Sizing Guide
For Zone I-IV. For Zone V, see the next section.
1. Determine cu. ft. volume for the room to be
heated (length x width x height of the room = cu. ft.)
2. Find your heating zone on the map above.
3. Multiply the cubic volume by the heating factor
located on the adjacent chart.
EXAMPLE:
Your house is of average construction and you wish to use a
thermostatically controlled vent-free appliance. The area you
wish to heat is 30’ x 15’ x 8’ high. The cubic feet will be 30’ x
15’ x 8’ = 3,600 ft
3
.
Refer to the chart, multiply the appropriate chart-value by the
cubic feet of the area. 4.05 x 3,600 ft
3
= 14,580 Btu. This is
the maximum Btu output of a vent-free heating appliance
installed in this room.
1. These charts are intended to be used as a guide only and the section for Zone I-IV is based on providing enough BTU's to heat a room in that particular zone even
during a power outage. The section for Zone V is per the sizing guidelines published by the Vent-Free Gas Products Alliance.
2. Actual heat loss may vary according to insulation values and exposed window and/or door areas.
3. BTU's needed (for Zones I-IV) may be reduced by 15% for well insulated rooms or homes constructed after 1980.
4. When calculating room size please include any space that adjoins the room to be heated if there is no door between the two areas.
Room Heater Sizing Guide
EXAMPLE 1: You would like to provide supplemental heat for a room located in
Chicago, Illinois. The room is 20' long, 15' wide and 8' high. The cu. ft. of the room
is 20' x 15' x 8' = 2400 cu. ft. Then locate Chicago on the heating zone map (Zone
IV). Heat required = Heating Factor x Cu. Ft. (7.5 x 2400 = 18,000 BTU/HR).
EXAMPLE 2: You would like to provide supplemental heat for the same size room
located in Dallas, Texas (Zone II). Heat required = Heating Factor x Cu. Ft. (4.8 x
2400 = 11,520 BTU/HR).
How to Choose the Correct Sunstar Corcho Heater for Your Room
How to Choose the Correct Sunstar Corcho Room Heaters (Zone V)
NOTES
I
II
III
IV
V
4.0
4.8
5.5
7.5
See Below
Zone Heating Factor
Heating Region
Region V 5.55 4.50 4.05
Sizing Guidelines for Vent-Free Gas Products Installed in Isolated Spaces in Heating Region Shown on Map
House Construction
Appliance Operation
Maximum Input Rate Permissible to Maintain Indoor Air Quality Btu/ft
3
Loose Average Tight
4.50 4.05
4.05
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