The 5 Best 40000 BTU Heaters (2023 reviews)

This heater is conveniently equipped with a thermostat for superior control of the temperature in your space. The inside thread on the 20 lb LP tank is a REVERSE THREAD. It fits in the inside thread of the propane tank, not outside like barbecue connections or most small propane connections. This heater is meant to be hooked up with tubing and regulators.

This heater in particular is 30, 000 BTU and will heat up to 1000 square feet. The heater can be hooked up to your 500 gallon propane tank. This heater is very nice and easy to install.

Why We Like This:

Simple and easy to set up
Great supplemental heat in super cold times
Great heat for off grid cabin
Excellent heater, easy installation, warm waves of comfort for your man-cave

Best Runner Up: Mr Heater 40000 BTU Heater

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The latest mr heater 40000 btu heater is an absolute beast in terms of its features, and rightfully takes the top spot with ease. This furnace heats a two-car garage easily and makes it a far more tolerable work space. It can go and keeps the garage at 55f easily, even when it is sub zero temps outside. It regulates the output according to the room temp, and your setting.

It does a good job of heating it in the winter. It's a great backup during the coldest part of winter for natural gas users. It heats up a 1000 sq foot room with ease. The metal grill does get hot, so position your heater high enough to where young children cant touch it as you would with any heater. It's perfect for heating a 12x24 space.

Why We Like This:

Good quality work perfect great for winter
Ideal for when the power goes out but you still have gas
Gives a tremendous amount of heat
Good workmanship and very easy to install

Best For ventless Heater: Rinnai 40000 BTU Heater

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Not everyone likes to purchase heater for their daily purpose, but the rinnai 40000 btu heater would be an anomoly. The rinnai heater is made to work in indoor vented rooms. It features a flame failure device, overheat switch, oxygen depletion sensor, and tilt switch designed to automatically disable gas/power if the device overheats, overturns, or is extinguished. It would easily heat a double-wide mobile home, given proper insulation. It keeps the room toasty warm while using very litte propane. It also will not restart once power is restored.

The heater can also be set at an "extremely" low temperature allowing it to operate only when room temperature goes below that set temperature. It features ranging from auto-timer functions all the way to economy mode settings. It comes with a shut-off valve where the feed line connects at the back, which is handy. The unit are terrifically efficient, cool to the touch, extraordinarily responsive to their thermostats and quiet.

Why We Like This:

More creaking floors and no more gaps in the flooring due to excessive dryness
Puts out a lot of heat for a small unit
Comes with a shut-off valve only

Best With Fan: Ashley Hearth 40000 BTU Heater

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We would, of course, be remiss if we didn't mention ashley hearth 40000 btu heater for daily purpose. Ashley Hearth makes this heater in a propane/LP model. It has a 1 to 3 temperature control on the 10k btu unit. The pilot light works great. It has a thermostat on the bottom so if its set to 3 when it hits room temp it kicks it down. The hardware to mount it rests near the top of the stove, so you see all of it. The pilot puts out twice as much heat as other pilots and the thermostat never overheats the house. It is a great heater for direct vent, a fan blower would make it perfect.

Why We Like This:

Works great and dont smell any different or nothing like that
Natural movement of air or liquid from cold to hot
Electricity there is no fan it is gravity vented
Single pilot light has 4 flames at cardinal directions

Best PREMIUM: Amazon Renewed 40000 BTU Heater

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We are personally inclined towards amazon renewed 40000 btu heater, it is a bit pricy, but it overachieves its purpose and long time functional. It is certified refurbished heater but includes all original accessories as new. Battery Assisted Push-button ignition with Built-in pilot oxygen depletion sensor (ODS) immediately shuts down the heater if carbon monoxide or lack of oxygen is detected.

Why We Like This:

Foot hose and regulator assembly included
Durable black powder coating finish with
New and hot release