Few systems in a home are as important as its heating, air conditioning, ventilation, and air treatment systems, and few systems cost the homeowner as much to maintain and use each year. As energy needs and costs continue to rise, energy-efficient solutions to heating and cooling are in ever-increasing demand. According to the Department of Energy's Annual Energy Outlook 2002 with Projections to 2020 report, energy consumption in the residential sector will increase 22% between 2000 and 2020; an increased use of electricity will account for 81% of this growth.

The DOE's report predicts that although the use of energy for heating in the residential sector increased by 1.9% between 1990 and 1997, higher-efficiency heating equipment and more stringent building codes will slow future growth of heating energy consumption.

This year the DOE increased required minimum efficiency standards by 20% for home air conditioners and heat pumps manufactured for distribution in the United States, effective January 23, 2006. The new standard will require central air conditioners to operate at an efficiency of 12 SEER (Seasonal Energy Efficiency Ratio) and heat pumps to operate at an efficiency of 7.4 HSPF (Heating System Performance Factor). Many heating and cooling systems already operate at the new efficiency ratings or better.

The energy outlook report predicts that the new standard will save the nation's consumers $2 billion between 2006 and 2030.

York International Unitary Products Group. The Stealth Hot Heat Pump combines the company's Twin-Single compressor with its Comfort Enhancer microprocessor to deliver heat discharge temperatures of up to 110 degrees. When cooling, the heat pump can achieve a 15.7 Seasonal Energy Efficiency Ratio; while heating, it can achieve a 9.3 Heating System Performance Factor. The heat pump is available in capacities ranging from 2 to 5 tons. (877) 874-7378. www.yorkupg.com.

Courtesy Friedrich

Friedrich. A large-capacity Dual Zone Ductless split-system air conditioner will cool two adjoining rooms or long narrow rooms, according the manufacturer. Two indoor units connect to a single outdoor unit; each unit can be controlled independently for zone cooling. Four fan speeds, auto-shut flaps, auto-restart, and an ambient operating temperature down to 0 degrees are the model's newest features. The system comes with a wireless remote control. (800) 541-6645. www.friedrich.com.

Panasonic Building Products. The WhisperLine remote mounted in-line ventilation fan provides multiple task ventilation in one room or ventilates two rooms. Available in four models, the fan is rated for continuous run ventilation with multiple inlets. An insulated fan housing prevents condensation, the company says. (800) 211-7262. www.panasonic.com/building.

Courtesy Watts Radiant

Watts Radiant. SunTouch UnderFloor electric radiant heating mats are UL-listed for use under existing wood subfloors. They can be installed in 16-inch joist bays within an inch of the subfloor's underside. (888) 432-8932. www.suntouch.net. UNICO. Designed for use in buildings without ductwork or with inadequate ductwork, the company's mini-duct system's flexible, 2-inch-diameter ducts can be routed through and around existing structures. The system connects to most outdoor heating and cooling units and provides uniform temperatures throughout a room, according to the manufacturer, while reducing humidity by 30%. Register covers measure 4 inches in diameter and can be painted. (800) 527-0896. www.unicosystem.com.

Courtesy Carrier Corp.

Carrier Corp. The WeatherMaker 8000 gas furnace incorporates the company's QuieTech system, which consists of a redesigned burner, inducer, and fan, to provide quiet operation with 80% Annual Fuel Utilization Efficiency, says the maker. The furnace also offers a more compact heat exchanger, shorter cabinet, and four standard installation positions. (800) CARRIER. www.carrier.com.

Courtesy Lennox Industries

Lennox Industries. The HSX15 air conditioner is designed with a patent-pending fan blade, an insulated compressor compartment, and the company's SilentComfort technology to reduce operating noise, says the maker. The air conditioner is an EnergyStar product with a Seasonal Energy Efficiency Ratio of up to 15.75 and uses the EPA-recognized chlorine-free R410A refrigerant. (800) 953-6669. www.lennox.com. Heil Heating amp; Cooling Products. The QuietComfort 14 Series split system air conditioners are available in 2- through 5-ton capacities. The system can achieve up to a 15.0 SEER rating when matched with a variable-speed air handler or furnace. The system's compact design makes installation easier, says the company, and its narrow clearance allows it to be installed 6 inches from the home. (800) 315-4370. www.icpusa.com.

Courtesy Honeywell

Honeywell. The whole-house Clean Steam humidifier, model number HE440A, filters water twice to remove chlorine, particulates, and other dissolved solids and to prevent residue build-up in the reservoir and on the heating element, according to the manufacturer. The unit's reverse osmosis filter averages a two-year life span, and the chlorine filter averages one year. The unit is rated at 12 gallons per day. www.honeywell.com.