time_point<std::chrono::system_clock> lastTime;
-    int32_t getTotalCFM(void);
+    double getTotalCFM(void);
     bool calculate(double &val);
     void setupMatches(void);
 };
\ No newline at end of file