1. How the number of air purifiers for the 100 sq ft. area can be calculated. We need to consider
how much air is in our office and how fast an air purifier can clean that amount of air.
Definitions
ACH- Air changes per hour is simply the amount of times all of the air in a room is
replaced with completely new air, in one hour. A value of ‘5’ air changes per hour
means a room’s entire volume of air is replaced with new air 5 times in one hour.
CFM- stands for cubic feet per minute, and this number provides insight into the
efficiency of the air purifier, namely how many cubic feet per minute this air purifier
can scrub.
2. Calculating The Amount Of Indoor Air Let’s calculate the volume of indoor air. The equation we
use is:
Volume (indoor air) = Indoor area (in sq ft) x Ceiling height (in ft)
For example, Area: 1,00 sq ft home
ceiling height : 10 ft
Volume (indoor air) = 100 sq ft x 10 ft = 1,000 ft3
So we’re dealing with 1,000 cubic feet of air.If we want to clean that amount of air with an
air purifier properly, we need to clean it about 4 times every hour.We talk about 4 ACH or
Air Changes Per Hour.
Essentially, that means that we need to clean 4 x 4,000 ft3 = 16,000 ft3 of air per hour.
Now, let’s see what amount a single air purifier can purify per hour.
3. Capacity Of An Average Air Purifier
An average air purifier has an airflow of 200 CFM. That means that it
cleans 200 cubic feet of air per minute.
In 1 Hour: 200 CFM x 60 = 12,000 cubic feet per hour.
One purifier can properly clean 12,000 ft3 per hour.
But to clean a 100 sq ft home, we need to clean 16,000 ft3 of air per hour.
4. Total Number Of Air Purifiers Needed
If 1 air purifier cleans 12,000 ft3 of air, 2 of them will clean 24,000 ft3. But we need
to clean 16,000 ft3.
No. of air purifiers = Amount of air to be cleaned (in ft3/h) / Air purifier airflow (in
ft3/h)
No. of air purifiers = `16,000 ft3/h / 12,000 ft3/h = 1.5 air purifiers
Obviously, we would need 1.5 air purifiers.
We use a different number of air changes per hour (ACH). The
recommended ACH for the cleanest indoor air is 4.
5. S.No.
Coverage Area
Air Changes Per
Hour (ACH)
Number Of Air
Purifiers Needed
1
100 sq ft 4 1
Table Of How Many Air Purifiers Do You Need For Different Home/Office Sizes
6. Cost analysis of Air purifier and Air purifying plant
Air purifier Air purifying plant
The rated power of a modern air purifier
is 50 watts on average.
Air purifying plant cost approx from Rs
400 to 800.
Planters Pot range of size diameter 15
inches to 20 inches ranges approx from
Rs 1700 to 2200.
kW per day
Most of the air purifiers have watts range
from 50 – 70 watts.
Let’s Consider the air purifier you want
to buy consumes 50 watts per hour. If
you run the air purifier up to 8 hours a
day, it will consume 50 x 8 = 400
watts/day.
Electricity companies measure kW.
As 1 kW= 1000 watts, we need 400/ 1000=
0.4 kW electricity per day for an air
purifier.
Let take average of Air pruifying plant of
Rs 700.
Let take average of Planters pot of
diameter 15 inches is Rs 1900.
Total Sum of One complete unit of Air
Purifying Plant is= 700 + 1900= Rs 2600
7. Air purifier Air purifying plant
kW per Month
If an air purifier consumes 0.4 kW
electricity per day, it will consume (0.4 x
30) = 12 kW per month.
kW per Year
for calculating the per year cost, we have
to multiply 12 kW with 12, because 1
year consists of 12 months.
So, kW per year (12 x 12) = 144 kW per
year.
There are list of 15 air purifying plant
which is identified and one complete
unit cost Rs 2600.
Therefore , 15 air purifying plant cost =
Rs 15 X 2600= Rs 39000.
For 100 branches it cost around = 100 X
39000= Rs 3900000= Rs 39 Lakhs
The current electricity tariff rates for
domestic consumers of Delhi are
₹3)/kWh for usage up to 200 kWh, ₹4.5
/kWh for 200-400 kWh, ₹6.5)/kWh for
400-800 kWh, ₹7 /kWh for 800-1,200
kWh, and ₹8/kWh for consumption over
1,200 kWh
If we plant 10 air purifying plant which
is identified and one complete unit cost
Rs 2600.
Therefore , 10 air purifying plant cost =
Rs 10 X 2600= Rs 26000
For 100 branches iit cost around = 100 X
26000= Rs 2600000= Rs 26 Lakhs
8. Air purifier Air purifying plant
Cost Calculating for an Air Purifier
The electricity costs vary in different
states . In theDelhi it is ₹7/kWh for 800-
1,200 kWh.
Cost of running Air purifier for the whole
year at an average rate of 8 hours per day
with electricity cost Rs. 7/ Kwh = 144 x 7
= Rs 1008 per year
But Rs 39 Lakhs and Rs 26 Lakhs are the
one time cost for the 100 hundred
branches for these low maintenance
plant. These air purifying plant can be
use for 5 years or more with low
maintenance. In low maintenance
includes watering and no direct sunlight
office lightings is sufficent for these
plants for air purification.
9. Air purifier Air purifying plant
The Air Purifier of Philips with 50watts to
56 watts cost average Rs 8999 to Rs 13999 so
average Cost Rs 11499.
Therefore , One complete unit of an air
purifier one time cost = Rs 11499
For 100 branches with 5 air purifier in oen
branch it cost around = 100 X 11499X 5= Rs
57,49,500
For 100 branches per annum with 5 air
purifier it cost around = 5X100 X 1008 = Rs
504000.
If 1 air purifier running for the whole year
at an average rate of 8 hours per day then 5
air purifier for 2000 sq ft will cost = Rs 1008
X 5 = Rs 5040
Then 100 branches electricity cost with 5 air
purifier per annum = 5040 X 100=Rs 504000
But Rs 39 Lakhs and Rs 26 Lakhs are
the one time cost for the 100 hundred
branches for these low maintenance
plant. These air purifying plant can be
use for 5 years or more with low
maintenance. In low maintenance
includes watering and no direct
sunlight office lightings is sufficent for
these plants for air purification.
10. Air purifier Air purifying plant
Then 100 branches electricity cost with 5 air
purifier per annum = 5040 X 100=Rs 504000.
Then=one time cost for the 100 branches with 5
air purifier + 100 branches electricity cost
with 5 air purifier per annum = 57,49,500+
504000= Rs 62,53,500
Rs 62 lakhs is total cost of installing 5 air
purifier in 100 branches out of which Rs 5
Lakhs per annum is the lectricity cost of
running 5 air purifier in 100 branches for the
whole year.
But Rs 39 Lakhs and Rs 26 Lakhs are
the one time cost for the 100
hundred branches for these low
maintenance plant. These air
purifying plant can be use for 5
years or more with low
maintenance. In low maintenance
includes watering and no direct
sunlight office lightings is sufficent
for these plants for air purification.
