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Condensing Boilers

27 products

Showing 1 - 27 of 27 products

This collection covers high-efficiency condensing boilers from IBC, Navien and US Boiler. It includes IBC SL G3 fire tube boilers from 85,000 to 260,000 BTU input and the VX series, and US Boiler (Burnham) Aspen fire tube boilers, with efficiencies of 95 to 96 percent and elevation ranges up to 10,000 or 12,000 feet.

Size the boiler to a room-by-room heat-loss calculation, and check its turndown ratio so it modulates well at low loads. Condensing boilers reach rated efficiency with low return water temperatures, so review the emitters and controls. Confirm the vent material and length limits, condensate drain and neutralizer, gas supply size and whether a pump is included.

See also: Boilers, Combination Heating & DHW Boilers, Water Treatment, Anti-Freeze & Condensate.

Frequently asked questions

Why does a condensing boiler need low return water temperature?

It only condenses flue gas, and reaches its rated efficiency, when return water is cool enough. Radiant floors, low-temperature emitters and outdoor reset controls help.

Does a condensing boiler need a condensate neutralizer?

The condensate is acidic, so most installations need a drain and a neutralizer. See condensate neutralizers.

What venting does a condensing boiler use?

Sealed-combustion condensing boilers vent in PVC, CPVC, polypropylene or stainless, as the manufacturer lists. Check the maximum vent length for your model.

Showing 1 - 27 of 27 products

Navien NHB-55 High Efficiency Condensing Heating Boiler, 55,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NHB-55 High Efficiency Condensing Heating Boiler, 55,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NHB-55 Condensing Heating Boiler, 55,000 BTU, Indoor Wall-Hung, NG/LP Convertible - Original NHB Series

$2,460.99

Only 3 units left

Aspen - 320,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,100'

US Boiler US Boiler (Burnham) ASPN-320A-6L00 Aspen - 320,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,100'

$14,573.18

Only 2 units left

Aspen - 270,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,100'

US Boiler US Boiler (Burnham) ASPN-270A-6L00M Aspen - 270,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,100'

$11,648.20

Only 1 unit left

Aspen - 155,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,100'

US Boiler US Boiler (Burnham) ASPN-155A-6L00M Aspen - 155,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,100'

$8,036.53

Only 1 unit left

Aspen - 110,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-10,100'

US Boiler US Boiler (Burnham) ASPN-110A-6L00M Aspen - 110,000 BTU Input - Fire Tube Boiler, 96% Efficient, No Pump Included - Elevation Range 0-10,100'

$3,150.00

Only 5 units left

Aspen - 85,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-10,100'

US Boiler US Boiler (Burnham) ASPN-085A-6L00M Aspen - 85,000 BTU Input - Fire Tube Boiler, 96% Efficient, No Pump Included - Elevation Range 0-10,100'

$2,545.88

Only 1 unit left

Alta - 180,000 BTU Input - Water Tube Boiler, 95% efficient, includes Grundfos Pump - Elevation Range 0-10,000'

US Boiler US Boiler (Burnham) ALTA-180-1G00 Alta - 180,000 BTU Input - Water Tube Boiler, 95% Efficient, Includes Grundfos Pump - Elevation Range 0-10,000'

$4,264.93

Only 3 units left

Alta - 150,000 BTU Input - Water Tube Boiler, 95% efficient, includes Grundfos Pump - Elevation Range 0-10,000'

US Boiler US Boiler (Burnham) ALTA-150-1G00 Alta - 150,000 BTU Input - Water Tube Boiler, 95% Efficient, Includes Grundfos Pump - Elevation Range 0-10,000'

$4,486.40

Only 4 units left

Alta 120MBH Boiler Nat Gas 0-10k Alt

US Boiler US Boiler (Burnham) ALTA-120-1G00 Alta 120MBH Boiler Nat Gas 0-10k Alt

$4,305.65

Only 4 units left

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 80,000 BTU/h, Indoor Wall-Hung

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 80,000 BTU/h, Indoor Wall-Hung

Navien Navien NHB-80H Condensing Heating Boiler, 80,000 BTU, Indoor Wall-Hung, NG/LP Convertible - NHB-H Series

$2,525.00

In stock, 6 units

Navien NHB-80 High Efficiency Condensing Heating Boiler, 80,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NHB-80 High Efficiency Condensing Heating Boiler, 80,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NHB-80 Condensing Heating Boiler, 80,000 BTU, Indoor Wall-Hung, NG/LP Convertible - Original NHB Series

$3,030.00

Only 1 unit left

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 55,000 BTU/h, Indoor Wall-Hung, Residential/Commercial

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 55,000 BTU/h, Indoor Wall-Hung, Residential/Commercial

