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An efficient heating system is key to keeping utility costs down and keeping homes comfortable year round.
HIGH-EFFICIENCY MODULATING GAS FURNACE 


VIRTUES
> Uses less energy than a conventional gas furnace
> Variable speed technologies ensure more even temperatures throughout the home


CAVEATS
> Cost can be twice that of conventional furnace


 


At the heart of most home heating systems is a furnace, a boiler, or a heat pump. A furnace burns fossil fuel to heat air that’s forced by a blower fan through a series of ducts to the living spaces; a boiler heats water that’s then pumped to a hydronic, or water-based, distribution system. Most heat pumps run on electricity. They don’t create heat, but rather extract it from the air or the ground. Heat pumps are available for use with forced air and hydronic distribution systems. If you want to minimize your fuel bill, an Energy Star rating is a minimum standard for these appliances.


GAS FURNACE SUPER EFFICIENT
A high-efficiency modulating gas furnace is the most efficient furnace you can get, with efficiencies as high as 97% (that’s the percentage of the fuel’s potential energy delivered as heat). They achieve this feat with a series of technical innovations. For instance, a second heat exchanger recovers latent heat from the furnace exhaust by condensing it to water vapor, while a modulating valve varies flame intensity by varying the amount of gas delivered to the combustion chamber. Flame modulation is an energy saver for the same reason that using cruise control on the highway burns less gasoline than driving in stop-and-go traffic. These furnaces include variable speed blower fans with high-efficiency electric motors. The ability to vary air-flow and flame intensity lets means nearly constant room temperatures and better air circulation.


 


HIGH EFFICIENCY BOILER


VIRTUES
> Quiet operation—no air blowing
> Relatively easy to zone
> Lack of fan means lower electric use than a forced air system
> Distribution system takes up much less space than ductwork


CAVEATS
> Up to 50% more expensive than a conventional boiler
> There are fewer high-efficiency boilers to choose from than there are high-efficiency furnaces


 


HIGH EFFICIENCY BOILER BURN HEAT
A boiler burns oil, natural gas, or propane, to heat water. That heated water is then pumped through a system of pipes to radiators, baseboard heaters, or a radiant floor.


A good boiler will offer efficiencies of 90% to 95% and will include many of the same technologies as a high- efficiency furnace. These include a modulating burner that matches the heat output to whatever the thermostat is calling for at the moment, advanced heat exchangers to extract more heat from the same amount of fuel, and the ability to recover heat from the exhaust gas by condensing it. The resulting exhaust is cool enough to be vented out of a plastic pipe. In the best cases, this condensing process can squeeze 10%–12% more usable energy out of the fuel.


 


RHEEM GAS/ELECTRIC SPLIT SYSTEM
Split systems are very common in U.S. homes. They include an outdoor air conditioner or heat pump and an indoor gas furnace. This ultra-efficient Rheem system pairs a 19.50 SEER air conditioning unit with a 94.8 A.FU.E condensing gas furnace. www.rheem.com


LENNOX SLP98V VARIABLE-CAPACITY GAS FURNACE
Besides offering a 98.2% AFUE, this variable speed furnace claims to be virtually silent even when running at full capacity. It automatically adjusts fan speed, heat, and airflow capacity in increments as small as 1% for the ultimate in temperature control. www.lennox.com

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