Does a Space Heater Use a Lot of Electricity?

Heating bills can be one of the biggest expenses for those of us living in colder climates, especially in the winter. With many American families facing difficulties paying for heating costs, finding a more efficient way to stay warm is a priority.

If you’re looking for ways to lower your heating bill, then you may have thought about investing in a space heater to warm just one room within your home. But are space heaters really more effective than central heating — or are you just exchanging heating and gas bills for higher electricity bills?

This post takes a look at the average cost of space heaters and how they can help save you money — if you use them the right way.

How much electricity does a space heater use?

A 1,500-watt space heater running continuously for eight hours uses 12 kWh, or 360 kWh of electricity over 30 days. Your actual consumption depends on the heat setting, how long you run it, and whether its thermostat cycles the heater off.

Does a space heater use a lot of electricity? 

Space heaters use a lot of electricity usually ranging from 500 to 1500 watts. Running one for long periods can lead to a noticeable increase in your electric bill, as they are considered high-energy appliances compared to many others. Here are few reasons why space heaters can significantly increase your electricity bills: 

• Most space heaters operate at 1,500 watts, consuming 1.5 kilowatt-hours (kWh) for every hour of use.     

• Space heaters are designed for small areas. Attempting to heat larger spaces requires the heater to run longer and at higher settings, leading to increased energy usage and higher costs. When used alongside central heating systems, space heaters add to the total energy consumption, further elevating electricity bills. 

• Not all space heaters are equally efficient. Models without energy-saving features, such as thermostats or timers, may operate continuously, consuming more electricity.

How many watts does a space heater use?

Most space heaters use around 1,500 watts on high and 750 watts for the low setting, but note that wattage can vary widely across models. Even small, portable space heaters are able to offer up to 1,500 watts performance. Larger space heaters will cover more space within a room, which can enable it to run for shorter periods of time.

Check the product label or owner’s manual to confirm your heater’s wattage.

How to calculate your space heaters wattage

If your space heater’s label lists volts and amps but not watts, you can estimate its wattage by multiplying the two:

Watts = volts × amps

For example, a heater rated at 120 volts and 12.5 amps uses approximately 1,500 watts at that setting. Divide watts by 1,000 to convert to kilowatts: 1,500 watts = 1.5 kW.

To calculate electricity consumption, multiply kilowatts by operating hours. Running that heater continuously for six hours uses 1.5 kW × 6 hours = 9 kWh.

How much does it cost to run a space heater?

Once you know your space heater’s kWh average for a span of time, you’ll need to multiply that value by the kWh usage rate charged by your utility company.

At the U.S. average cost of 18.34 cents per kWh, it would cost an average of $50 a month — so around $198 for the winter months — to run a 1,500 watt space heater for six hours a day.

Of course, you don’t have to run your space heater at max capacity, and running it at lower settings can help you reduce electricity costs. Here is a quick reference guide estimating how much it would cost to operate a space heater at both low and high settings for a set period of time.

Can a space heater raise your electric bill?

A space heater can noticeably raise your electric bill, especially if you run it for several hours each day. For example, a 1,500-watt electric space heater running continuously for six hours a day uses 270 kWh over 30 days. At an electricity rate of 18.34¢ per kWh, that represents approximately $49.52 in additional monthly electricity costs, assuming your other electricity use stays the same.

Your actual increase depends on your electricity rate, heat setting, and how long the heater actively heats. A thermostat that cycles the heater off can reduce consumption compared with continuous operation, while using multiple heaters increases it.

What affects how much electricity a space heater actually uses? 

Not all space heaters use energy equally. Depending on your model and how long you use it, a space heater can consume different amounts of energy which can result in different billing amounts. Here are some of the biggest factors that affect how much energy your space heater uses: 

1. Heat Settings, Thermostats, and Runtime

Space heaters convert electricity into heat, but some energy is often lost as light or motion, reducing overall efficiency. Some thermostats within your space heater are more modern and help maintain a steady temperature by cycling the heater on and off, preventing unnecessary energy use, but their quality can vary. 

Heaters with fans also distribute heat faster and more evenly, reducing runtime and improving energy efficiency.

2. Room Size

Using a heater that’s the right size for the room prevents it from overworking or cycling too often, saving energy. Larger rooms need more energy to heat evenly while smaller rooms might only need a portable space heater to do the trick.

3. Insulation

In the same way, poor insulation lets heat escape, forcing the heater to work harder. When a home is well-insulated, heat remains trapped inside for longer periods, reducing the need for the heater to run continuously. To improve insulation, consider adding weather stripping around doors and windows to seal air leaks.

4. Ceiling Height

In rooms with high ceilings, warm air rises and accumulates near the top, leaving the lower living space cooler. This means the heater has to run longer to maintain warmth at the desired level, increasing energy consumption. 

Space heater vs. central heating: which uses less energy?

During the winter months, is it cheaper to turn up the thermostat or use a space heater?