Navien Navien NHB-55H Condensing Heating Boiler, 55,000 BTU, Indoor Wall-Hung, NG/LP Convertible - NHB-H Series, up to 15:1 Turndown

$2,767.50

In stock, 12 units

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 150,000 BTU/h, Indoor Wall-Hung, Residential/Commercial NHB-150

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 150,000 BTU/h, Indoor Wall-Hung, Residential/Commercial NHB-150

Navien Navien NHB-150H High Efficiency Condensing Heating Boiler, 150,000 BTU, Indoor Wall-Hung, NG/LP Convertible

$3,540.00

In stock, 7 units

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 110,000 BTU/h, Indoor Wall-Hung, Residential/Commercial

Navien High Efficiency Condensing Heating Boiler Max Htg Input: 110,000 BTU/h, Indoor Wall-Hung, Residential/Commercial

Navien Navien NHB-110H Condensing Heating Boiler, 110,000 BTU, Indoor Wall-Hung, NG/LP Convertible - NHB-H Series, up to 15:1 Turndown

$3,146.39

In stock, 17 units

Navien NHB-110 High Efficiency Condensing Heating Boiler, 110,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NHB-110 High Efficiency Condensing Heating Boiler, 110,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NHB-110 Condensing Heating Boiler, 110,000 BTU, Indoor Wall-Hung, NG/LP Convertible - Original NHB Series

$3,277.50

Only 5 units left

Navien NFB-399C High Efficiency Condensing Heating Boiler, 399,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NFB-399C High Efficiency Condensing Heating Boiler, 399,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NFB-399C High Efficiency Condensing Heating Boiler, 399,000 BTU, Indoor Wall-Hung, NG/LP Convertible

$12,300.00

Only 5 units left

Navien NFB-301C High Efficiency Condensing Heating Boiler, 301,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NFB-301C High Efficiency Condensing Heating Boiler, 301,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NFB-301C High Efficiency Condensing Heating Boiler, 301,000 BTU, Indoor Wall-Hung, NG/LP Convertible

$9,755.99

In stock, 6 units

Navien NFB-200H High Efficiency Condensing Heating Boiler, 200,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NFB-200H High Efficiency Condensing Heating Boiler, 200,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NFB-200H High Efficiency Condensing Heating Boiler, 200,000 BTU, Indoor Wall-Hung, NG/LP Convertible

$3,412.50

In stock, 7 units

Navien NFB-175H High Efficiency Condensing Heating Boiler, 175,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien NFB-175H High Efficiency Condensing Heating Boiler, 175,000 BTU, Indoor Wall-Hung, NG/LP Convertible

Navien Navien NFB-175H High Efficiency Condensing Heating Boiler, 175,000 BTU, Indoor Wall-Hung, NG/LP Convertible

$3,810.00

Only 3 units left

VX Series - 199,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC VX Series - 199,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC IBC VX199 VX Series - 199,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,000'

$4,036.99

Only 3 units left

VX Series - 150,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC VX Series - 150,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC IBC VX150 VX Series - 150,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,000'

$4,105.47

Only 1 unit left

VX Series - 110,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC VX Series - 110,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-10,000'

IBC IBC VX110 VX Series - 110,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-10,000'

$3,778.52

Only 2 units left

SL Series - 199,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-12,000'

IBC SL Series - 199,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-12,000'

IBC IBC SL-30-199G3 SL Series - 199,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-12,000'

$7,595.03

Only 4 units left

SL Series - 260,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-12,000'

IBC SL Series - 260,000 BTU Input - Fire Tube Boiler, 95% efficient, No Pump Included - Elevation Range 0-12,000'

IBC IBC SL-26-260G3-NG SL Series - 260,000 BTU Input - Fire Tube Boiler, 95% Efficient, No Pump Included - Elevation Range 0-12,000'

$8,185.42

Only 5 units left

SL Series - 160,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC SL Series - 160,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC IBC SL-20-160G3 SL Series - 160,000 BTU Input - Fire Tube Boiler, 96% Efficient, No Pump Included - Elevation Range 0-12,000'

$6,252.00

Only 5 units left

SL Series - 115,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC SL Series - 115,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC IBC SL-14-115G3 SL Series - 115,000 BTU Input - Fire Tube Boiler, 96% Efficient, No Pump Included - Elevation Range 0-12,000'

$4,948.64

In stock, 8 units

SL Series - 85,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC SL Series - 85,000 BTU Input - Fire Tube Boiler, 96% efficient, No Pump Included - Elevation Range 0-12,000'

IBC IBC SL-10-85G3 SL Series - 85,000 BTU Input - Fire Tube Boiler, 96% Efficient, No Pump Included - Elevation Range 0-12,000'

$4,900.17

Only 2 units left

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