6 Best Space Heater For 400 Square Feet – Reviews 2022

Picking a space heater sized to the room you want to heat is important. You don’t want to oversize or undersize the heater because the impact it has on your bills and comfort might not be what you anticipate.

In this review, we have the best space heater for 400 square feet room. You’ll find different types of heaters, including infrared, ceramic, propane, and wall heaters.

All these units have their advantages and disadvantages, and you can choose one depending on your needs.

Space Heater For 400 Square Feet Comparison Table

Factors to Consider When Buying a Space Heater for 400 Square Feet

Getting the perfect space heater for 400 square feet can be a challenge. You need to choose from many models that are easily available on the market. All the models differ from each other in terms of heating capacity, design, safety features, and even the fuel that they use.

Here are a few important factors that you should use to evaluate options when choosing a heater for your 400-square feet space.

Fuel Type

space heater for 400 square feet distributing warm airSpace heaters use either electricity or hydrocarbon fuel to produce energy. Electric heaters convert electric energy into heat energy through a heating element. The heating element may transfer the heat through convection or radiation.

Electric heaters that have a ceramic heating element are effective because they provide uniform heat in large air spaces. The ceramic element rotates to project radiation in different areas of the room.

Electric heaters that utilize the convection heating method directly warm the air currents that come into contact with their heating elements.

Some heaters produce heat energy by burning hydrocarbon fuel (either kerosene or propane). Propane or kerosene-burning heaters are designed to be used in outdoor spaces because they produce hydrocarbon.

As a result of burning the hydrocarbons, they produce carbon dioxide. Because carbon dioxide is a very poisonous yet odorless gas, it is recommended that propane or kerosene-burning heaters should not be used in airtight places.

Heating Capacity

The heating capacity of heaters is usually expressed in terms of either wattage or British Thermal Unit (BTUs). The value usually determines whether a heater can provide the required heat in a given space. Therefore, it is necessary to determine how useful a heater will be by considering its heating capacity.

To find the heating capacity of a heater, divide the BTU unit by 40. If a heater has an indicated BTU level of 20,000, then it can be used to provide warmth in a room that measures up to 500 square feet.

You can also determine the heating capacity of a heater by dividing the indicated wattage value by 10. If a heater operates at 1,500w, then it can be used to provide heat in a room that does not exceed 150 square feet.

Your heating requirements are determined by many factors apart from the size of the room. The outside climate, specific conditions in the room, and whether you have a central heating system are the most important ones.

If you choose to use your heater as a supplemental source of heat, then it is wise to use one with low heating capacity. However, if you rely on the heater as your primary source of heat at home, then choosing a high-performance one will be your priority.


Heaters may be stand-alone or wall-mountable. Stand-alone heaters are designed to be highly portable and mobile. You can move them from one place to another whenever they are required. Some standalone heaters have small casters to enhance mobility. Others have handles that you can use to carry them to different places.

Wall-mountable heaters are sold with special brackets for mounting. The heaters can be mounted on recessed walls or any other appropriate place, depending on their design.

Heaters may be tower or cabinet-shaped. Tower-shaped heaters occupy little space but can be easily get knocked down. Their sleek and compact design may also augur well with most modern interior décor styles.

Cabinet-shaped heaters are bulkier than tower-shaped ones. They occupy more space than other types of heaters. Therefore, choosing a cabinet-shaped heater requires one to consider where they should be placed in a room.


Heaters have different levels of control that allow customization and enhanced safety. Most common heaters have a built-in and programmable thermostat. You can use the thermostat to determine when the heater should run and the ideal temperature.

Heaters may also have two or three-level settings for heating capacity. These are usually labeled as either low and high, or low, medium, and high. By adjusting the heating controls, you can determine the level of heat that is produced.

In the case of fuel-burning heaters, the level at which it operates determines the runtime. At low levels, the heaters tend to run for a long time without requiring to be refueled.

Safety Features

Some heaters inbuilt advanced heating features, including the ability to switch off automatically when the oxygen levels fall or the heater gets knocked down. Other heaters automatically switch off when the surface temperature rises rapidly.

The purpose of including all these features is to protect the heater and users.

The Oxygen Deficiency Level protects the inner components of fuel-burning heaters from getting damaged when the heater is unable to burn fuel properly.

The anti-overheating features in electric heaters help to prevent the heaters from getting damaged or causing fires when they overheat.

If you’re not sure how to go about using space heaters, it’s wise to read the manufacturer’s guidelines and follow them to the letter. You can also find space heaters safety checklists from relevant sites online.