A space heater can reduce total heating energy use when you warm one occupied room and lower the central thermostat. However, it isn’t automatically more efficient than central heating. The comparison depends on your central heating system, how much space you heat, and how long each system runs.

For example, using a space heater in your home office may let you keep the rest of the house cooler during the workday; if this strategy is used consistently, this can lead to energy savings over time. However, if you leave your central thermostat unchanged and run a space heater at the same time, you generally increase your total energy use.

Types of space heaters and their electricity use

Let’s dive in some of the benefits and drawbacks for various types of heaters for your home. 

Electric Space Heaters 

Electric space heaters are ideal for small, enclosed spaces like bedrooms, home offices, or living rooms. They are portable, easy to use, and can be plugged into any standard outlet, making them a versatile choice for supplemental heating. These heaters are perfect when you need quick, focused warmth without heating the entire house. However, they can increase energy bills if used for extended periods, so they are best for short-term or occasional use. 

Wattage: 1,500 

Average Electricity Use Per Month: 360 kWh* 

Estimated Average Electricity Cost: $66.02

Sealed Combustion Heaters 

Sealed combustion heaters are highly efficient and safe, making them an excellent choice for well-insulated homes or large spaces like basements or garages. These heaters pull air for combustion from outside the building, ensuring no indoor air is used or contaminated. This design prevents drafts and reduces the risk of carbon monoxide exposure, making them safer than traditional combustion heaters. 

Wattage: 40-120 

 Average Electricity Use Per Month: 9.6–28.8 kWh*   

Estimated Average Electricity Cost: $1.76–$5.28 

Fan Heaters 

Fan heaters are compact and lightweight, making them a convenient option for bathrooms, kitchens, or other small rooms that need quick warmth. They use a fan to blow air over a heating element, rapidly warming the space. Their portability makes them easy to move wherever you need heat. However, they can be noisy and are not the most efficient choice for prolonged use or heating larger areas, making them better suited for spot heating. 

Wattage: 750-900 

Average Electricity Use Per Month: 180–216 kWh*  

Estimated Average Electricity Cost: $33.01–$39.61

Garage Heaters 

Garage heaters are designed specifically for larger, uninsulated spaces like garages or workshops. They come in various types, including electric, propane, and natural gas models, providing powerful heating to combat cold temperatures in these areas. These heaters are a great choice for DIY projects or working in garages during the winter.  

However, they can be energy-intensive, and proper ventilation is essential for non-electric models. Placement should ensure even heat distribution and safe operation, ideally mounted on the wall or ceiling to save space. 

Wattage: 3,000W to 10,000 

Average Electricity Use Per Month: 720–2,400 kWh*   

Estimated Average Electricity Cost: $132.05–$440.16  

Electric Wall Heaters 

Electric wall heaters are a space-saving solution for permanent heating in areas like bathrooms, hallways, or entryways. They are mounted directly onto the wall, making them ideal for rooms where floor space is limited. These heaters provide consistent warmth and are an efficient choice for small to medium-sized areas. However, they require installation and are not portable, which makes them less versatile than other options. 

Wattage: 1,000-4,000 

Average Electricity Use Per Month: 240–960 kWh*   

Estimated Average Electricity Cost: $44.02–$176.06 

Radiant Heaters 

Radiant heaters are designed to provide direct, targeted warmth to people and objects rather than heating the air. This makes them ideal for living rooms, workspaces, or areas where people remain stationary. They are highly energy-efficient and excellent for quick heating, but they may not evenly warm an entire room. Radiant heaters are best used for focused comfort in smaller or specific areas. 

Wattage: 1,200-1,500 

Average Electricity Use Per Month:  288–360 kWh*   

Estimated Average Electricity Cost: $52.82–$66.02

Infrared/Reflective Heaters 

Infrared heaters work by emitting electromagnetic waves that warm people and objects directly, similar to the way sunlight feels. They are quiet, energy-efficient, and great for spot heating in dining rooms, bedrooms, or cozy corners like reading nooks. While they provide immediate warmth, they are less effective for heating large, open spaces since they don’t heat the surrounding air. These heaters are ideal for localized warmth in specific areas of your home. 

Wattage: 1,000-1,500  

Average Electricity Use Per Month:  240–360 kWh*   

Estimated Average Electricity Cost: $44.02–$66.02 

Ceramic Heaters 

Ceramic heaters are a popular choice for bedrooms, living rooms, or home offices due to their efficient and quick heating capabilities. They use ceramic plates to generate heat and often include built-in safety features like overheat protection. These heaters are portable, easy to use, and provide consistent warmth in small to medium-sized rooms. However, they may not be powerful enough for heating larger spaces, making them best suited for focused use. 

