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.

The Genesis Series, a long-running low-voltage cable line associated with Honeywell and Resideo, supplies thermostat wire, alarm cable, and structured wiring used in security and HVAC controls. The Genesis line is a daily install for low-voltage contractors.

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.

Imperial Manufacturing Group produces HVAC accessories including pipe and duct fittings, dampers, range-hood ducting, and chimney accessories. The Canadian-headquartered company supplies HVAC wholesalers and home centers across North America.

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.

Intermatic produces electromechanical and digital timers, pool and spa controls, surge protectors, and lighting controls. Its T-series wall and panel-mount timers are workhorses in pool, irrigation, and outdoor lighting applications.

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.