Furnace Face-Off: Single-Stage vs. Two-Stage

Technician changing a furnace filter

Benefits of a Single-Stage Furnace vs Two-Stage Furnace

Considering that a gas furnace is a 15- to 30-year investment, you want to make sure that you’re buying the ideal heating equipment for your home. Ultimately, you want a unit that’s going to heat your home quickly, evenly, and efficiently. While the correct furnace size is essential to avoid problems like short-cycling, furnace type is also critical when it comes to preventing issues like cold spots and astronomical gas bills.

Below we’ll break down the main characteristics, pros, and cons of two popular furnace types:

  • Single-stage

  • Two-stage

What Is a Single-Stage Furnace?

How Single-Stage Furnaces Operate

Single-stage furnaces have a single power mode: on. This means that whenever the furnace is on, it's running at full power.

Single-Stage Furnace Pros and Cons

Because this furnace type’s design is relatively basic (when compared to two-stage or variable furnaces), it is the least expensive type to purchase. This is its main advantage.

However, the single power mode can be problematic when it comes to heating a large or multi-story home. Because the furnace will run at full power whenever it is on, the areas near the vents will warm up quickly. While the rest of your home’s temperature plays catch-up, your thermostat might “think” that your whole house has reached your desired temperature and shut the furnace off prematurely. This results in warm and cold spots around your home.

To prevent cold spots, many homeowners will raise the desired temperature on their thermostat so that the furnace won’t shut off so early. While this does solve one problem, it creates a different one: higher energy bills.

Should I Buy a Single-Stage Furnace?

A single-stage furnace is usually adequate to meet the heating needs of a small- to medium-sized, one-story home.

However, if you own a larger home, you may also want to consider a single-stage furnace if you urgently need a furnace replacement but also know that you'll be moving soon. A two-stage furnace can cost several hundred dollars more to purchase, so if you won't be in your home long enough to benefit from the energy savings it will provide, the price tag might not be worth it.

What Is a Two-Stage Furnace?

How Two-Stage Furnaces Operate

Two-stage furnaces can operate at two different power levels: high power and low power. Most of the time, the furnace will run at low power. If outdoor temperatures drop drastically, the furnace can use its high power mode to help your home reach your desired temperature.

Two-Stage Furnace Pros and Cons

The ability to switch between two power modes makes two-stage furnaces more energy-efficient than their single-stage counterparts. The low power mode allows the unit to conserve energy as well as reduce temperature fluctuations and uneven heating in your home.

That being said, the improved comfort and lower energy bills do come with an initial drawback. Two-stage furnaces cost a couple hundred to several hundred dollars more to buy than a single-stage furnace. This price truly makes this equipment a long-term investment in your comfort and energy savings.

Should I Buy a Two-Stage Furnace?

You are most likely to benefit from owning a two-stage furnace if you own a two or multi-story home in which you intend to spend the next several years or more. Otherwise, you won’t get to reap the long-term benefits of lower energy bills. You might also want to consider a two-stage furnace if your home’s single-stage furnace is unable to heat your home evenly.

Should I Get a Single-Stage Furnace or a Two-Stage Furnace?

Ultimately, YOU want to be the winner in this battle of the furnaces! The right model for you depends on several factors: your budget, your home's size and layout, how long you intend to live there, and your home's unique heating challenges.

At Air Care & Canyon Lake Air Conditioning, our team of Canyon Lake heater experts is committed to helping you find the furnace that’s the best match for your home. Contact us online or call us at (210) 794-6859.

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