Best Space Heater For 400 Square Feet

1. Mr. Heater MH18CH Radiant Cabinet LP Heater

Mr. Heater MH18CH Radiant Cabinet LP Heater,Black
  • Hi-med-low regulator
  • Automatic low oxygen shutoff system
  • No electricity needed
  • CSA certified. Outdoor use only. Run time (hours at maximum BTU) is 24 Hours and run time (hours at minimum BTU)is 72 Hours
  • Heats up to 450 square feet

The MH18CH is a versatile radiant cabinet heater that you can rely upon to provide heating in large outdoor spaces for extended times.

Its 20lbs propane tank can drive it for 72 hours when you choose the low BTU level of 6,000. When the heater is working at the maximum BTU level of 18,000, it can provide enough warmth for a space of 400 square feet for 24 hours.

It is very convenient to use this heater in outdoor settings. Its long runtime saves you the inconvenience of having to worry about refilling its tanks regularly. Besides, the cabinet design makes the heater very portable.

The only drawback of the MH18CH is that you cannot harness its massive heating power in an indoor setting. All propane burning heaters are designed for outdoor space. Also, the heater produces some noise when running.


  • The heater is very durable because the casing is well designed and made of high-quality steel
  • It is very convenient to use it for outdoor heating purposes because it can run for up to 72
  • The heater has advanced safety features, including a low-oxygen shutoff system


  • It has been designed to be used in outdoor spaces only
  • The heater is slightly noisy when working

2. Mr. Heater Corporation MH18B Portable Propane Heater

Mr Heater 4000 to 18000 BTU 3 Setting Portable LP...
  • Propane Tank Heater: Heat up your camping or picnic area, porch, shed, and more with a handy propane heater with variable settings for custom warmth anytime, anywhere you bring it
  • Heat Levels: Gives off 4,000, 9,000, or 18,000 BTU per hour with a 450-square feet heat range and can be used with propane tanks up to 40 lbs with the use of an additional hose and filter
  • Simple Usage: Single control start knob allows easy usage with a piezo sparking mechanism for reliability with automatic safety shutoff in case the patio heater tips over
  • Possible Connections: Can connect to a pair of 1 lb propane tanks with 2 swivel regulators for a remote gas supply for your outdoor heater; Hose, filter, batteries, and propane are not included
  • Possible Connections: Can connect to a pair of 1 lb propane tanks with 2 swivel regulators for a remote gas supply for your outdoor heater; Hose, filter, batteries, and propane are not included

The MH18B is a small but very powerful propane burning heater that can be used to provide heat in medium outdoor spaces, including small garages

It has several features that make it an excellent companion to anyone who needs a safe source of heat at any workstation, including garages and sites of sporting activity.

Unlike many other propane-burning heaters, the MH18B utilizes convection and radiation heat transfer methods.

Through convection, the heater easily warms all the cool air that comes into contact with its heating element. Also, via radiation, the heater warms all objects within its vicinity to rapidly create a comfortable outdoor environment.

This compact heater has all the safety features that you would expect to find in any standard outdoor heater. It automatically goes off when oxygen levels fall within the recommended standards.

Also, when tipped over, the heater automatically shuts off. This is a particularly useful feature because the heater can easily be knocked down, owing to its small footprint and compact design.


  • The compact design and inclusion of a strong handle maximizes its portability
  • Enhanced heating capacity because of the combination of radiant and convection heating methods
  • Easy starting using the piezo ignition system


  • Fan sold separately

3. Optimus H-7328 22″ Oscillating Tower Heater

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The Optimus H-7328 is a unique heater, thanks to its heating method and design. It utilizes a ceramic element to pass radiation to animate and inanimate objects in a room. The heating element is fixed on an oscillating base.

The constant oscillation of the base projects the heater in different areas of the room and ensures that the radiation is evenly distributed in the entire space. Thus, this heater rapidly creates and maintains a cozy feeling in an indoor space.

The tower design, compact size, and excellent finish of the heater can be an addition to your interior décor style if used carefully. You can place the heater conveniently at any point in your room to maximize the look and feel of your living room or bedroom. The colors of the heater blend with most modern interior décor styles.


