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High Efficiency Gas Boilers

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Product Image of 549,000 BTU Output Knight XL Commercial Boiler, M13 (Natural Gas)
$20,013.16 each
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Product Image of SVF Series 1 1500, 1,259,000 BTU Output High Efficiency Gas Boiler (NG)
$47,814.34 each
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Product Image of ACB-199S-P 199,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler (LP)
$6,130.17 each
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Product Image of ACB-150H-N 150,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler, High Altitude (NG)
$5,488.59 each
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Product Image of ZWB 28-3A Greenstar 100P 79,000 BTU Combi Gas-Fired Wall-Hung Condensing Boiler
$3,824.87 each
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Product Image of SlimFit Series 2 1000L, 833,000 BTU Output High Efficiency Gas Boiler (NG)
$35,985.94 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)
$4,432.99 each
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Product Image of Aspen Firetube 126,000 BTU High Efficiency Wall Hung Condensing Gas Fired Boiler
$5,911.68 each
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Product Image of GB162-80 226,000 BTU Logamax Plus High Efficiency Gas Fired Hot Water Boiler
$7,700.91 each
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Product Image of 675,000 BTU Output Knight XL Commercial Boiler, M13 (Natural Gas)
$26,746.82 each
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Product Image of ECO Tec Series 2 80-H 64,000 BTU Output High-Efficiency Residential Heat-Only Condensing Boiler (NG)
$3,326.53 each
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Product Image of ES2-3, 51,000 BTU Output High Efficiency Cast Iron Boiler (NG)
$3,368.00 each
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Product Image of SVF Series 1 2000, 1,672,000 BTU Output High Efficiency Gas Boiler (NG)
$55,972.68 each
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Product Image of ES2-4, 77,000 BTU Output High Efficiency Cast Iron Boiler (LP)
$3,218.00 each
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Product Image of 161,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger - High Altitude (Wall Mount) (NG)
$6,586.29 each
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Product Image of ACB-150H-P 150,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler, High Altitude (LP)
$5,488.59 each
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Product Image of 110,000 BTU Noble Fire Tube Combi Boiler (LP)
$3,499.47 each
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Product Image of PF-80 - 64,000 BTU Output PUREFIRE High Efficiency Residential Boiler (LP Gas)
$5,846.68 each
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Product Image of SVF Series 1 600, 588,000 BTU Output High Efficiency Gas Boiler (NG)
$16,557.26 each
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1-888-757-4774
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Product Image of SlimFit Series 2 1000R, 833,000 BTU Output High Efficiency Gas Boiler (NG)
$35,985.94 each
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1-888-757-4774
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Product Image of SlimFit Series 3 550, 450,000 BTU Output High Efficiency Gas Boiler (NG)
$16,631.37 each
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1-888-757-4774
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Product Image of ALP080B 63,000 BTU Output Condensing Boiler (Wall or Floor Mount)
$4,682.97 each
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Product Image of SlimFit Series 2 1500L, 1,250,000 BTU Output High Efficiency Gas Boiler (NG)
$45,834.89 each
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1-888-757-4774
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Product Image of EVG 220 Series 2 - 179,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)
$6,066.49 each
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Product Image of Aspen Firetube 164,000 BTU High Efficiency Wall Hung Condensing Gas Fired Boiler
$5,776.71 each
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Product Image of 44,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Floor Mount) (NG)
$4,818.57 each
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Product Image of ZBR 28-3 Greenstar 100 79,000 BTU Heat Only Gas-Fired Wall-Hung Condensing Boiler
$3,823.31 each
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Product Image of ECO Tec Series 2 110-H 87,000 BTU Output Natural Gas Boiler
$3,697.28 each
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Product Image of ES2-8, 181,000 BTU Output High Efficiency Cast Iron Boiler (NG)
$5,408.16 each
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Product Image of ES2-3, 51,000 BTU Output High Efficiency Cast Iron Boiler (LP)
$2,937.00 each
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Product Image of SVF Series 1 3000, 2,499,000 BTU Output High Efficiency Gas Boiler (NG)
$69,259.43 each
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1-888-757-4774
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Product Image of Aspen Firetube 264,000 BTU High Efficiency Light Commercial Condensing Gas Fired Boiler
$8,704.28 each
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Product Image of ES2-6, 128,000 BTU Output High Efficiency Cast Iron Boiler (LP)
$4,113.00 each
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Product Image of KBR21-3 Greenstar 79 79,000 BTU Gas Fired Floor Standing Condensing Boiler
$4,722.68 each
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Product Image of 229,000 BTU Output Knight High Efficiency Boiler w/ Fire Tube Heat Exchanger (Wall Mount) (NG)
$9,316.37 each
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Product Image of ACB-150S-N 150,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler (NG)
$5,488.59 each
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Product Image of RCB301AN 301,000 BTU Commercial Wall Mounted Boiler (NG/LP)
$10,274.06 each
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Product Image of SVF Series 725, 6,160,000 BTU Output High Efficiency Gas Boiler
$21,068.46 each
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Product Image of SlimFit Series 2 1500R, 1,250,000 BTU Output High Efficiency Gas Boiler (NG)
$43,662.08 each
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1-888-757-4774
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Product Image of KWB 35-3 Greenstar Combi 131 103,000 BTU Gas-Fired Floor Standing Condensing Boiler
$6,187.39 each
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Product Image of ACB-199H-P 199,000 BTU ProLine XE High Efficiency Ultra-Low NOx Combi Boiler, High Altitude (LP)
$6,130.17 each
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Product Image of 549,000 BTU Output Knight XL High Efficiency Boiler (Natural Gas)
$19,912.99 each
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Product Image of VITODENS 100-W Wall-Mounted Gas Condensing Non-Combi Boiler
$6,963.85 each
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Product Image of 150,000 BTU Noble Fire Tube High Efficiency Boiler (NG)
$3,168.96 each
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Product Image of PF-140 - 114,000 BTU Output PUREFIRE High Efficiency Residential Boiler (Nat Gas)
$8,201.15 each
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Product Image of ECO Tec Series 2 199-H 160,000 BTU Output High-Efficiency Residential Heat-Only Condensing Boiler (NG)
$4,300.09 each
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Product Image of Aspen Firetube 90,000 BTU High Efficiency Wall Hung Condensing Gas Fired Boiler
$4,138.29 each
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Product Image of 425,000 BTU FTXL Fire Tube High Efficiency Boiler, M13 (Natural Gas)
$18,074.54 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.