Did you know?
If the room air temperature is less than 65 degrees many 80% efficient furnaces will experience condensation (water) in the heat exchanger. Condensation in the heat exchanger is a problem because it will rust out the heat exchanger and cause per-mature failure of the heat exchanger. Lennox has two 80 % efficient furnace models that have stainless steel heat exchangers which reduces the rust problem.
It is also possible to have the same problem exist in a 90% efficient furnace. These high efficiency furnaces have a primary and a secondary heat exchanger. The primary heat exchanger on many 90% efficient furnaces is made from aluminized steel and condensation will rust the primary heat exchanger. The secondary heat exchanger of most 90% efficient furnaces is made from stainless steel and is not affected by condensation because it is designed for condensation. Sometimes these furnaces are called condensing furnaces and this is why they have a higher efficiency that 80% efficient furnaces. Lennox has three 90% efficient furnaces that have both the primary and the secondary heat exchanger made from stainless steel. Stainless steel is much more resistant to rust from condensation and or water.
So the point being, sometimes trying to save money by keeping the thermostat down below 65 degrees can end up costing money down the road by having to replace parts or even equipment.
