diff --git a/cara/apps/calculator/templates/calculator.form.html.j2 b/cara/apps/calculator/templates/calculator.form.html.j2
index aa4bd74c..3e12229a 100644
--- a/cara/apps/calculator/templates/calculator.form.html.j2
+++ b/cara/apps/calculator/templates/calculator.form.html.j2
@@ -213,10 +213,10 @@
     <li>Natural ventilation = the window opening distance is between the fixed frame and movable part when open.</li>
     <li>HEPA filtration = the air flow of the device. The following values are based on the different fan velocities of a specific commercial device proposed by the HSE Unit:</li>
     <ul>
-        <li>Level 6 (max) = 430 m^3/h (noisy)</li>
-        <li>Level 5 = 250 m^3/h (ok w.r.t. noise)</li>
-        <li>Level 4 = 130 m^3/h (silent)</li>
-        <li>Level 3 = 95 m^3/h (silent)</li>
+        <li>Level 6 (max) = 430 m<sup>3</sup>/h (noisy)</li>
+        <li>Level 5 = 250 m<sup>3</sup>/h (ok w.r.t. noise, recommended)</li>
+        <li>Level 4 = 130 m<sup>3</sup>/h (silent)</li>
+        <li>Level 3 = 95 m<sup>3</sup>/h (silent)</li>
     </ul>
   </ul>
   <b>Activity types:</b><br>