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Can You Use Propane Heater Indoors? (Are They 100% Safe?)

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    To heat an oversized room, you might be thinking of installing a propane heater instead of electric or other types. But, can you use propane heaters indoors, and are they safe at all? 

    “Yes! A few propane heaters are useable indoors, and those contain ODSTip-OverFlameout, and a few more safety sensors to keep you secured inside the room. But you have to ensure proper ventilation to pass the carbon dioxide outside and give an entrance to the oxygen.”

    6 Different types of propane heaters are available, E.g

    • Blue Flame (Indoor)
    • Radiant (Indoor)
    • Big Maxx (Cleanest Indoor)
    • Propane Cabinet Heater (Outdoor)
    • Buddy Heater (Portable & Good for tent)
    • Tank Top Model ( Totally Outdoor)
    • Torpedo/Salamander Heater (Open Workshops & outdoor) 

    Among them, the blue flame, radiant, and big max models have been particularly manufactured for indoor operations.  

    Here’s an indoor propane heater data table of air quality and temperature changes based on my test result.

    Model/Time0 Min15 Min30 Min45 Min
    Blue FlameCO = 0 ppm
    CO2 = 557 ppm
    Temperature = 55°F 
    CO = 0 ppm
    CO2 = 600 ppm
    Temperature = 61°F
    CO = 0 ppm
    CO2 = 750 ppm
    Temperature = 70°F
    CO = 0 ppm
    CO2 = 900 ppm
    Temperature = 75°F
    RadiantCO = 0 ppm
    CO2 = 450 ppm
    Temperature = 49°F
    CO = 0 ppm
    CO2 = 500 ppm
    Temperature = 63°F
    CO = 0 ppm
    CO2 = 650 ppm
    Temperature = 69°F
    CO = 0 ppm
    CO2 = 700 ppm
    Temperature = 73°F
    Big MaxxCO = 0 ppm
    CO2 = 458 ppm
    Temperature =39°F
    CO = 0 ppm
    CO2 = 458 ppm
    Temperature = 49°F
    CO = 0 ppm
    CO2 = 458 ppm
    Temperature = 61°F
    CO = 0 ppm
    CO2 = 469 ppm
    Temperature = 70°F

    Don’t miss reading my paragraph on Propane Heater vs Carbon Monoxide below. 

    Let’s dive in…

    Can you use propane heater indoors? Replied!

    Blue Flame and Radiant Propane Heater for Indoors

    Yes… You can use propane heaters indoors but those have to be indoor models.

    Firstly, the blue flame and radiant heaters are widely used for large living rooms, garages, shops, restaurants like 500 to 1000+ square feet.

    They are widely available in 10,000, 20,000, and 30,000 BTU variants, and a few of them are duel fuel so that you can use both LPG and natural gas. 

    Though they are ventless, you need to keep your window cracked. But these propane heaters don’t emit any toxic gases like carbon monoxide or anything poisonous if you ensure sufficient airflow.

    However, burning propane produces a small amount of CO2 and water vapor, similar to the air we exhale while breathing. Of course, it’s safe.

    Buddy heaters are the portable version of indoor radiant models and are widely used by passionate campers in the USA.

    You might have a look at this mostly-used indoor propane heater

    Check Details on Amazon

    Buddy heater, safe for tent indoors

    The most significant advantages of blue flame and radiant propane heaters

    • They don’t require electricity and keep you warm during a power outage.
    • They are enormously energy-efficient and offer a significantly low-cost operation.

    Later I’ll discuss more on this article.

    Big Maxx is exceptional and the only available “fan forced” type indoor propane heaters. However, it’s not an oscillating heater.

    They require electricity to ignite the combustion and spin the fan. These are suitable for gigantic garages or workshops and available in 50,000 and 80,000 BTU models. 

    Notably, Big Maxx is the only propane heater in the UNIVERSE that can be used in an enclosed insulated room. 

