MODEL

DIMEN-
SIONS

INPUT
MINIMUM
(BTU/HR)

INPUT
MAXIMUM
(BTU/HR)

MAXIMUM
HEATING
EFFICIENCY

OUTPUT
MINIMUM
(BTU/HR)

OUTPUT
MAXIMUM
(BTU/HR)

MAXIMUM
HEATING
CAPACITY

VIEWING
WINDOW SIZE (SQ.IN.)
CLICK HERE FOR DETAILS

HEARTHSTONE
STERLING HT
VERTICAL VENT

29-1/2"W
21"D
27-1/8"T

NG
13,900
LP
11,600

NG
38,000
LP
38,000

85%

NG
11,815
LP
9,860

NG
32.300
LP
32,300

UP TO
1,800
Sq Ft

HEARTHSTONE
TUCSON DX

21"W
14-1/2"D
25"T

NG
18.000
LP
21,600

NG
25,000
LP
25,000

83%

NG
14,940
LP
17,928

NG
20,750
LP
20,750

UP TO
1,200
Sq Ft

HEARTHSTONE
STOWE DX

22-1/4"W
16-5/8"D
26-1/4"T

NG
18,000
LP
21,600

NG
26,000
LP
25,000

83%

NG
14,940
LP
17,928

NG
21,580
LP
20,770

UP TO
1,200
Sq Ft

HEARTHSTONE
TRIBUTE DV

23-7/8"W
18"D
24-1/8"T

NG
10,600
LP
10,400

NG
18,000
LP
17,500

82%

NG
8,692
LP
8,528

NG
14,760
LP
14,350

UP TO
800
Sq Ft

HEARTHSTONE
MODENA

18"W
19"D
49"T

NG
15,000
LP
15,000

NG
26,500
LP
26,500

80%

NG
12,000
LP
12,000

NG
21,200
LP
21,200

UP TO
1,200
Sq Ft

HEARTHSTONE
LUNO

20"W
18"D
45-3/4"T

NG
15,000
LP
15,000

NG
26,500
LP
26,500

80%

NG
12,000
LP
12,000

NG
21,200
LP
21,200

UP TO
1,200
Sq Ft

HEARTHSTONE
BARI DV

19-1/2"
Diameter
44"T

NG
16,000
LP
15,000

NG
26,500
LP
26,500

80%

NG
12,800
LP
12,000

NG
21,200
LP
21,200

UP TO
1,200
Sq Ft

HEARTHSTONE
STERLING HT
REAR VENT

29-1/2"W
21"D
27-1/8"T

NG
13,600
LP
11,900

NG
33,000
LP
33,000

80%

NG
11,016
LP
9,877

NG
26,600
LP
27,400

UP TO
1,600
Sq Ft

HEARTHSTONE
CHAMPLAIN

26-1/2"W
20" D
29" T

NG
18,000
LP
18,000

NG
36,000
LP
36,000

80%

NG
14,400
LP
14,400

NG
28,800
LP
28,800

UP TO
1,800
Sq Ft

HEARTHSTONE
BRISTOL DX

22-1/2"W
19-1/4"D
26-3/8"T

NG
16,000
LP
10,000

NG
36,000
LP
33,000

80%

NG
12,800
LP
7.900

NG
28,800
LP
26,070

UP TO
1,800
Sq Ft

NOTES

INPUT RATINGS:
Manufacturers size their gas appliances by the heat INPUT rating, measured in British Thermal Units (BTU's). This is a measurement of the heat value of the gas the appliance burns per hour. If the rate of burn is adjustable, the input rating is given at both the lowest and highest burn settings. One THERM of natural gas or one GALLON of LP gas each contain about 100,000 BTU's of heat value, so a gas appliance with an input rating of 20,000 - 30,000 BTU/hr will consume approximately one therm of natural gas or one gallon of LP every five hours when adjusted to its lowest setting, and every 3-1/3 hours when adjusted to its highest setting.

EFFICIENCY RATINGS:
The steady state efficiency rating tells us how effectively a given gas appliance turns fuel into heat. Many factors affect this rating, including altitude, composition of fuel gas, length of intake/exhaust pipe, outdoor temperatures, atmospheric conditions, etc. Some companies publish only the lowest tested efficiencies, some just the highest, some publish both the lowest and highest, and some use an average. For this chart, we've used the HIGHEST steady state efficiency rating, interpolating the unpublished data where necessary.

OUTPUT RATINGS:
To determine the minimum & maximum heat OUTPUT, we multiply the minimum & maximum INPUT ratings by the EFFICIENCY rating. For example, a gas stove or fireplace with an efficiency rating of 75% and an adjustable input rating of 20,000 - 30,000 BTU/hr will deliver 15,000 BTU's of heat per hour at its lowest setting (20,000 x 75%), and 22,500 BTU's of heat per hour at its highest setting (30,000 x 75%).