Calculator 1: Use this if you want to work out the true cost of clean air or calculate how many air changes per hour you get from your air purifier?

Calculator 2: Use this if you want to compare up to 3 air purifiers to help you decide which is the most cost-effective for your space.

If you are looking to purchase for a school and need a set number of air changes per hour according to ASHRAE or NEU standards, download our Excel calculator (3). It has the detail you need to tell you what speed you can run each purifier on to meet the max noise level for our class.

1. Air Change per Hour (ACH) calculator

NB: If you have 3 CADR numbers for Dust, Pollen & Smoke, use the lowest which is Smoke or Formaldehyde.

RESULT ONE: Volume of clean air for every £ spent on your purifier

RESULT TWO: No of Air Changes per Hour (ACH) for your room size

RESULT THREE: Time it takes to clean the air at that setting (if you only have one CADR, this will be for the highest setting only)​

2. Compare cost effectiveness of air purifiers

Using a room size of 15m2, you can compare up to 3 purifiers to find out what volume of clean air you get for every £ spent on this purifier. This calculator lets you see the true cost of clean air. ​

NB: If you have 3 CADR numbers for Dust, Pollen & Smoke, use Smoke.

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3. Total CADR you for 5-6 air changes per hour

Total CADR based on needing 3 ACH (homes) to 6 ACH (classrooms).

Note that most CADR figures are given on top settings which may be too loud for most homes/classes.

Click image to download the calculator

We provide data for our air purifiers on all settings:

DescriptionThe SqairBlast MiniBlast Maxi
CADR (m3/h) – smoke/VOC70 – 180 – 315
(low – mid – high)
340 – 450 – 740
(low – mid – high)
450 – 680 – 950
(low – mid – high)
Coverage (m2)15 – 22 – 40m2
(low – mid – high)
48 – 63 – 85m²
(low – mid – high)
74 – 99 – 130m2
(low – mid – high)
Noise levels (dBA)23 – 43 – 52
(low – mid – high)
36 – 43 – 49
(low – mid – high)
29 – 37 – 43
(low – mid – high)
Size L x W x H (cm)33 x 33 x 3757 x 57 x 691170 x 57 x 69
Smart Air low cost purifiers

Smart Air is a social enterprise that creates simple, no-nonsense air purifiers and provides free education to protect people’s health from the effects of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.

Certified B-Corp air purifier company