Modulating Gas Furnaces – Furnace Purchase Options
Modulating Gas Furnaces - Gas furnace manufacturers have for many years been working on modulating furnaces to make furnaces more efficient. Before modulating furnaces, the highest rated (efficiency-wise) were two-stage gas furnaces. Then came the modulating furnaces.
Efficiency ranges started increasing to 98% and fractionally more than 98% for some modulating gas furnaces. Always check the AHRI website for the certified efficiency of any HVAC product you purchase. What makes this furnace different than the other types of gas furnaces you can purchase?
Modulating gas furnaces are also condensing gas furnaces. All-natural gas and propane gas has a small percentage of moisture in the gas. When the combustion process takes place the moisture in the gas turns into steam. A condensing gas furnace has two heat exchangers.
In the secondary heat exchanger, any residual heat is absorbed into the exchanger, and the air passing around the exchanger. This maximizes the amount of heat used by the furnace. It also makes it far more efficient than a non-condensing gas furnace. That moisture is then drained down the same drain the air conditioner uses. The moisture produced by the evaporator coil.
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