RS4100004 Rev. 0
6
Size of Area to
Required Air Conditioner Cooling Capacity—Btu/hour
be Cooled
Room below attic;
Room with occupied
Top floor under
(in square feet)
insulated ceiling above
room above
insulated roof (no attic)
100
3500 to 4000
4000 to 4500
4500 to 5000
150
4000 to 5000
4500 to 5000
5500 to 6500
200
4500 to 5500
5000 to 6000
6000 to 7000
250
5000 to 6000
5500 to 6500
7500 to 8500
300
6000 to 7000
6500 to 7500
8500 to 9500
350
6500 to 7500
7000 to 8000
10000 to 11000
400
7000 to 8000
8000 to 9000
11000 to 12000
450
7500 to 8500
8500 to 9500
11500 to 12500
500
8000 to 9000
9500 to 10500
13000 to 14000
600
9500 to 10500
11000 to 12000
15000 to 16000
700
10500 to 11 500
12000 to 13000
17000 to 18000
800
11500 to 13000
13500 to 14500
19000 to 20000
900
12500 to 14000
14500 to 16000
21000 to 22000
1000
13500 to 15000
15500 to 17000
23000 to 24500
1200
16000 to 17500
18000 to 20000
26500 to 28500
1400
18000 to 20000
21000 to 23000
30500 to 32500
1600
20000 to 22000
23000 to 25000
1800
22000 to 24000
25500 to 27500
2000
24000 to 26000
28000 to 30000
Additional conditions:
·
If average occupancy of area is more than two people, add 600 Btu/hour per person. If average is one person,
subtract 600 Btu/hour.
·
Add 1200 Btu/hour if area includes a kitchen.
·
If room is heavily shaded, subtract 10 percent from capacity. Increase capacity by 10 percent if area is very sunny.
Note:
For best results, select a room air conditioner with cooling capacity (Btu/hour rating) closest to, but not
exceeding, estimated size.
Sizing Instructions
Sizing Room Air Conditioners for Area
Being Cooled
Many problems with room air conditioners are a result of
units that are oversized or undersized for a given area.
Oversized units cool an area before humidity can be
adequately removed, resulting in air that feels cold and
clammy. Undersized units do not provide sufficient
cooling.
The following table contains guidelines for sizing a room
air conditioner for a given area. To size unit:
1. Determine size (in square feet) of area to be cooled,
then locate size in table.
2. Based on location of room in building, select
appropriate column in table associated with size of
room:
·
Room below attic; insulated ceiling above.
·
Room with occupied room above.
·
Top floor under insulated roof.
Number shown in table cell corresponding to room size/
location is approximate capacity (in Btu/hour) required of
an air conditioner to ensure adequate cooling of area.
NOTE: Make sure additional conditions, shown at
bottom of table, are taken into account when
determining size of unit.
