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High Efficiency Gas Boilers

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Product Image of NRCB180DV 180,000 BTU Combi Boiler (NG)
NRCB180DV 180,000 BTU Combi Boiler (NG)
SKU: NRCB180DV-NG
Noritz
SKU: NRCB180DV-NG
Brand: Noritz
(1)
$2,866.00 each
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Product Image of Ultra 299 - 234,000 BTU Output High Efficiency Boiler - Series 4 (Nat Gas or LP)
$7,866.82 each
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Product Image of 69,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Wall Mount) (NG)
$4,085.94 each
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Product Image of 182,000 BTU Output FT Series High Efficiency, Floor Standing Heat Only Fire Tube Boiler (NG or LP)
$4,566.85 each
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Product Image of Simplicity 199 Combination Wall Mount Boiler, 199,000 BTU (NG)
$3,656.10 each
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Product Image of 121,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Floor Mount) (NG)
$5,379.11 each
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Product Image of B1KE-199 199,000 BTU Vitodens 100-W Gas-Fired Wall-Mounted Condensing Combi Boiler
$5,864.12 each
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Product Image of ZWB 42-3 Greenstar 151 117,000 BTU Combi Gas-Fired Wall-Hung Condensing Boiler
$5,587.01 each
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Product Image of Simplicity 110 Combination Wall Mount Boiler, 110,000 BTU (NG)
$2,995.50 each
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Product Image of AB-80C AquaBalance Combination Wall Mount Gas Boiler, 65,000 BTU (NG)
$2,708.74 each
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Product Image of 69,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Floor Mount) (NG)
$4,486.04 each
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Product Image of 229,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Floor Mount)
$8,882.46 each
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Product Image of PF-80 - 64,000 BTU Output PUREFIRE High Efficiency Residential Boiler (Nat Gas)
$4,879.38 each
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Product Image of Simplicity 150 Combination Wall Mount Boiler, 150,000 BTU (NG)
$3,184.37 each
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Product Image of Ultra 80 - 62,000 BTU Output High Efficiency Boiler - Series 4 (Nat Gas)
$3,742.23 each
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Product Image of AB-120H AquaBalance Heat-Only Wall Mount Gas Boiler, 97,000 BTU (NG)
$2,857.12 each
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Product Image of IP175S 175,000 BTU Condensing Wall Mounted Boiler (NG/LP)
$3,071.90 each
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Product Image of 89,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Floor Mount) (NG)
$4,838.09 each
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Product Image of ALP150B 119,000 BTU Output Condensing Boiler (Wall or Floor Mount)
$6,119.14 each
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Product Image of KWB42 Greenstar Combi FS-151 Floor Condensing Boiler
$4,676.82 each
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Product Image of EVG 155 Series 2 - 124,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)
$4,871.42 each
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Product Image of Greenstar ZBR21-3 62,000 BTU Output Gas Fired Wall Mounted Boiler - Heat Only (NG/LP)
$3,509.90 each
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Product Image of ACB-110H-N 110,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler, High Altitude (NG)
$5,078.60 each
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Product Image of 387,000 BTU Output Knight XL High Efficiency Boiler (NG)
$13,423.05 each
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Product Image of 44,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Wall Mount) (NG)
$4,038.25 each
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Product Image of 110,000 BTU Noble Fire Tube High Efficiency Boiler (NG)
$2,690.99 each
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Product Image of ZWB 28-3A Greenstar 100P 79,000 BTU Combi Gas-Fired Wall-Hung Condensing Boiler
$4,011.61 each
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Product Image of Oneida CO-150 Output High Efficiency Combi Modulating Condensing Gas Boiler
$2,585.53 each
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Product Image of EVG 220 Series 2 - 179,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)
$6,666.47 each
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Product Image of Ultra 80 - 62,000 BTU Output High Efficiency Boiler - Series 4 (Propane)
$3,721.00 each
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Product Image of PF-110 - 89,000 BTU Output PUREFIRE High Efficiency Residential Boiler (LP Gas)
$6,617.24 each
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Product Image of ALP105B 83,000 BTU Output Condensing Boiler (Wall or Floor Mount)
$5,332.06 each
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Product Image of PF-210 - 168,000 BTU Output PUREFIRE High Efficiency Residential Boiler (Nat Gas)
$6,903.30 each
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Product Image of EVG 399 - 333,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)
$10,777.26 each
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Product Image of 199,000 BTU Noble Fire Tube High Efficiency Boiler, High Altitude (NG)
$4,158.99 each
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Product Image of Wall-Mount Bracket Jacket Side (Includes Screws), 383-200-115
$12.79 each
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Product Image of ZWB 28-3 Greenstar 100 79,000 BTU Combi Gas-Fired Wall-Hung Condensing Boiler
$5,531.46 each
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Product Image of EVG 110 - 88,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)
$3,775.94 each
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Product Image of ZBR 28-3 Greenstar 100 79,000 BTU Heat Only Gas-Fired Wall-Hung Condensing Boiler
$4,634.58 each
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Product Image of ALP285B 229,000 BTU Output Condensing Boiler
ALP285B 229,000 BTU Output Condensing Boiler
SKU: ALP285BF-4T07
Burnham
SKU: ALP285BF-4T07
Brand: Burnham
$10,381.72 each
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Product Image of ES2-6, 128,000 BTU Output High Efficiency Cast Iron Boiler (NG)
$4,892.28 each
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Product Image of RCB399AN 399,000 BTU Commercial Wall Mounted Boiler (NG/LP)
$13,365.63 each
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Product Image of PF-110 - 89,000 BTU Output PUREFIRE High Efficiency Residential Boiler (Nat Gas)
$7,019.09 each
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Product Image of ACB-110S-N 110,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler (NG)
$5,078.60 each
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Product Image of ALP210B 168,000 BTU Output Condensing Boiler (Wall or Floor Mount)
$6,832.48 each
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Product Image of KBR21-3 Greenstar 79 79,000 BTU Gas Fired Floor Standing Condensing Boiler
$5,598.29 each
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Product Image of ZBR 35-3 Greenstar 131 103,000 BTU Gas-Fired Wall-Hung Condensing Boiler
$5,884.80 each
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Product Image of SlimFit Series 3 750, 610,000 BTU Output High Efficiency Gas Boiler (Natural Gas)
SlimFit Series 3 750, 610,000 BTU Output High Efficiency Gas Boiler (Natural Gas)
SKU: 383-600-331
Weil-McLain
SKU: 383-600-331
Brand: Weil-McLain
$18,266.37 each
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More About High Efficiency Gas Boilers
Maximize Heat, Minimize Waste.