    Cause they have a chimney, which remains connected with the combustion chamber and throw the exhaust away. The combustion chamber and heat exchanger remain sealed so that no gasses or fumes can enter the room. 

    So, Big Maxx doesn’t ruin the air quality and keeps it clean like a forced-air electric space heater.

    In the next portion, I’ll describe briefly.

    • Specific indoor propane heaters and their suitable place of operation.
    • Advantages and Disadvantages of particular indoor models.
    • Cautions and safety that you need to be awarded of.
    • Our air quality monitoring and overall experience during test operations.

    1. Blue Flame Indoor Propane Heaters – Safe for Large Insulated Spaces

    Blue Flame Propane Heater for Indoors

    Blue flame heaters are very similar to the gas stoves of your kitchen. They emit flame through a gas burner and consume propane with oxygen from the fresh air.

    If you have been using a gas cooktop safely, maintaining a few cautions in your kitchen for many years, you shouldn’t get confused about whether a blue flame heater is a safe use indoors or not. It’s safe.

    These models are known as ventless cause you won’t require any chimneys or such ventilations. But you will need fresh airflow inside the room.

    As the flame remains protected inside the grill, it’s hard for anything to get in touch with it. But, you shouldn’t keep any flammable objects such as cloths, cotton, dry woods, flammable liquids, etc., within a 4 feet radius.

    Additionally, as these models are wall mount, you can safely mount them on brick/concrete walls. But if your living room has a wooden wall, you should keep the heater standing on its feet on the floor.

    Air Quality Monitoring Result & Heating Performance

    Here’s my location and testing kits detail

    • Location: Phoenix, Arizona
    • Month: January
    • Average Environment Temperature Was: 45°F to 60°F
    • CO2 Detector: Gain Express A017755
    • CO Detector: Kidde Nighthawk Carbon Monoxide Detector
    • My Living Room Size: 500 Square Feet
    • Heater’s Model: Mr Heater Blue Flame 20,000 BTU Propane Heater

    At the starting point, my living room’s carbon dioxide (CO2) level was 600 ppm, and the carbon monoxide (CO) level was 0 ppm. I’ve kept my slider window 6 inches (about 2sqft) open. However, the temperature was 55°F.

    First 15 Minuit: The room temperature raised from 55°F to 61°F, which wasn’t impressive, but I could detect the issue. The hot air was rising towards the room, so I had placed a fan at the top of the heater, and it started working well.

    CO2 Level: 600 ppm

    CO Level: 0 ppm

    Temperature Remained: 61°F

    15 to 30 Minutes:  Room temperature raised to 70°F, which was expected. Slightly CO2 level increased, but no CO was detected.

    CO2 Level: 750 ppm

    CO Level: 0 ppm

    Temperature Remained: 70°F

    30 to 45 Minutes: Room temperature raised to 75°F, which was the preset range of the thermostat. Also,

    CO2 Level: 790 ppm

    CO Level: 0 ppm

    Temperature Remained: 75°F

    Here the thermostat turned the heater off.

    I’ve kept the heater running for the next 6 hours, and here’s the final result.

    CO2 Level: 900 ppm

    CO Level: 0 ppm

    Temperature Remained: 75°F

    Then I’ve turned off the heater and slightly opened the window, and within 5 minutes, the CO2 level decreased to 590 ppm.

    Final Analysis: Blue flame propane heater doesn’t produce Carbon Monoxide (CO) at all as nothing was detected. But it had raised the CO2 level by 300 ppm, which isn’t harmful. But you can minimize that by keeping open the lower portion of the window cause CO2 is heavier than the air.

    2. Radiant Indoor Propane Heaters – Safe and Great for Lower Insulated Large Spaces

    Radiant Propane Heater for Indoors

    I’ve tested a ProCom 20,000 BTU propane radiant heater inside the same 500 square feet living room with all similar monitoring kits, where I’ve tried the blue flame heater previously. 