Wattage: 1,500 

Average Electricity Use Per Month:  360 kWh*   

Estimated Average Electricity Cost: $66.02 

Kerosene Heaters 

Kerosene heaters are a powerful heating solution for garages, workshops, or emergency situations in off-grid areas. They produce strong, consistent warmth and are a reliable option when electricity isn’t available. However, they require kerosene fuel, which can be messy to handle, and produce fumes that necessitate proper ventilation. Kerosene heaters are best for outdoor or semi-outdoor use where robust, portable heating is needed. 

These run entirely on liquid fuel and require 0 watts of electricity, making them popular for emergency power outages. 

• Standard indoor radiant models: 10,000 to 12,000 BTUs/hr 

• Large omnidirectional convective models: 23,000 BTUs/hr 

*Based on operating the heater for 8 hours per day for 30 days and an electricity rate of 18.34¢ per kWh. Actual electricity use and costs vary based on heater wattage, operating time, thermostat cycling, settings, and local electricity rates. 

**Propane and kerosene heaters generally use fuel rather than electricity, although some models may use electricity for fans, ignition systems, or other components. 

Can you leave a space heater on all night? 

It’s not recommended to leave a space heater on all night. Doing so increases the risk of fire hazards. While modern space heaters often include safety features like tip-over protection and auto shut-off, it’s generally not recommended to run them unattended overnight. Here’s why: 

1. Even with built-in safety features, space heaters can overheat, malfunction, or ignite flammable materials nearby, such as curtains, bedding, or furniture. According to the National Fire Protection Association (NFPA), space heaters are responsible for more than one-quarter (29%) of home heating fires. 
2. Fuel-burning space heaters, such as kerosene or propane models, can emit carbon monoxide if not properly ventilated, leading to potentially fatal poisoning. 
3. In poorly ventilated rooms, unvented space heaters can deplete oxygen levels, which may cause respiratory issues or even suffocation. 
4. Prolonged operation may cause the heater’s internal components to overheat, even if the exterior feels cool to the touch, increasing the likelihood of failure. 

If you left it on all night, for example, from 10 PM to 6 AM, that’s 8 hours. At the average U.S. electricity rate of 18.34 cents per kWh, running a space heater for 8 hours daily can add approximately $2.20 per day, or about $66.02 per month, to your energy costs. 

FAQs

Do portable heaters use a lot of electricity?

At an average of 1,500 watts for the high setting, space heaters use a high amount of electricity compared to other appliances. Even full-sized refrigerators only average around 800 watts. While some smaller appliances such as hair dryers can draw even larger quantities of electricity, they’re used for a much shorter amount of time.

Are all electric space heaters 1,500 watts?

On average, most commercial space heaters will have a maximum high setting of 1,500 watts and a lower setting of 750 watts.

How big of a room can a 1,500 watt space heater heat?

Assuming 8-foot ceilings and good insulation, it takes roughly 10 watts of heating power for every square foot of floor area in a room. So, the average 1,500-watt heater should be able to heat a 150 square foot room. However, that equation changes a bit due to other variables, such as higher ceilings, lack of insulation, number of windows, and average outside temperature.

What’s the best time to run a space heater?   

The optimal time to use a space heater is when you’re present in the room and need additional warmth. It’s important to turn off the heater when you leave the room or go to sleep to ensure safety. 

Can you plug a space heater into a surge protector? 

No, you should not plug a space heater into a surge protector, power strip, or extension cord, as this can cause overheating and potentially lead to a fire. Always plug space heaters directly into a wall outlet. 

How can I save electricity with my space heater?

Smart and careful usage of a portable space heater will help save you money, but excessive use can run up your electricity bill. Here’s what you need to know to save on electricity when using a space heater.

• Determine when to use your central heating vs. an electric space heater. If everyone is gathered together in one room, then using a single space heater makes sense rather than heating up the entire house. However, if you have people in multiple rooms, it’s more efficient to heat the house rather than run many different space heaters at the same time.
• Use a timer or settings to automatically set your space heater. The longer a space heater runs, the more electricity it consumes. Modern space heaters will have automatic settings to turn off after a set amount of time or when the area reaches a specified temperature. Using these automatic presets can ensure you’re not wasting electricity.
• Cover up while indoors during the winter months. The best way to stay warm during the winter months is to dress warm. Wear extra layers of clothing, socks, and slippers to keep warm as you move through the house. That way, you don’t need to set your space heater or your central heating too high.
• Take the right steps to better conserve heat in your home. Besides dressing warmly, there are other ways to winterize your house to conserve heat. Purchasing smart thermostats, buying heavy curtains, covering air leaks, and updating your insulation are the most efficient ways to save money on heating.
• Select an energy plan that fits with your lifestyle. If you want more control over your energy bill and don’t want to worry about spikes in your kWh charges, see if your retail energy provider offers Unlimited Energy or Fixed-Rate plans. Fixed-rate plans guarantee a cost that does not change for a specified period of time, while unlimited energy plans allow you to pay the same amount every month without worrying about fluctuating energy costs.*

* Restrictions apply. Enrollment based upon program eligibility. Customers using more than 125% of normal monthly usage as determined by Santanna may be required to switch plans.