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Frequently Asked Questions

Frequently Asked Questions

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Lennox Energy Efficiency

What is two-stage heating?

Two-stage heating means the furnace has two levels of heat output: high for cold winter days and low for milder days. Since the low setting is adequate to meet household heating demands 80% of the time, a two-stage unit runs for longer periods and provides more even heat distribution.

Longer, low-capacity operation has many advantages:

Consistent comfort

Two-stage heating eliminates the temperature swings associated with standard furnaces, regulating temperature to within as little as one degree of the thermostat setting.

Quiet operation

Two-stage furnaces start in the first stage, when the amount of heat required is lower, instead of reaching full capacity all at once. That means there's no sudden "kick" or blast of air.

Improved air filtration

Low-speed operation allows your filters to capture more contaminants (because air is constantly passing through them), so you can breathe easier.

Efficient performance

Because the furnace operates mostly in its lower-capacity first stage, it burns less fuel than a standard furnace that always runs at full capacity and shuts off when the heating demand has been met.

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