    Here’s the test result.

    This day, my room temperature was 49°F, the CO2 level was 450 ppm, and the CO level was 0 ppm. I’ve kept the lower portion of the window around 8 inches open this time to check whether the radiant model really works in an uninsulated room.

    First 15 Minuit: Temperature raised to 63°F! Which was surprising, but the whole room temperature wasn’t the same. I felt hotter remaining in front of the radiant panel, and the temperature was slightly low at the corner.

    CO2 Level: 500 ppm

    CO Level: 0 ppm

    Temperature Remained: 63°F

    Second 15 Minutes: Temperature raised to 69°F, slightly lower than expected. But as I’ve said, I made the room less insulated.

    CO2 Level: 650 ppm

    CO Level: 0 ppm

    Temperature Remained: 69°F

    Third 15 Minutes: Temperature raised to 75°F, which was the preset level, so the thermostat turned the heater off.

    CO2 Level: 700 ppm

    CO Level: 0 ppm

    Temperature Remained: 73~75°F

    I’ve operated the heater for the next 6 hours restlessly, though the thermostat automatically turned on/off the heater multiple times. 

    Final Analysis: Yes, the radiant heater works well in the less insulated room, and this propane heater doesn’t make any Carbon Monoxide (CO). The CO2 level was produced less than the blue flame model, but I think it was due to keeping my window more widely open.

    So, both the blue flame and radiant propane heaters are safe to use indoors, considering they don’t produce toxic gasses like carbon monoxide. But they produce carbon dioxide, so I never suggest you sleep with these heaters.

    But, both these models have flames inside, so be aware of fire hazards. Never keep any dry papers, clothes, or anything flammable surrounding it. (At least 5 feet away)

    3. Big Maxx Indoor Propane Heaters – Provide The Safest and Cleanest Hot Air

    As I’ve noted, Big Maxx is the only fan forced gas heater that works similarly to the 240V garage heater. Instead of electrical heating elements, Big Maxx has a gas combustion chamber and heat exchanger.

    The heat exchanger and flames remain inside a combustion chamber, entirely separated from the indoor portion, and a chimney throws the exhaust outside. 

    So the AIR inside the room remains completely clean while using Big Maxx.

    But they are gigantic and only available with 50,000 BTU and 80,000 BTU. I required a giant garage/workshop to test its performance and air quality. 

    So I met “Michale,” who is a 2000 square feet workshop owner in Phoenix and a long term “Big Maxx” user.

    Here’s the result of My Air Quality & Performance Test.

    • Location: Arcadia, Phoenix, AZ.
    • Month: January
    • Average Environment Temperature Was: 32°F to 45°F
    • CO2 Detector: Gain Express A017755
    • CO Detector: Kidde Nighthawk Carbon Monoxide Detector
    • Michale’s Garage Size: 1165 Square Feet
    • Heater’s Model: Mr Heater Big Maxx 80,000 BTU Propane Heater

    In the beginning, I found the CO2 level 458 PPM, CO level 0 PPM, and the room temperature 39°F. There was no ventilation in Michale’s 1165 sqft workshop. The whole space was fully insulated.

    We turned the heater on, and here’s the test result.

    First 15 Minuit: Temperature raised to 49.7°F, which was natural. Smaller spaces should heat faster. But the fascinating fact is we didn’t find any changes on the air quality monitor. Here’s the result.

    CO2 Level: 458 ppm (Unchanged)

    CO Level: 0 ppm (Unchanged)

    Temperature Remained: 49.7°F

    Second 15 Minuit: Now the temperature raised to 61.3°F, and we didn’t detect any change in CO2 level. Also, no CO was detected!

    CO2 Level: 458 ppm (Unchanged)

    CO Level: 0 ppm (Unchanged)

    Temperature Remained: 61.2°F

    Third 15 Minuit:  This time, the workshop temperature raised to 70°F, and the thermostat turned the heater off. Slightly the CO2 level increased, but that is not notable. However, No CO was detected.