High-efficiency gas boilers deliver reliable heat while keeping fuel costs in check. Condensing boilers squeeze every BTU from natural gas and propane, pushing AFUE ratings above 90% and cutting fuel costs and emissions without sacrificing performance.

Why Choose a High-Efficiency Gas Boiler
Unlike older boilers, condensing models feature a secondary heat exchanger that captures extra heat from flue gases. That boosts efficiency, reduces return-water temperatures, and cuts energy waste. Over time, savings on utility bills often exceed the investment in a high-efficiency boiler installation.

Natural Gas Boilers vs Propane Gas Boilers
Natural gas boilers offer lower per-BTU fuel costs where utility lines exist. Propane gas boilers bring flexibility for off-grid homes or areas without mains gas. Both fuel types support condensing technology, modulating burners, and outdoor reset controls to keep systems responsive and efficient.

Choosing the Right High-Efficiency Boiler
  • Calculate heat load. Match BTU output to the home’s square footage and insulation levels.
  • Aim for 95% AFUE or higher when possible.
  • Check venting. Condensing boilers need PVC or stainless vent kits for low flue temperatures.
  • Look for modulating burners and outdoor reset controls for peak efficiency.

Installation & Maintenance Tips
  • Pump a condensate neutralizer to protect drains from acidic condensate.
  • Schedule annual tune-ups: clean heat exchangers and check burner performance.
  • Inspect vent pipe seals and PVC connections for leaks.
  • Verify proper combustion air intake in tight, high-efficiency homes.


FAQs about High-Efficiency Gas Boilers

What is a condensing boiler?
A condensing boiler uses a secondary heat exchanger to extract extra heat from flue gases, boosting efficiency and lowering return-water temperatures.


How do I choose between natural gas and propane boilers?
Choose natural gas boilers for lower fuel costs where lines exist. Select propane gas boilers for flexibility in off-grid settings.


What does AFUE mean?
AFUE (Annual Fuel Utilization Efficiency) measures how efficiently a boiler converts fuel into heat over a year. Look for ratings above 90%.


Are there rebates for high-efficiency boiler installation?
Many utility companies and government programs offer rebates or tax credits for boilers with AFUE ratings of 90% or higher. Check local incentives.


How often should I service a high-efficiency boiler?
Annual maintenance is recommended: clean heat exchangers, inspect burners, and verify proper venting to maintain peak performance.