10 Best Gas Heaters For Indoor Use 2025 in the United States

The Rinnai EX38DTWN Direct Vent Wall Furnace is an indoor natural gas heater designed to deliver efficient and consistent heating with a capacity of 38,400 BTU. This makes it suitable for medium to large rooms, up to 1600 square feet. Its advanced modulating technology ensures even heat distribution, eliminating cold spots and providing a cozy environment.

The heater features a programmable thermostat, allowing users to customize temperatures according to their needs and offering integration with Wi-Fi-enabled systems for enhanced convenience. Safety is a key strength, with a cool-to-the-touch cabinet and self-diagnostic electronics making it safe for families with children. Additionally, it is energy-efficient, minimizing fuel consumption without compromising on heat output, which is beneficial for reducing energy bills.

The unit is compact and wall-mounted, saving space, and fitting seamlessly into modern homes and urban apartments. However, its weight of 108 pounds may be a drawback for some users when it comes to installation. Another consideration is the need for proper ventilation as it is a direct vent heater. The Rinnai EX38DTWN is a reliable and efficient choice for those seeking a safe and customizable heating solution, particularly suited for home or office use.

The Rinnai EX22DTWN Direct Vent Wall Furnace is a robust indoor natural gas heater, boasting a heating capacity of 21,500 BTU, which makes it well-suited for maintaining warmth in various room sizes. One of its standout features is the advanced modulating technology that enables consistent and efficient heating, ensuring that cold spots are effectively eliminated. This can be particularly beneficial for those seeking a comfortable and evenly heated living space. Additionally, the heater's programmable thermostat provides customizable comfort, allowing users to set specific temperatures and even integrate with Wi-Fi systems for added convenience.

This level of control can be a big plus for users who want to manage their home heating efficiently and effortlessly. Safety is a top priority with this unit, evidenced by the cool-to-the-touch cabinet and self-diagnostic electronics, which make it a safe choice for households with children. The compact, wall-mounted design is another attractive feature, especially for urban residents or those with limited space, as it does not take up floor space and blends well with modern interiors.

However, the product requires proper ventilation due to its direct vent design, which might necessitate professional installation if you are not handy. Despite the energy efficiency claims, users should still monitor their energy consumption to ensure it meets their personal efficiency standards. While the unit is fairly quiet, it might not be completely noiseless, depending on individual sensitivity to sound. The Rinnai EX22DTWN is a reliable, efficient, and safe option for indoor heating, particularly suitable for families and those living in compact spaces.

The ProCom ML100TBA-B is a ventless propane gas heater that delivers up to 10,000 BTU, suitable for heating small to medium indoor spaces up to 500 square feet like bedrooms, home offices, or living rooms. Its blue flame technology offers efficient radiant heat without requiring electricity, making it handy during power outages. The heater features a thermostat with three settings (high, medium, low) allowing you to control the warmth according to your comfort level.

Safety is well-covered with a built-in oxygen depletion sensor (ODS) that automatically shuts off the heater if oxygen levels drop or carbon monoxide is detected. This model is ANSI certified, adding reassurance about its safety standards. Ventilation requirements are minimal since it’s a ventless unit, but proper room ventilation is still important to prevent gas buildup.

The heater is compact and lightweight (around 16 pounds), with a slim design that can be mounted on a wall or placed on the floor using included hardware, which adds flexibility in tight spaces. While it lacks electronic ignition (it uses a push-button ignition), it still offers reliable start-up without batteries or power. Users should ensure adequate airflow since ventless propane heaters can affect indoor air quality if not used properly. This unit serves as a practical choice for those needing a portable, efficient propane heater with solid safety features for small indoor areas, especially where electricity isn’t available or reliable.