Blue Flame vs Radiant (Infrared) Heating: What’s the Difference?

According to the Department of Energy, heating is the top consumer of energy in US homes, accounting for up to 42% of the typical household’s utility bill. One way to add warmth without turning the thermostat all the way up is to use a gas vent-free heater as an additional heating source.

In this guide, we discuss the two different types of ventless gas heaters: blue flame and radiant heating. Read on to learn their differences to help you decide which type is right for you.

Blue Flame vs Radiant Heating: What’s the Difference?

Offered in both natural gas and liquid propane, the two main types of vent-free heaters are blue flame and radiant heating, also known as infrared heating. While both use different methods to keep you feeling warm and toasty, they do have some things in common.

• Both heaters will heat in the event of a power outage. Only the blower (if the unit has one) will not work.
• Both infrared and blue-flame heaters have Oxygen Depletion Sensors (ODS), which will shut off the heater before it reaches an unsafe level.
• Both are vent-free heaters. Since vent-free heaters add moisture to a room, it’s wise to periodically open a door or window while running your heater.

With their similarities out of the way, let’s look at their key differences.

Blue Flame Heaters

A blue-flame heater heats the air in the room. First, the heater heats the wall where it is installed. The heat then moves up toward the ceiling to eventually cover the entire room.

Because blue flame heaters heat the air vs objects in a room, they’re ideal for insulated spaces. A ceiling fan with the blades reversed can help to circulate the warm air and make the heater more efficient.

There’s not much of a disadvantage to blue flame heaters. Although it may take longer to feel the effects of a blue flame heater, it can heat an entire room vs just the objects in it.

Infrared Heaters 

Infrared heaters, also known as radiant heaters, provide direct radiant heat. This means they use electromagnetic radiation — just like the sun — to directly heat objects in the room. With radiant infrared heat, there’s no waiting to get warm — you’ll be warm instantly when you stand in front of the heater, just as if you were standing in front of a fire.

Because infrared heaters transfer heat directly to objects, they’re ideal for uninsulated spaces such as garages or unfinished basements. If you install your infrared heater close to the area where you spend your time, you’ll get the warmth you need to stay comfortable.

The disadvantage of infrared heaters is that they run the risk of igniting nearby objects. If you choose to go with infrared heat, be sure to keep furniture, clothing and children at a reasonable distance from the heater. It can also take longer to heat air and objects that are not directly in front of the path of the heater.

Blue Flame vs Infrared Heater: Pros and Cons

Blue Flame Heaters

Pros:

• Fast heating for small to medium-sized rooms.
• Efficient in enclosed spaces due to direct air warming.
• Often more affordable than radiant heaters.

Cons:

• Less effective in large or poorly insulated areas.
• Heat can rise quickly, leaving lower parts of the room cooler.

Radiant Heaters

Pros:

• Ideal for targeted heating; warmth is felt quickly when near the heater..
• Can be used in partially open areas like patios or workshops.
• Doesn’t rely on air circulation, making it suitable for drafty spaces.

Cons:

• Ineffective for heating entire rooms unless consistently used.
• Higher upfront cost compared to blue flame heaters.
• Limited effectiveness in very large, enclosed spaces due to targeted heating.

Ideal Usage for Blue Flame vs. Radiant Heating

When to use blue flame heaters:

• Insulated living spaces like living rooms, workshops, and basements where air circulation can spread warmth efficiently.
• Spaces that need quick heating without direct heat focus.

When to use radiant heaters:

• Larger, open, or drafty spaces where direct heat is necessary.
• Outdoor settings where airflow is high
• Semi-enclosed areas where it’s difficult to retain heated air.

Blue Flame vs. Radiant Heating Costs

Blue Flame Heaters

Price: Generally lower than radiant heaters, depending on the model and BTU capacity. Smaller blue flame heaters can start around $200, while larger, wall-mounted models might be priced higher.

Running Costs: Blue flame heaters can be energy efficient in enclosed spaces, especially with thermostat settings. However, they may use more fuel in larger or less insulated spaces to maintain the desired warmth.

Radiant Heaters:

Price: Radiant heaters tend to be slightly pricier, with entry-level models around $300 and larger, more durable outdoor units costing more.

Running Costs: Because radiant heaters don’t heat the air, they can save more energy by focusing heat only where it’s needed, particularly in outdoor or semi-open environments.

