diff --git a/cara/apps/calculator/templates/calculator.form.html.j2 b/cara/apps/calculator/templates/calculator.form.html.j2
index e93ea571..acad0a0b 100644
--- a/cara/apps/calculator/templates/calculator.form.html.j2
+++ b/cara/apps/calculator/templates/calculator.form.html.j2
@@ -218,8 +218,8 @@
   This tool simulates the long range airborne spread SARS-CoV-2 virus in a finite volume and estimates the risk of COVID-19 infection. It is based on current scientific data and can be used to compare the effectiveness of different mitigation measures.<br>
   <b>Ventilation data:</b> <br>
   <ul>
-    <li>Mechanical ventilation = check the flow rates with the concerned technical department.</li>
-    <li>Natural ventilation = the window opening distance is between the fixed frame and movable part when open (commonly used values are window height = 1.6m and window opening = 0.15m). In case of periodic opening, specify the the duration (e.g. for 10 min) and frequency (e.g. every 60 min).</li>
+    <li>Mechanical ventilation = the HVAC supply of fresh air. Check the flow rates with the concerned technical department.</li>
+    <li>Natural ventilation = the type of window opening. The opening distance is between the fixed frame and movable part when open (commonly used values are window opening between 0.6 and 0.15 m). In case of periodic opening, specify the duration (e.g. for 10 min) and frequency (e.g. every 60 min).</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<sup>3</sup>/h (noisy)</li>