A while ago, homeowners used solid-fuel (wood, coal) stoves to heat their homes. Today, the more elegant solution is to use liquid-fuel heaters. Ventless propane heaters are especially popular; they are known also as ‘blue flame heaters’ due to their distinctive blue propane flame.

The best ventless propane heaters have clear advantages and maybe even clearer disadvantages you need to be aware of. Burning propane and especially the vent free design are the two key factors that make the use of ventless propane heaters indoors so appealing and unappealing at the same time.

how to install a ventless propane heater
Ventless propane heaters are usually mounted on the wall and require no venting. They are very energy-efficient but are not without some serious safety concerns (like carbon monoxide build-up).

Before we check which are the best ventless propane heaters currently on the market, let’s first learn a thing or two about how ventless propane wall heaters even work (without a vent or a chimney) and what are the pros and cons of using these blue flame heaters.

On top of that, we will look into which exact specifications to check when choosing the best vent free propane heater for your needs.

If you already know all about ventless propane heaters, you can skip to the list of the 5 best ventless propane heaters (complete with apples-to-apples comparison table, and reviews) here:

Skip To 5 Best Vent Free Propane Heaters Here

Let’s first cover the basics of how ventless propane heaters work by comparing their inner workings with heating appliances that require venting:

How Do Ventless Propane Heaters Work?

If you have seen one of these blue flame heaters in action, you know it all looks quite seamless. With the implementation of in-heater propane combustion, we can operate ventless propane heaters quite easily and with, even more importantly, up to 99.9% combustion efficiency.

The predecessor of ventless propane heaters were basically vented stoves. They used solid fuels like wood, coal, and pellets that have a lot less than 99.9% combustion efficiency and therefore generate quite a lot of smoke.

That’s why venting was essential. All that hot smoke had to be vented outdoors via a chimney (lot of energy was lost there). This also gave vented stoves an unlimited supply of fresh oxygen (a key element for every burning process).

The modern blue flame ventless propane heaters operate in a very different way. All the oxygen required to fuel the burning process is drawn right from the room in which the heater is located. This oxygen is mixed with propane gas and ignited to start the burning process.

The key advantage of using propane as a fuel source is the 99.9% efficiency. Other solid fuels like wood or pellets don’t burn away completely, and you have to deal with all the ash and resulting smoke.

The burning process heats up the air that was drawn from the room and releases it back to the room. With older stoves, hot smoke would go through the chimney, and you would lose this heat. In the case of ventless pellets stoves, the hot air goes directly into the room. That’s why ventless propane heaters are one of the most energy-efficient space heaters.

Everybody loves energy efficiency; however, as you might have figured reading about how ventless propane heaters work, there is a lot of cons we have to deal with as well. Most of them stem from the ‘vent free’ aspect of these propane heaters.

Let’s summarize all the reasons why we love and all the reasons why we hate ventless propane wall heaters:

Pros Of Ventless Blue Flame Heaters

There are 3 key reasons why vent free propane heaters are so popular:

  1. Superb energy efficiency (up to 99.9%). Ventless heaters dissipate almost all of the energy generated by burning propane back into the room. In standard heaters, you would see a lot of energy escape via the chimney. Propane also enables almost total combustion (up to 99.9%). All of it’s energy is converted into heating your home.
  2. Lowest possible low running costs (high-cost efficiency). Propane is very cheap compared to electricity (electricity can be up to 400% more expensive). All the heat generated by a ventless propane heater or a blue flame heater is distributed into the room. That means that the running costs of ventless propane heaters are extremely low; these units give a lot of heat at a very low fuel cost.
  3. Higher than 5,000 BTU heating output (up to 30,000 BTU). The problem with many heaters, especially those powered by electricity, is the 1,500W or about 5,000 BTU heating output. That’s quite a low heating output; the best propane ventless heaters can generate up to 30,000 BTU heating output, enough to adequately heat areas up to 1,000 sq ft on their own.

