A furnace is a long-term investment and one of the ways to make sure you get the most out of that investment is by understanding all the aspects of how the furnace works that impact its efficiency. One important consideration is choosing the option of a two-stage furnace rather than single-stage furnace.
The difference between one-stage and two-stage
Furnaces produce heat at one temperature throughout each operating cycle. As the heat concentrates in the home’s living spaces, the temperature rises. When the desired setting (the temperature the thermostat is set at) is reached, the furnace cycles off until the temperature drops. This is how a one-stage furnace operates. While this is effective, it is not the most efficient method for home heating.
As the name implies, a two-stage furnace has two stages of heating that are used to meet the current heating needs. It has the ability to run at full capacity when necessary, such as when the outdoor temperatures are especially low and the house needs to warm up quickly. When the temperatures are milder, however, it can operate on low-power mode to sufficiently heat the home while using less energy. Most of the time, homes can remain comfortable using only the low-power mode.
Advantages of a two-stage furnace
- Consistent comfort.
Two-stage heating eliminates the temperature swings associated with one-stage furnaces. Heating cycles are longer in low-power mode but at a fraction of the cost, so the furnace can maintain the temperature within as little as one degree of the thermostat setting at all times, without wasting energy.
- Quiet operation
Because a two-stage furnace starts in the first stage, when less heat is required, it doesn’t reach full capacity all at once. This eliminates that sudden blast of air.
- Better air filtration
The air filter can more easily capture more contaminants because air is constantly passing through it.
- Efficient performance
Even though it is running longer, the lower-capacity first stage burns less fuel than a standard furnace that runs at full capacity and turns on and off throughout the day.
One-stage furnaces are less expensive to purchase, but it is important to factor in the energy savings over the life of the furnace. One-stage furnaces also have a harder time maintaining even heat throughout multi-story homes. Because they run at full power all the time, the areas closest to the vents will heat faster than those farther away. This can contribute to hot and cold spots.