The Model HW100 and Model HV100 series boilers are the latest residential boilers from this company. These gas-fired residential boilers have thicker walls and up to 30 percent more cast iron than competitive boilers, according to the company. These new features allow for better heat transfer, heat retention and a fuel efficiency rating of up to 84 percent. Both boilers are designed with a compact footprint, enabling them to be installed in tight spaces. The HV100 boilers feature an efficient power-vented system that provides the user with an option of venting flue gases up the chimney or directly through an outside wall.

Hydrotherm, 260 N. Elm St., Westfield, MA 01085; (413) 564-5515; www.hydrotherm.com.