Honeywell is a multinational supplier of building controls, residential thermostats, security systems, and HVAC controls. Its T-series thermostats and zone-control systems (now under Resideo) are deeply entrenched in HVAC service work.

Heat Transfer Products (HTP) manufactures high-efficiency boilers, water heaters, and indirect tanks including the Elite, UFT, and Phoenix product lines. The Massachusetts-based brand competes head-on with Lochinvar in residential and light-commercial hydronics.

Huntington Brass produces decorative kitchen and bath fixtures including faucets, shower trim, and accessories in a wide range of finishes. The brand serves designers and showrooms specifying mid-to-high-end residential plumbing.

Husky is The Home Depot's professional tools and storage line, including pliers, wrenches, screwdrivers, and tool storage. Its lifetime-warranty hand tools are widely used by plumbers, electricians, and other tradespeople.

ICM Controls manufactures HVAC and refrigeration controls including head-pressure controls, defrost timers, hard-start kits, and motor-protection modules. Its boards and modules are common service replacements for furnace, heat-pump, and refrigeration equipment.

Infinity Drain designs linear and decorative shower drains, including barrier-free curbless installations, in stainless steel and finishes ranging from satin to matte black. The brand is widely specified in luxury bath remodels and accessible designs.

InSinkErator, an Emerson business, is the world's largest manufacturer of food-waste disposers and instant-hot-water dispensers. Its Evolution and Badger lines are sold to homeowners, plumbers, and OEMs.

Jaclo manufactures decorative bathroom and kitchen plumbing including showerheads, hand showers, body sprays, supply lines, and exposed-style trim. The New Jersey-based brand is favored for its broad finish library used in mid-to-high-end residential builds.

John Guest, a Reliance Worldwide brand, produces push-to-connect plastic and brass fittings used in plumbing, water filtration, and beverage applications. Its Speedfit and ProLock connectors are a quick-install standard for water filtration and PEX-based plumbing.

K-Rain Manufacturing produces irrigation rotors, valves, and controllers for residential and commercial sprinkler systems. The Florida-based brand competes with Hunter, Rain Bird, and Toro across the irrigation distribution network.