Preferred Series BW9 Boiler (Best)

• 90 AFUE
• Gas-fired
• Integrated boiler control
• Cast-aluminum heat exchanger
• Optional PVC pipe installation
• 5-year parts limited warranty and a 15-year parts limited wa...rranty on heat exchanger section

Preferred Series BW3 Boiler (Better)

• Up to 84.4 AFUE
• Cast iron heat exchanger
• Gas-fired models
• Stainless steel/titanium alloy composite burners
• Fiberglass insulated casing
• Small, compact design
• 5-year parts limited warranty and a 20-year parts limited wa...rranty on heat exchanger section