A monitor heater is an oil-fueled, forced-air home heating system that capitalizes on the principle that hot air rises.

A monitor heater is usually situated in the basement or the downstairs level of a home, but not because it is unsightly; the monitor is actually a very attractive appliance. It resembles a large space heater, but the top houses a control panel on which one can find digital temperature settings, a clock, and of course, the on and off switch. There is also a feature that allows users to set the monitor heater to different temperatures for different times of the day or night.

The monitor heater should be placed against an outer wall, allowing a hose at the back to draw in outside air for combustion. It heats the cold air on its way in through the hose. This is the most efficient means of home heating because the monitor heater does not re-use warm air in the home. The only ventilation hole is the small opening (about 2 inches or 5 cm in diameter) where air is sucked in.

Monitor heaters are fueled with kerosene oil, which is far less expensive than electric heat and other fuel oils. The only source of fuel that is slightly less expensive than using the monitor heater, is wood; but wood is messy, takes up a lot of space, and the stove must be attended regularly. A monitor heater draws in oil from an oil tank and can be left unattended for months. These heaters are one of the safest modes of home heating. They do not present the fire hazard of wood stoves, or the carbon monoxide concern of natural gas.

A monitor heater heats up to about 2000 square feet of space (186 sq. meters), regardless of the style of home. It forces warm air into the room where it sits, and it makes use of vents in the ceiling, as well as door ways and staircases, where the heat rises to the next level of the home.

The monitor heater provides a consistent stream of warm air into the home that is quiet, clean and odor-free.