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Infrared Radiant Heat vs Forced Air Heat (Hot Air)

So you are debating between radiant heat or hot air for your commercial/industrial application. The radiant heaters look cool, but is radiant heat a gimmick? All of our houses and office buildings are heated and cooled with air, so we know that works, right? We’ll walk you through our thought process when qualifying a project for radiant heat vs forced air heat.

Some groundwork first – the radiant heaters we offer and that are discussed in this article are overhead type (not in-floor), gas fired (natural gas / propane) or electric. The unit heaters we are discussing are gas-fired, although the same conversation applies to any type of forced air heat (electric, oil fired, etc).

The applications we are discussing are generally indoors, commercial/industrial type spaces that are open – for example one or multiple big spaces, not an office building with 20 offices.

We offer both types of heaters, Re-Verber-Air unit heaters and Re-Verber-Ray radiant heaters.

On a side note – if your space is outdoors (restaurant patio or outdoor dining space, for example), there is no question that radiant heat is the only option. Check out our patio heaters here to get started.

When to Choose Hot Air (Forced Air) Heat

Our first question: What are your insulation values in the roof and walls? For hot air to be effective and efficient, the heat can’t be able to escape through cracks or poor insulation. We are looking for a minimum R13 in the walls and R19 in the roof. Garage doors should be insulated. Windows should be sealed and properly installed. We want a space that is going to hold the hot air for a long period of time without leaking outside too fast.

Our second question: What are you doing in the space? If you are opening and closing garage doors frequently, even if its just a few times a day, the hot air will quickly take the path of least resistance – outside. You will lose all the heat that has built up in the space and will need to recover by blasting hot air for a long period of time.

Our 3rd questions: What is your ceiling height? If the ceiling is under 12’ – plus you have good insulation and aren’t opening/closing big doors frequently – then we may recommend unit heaters (Note: we do offer low-clearance radiant heaters that can be mounted as low as 8’ from the floor, so you may still qualify for radiant heat). Remember that hot air naturally rises – so if you have 16’ ceilings, the hot air rises to the top first and then will work its way down to the floor level. For projects that require hot air in buildings with tall ceilings, we always recommend a “High Volume Low Speed Fan” solution to help move the heat that sits in the ceiling space down to the floor level.

NOTE 1: If you are doing anything that causes a lot of dust (welding, woodworking, etc), hot air can cause a big mess with the particles flying around in the air.

NOTE 2: If you need something that operates quietly, we will steer you away from unit heaters. Radiant heaters are exponentially more quiet than hot air unit heaters.


When to Choose Radiant Heat

If your ceilings are over 12’ we start exploring radiant heat. In applications with tall ceilings radiant heat has been proven to save 23-50% of fuel over forced air (we have studies and articles on file if you would like to read more about this topic). With the radiant heat bypassing the air and going directly to the floor, you are heating the ground level of your space first instead of the ceiling space first.

If your building is old with poor insulation, or even NO insulation, we recommend radiant heat. Whereas hot air would quickly escape a poorly insulated space, radiant heat sinks into the floor and re-radiates back up long after the heaters shut off. By bypassing the air, radiant heat is the most efficient and effective way to heat old buildings or poorly insulated buildings.

If you open and close garage doors frequently, we will recommend radiant heat. Cold air rushes in when garage doors are open, and hot air escapes. While you will experience some heat loss with radiant heat when large doors open, there will be faster recovery since the space is already holding a lot of heat in the concrete floor and objects in the room.

If you are woodworking, welding, or simply require no air movement in the space, we will recommend radiant heat.

If you want something quiet, we will recommend radiant heat.

If you want something that might qualify for rebates through your natural gas provider (for gas fired radiant heaters) or electric company (for electric radiant heaters), then we will recommend radiant heat. We can also help you find out if rebates are available in your area.



Comfort Differences

Radiant heat is the same type of heat emitted by the sun. Think of a cloudy day that is a little chilly due to the wind, and then the sun comes out from the clouds and feels nice and warm on your face, skin, and clothes. That is radiant heat. Or think of a concrete or asphalt surface that has been exposed to the sun on a hot summer day – if you are barefoot, the surface is hot – and sometimes very hot!

Radiant heat sinks into the floor, using it as a “heat sink” and re-radiating the heat back up. It also sinks into all objects that are in the path of the radiant heat beams (tools, boxes, automobiles, etc) thus warming those objects up too. No more cold feet with radiant heat, since the floor is holding a lot of the heat.

Other advantages to radiant heat: No air movement. Also very quiet, so comforting to the ears!

Hot air unit heaters blow hot air, which will warm up a space to a nice comfortable temperature just like in your house (assuming you have a well insulated space with low ceiling heights and minimal garage door opens/closes). The floor can still be relatively cold, so cold feet may be an issue. Hot air may not be very comfortable if the hot air is blowing directly on you at a high velocity, so consider strategically mounting the heater.



The biggest limiting factor for radiant heaters is the “clearances to combustibles.” These clearances can be best described as an imaginary rectangle around the heater in which nothing “combustible” can be within the rectangle. Examples of combustible items include anything that can catch fire or melt, such as: wood, cardboard, rubber, electrical wires, drywall, etc. Non-combustible items include metal, concrete block, etc.

Here is an example of clearances for a typical 100,000 BTU radiant tube heater:

Top clearance is 6 inches, the sides are 14 inches, and the below clearance (the big number) is 66 inches:

Unit heaters have very small clearances, only requiring a few inches around the unit of nothing combustible. So, if your space is very “busy” with combustible items and clearances simply cannot be met with radiant heaters, then forced air heat may be the only option.


Radiant heat is great for buildings with tall ceilings. You can hang some radiant heaters up to 50’ high and get effective heat to the floor. The savings in fuel costs for buildings with tall ceilings can be huge. Radiant heat is usually more comfortable and much more quiet. Some people really like the fact that radiant heaters do not cause air movement.

Unit heaters are generally cheaper in cost. They are great for buildings that are well insulated, with low ceilings, and little to no openings/closings of garage doors.

We pledge to stay 100% objective when consulting you on whether to use radiant heat or forced air. Our most popular equipment options include radiant tube heaters, electric radiant heaters, and forced air unit heaters. We will guide you in the right direction – if you want to get started simply fill out a Project Details form here.

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