    CO2 Level: 469 ppm 

    CO Level: 0 ppm (Unchanged)

    Temperature Remained: 70°F

    Moral of the Experiment: Big Maxx models are the cleanest propane heater for indoors, considering the impact on Air Quality.

    4. Buddy Heaters – Portable & Good for Using Inside Tents.

    Buddy Indoor Propane Heater

    Theoretically, buddy heaters are entirely similar to the radiant propane heaters I experimented with above. So, there shouldn’t be any reason behind not using them in ventilated indoors or living rooms, but…

    Buddy heaters store an LPG canister inside, which is a hazard for indoors.

    However, there’s a legal restriction in storing any LPG cylinder or canister inside a living room in a few states.

    Now you might think of using a long hose line to supply propane to your buddy heater, keeping the cylinder outside. Yes, that’s might be the solution but

    • Buddy doesn’t contain a thermostat to maintain your room temperature.
    • Lighting up, buddy, isn’t as effortless as indoor radiant models as there are no electronic ignitions. Even sometimes, it requires manually lighting up using a gaslighter.

    So, continuously using a buddy heater indoors is a hassle, and you won’t have any control over the room temperature.

    Then how a buddy propane heater is better for use inside a tent?

    During a camp session, the environment temperature remains too chilled, and most importantly, tents are not as heat insulated as wooden or concrete walls. So, the heat doesn’t stay sealed, and the tent temperature can’t rise too much.

    But buddy heater doesn’t produce any Carbon Monoxide, so the air quality doesn’t get ruined at all. However, you have to keep the tent zipper slightly open to ensure proper ventilation.

    5. Propane Torpedo Heater – Safe for Garage / Workshops but Not Enclosed Indoors

    Indoor propane torpedo heater

    Torpedo models are great as construction site heatershowever, garage and workshop owners widely use them. 

    The Torpedo heater contains an electric fan to pass sufficient air through the combustion, allowing more propane molecules to be burnt inside a little space. So, inside adequate airflow/ventilation, it’s okay to operate a torpedo heater, but insufficient ventilation might produce toxic gases and fumes. 

    Though all the torpedo heater contains an ODS sensor to instantly detect any oxygen insufficiency, you should never try to use it inside an enclosed space, no matter how large it is.

    Please remember that torpedo model aren’t any “Indoor Heating Solution.” While using them inside workshops, ensure following all cautions and carefully handling the propane tank and the torpedo heater.

    It’s the only heater that can produce a bit of carbon monoxide if there’s a lack of fresh air. (Though it’s too hard for a propane heater to make CO without any 3rd party reactor.)

    But for open spaces like a construction site, it’s totally safe.

    Propane Heater & Carbon Monoxide

    When somebody attempts to choose a propane heater, their first concern remains regarding protection from CO production. Logically, the concern is ethical, but your soul will feel relaxed after reading my scientific explanation.

    Be clear that “It’s too hard to produce CO by using a propane heater.” Yes, you’ve read right! 

    The chemical reaction that happens during propane burning is called propane combustion, which could happen in two methods.

    • Complete Combustion (Happens while using a propane heater).
    • Incomplete Combustion.

    Here’s a Youtube Video demonstrating these procedures.

    Carbon monoxide could be produced by performing only Incomplete combustion. 

    Complete combustion happens while propane gets sufficient airflow to get burned. Here’s what the chemical equation looks like. 

    C3H8 + 5 O2 → 3 CO2 + 4 H2O + Heat

    As you can see here, one propane molecule requires three oxygen molecules to get burned entirely and produce carbon dioxide, water vapor, and heat.

    The good fact is, your room air holds far more than 5X oxygen that your propane heater requires to consume. However, when you keep the window cracked, the oxygen level remains tends to INFINITY while you only need 5X than the burning propane.