  • The oscillating base ensures even distribution of heat in the room
  • Highly customizable because of the advanced controls, including a thermostat and remote control
  • Enhanced safety features, including a tip-over safety switch and an anti-overheating switch
  • Elegant modern design with a visually appealing red and black finish


  • The small base makes the heater vulnerable to getting knocked down when used in a busy home

4. Comfort Glow GCH480 Propane(LP) Cabinet Heater

Comfort Glow GCH480 Propane(LP) Cabinet Heater
  • Not for use in living areas; Variable output (6K-12K-18K BTU's)
  • Instant radiant infrared heat.Heating Area: 450 sq. ft
  • Hose and regulator included; 20 lb. propane(LP) cylinder (not included)
  • Protective front grill; Four rolling casters for easy mobility
  • ODS, oxygen depletion sensor, safety feature
  • Push button ignition
  • Operates on 20 lb liquid propane cylinder
  • Adjustable heat control
  • Built-in wind shield
  • 18000 BTU's and heats up to 650 square feet

If you are looking for a space heater that is highly portable and delivers solid performance, then the GCH480 may be the right choice for you. With three variable outputs, you can adjust its performance to suit your heating needs.

When operating on the maximum mode, the heater delivers enough heat to warm outdoor spaces that are 450 square feet large. The heater delivers a maximum runtime of about 72 hours when it is operating in the low BTU mode. You can easily toggle between the low, medium, and high modes according to your needs.

Despite its excellent performance and great portability, this heater has several weaknesses. Notably, you cannot conveniently use this propane-burning heater in indoor spaces.

This is because it produces carbon monoxide, which is a very poisonous gas. Also, you will have to buy a propane heater to enjoy the great performance of this space heater.


  • The four rolling casters enhance the mobility and portability of the heater
  • It has inbuilt safety features, including the oxygen depletion sensor
  • Utilizes radiation to provide steady heating in large outdoor areas over 450 square feet


  • It cannot be used in indoor spaces
  • The propane cylinder is sold separately

5. KING PAW2422-W PAW Electric Wall Heater

KING PAW2422-W PAW Pic-A-Watt Electric Wall...
  • Original Pic-A-Watt Element
  • Multiple Wattage Options, to Tailor to a Room’s Specific Heating Requirements
  • Patented Smart Limit Protection
  • Whisper Quiet Squirrel Cage Blower
  • Wall Can w/ QuickSet Stud Tabs
  • Proudly Made in the USA with U.S. & Global Materials
  • 5-Year Limited Warranty

The KING PAW Electric Wall Heater is the ideal device for heating large indoor spaces such as living rooms, master bedrooms, and even offices.

It has an adjustable heating capacity control system that you can use to tailor the performance of the heater to your heating requirements. This can be done using the original Pic-a-Watt element included with the heater.

The best heaters for use in living and bedrooms are those with very low noise levels and footprints. This heater meets these two ideals. You can easily mount it on a recessed wall to avoid taking up much space on the floor.

Besides, it has a patented squirrel cage blower technology that minimizes the noise produced by the fan during operation.

But the convenience of having a high-performance, quietest wall-mountable heater in your home comes at a cost. Although special tabs for quick setup are provided, the process of mounting the heater onto the wall requires a good level of skill and takes time.


  • Ideal for use in bedrooms and living rooms because its patented squirrel cage blower delivers whisper-quiet operation
  • Advanced control features for adjusting the heating capacity increase convenience to users
  • The heavy-duty steel casing maximizes the durability of the heater


  • The installation process may take longer than expected if you are not skilled enough

6. TPI Corporation HF686TC Fan Forced Portable Heater

One of the hallmarks of the HF686TC space heater is that it can be used to more several other things apart from providing spot heating in outdoor areas that have low traffic such as garages.

Because the heater can project and throw hot air up to 10 feet away, it can be used as a small-scale industrial dryer. Also, thanks to its forced-fan system, this heater can be used as an air circulator in outdoor settings.

The HF686TC delivers excellent performance when used as a heater in outdoor spaces that measure up to 450 square feet. Through radiation, effectively distributes heated air to maintain a comfortable environment.

However, you will have to cope with the need to constantly carrying out maintenance procedures if you choose to use this heater. It is necessary to regularly wipe the heater to keep it in good shape.


  • Designed to be used for spot heating with a 10-feet air throw capacity, a forced fan system, and adjustable body design
  • Highly portable because of its compact design and small size of components
  • Very versatile because it can be used as a heater, dryer, and air circulator


  • It requires constant maintenance procedures to remove loose dust and other contaminants


You definitely can find the best space heater for 400 square feet room. But first, you must consider all the important factors before deciding on a specific model.

All the space heaters reviewed in this article can be used in different rooms, whether it’s your living room, garage, basement, or office. They also use different types of heating options so it’s upon you to decide what you prefer.