Our Weil-McLain gas boiler has been operating with few problems, but it's now over 20 years old and its efficiency is relatively low. With monthly gas bills climbing over $700 in the colder months, I'm thinking that it's probably time to start considering a more efficient alternative. I've heard about condensing modulating boilers that provide over 90% efficiency, but other than having heard that the Triangle Tube Prestige boilers offer a good combination of value and reasonable installation, I know little about these things. So I'm wondering about the pros and cons of going this route, what brands I should consider, and a rough idea of what costs are involved in making the switch (including any federal tax credits or rebates that may be available. My house is a 40-year-old colonial with about 3,300 sq. ft. in Southern Connecticut. All suggestions greatly appreciated.