Here’s What to Know About the Differences Between Convection and Radiant Space Heaters

When you’re sitting at home wrapped under 40 blankets in an effort to keep the electric bill down, knowing the difference between types of heaters is probably the least of your concerns. But rather than resorting to wearing your puffer coat indoors, understanding what space heater is best will allow you to pick the best one for your situation and may even cut back on your monthly expenses.

Chuck Schwartz, the HVAC Director of Training and Technical Support at Ferguson, and Randy Light, the Senior Merchant of Portable Heating at The Home Depot, both gave us the rundown on convection and radiant space heaters so you don’t feel like it’s a shot in the dark the next time you’re shopping for one.

But before the differences get addressed, there are a few general rules of thumb to keep in mind when you have a space heater — no matter the type. “Space heaters should be maintained and used according to the manufacturer’s directions, in order to avoid the risk of fires,” Light says, adding that most models these days have some kind of safety tech to lower the hazard, including adjustable thermostats, automatic overheat protection, tip-over protection, and cool-to-the-touch features. 

Light also suggests keeping heaters away from flammable objects and water, allowing plenty of space for ventilation, avoiding using them with an extension cord, and unplugging them once you leave the room. Following these guidelines will ensure you’re being as safe as possible while you’re cozying up your space. All prepped? Here’s what to know about convection and radiant heaters.

A lot of science goes behind what many would consider a basic heater. “To understand convection heat, you need to know that there are three basic types of heat transfer: conduction, radiation, and convection,” says Chuck Schwartz, the HVAC Director of Training and Technical Support at Ferguson. “Conduction is when one object touches another. Most everyone has experienced conduction when they grabbed the hot handle of a pot.” He explains this is opposed to radiation, which “travels via waves without any medium such as the pot handle.”

So, how does this reaction work when it comes to warming up your space? “First, it heats an element component inside the unit with electricity, then transfers the heat into the air using a fan or natural rising warm air, making sure the heated air is distributed evenly throughout the room,” explains Light.

While there is a lot of annoyance that comes with the cost of heating your apartment or home in the winter, convection heaters are pretty cost-efficient and may help you lower that heating bill. “Your average convection heater uses 1500 watts of electricity per hour. The actual cost to use the heater is based on local electrical rates. Based on national averages, it may cost around $0.20 per hour to use a convection heater,” says Light. He also mentions that this can save a lot of money in comparison to other heaters since you’ll be heating one room rather than the entirety of your home.

“The difference between the two types of heaters is based on the heat transfer — one needs a medium for the heat to travel and the other does not,” says Schwartz.

Radiant heaters don’t require air for heating. Schwartz says a radiant heater doesn’t need air to pass across its surface to transfer heat. Instead, the heat moves via radiant heat waves until something (like you) absorbs that heat.

Convection heaters need air to produce warmth. Unlike a radiant heater, a convection heater allows air to pass across the heater; that’s how it transfers that heat into a space. As the device warms the air, the heat rises and travels on molecules of air or water from hot to cold. This process can be a natural movement of air or forced by a fan. “Typically, calling something a convection heater suggests the natural convection of air moving without a fan,” notes Schwartz.

There are differences in heaters beyond simply whether they require airflow or not. Here are the subcategories under both radiant and convection heaters.

“Ceramic space heaters are a type of convection heater that warms the air over hot ceramic plates using a fan. The body of the heater stays cool to the touch, and the heating element lasts for many years,” says Light. He also adds that this is often an excellent choice for homes with kids and pets.

Ceramic heaters like this one are also typically small and portable, meaning that you can move them from room to room as needed, which is perfect if you need to heat an infrequently used guest room in a pinch.

There are also forced air heaters (aka fan-forced heaters), which warm and move air through the use of fans. Light says forced air heaters like this one are popular among offices and small workspaces.

Forced air heaters are also a common way of heating and cooling an entire house or building. Hot air is pushed through vents and ducts connected to a central unit, often referred to as a heat pump, creating a consistent temperature throughout a home.

Although this type of heating isn’t mobile, it’s an ideal way to get cozy in specific spaces, such as bathrooms and bedrooms. An in-floor duct system allows heated liquid to flow, therefore warming the area under your feet.

Sometimes, electrical wiring is used in bathrooms under tile to create warmth. This type of heating takes a while to heat up, but it’s also an energy-efficient way to provide warmth in one room or throughout an entire house.

You also might be familiar with oil-filled heaters, which Light says are both convection and radiant because they heat the air and give off radiant heat when you’re nearby.

“These are ideal for a living room, bedroom, or den and tend to retain heater for longer periods of time, even when the power is turned off,” he says. This holding of heat helps to maintain an even temperature in a room.

On a larger scale, many older apartments and houses use heated water in traditional radiators. A central boiler boils water and sends heat throughout a system of radiators. Although each room may have a radiator, there are more effective ways to evenly heat a home or room than this type of heat.

If you don’t want to deal with installing ductwork or want each room to be at a separate temperature, then a mini-split is the answer.

These heaters have the ability to both cool and heat and are ideal for older homes when installing ducts would be cost-prohibitive or unfeasible. Mini-splits also work well to assist whole-house heating systems that may not be able to keep up with fluctuating temperatures.

Lastly, Light points to infrared heaters, which are especially useful for small spaces, like under your desk or in a bedroom.

Also known as heat lamps, this type of space heater has a core that is heated to a high temperature. The warmth is then transferred to another object via electromagnetic radiation.

Although it sounds highly technical, these devices are one of the cleanest burning types of heat. Some infrared heaters are also rated for outdoors, so be sure you’re buying the right type for where you’ll be using it.