On top of that, ventless propane heaters don’t require a chimney to function. This gives you quite a few additional options where to install it. In heaters that require a chimney, you can’t really choose where the heater will be located; it has to be located under the chimney.

Some homeowners also find the look – the blue flames – quite appealing and use the ventless propane heaters as a part of interior design.

Now let’s look at some disadvantages:

Cons Of Ventless Propane Heaters

A lot of people are wondering how safe the ventless propane heaters actually are. These heaters are superbly energy efficient and provide a lot of heaters but if ventless propane heaters are not safe to operate indoors, homeowners will have little use of them.

The key part are the safety features; we will cover those under the section about how to tell which ventless propane heater is the best.

There are 3 distinct disadvantages of ventless propane heaters and they are all connected to the vent-free design. These are:

  1. Carbon monoxide build-up. Carbon monoxide is a side product of burning propane and it can be deadly. Ventless propane heaters distribute all products of burning propane back into the room; including the potential carbon monoxide side product. That’s why all the best blue flame heaters include ‘Oxygen Depletion Sensor’ or ODS for short.
  2. Oxygen depletion. Even the best propane vent-free heaters draw the oxygen needed for burning propane from indoors. Without proper ventilation or any other means of delivering oxygen to the room the ventless propane heater is in, the levels of oxygen can fall too low. Breathing air with a too low oxygen concentration (well below 20%) can lead to asphyxiation.
  3. Increase in humidity levels. When burning propane, ventless propane heaters can additionally generate water vapor. This water vapor is then distributed throughout the room the heater is located in and raises the relative humidity rates. High humidity rates (above 60%) can readily lead to mold and mildew growth. Using a dehumidifier and a ventless propane heater together is not such a bad idea.

Especially the safety concerns are quite concerning. Some states like California have even decided to ban all ventless heaters powered by gas (natural gas or propane). Here is an outtake from California’s Health and Safety Code:

“No person shall sell, or offer for sale, any new or used unvented heater that is designed to be used inside any dwelling house or unit, with the exception of an electric heater, or decorative gas logs for use in a vented fireplace.” (Califonia’s law banning ventless gas heaters)

In fact, the best propane ventless heaters are usually the ones with the best safety features. If the safety concerns are adequately taken care of, these blue flame heaters are quite wonderful. If you don’t take care of the safety concerns, they can be – with a lack of a better word – deadly.

Specification To Check Before Buying A Blue Flame Propane Heater (Safety Is Key)

Here’s the deal:

The best propane ventless heater is the safest propane ventless heater.

Safety is the #1 concern you should have when picking any blue flame heater. How to check for safety? Check for safety features such as:

  1. ODS. Oxygen Depletion Sensor is an essential part of every good propane vent free heater.
  2. Flame failure device.
  3. Overheat switch.
  4. Tilt switch.

All these safety features are there to address the biggest cons of any propane ventless heater. One useful tip is this:

Check for reliable brands.

Reliable and well-known brands can’t afford to produce a ‘dangerous’ heater. That’s why the #1 best ventless propane heater in the table below is made by Rinnai (it also has all the required safety features, and more). Rinnai, Martin and Mr Heater are three main brands here; Dyna-Glo, for example, is more specialized for blue flame heaters (not a universal brand).

Another key part to check for when buying a propane heater that doesn’t need venting is the build-in thermostat. Built-in thermostat found in #1 Rinnai and #2 Martin heaters will make your life much easier; you can easily set the temperature and forget about it, and the propane ventless heater will be even more energy-efficient (delivering only as much heating as required to hold the set temperature). The build-in thermostat, quite understandably, does significantly increase the price of a ventless propane heater.