    So, there’s nothing to be worried about at all. Only you need to install an air quality monitoring system for safety purposes and proper ventilation; that’s it.

    Incomplete combustion occurs when propane burns in lack of oxygen. As I already have said, it’s too hard to produce CO with a propane heater and almost impossible. This reaction is performed inside a highly pressurized combustion chamber in the laboratory.

    Here’s the equation

    2 C3H8 + 9 O2 → 4 CO2 + 2 CO + 8 H2O + Heat.

    As you can see, each propane molecule requires 4.5 molecules of oxygen to produce carbon monoxide as a byproduct. But, inside your room, the amount of oxygen molecule remains in infinity. So, the incomplete combustion reaction is impossible there.

    Note: Carbon monoxide is too toxic, and you shouldn’t neglect it at all. The problem is CO is smell-less & test less gas, so there’s no way to identify it without an electronic detector. So, to remain risk-free, always keep a CO detector beside the propane heater indoors, ensuring proper ventilation.

    How does the ODS sensor restrict Carbon Monoxide Production?

    ODS stands for Oxygen Depletion System, and the whole unit works mechanically, so it’s much more reliable than an electric circuit. I’ve drawn two pictures to demonstrate the functionalities.

    ODS Sensor of Indoor Propane Heater

    Image 1:  The leading equipment of the ODS Sensor is a Thermocouple.

    I’ve shown in the picture how the Pilot light, ignitor (Sparker), and thermocouple remain placed side by side inside a propane heater.

    Firstly, the sparker ignites the pilot light, and the flame starts lighting up the burner. The pilot has no uses once the burner gets lit up, but the pilot remains lit through the whole operating session.

    The gas valve remains connected to the pilot light, and if the pilot goes OFF, the whole gas valve takes shuts down.

    When propane burns in full combustion and the oxygen level remain full inside the room, the pilot light covers the thermocouple like Image 1.

    Thus the thermocouple can sense that there’s no lack of oxygen and keeps your propane heater safely ON indoors. 

    Low oxygen level vs ODS sensor

    Image 2: Naturally, environment air contains 20.9% oxygen; when it drops to 19% to 18%, the pilot’s flame jumps front like the Image I’ve shown.

    If the flame jumps even slightly (19% oxygen), the thermocouple senses lower temperature and transmits a signal to the gas valve. So instantly, the pilot light gets shut down and restricts CO production.

    Here’s a short youtube video describing ODS functionality. 

    Note: Undoubtedly, carbon monoxide is highly poisonous, and we should always be aware of it. As it has no test or smell, we can’t identify its existence. As a result, CO is called a silent killer.

    To learn more about its poisoning, you may read an article on Carbon Monoxide Poisoning here.

    Two Other Essential Sensors In Addition to ODS 

    Tip-Over Safety Sensor: This sensor ensures ultimate safety against spreading flame in case the heater gets tipped over due to any accidental force.

    Tip Over Safety Valve of Indoor Propane Heater

    The tip-over sensor is a little mushroom head-shaped chamber that holds a steel ball inside. A pair of metal connectors remain at the bottom of the chamber. When the heater remains stood perfectly, the steel ball touches the lower metal plates due to gravity. Tipping over the heater throws the ball towards the top and disconnects the plates.

    While the lower plates remain connected, a thermocouple keeps the gas valve open.

    The gas valve instantly goes closed if the connector plates get disconnected due to tilting the heater.

    Thus the tip-over sensor keeps your indoor propane heater secured.

    Here’s a Youtube video that shows the tip-over sensor.

    Flameout Shut-Off Sensor:  This mechanism protects indoor propane heaters from flameout by any forced air and resists spreading unburned propane.

    I’ve said previously that the pilot light always remains lit during the operation. So that if the burner goes off, the pilot can light it again. 

