Rinnai. The maker’s new wall-mounted boilers use condensing technology to heat a whole house and provide domestic hot water while operating at up to 96.5% efficiency. The Energy Star–qualified units use less energy than a traditional gas boiler, and are easily installed in retrofit situations. To meet individual users’ needs, two series are available: The E Series designed for homes with small domestic hot water requirements, and the Q series, which work in all homes, including those requiring zone heating. 800.621.9419. www.rinnai.us.