Other specifications the check include:

  • Heating capacity (measured in BTUs): Vent free propane heaters are capable of generating up to 30,000 BTU of heating output. However, the ones with the biggest BTU range are usually the most popular because they can provide different heating outputs readily, thereby increasing energy efficiency and adjusting very well to your heating requirements.
  • Heating area (measured in sq ft): Depending on the heating capacity, the ventless propane heaters can provide central or supplemental heating. How large a room or home can such a blue flame heater heat is usually specified by the manufacturer. You will find the specified heating area numbers in the comparison table of the best ventless propane heaters below.
    how many square feet can ventless propane heaters heat up
    Some directions of how to determine how big an area can a ventless propane heater heat (for Rinnai units).

With all that in mind, let’s look at which are the best blue flame heaters (requiring no vents and powered by burning propane) currently on the market:

Best Ventless Propane Heaters (Blue Flame Heaters Included)

  1. Best Ventless Propane Heater Overall: Rinnai FC824P (Safest And Most Reliable)
  2. Best High-End Vent Free Propane Heater With Thermostat: Martin MDV20VP
  3. Best Blue Flame Heater With 30,000 BTU Output: Dyna-Glo BFSS30LPT-2P
  4. Best Mr Heater Ventless Propane Heater: Mr. Heater F299830
  5. Good Vent Free Propane Heater With Thermostat And Blower: Bluegrass B30TNIR-BB
Ventless Propane Heaters: #1 Rinnai FC824P #2 Martin MDV20VP #3 Dyna-Glo BFSS30LPT-2P #4 Mr. Heater F299830 #5 Bluegrass B30TNIR-BB
Photo: Rinnai FC824P (Safest ventless propane heater And Most Reliable) Martin MDV20VP ventless propane heater Dyna-Glo BFSS30LPT-2P blue flame heater Mr. Heater F299830 vent free propane heater Bluegrass B30TNIR-BB ventless blue flame heater
Heating Capacity: 8,000 – 22,000 BTU 11,000 – 20,000 BTU 24,000 – 30,000 BTU 30,000 BTU 30,000 BTU
Specified Heating Area: Up to 1,600 sq ft Up to app. 1,000 sq ft Ideal up to 1,000 sq ft Up to 750 sq ft Up to 1,450 sq ft
Safety Features: Flame Failure, Overheat Switch, ODS, Tilt Switch Glass Ceramic Window, USA and Canada Certified ODS ODS, Not approved in California or Canada ODS
Built-in Thermostat? Thermostat control knob Thermostat control knob Thermostat control knob
Price: $$$$ $$$$ $$$$ $$$$ $$$$
Average Rating: 4.9 out of 5 stars 4.8 out of 5 stars 4.2 out of 5 stars 4 out of 5 stars 3.8 out of 5 stars
Availability: Check Price Check Price Check Price Check Price Check Price

1. Best Ventless Propane Heater Overall: Rinnai FC824P (Safest And Most Reliable)

Rinnai is one of the world’s best-known gas heater producers. This is the Japanese company that makes the best tankless water heaters, condensing boilers, direct vent furnaces, and, of course, the best ventless propane heaters. Their latest models – the Rinnai FC824P – is the best and the safest propane heater currently on the market (by a large margin).

First of all, the Rinnai FC824P is all about safety. It has all the required safety features like Oxygen Depletion Sensor and overheat switch, and more. On top of these two essential safety checks, the Rinnai FC824P has a child-safe cool-to-touch cabinet with a safety lock, tilt switch, and even the flame failure device.

In addition to being the safest ventless gas heater, the Rinnai FC824P also has a built-in thermostat. It adjusts the heating output as needed to sustain the room temperature.

As far as heating capacity, the Rinnai FC824P can produce anywhere from 8,000 BTU to 22,000 BTU heating output. That’s a very wide heating output interval the built-in Rinnai thermostat can use to adequately and efficiently heat areas up to 1,600 sq ft.

