Lennox markets three different series of boilers.
What are the 10 Best Boilers?
There are two boilers in this series and they’re the least expensive models. Both the GSB8-ES and the GWB8-ES have AFUE ratings of around 82% and are designed to use natural gas as fuel. They have an electronic ignition, vent dampers, and fiberglass insulation, all of which reduce their energy consumption. Efficiency is also improved by a draft fan, which increases the ability to vent combustible gas.
Both come in a range of sizes that can fit in small spaces, basement or otherwise.
The GWB8-IE is a mid-price, mid-efficiency gas boiler, with 84% AFUE. It has slightly better insulation than the other models. It also comes with a pressure switch to ensure that the flue is clear and safe.
The COWB2, also in the Elite Series, is the only oil-fueled boiler manufactured by Lennox. It has an AFUE rating of 85%. It uses a Beckett burner and a cast-iron heat exchanger. This boiler comes (optionally) with a tankless coil, which doubles as a source of hot water for the house.
Dave Lennox Signature Collection
There is only one model in this series: the GWB9-IH. It is the most expensive and also the most efficient (90% AFUE) boiler. It is fueled by natural gas. An aluminum heat exchanger makes the boiler more efficient and three times faster than iron. Aluminum alloy is also less likely to corrode. This model is the only Lennox boiler that receives an EnergyStar efficiency rating. It is also relatively quiet.
This boiler requires the use of CPVC pipe (which comes with it) for five feet worth of venting. The rest of the vent system can use PVC piping, which is inexpensive and relatively easy to install. The apparatus has a baked-on paint finish that will preserve its appearance over time.
Care and Maintenance
Lennox recommends having boilers evaluated by a qualified technician on a yearly basis to ensure that all systems related to the boiler are safe and functioning optimally.
The GSB8-ES has a twelve-year warranty for its heat exchanger; the GWB8-ES has a 20-year warranty. Both of these have a one-year warranty for their other parts. The Elite series models have twenty-year warranties on their heat exchagners and one-year warranties on everything else. Finally, the DLSC boiler has only a fifteen-year warranty on its heat exchanger, but a ten-year warranty on the rest of the parts.