BVS Home Experts

How Much Power Does a Furnace Use?

Electric and gas furnaces are typically efficient overall, but how much power does a furnace use? Find out more from BVS Home Experts!

How much electricity does a furnace require to run optimally? An outdated furnace causes sky-high electric bills, but modern technology has made great strides in this industry. If you’re questioning your furnace’s consumption, it may be time to think about an upgrade with Katy’s professional furnace installation service.

Below, BVS Home Experts share what you need to know about your furnace’s energy consumption, efficiency, and everything in between.

Energy Definitions: A Quick Guide

You may have heard the terms “watt” and “volt,” but what exactly do they mean for your furnace? Here is a short guide:

  • Watt: Measures the amount of energy consumed 
  • Volt: Measures the speed of energy consumption
  • Kilowatt: One thousand watts
  • Kilowatt Hours: Energy consumption measured over one hour

These terms will come in handy when analyzing your furnace’s energy consumption as you consider whether it is working as efficiently as it should be. You might also want to consider that newer furnaces are typically more energy efficient than older models.

Two Ways a Furnace Uses Power

Gas furnaces use propane or natural gas to produce heat, but they can’t run on gas alone. They need electricity to operate. Total electric furnaces use electricity throughout the heating cycle.

So, both types of furnaces use power, but the majority of this consumption happens with two main functions: starting the motor and operating the furnace blower. Here’s how the amount of power a furnace uses depends on these two components:


Before your furnace can run, it has to start up using a jolt of electricity. A newer furnace uses less electricity to ignite. However, many older starters stay hot the entire time the furnace runs, which consumes more electricity.

Both gas and electric furnaces will typically use electricity during the ignition process. However, a gas furnace uses so little electricity for ignition that it shouldn’t make a difference to your power bill.

Operating the Furnace Blower

Once your furnace ignites, it uses power for the entirety of the heating cycle. The furnace blower motor is the biggest energy drain on your unit, running on about 110 volts. It runs as many hours per day as you require it to keep you warm.

Gas furnaces may use electricity to operate the furnace blower, just like electric furnaces. When it comes to energy consumption, a gas furnace will draw the most power to the furnace blower. However, gas heats the property faster than an electric furnace, so it is often more energy-efficient.

Measuring Your Furnace’s Power Uses Wattage Conversion

How much power does a furnace use overall? The answer depends heavily on the size of the unit. The larger the furnace in your home, the higher your energy bill will be each month.

Horsepower units convey furnace power. A gas furnace may use as much as 1 HP (1 unit of horsepower is equal to 375.5 watts). Once you know how many watts your furnace uses, you can calculate the cost per kilowatt hour. 

Would you like some assistance? A professional HVAC technician from BVS Home Experts could help you calculate the usage cost to determine if you have the most efficient furnace for your space.

Variable Speed Motors Adjust the Consumption Somewhat

Furnaces have variable speed motors that will not operate at full capacity all the time; great news for your energy bill. This motor detects the temperature in your home and adjusts it accordingly to reduce power consumption. That’s how both gas and electric furnaces cycle off and on to maintain the temperature indoors. 

So, a 20,000-watt furnace won’t necessarily consume the full 20,000 watts in one hour.

Furnace Generators Should Match Your Energy Needs

In the event of a power failure, a generator comes in handy. However, you need that generator to power your furnace, and the size choice depends on the wattage of your furnace. 

Buy a generator that is slightly more powerful than you need to be safe. The most popular power level of furnaces is ½ HP (367.8 watts). For that size furnace, you need a generator that is at least 500 watts to run. 

Your Electric Bill Requires a Look at Location Averages

Budgeting for your monthly electric bill can be confusing, even when you know the wattage of your furnace. It would be enlightening if the bill showed how much it costs to run each appliance in your home, big or small. Unfortunately, it only shows the total electricity consumed during the month.

So, how much power does a furnace use? The monthly cost primarily depends on where you live. For example, California is way above the US average electricity rate in kilowatt-hours, while Michigan is only slightly over the national average, with Washington state a little below it.

Be sure to look at your state’s tables and graphs for an idea of your furnace’s expected energy use over the course of a year. Most household furnaces only operate for four months per year. You may experience higher power bills during those months, but over a year, it could turn out to be surprisingly cost-effective with an energy-efficient unit.

Energy-efficient Furnaces Cost Less Long-term

When determining the monthly cost of running a furnace, volts and watts aren’t the only factors—purchasing an efficient furnace for your home also lowers your cost commitment. Maintenance also helps because when a professional services your furnace, they leave it spotlessly clean with no parts showing signs of wear.

Call BVS Home Experts to Get A More Economical Furnace

A furnace’s power consumption depends on factors like its age and maintenance schedule. A well-maintained furnace will keep you and your family warm without driving up electricity costs. However, the best way to know whether you have the most energy-efficient furnace possible is by scheduling an appointment with a professional.

How much power does a furnace use if it’s a brand-new model? Find out when you call BVS Home Experts at 281-916-8699 for dependable service in Katy, TX!

Author Bio:

Ronald Via

Ronald is one of the key contributors to BVS Home Experts, a family-owned and operated full-service air conditioning and heating company serving the Katy and West Houston areas. With a deep understanding of air conditioning and heating concerns, Ronald brings a wealth of knowledge to our readers.

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