All in all, the Rinnai is universally consider the best brand for ventless propane heaters. Their Rinnai FC824P is the current flagship model and is considered one of the most reliable and definitely the safest ventless propane heater option on the market:

Rinnai Ventless Heater Review


  • Safest propane heater (with ODS, tilt switch, overheat switch, flame failure, etc.)
  • Built-in thermostat (increases energy and cost efficiency; and it’s easy to set)
  • Wide heating output interval (from 8,000 BTU to 22,000 BTU)
  • Rinnai is the best overall brand; known for reliability and safety

  • Rinnai brand and built-in thermostat do increase the overall price

2. Best High-End Vent Free Propane Heater With Thermostat: Martin MDV20VP

Martin MDV20VP is one of the best engineering indoor ventless propane heaters with a built-in thermostat. It also has a very appealing design, finished with the glass-ceramic window through which you can see the distinct blue flame ventless propane heaters are known for.

With up to 20,000 BTU heating output, the Martin MDV20VP has an estimated heating area of up to 1,000 sq ft. The useful thing for every ventless propane heater with a built-in thermostat is a wide BTU output interval. The Martin MDV20VP can lower the heating output to as low as 11,000 BTU. This gives the thermostat quite a range of heating outputs to work with and to adjust the output very closely to heating requirements.

Sadly, less is known about the full range of safety features the Martin MDV20VP provides. It does have a ceramic glass window that’s not burning hot to the touch. The unit is also certified in both the USA and Canada but, for example, it can’t be sold in California due to California’s Safety and Health code.

On top of that, the Martin MDV20VP is one of the few premium ventless propane heaters that cost more than $1,000. That’s not ideal.

Nonetheless, the beautiful engineering and aesthetics of the Martin MDV20VP are quite outstanding. If you have the money to invest in a premium vent free propane heater, the Martin MDV20VP is definitely a good choice:

Martin Ventless Heater Review


  • Premium high-end vent free propane heater
  • Has a built-in thermostat for easy use
  • 11,000 BTU – 20,000 BTU heating output
  • Reliable engineering and aesthetic design

  • Above-average $1,000+ price tag
  • Not a lot is known about it’s safety features

3. Best Blue Flame Heater With 30,000 BTU Output: Dyna-Glo BFSS30LPT-2P

Best Blue Flame Heater With 30,000 BTU Output
Heating Capacity: 24,000 – 30,000 BTU
Specified Heating Area: Ideal up to 1,000 sq ft
Safety Features: ODS
Built-in Thermostat? Thermostat control knob
Dimensions (LxWxH): 28.1 x 10.5 x 24.1 inches
Weight: 24.6 lbs
Price: $$$$
Rating: 4.2 out of 5 stars

Dyna-Glo is a company specialized in manufacturing blue flame heaters. Their Dyna-Glo BFSS30LPT-2P model is the best and the strongest Dyna-Glo propane ventless heater. It can provide you with an outstanding 30,000 BTU of heating power.

Only the most powerful propane heaters that require no venting can produce 30,000 BTU of heating out, and Dyna-Glo BFSS30LPT-2P is one of the most reliable of these heaters. With so much heating output, this heater can heat up a 1,000 sq ft area on its own (with 30 BTU per sq ft heating power).

For this heating output to be safe, the Dyna-Glo BFSS30LPT-2P has a built-in Oxygen Depletion Sensor or ODS for short. This is a wall-mounted ventless propane heater that can be used in a garage or indoors.

It doesn’t have a built-in thermostat per se; it has a thermostat control knob. This works pretty much like a built-in thermostat but it doesn’t have the advantage of increasing energy efficiency in much the same way ventless propane heaters with built-in thermostats have. However, it does have a considerably lower price, and the lack of a built-in thermostat is definitely a large factor here.