    If any forceful wind turns off the pilot light (which is extremely tough), the thermocouple turns the gas valve off. Thus your indoor air remains clean from pungent propane, and you remain safe.

    Indoor Propane Heater Safety Tips 

    1. Check your heater for leaks using soapy water regularly, especially when you attach a new LPG cylinder each time. 
    2. Install your propane heater far away from any combustion or flammable materials existing indoors.
    3. Though it’s a tedious task, read the user manual guide carefully, at least the safety and hazard parts.
    4. Choose the right size propane heater for indoor space. Don’t go oversize at all.
    5. Don’t use a flammable spray like aerosol, air fresheners, insect killers surrounding a burning propane heater.
    6. Ensure your propane heater has ODS and automatic shut down sensor so that instantly it gets shut down at a low oxygen level.
    7. Tip-over safety should be a mandatory feature of your indoor propane heater.
    8. Please do not move the heater while it’s burning.
    9. Install an air quality monitor 3 feet away to detect any carbon monoxide production by the propane heater.
    10. Keep the window slightly open; 1 square foot for each 10,000 BTU is sufficient.
    11. Never leave your heater unattended, and don’t sleep turning it ON.
    12. Never put the heater on a table; an indoor propane heater isn’t a table heater.
    13. Never use an outdoor propane heater indoors.
    14. Instantly turn off the heater if you detect any smoke or unusual pungent smells. Any smells indicate that there’s gas leakage.
    15. Never touch the heater’s body while it’s in operation. Ensure the unit has a high temperature coated layer on it.

    4 Common Questions About Using a Propane Heater Indoors

    1. Are propane heaters safe in garages?

    Yes, propane heaters could be safely used in the garage. But, be aware of any flammable objects surrounding it. 

    • Do not store any gasoline, paint spray, alcohol, terpins, thinners, and any other flammable liquids within 10 feet of the propane heater. 
    • Also, ensure the proper ventilation keeping the door/window open about 1 square foot for each 10,000 BTU.

    If you prefer a blue flame or radiant model, a natural gas garage heater would be better than propane. You may read my article on high efficiency natural gas garage heater here.

    Or, if you require extreme level heat, then torpedo heaters are the best solution. In that case, for better portability and cutting down the operational cost, a kerosene torpedo heater should be the best alternative to propane. You may check my article on kerosene heater for garage here.

    2. How do you handle propane safely?

    • Storage: Only 1 lb to 20 lbs propane canister could be stored indoors. Never keep larger LPG cylinders inside, especially around any flames. Additionally, always store the tank vertically; if you don’t own a horizontal tank.
    • Be aware of flames: If you do any welding jobs or any sparks or ambers remain surrounding the room, keep your propane tank far away from it.
    • Smell Awareness: Propane has a pungent smell (mixed by the providers), so if you notice anything like that, please keep that canister away and check for leakage.
    • Refill: Always refill your 1 lb canister outside your home. Never fill the tank more than 80%, and check the safety valve with soapy water always after doing the refilling task.

    3. Differences between indoor and outdoor propane heaters

    Outdoor propane heaters are mighty powerful and don’t contain necessary safety features like indoors. Among them, the ODS sensor is notable.

    ODS sensors detect lower oxygen levels indoors to take instant shut-off, but an outdoor propane heater doesn’t require that.  

    However, tank top or patio propane heaters are used to spread heat towards 360 degrees surrounding it, and they radiate too high temperature, which could spread fire inside compact indoor spaces.

    Finally, the flame inside outdoor propane heaters aren’t remain protected with grills or sheets, so staying around it could be dangerous. 

    So, using an outdoor propane heater indoor is strictly restricted.

    4. Can I use outdoor propane heaters indoors?

    No, you should never use an outdoor propane heater indoors. 

    Outdoor propane heaters mean mainly patio and construction site heater, which are extremely overpowered and doesn’t contain indoor safety sensors. As a result, carbon monoxide production and spreading flames could be risks.