What to Consider When Choosing a Blue Flame vs. Infrared Heater

For Blue Flame Heaters:

1. BTU Rating

The BTU (British Thermal Units) capacity should match the room size for effective heating. Check out our handy BTU heating calculator to determine the size needed for your space.

2. Thermostat Control

Allows for easy temperature management and can improve efficiency by only heating as needed. Units that do not say thermostatic control will be manual control only meaning you have to turn them on and off from the control knob.

3. Safety Features

Look for oxygen depletion sensors (ODS) for safe indoor use, as well as automatic shut-off in case of overheating.

4. Mounting Options

Many models can be wall-mounted to save floor space, which is helpful for small rooms. Feet for a floor installation are generally sold separately.

For Infrared Heaters:

1. Infrared Technology

Quality of infrared heating varies, with ceramic and quartz elements often providing better, more consistent heat.

2. Adjustable Heat Levels

Some radiant heaters offer multiple heat settings to accommodate different heating needs.

3. Reflector Design

A good reflector can focus heat more effectively toward people or specific areas.

4. Safety

Overheat protection, tip-over shut-off features, and cool-to-touch casings can improve safety.

Our Recommended Ventless Gas Heaters

Blue Flame Heaters

Entry-level

HearthRite HBW10TN 10000 BTU Blue Flame Vent Free Gas Heater with Thermostat – Natural Gas

With 10,000 BTUs, this blue flame heater will gently warm the air, causing it to rise and create a natural circulation. Because it is a vent free gas heater, it operates at 99.9% efficiency and will continue to heat even through a power failure.

It has an Oxygen Depletion Sensor (ODS) that monitors the oxygen levels and shuts off the heater before the oxygen level in the room drops to an unsafe level. It also has top mount controls and a push button igniter for the standing pilot.

It comes with a wall mount, with an optional floor stand available separately.

Premium / smart

Empire Comfort Systems BF-30W 30,000 BTU Blue Flame Vent-Free Gas Heater with Thermostat

The BF-30 is equipped with a hydraulic thermostat and modulates from 8,500 BTUs to 30,000 BTUs for continuous temperature control. Once the preset comfort level is reached, the unit cycles the main burner flame from HI to LO and, when the thermostat is satisfied, to OFF while still leaving the pilot on. This reduces the large flame to a smaller flame while still emitting heat. 

It comes with push-button start, an Oxygen-Depletion Sensor that shuts off the unit if there is not enough available fresh air, and a new updated white finish.

Infrared Heaters

Budget-friendly

Heatstar HSSVFRD20 20000 BTU Vent Free Infrared/Radiant Heater with Thermostat and Blower

The HSSVFRD20 20,000 BTU Radiant heater features a blower fan and thermostatic control. This size heater is great as a supplemental heat source for areas that are about 500 square feet.

The thermostatic control knob offers 5 settings. The burner will cycle on and off based on the set temperature. Because it is gas powered, it will keep you warm during power outages. The blower fan will not operate during a power outage, but the heater will still generate heat to keep you warm and comfortable.

It includes both the wall mount bracket as well as base feet. 

High end

Empire Comfort Systems SR-30TW Vent Free 30000 BTU Infrared/Radiant Gas Heater with Thermostat Control

The SR30TW quickly fills the room with 30,000 BTU of warmth at the touch of a button. It has a hydraulic thermostat with top mounted controls for easy operation, while the push button igniter eliminates the need for matches.

This unit is available in Natural Gas SR-30TWNAT and Liquid Propane SR-30TWLP. A wall mount is included.

Summary

Choose blue flame heaters for:

• Enclosed, insulated rooms where air heating is efficient.
• Spaces where fast, general warmth is desired.
• Lower initial investment and lower fuel costs in smaller spaces.

Conversely, choose radiant heaters for:

• Drafty, semi-enclosed, or outdoor areas where direct heating is necessary.
• Situations where you want warmth focused on people or objects, not air.
• More energy savings in environments where consistent, direct warmth is needed.

It’s important to keep in mind that vent-free heaters should only be used as supplemental sources of heat. This means only operating the heater when you’re in the room and turning it off when you leave. This will ensure your heater delivers top performance all season long.

Looking for a Blue Flame or Infrared Heater? Let Us Help!

If you’re considering adding a supplemental heat source to your home this winter, take a look at our blue flame and infrared heaters, and browse all natural gas wall heaters for more selection. We offer heaters in various styles and capacities to suit your specific needs. 

As always, should you have any questions about our products, feel free to contact us. We’re happy to help you find the right heater for your home.