diff --git a/lib/sensiplan.js b/lib/sensiplan.js
index 1539f3a..a9ad09d 100644
--- a/lib/sensiplan.js
+++ b/lib/sensiplan.js
@@ -15,10 +15,15 @@ function getTemperatureStatus(targetDateString, previousDaysInCycle) {
       acc.high.push(curr)
     }
 
+    // regular rule
     // we round the difference because of JS decimal weirdness
     if (acc.high.length === 3 && rounded(curr - acc.ltl, 0.01) >= 0.2) {
       acc.shiftDetected = true
     }
+    // 1st exception rule
+    if (acc.high.length === 4 && curr > acc.ltl) {
+      acc.shiftDetected = true
+    }
 
     return acc
   }, {
diff --git a/test/fixtures/first-exception-rule.json b/test/fixtures/first-exception-rule.json
new file mode 100644
index 0000000..2b963ef
--- /dev/null
+++ b/test/fixtures/first-exception-rule.json
@@ -0,0 +1,67 @@
+[{
+  "date": "2018-06-04",
+  "temperature": {
+    "value": 36.7,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-05",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-06",
+  "temperature": {
+    "value": 36.47,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-07",
+  "temperature": {
+    "value": 36.49,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-09",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-10",
+  "temperature": {
+    "value": 36.62,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-11",
+  "temperature": {
+    "value": 36.55,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-12",
+  "temperature": {
+    "value": 36.8,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-13",
+  "temperature": {
+    "value": 36.86,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-14",
+  "temperature": {
+    "value": 36.77,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-15",
+  "temperature": {
+    "value": 36.63,
+    "exclude": null
+  }
+}]
\ No newline at end of file
diff --git a/test/fixtures/temp-shift.json b/test/fixtures/regular-rule.json
similarity index 100%
rename from test/fixtures/temp-shift.json
rename to test/fixtures/regular-rule.json
diff --git a/test/sensiplan.spec.js b/test/sensiplan.spec.js
index 3ca639e..25ab34e 100644
--- a/test/sensiplan.spec.js
+++ b/test/sensiplan.spec.js
@@ -1,7 +1,8 @@
 import chai from 'chai'
 import { getTemperatureStatus } from '../lib/sensiplan'
-import tempShift from './fixtures/temp-shift.json'
+import tempShift from './fixtures/regular-rule.json'
 import lowerTempDays from './fixtures/lower-temps.json'
+import firstException from './fixtures/first-exception-rule.json'
 
 const expect = chai.expect
 
@@ -17,7 +18,7 @@ describe.only('sensiplan', () => {
       })
     })
 
-    it('detects temperature shift', function () {
+    it('detects temperature shift according to regular rule', function () {
       const status = getTemperatureStatus('2018-06-14', tempShift)
       expect(status).to.eql({
         low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
@@ -26,5 +27,15 @@ describe.only('sensiplan', () => {
         shiftDetected: true
       })
     })
+
+    it('detects temperature shift according to 1st exception rule', function () {
+      const status = getTemperatureStatus('2018-06-14', firstException)
+      expect(status).to.eql({
+        low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
+        ltl: 36.6,
+        high: [36.8, 36.85, 36.75, 36.65],
+        shiftDetected: true
+      })
+    })
   })
 })
\ No newline at end of file