In short, Dyna-Glo BFSS30LPT-2P is your standard blue flame heater with very high 30,000 BTU heating output and basic safety features like ODS:

DynaGlo Blue Flame Heater Review


  • Distinct blue flame visible behind the glass ceramic window
  • Very high heating output (up to 30,000 BTU)
  • It’s fairly easy to install
  • Affordable price compared to the superb #1 Rinnai unit

  • Doesn’t have a built-in thermostat (only knob thermostat)
  • Does have ODS but little other safety features

4. Best Mr Heater Ventless Propane Heater: Mr. Heater F299830 (Freestanding Option)

Best Mr Heater Ventless Propane Heater: Mr. Heater F299830 (Freestanding Option)
Heating Capacity: 30,000 BTU
Specified Heating Area: Up to 750 sq ft
Safety Features: ODS, Not approved in California or Canada
Built-in Thermostat? Thermostat control knob
Dimensions (LxWxH): 27 x 11.3 x 23.8 inches
Weight: 26.8 lbs
Price: $$$$
Rating: 4 out of 5 stars

Mr. Heater is one of the best-known brands in heating. They manufacture reliable user-friendly heaters at very affordable prices. Mr. Heater F299830 model is the best Mr Heater ventless propane heater.

Similar to Dyna-Glo, the Mr. Heater F299830 is capable of generating up to 30,000 BTU heating out. That’s enough to heat up spaces up to 1,000 sq ft. However, Mr. Heater specified heating area is up to 750 sq ft; they seem to be playing it safe with this specification. After all, that would yield a 40 BTU per sq ft heating output in a 750 sq ft area.

To regulate the heating output, you have the basic knob-controlled thermostat (no built-in thermostat). That’s pretty much the standard temperature control.

Safety-wise, the Mr. Heater F299830 has the all-important ODS (sensor that detects the lack of oxygen) but the unit itself is not approved to be sold in Canada and, of course, in California.

All in all, the Mr. Heater F299830 is quite a reliable 30,000 BTU heater available at an affordable price point:

Mr Heater Ventless Heater Review


  • Best Mr. Heater ventless propane heater
  • Can provide you with 30,000 BTU of heating output
  • Fairly priced
  • Quite reliable

  • Doesn’t have a built-in thermostat
  • Apart from ODS, there is little in regards to the safety features
  • Not approved to be sold in Canada

5. Good Vent Free Propane Heater With Thermostat And Blower: Bluegrass B30TNIR-BB

Good Vent Free Propane Heater With Thermostat And Blower: Bluegrass B30TNIR-BB
Heating Capacity: 30,000 BTU
Specified Heating Area: Up to 1,450 sq ft
Safety Features: ODS
Built-in Thermostat? Thermostat control knob
Dimensions (LxWxH): 27.5 x 10 x 25.8 inches
Weight: 25.8 lbs
Price: $$$$
Rating: 3.8 out of 5 stars

Bluegrass B30TNIR-BB is one of the best ventless propane heaters with a thermostat and blower. Sadly, the thermostat is controlled via a knob (it’s not a built-in thermostat). It does, however, have a specified heating area of up to 1,450 sq ft; which is a lot more than standard 1,000 sq ft heating areas for most ventless propane heaters.

Safety-wise, you have the piezo-ignition (considered very safe) and the required ODS sensor. That’s pretty much it; it’s fairly unsafe if you made a head-to-head comparison with the #1 Rinnai unit’s safety features.

It does have a very low price tag for a ventless propane heater. While you’re expected to pay about $1,000 for a superb big brand heater, the Bluegrass B30TNIR-BB costs less than $300:

Bluegrass Ventless Heater Review


  • Up to 30,000 BTU heating output and 1,450 sq ft specified heating area
  • Does have an ODS and piezo-ignition
  • Very low price

  • Bluegrass is not a well-known brand
  • Doesn’t have a built-in thermostat
  • Isn’t as safe or as reliable as #1 Rinnai model, for example

This is our summary of been some key information about propane heaters that need no venting. It’s a very useful technology but the safety issues of using an unvented gas-powered heater indoors are still there and you need to take them seriously.


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