What is a Monitor Heater?

Paulla Estes
Paulla Estes

A monitor heater is an oil-fueled, forced-air home heating system that capitalizes on the principle that hot air rises. It 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 heater to different temperatures for different times of the day or night.

Kerosene oil, commonly used with kerosene lanterns, is used to fuel monitor heaters.
Kerosene oil, commonly used with kerosene lanterns, is used to fuel monitor heaters.

It's important to place monitor heaters 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 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. Monitor heaters draw 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.

Paulla Estes
Paulla Estes

Paulla is a freelance writer and website editor who currently lives in Maine. Paulla has a B.A. in English Literature from George Mason University and over 15 years of experience as a freelancer. She relishes the flexibility and consistency of working on wiseGEEK articles, as well as the opportunity to constantly learn something new.

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Discussion Comments


All monitors use diesel! And now with ULSD it is even a no maintenance issue with soot to burn no. 2 diesel. In the bush in Alaska, they get only three types of fuel if they are larger villages: Jet A, gasoline and 100LL. I can tell you that there are probably about as many monitor and toyo heaters in Alaska as wood stoves. They are the two primary heat sources, unless you are near Anchorage/Wasilla or Kenai where natural gas is available. They are simple heaters and easy to repair. A burner rebuild kit for my monitor is about $250. I can do it myself and it’s super simple – takes about an hour. If you know which end of the screwdriver to use, you can do it in less than three hours your first time, I would bet!

The diesel engines run fine off Jet A, a little dry for some seals in pumps, but no harm done. Being in aviation, every diesel vehicle at the airport runs off sumped Jet A from aircraft tanks, or Jet A right out of the fuel truck. Our ground power units are diesel, as well are Jet A powered. I've personally run about 1,000 gallons of Jet A through my 95 7.3 diesel, and I would run 1,000 more if I could get it for free after defueling a aircraft with an under wing panel leaking.

I ran eight ounces of two-stroke oil per 18 an gallon tank to help with lubrication of the injector seats, and it did quiet the injectors down a lot. That o-ring saved me from buying fuel all winter! I got $5,000 in fuel sumped for a $5 o-ring! Thanks. Call me again anytime in the future.

The fuels do not smoke more than the others. It is because the off road machines have larger injectors and are not as efficient in burning the fuel upon an increase in acceleration. The only issue is Jet A, which is cleaner and drier as far as lubrication properties, but it has the antimicrobial agent in it and has the lowest BTU rating. Kerosene is next, then no. 1 diesel and then no. 2 diesel has the highest BTU rating. No. 2 has too much paraffin wax and gels at about 20 degrees. All turbine engine aircraft can burn kerosene without any damage, as well as diesel, but you do not have the anti microbial agents (like prist) and one would want to clean their filters and make sure that it was from a clean source.

When I use no. 2 diesel in my truck, I get 18 miles per gallon, with no. 1 diesel, about 13 miles per gallon and with Jet A, about 10 if I’m lucky. If you have a monitor with an indoor tank (some places in Canada I know have basement fuel tanks), if you can get no. 2 diesel before winter hits, you can save yourself more money because of the BTU per gallon savings.

There was a lot of discussion about diesel in Toyo and Monitor heaters. They said never use diesel in them when they were made, but now with ULSD, it is perfectly fine. Several universities did tests when ULSD was coming out, and they saw no noticeable negative effects of using it, if not a plus because of less soot build up even compared to no. 1 heating oil. And if you have a source for offroad or no. 1 diesel, it’s all the same. Just the red dye for non tax usage. There’s not one difference in no. 1 heating oil and no. 1 diesel. Most fuel stations will start mixing no. 2 and no. 1 road diesel in early October, depending on location so they won't be stuck with bad fuel in their tanks in the winter time. They can't order no. 2 in the winter, because the refineries stop making it!

If you have a fuel station that sells "stove oil," it is going to be no. 1 diesel, and yes, people do pump it straight into the auxiliary tanks of their trucks, and then take the chance of being dipped for red dye fuel.

I run no. 2 diesel in my monitor if I am not willing to pay for an extra delivery of fuel after hours from my supplier. I’ve never had anything go wrong, and it’s all the same when it comes down to it now with ULSD. ULS is the base for all Jet A to ULSD no. 2 at the pumps. It all has to be low sulfur, and that means less soot!


@sunshined - I live in Oregon and though we don't have extreme winters, many people use monitor heaters in their home.

This is the most economical way of heating a home that we have ever used. When we moved here, this was the first time we used this type of heat for our home.

I have been very pleased with it and would recommend it to anyone. Our family room is in the basement, and this room always stays warm.

I have lived in other homes where the basement was always cold no matter how much you turned up the thermostat.


@honeybees - I know what a loud furnace sounds like. We lived in a manufactured home that was all one level. The furnace was right next to the living room.

Even though this was enclosed in a closet, you could hear it every time it came on and it was loud.

This is the first I have heard of a monitor oil heater before. Is this something that is more common in certain areas than others?

I live in the Midwest, and everyone I know uses a furnace in their home, or electric heat if they live in an apartment.


It sounds like the way you have your vents placed would make a big difference in how well the monitor heater works.

Our house has a stairway that leads up to a loft and an attached bedroom. Since hot air rises naturally, the loft area is always warm.

Even though there are vents in the attached bedroom, this room is always cold. It is the coldest room in the winter and the hottest in the summer.

I wonder if a monitor heater would make a difference here, or if you would need to do something different with the vents?

I really like the idea of an efficient and quiet way to heat your home. If you are in our basement, the furnace seems awful loud.


I used to live in a home where we burned a lot of wood in the fireplace during the winter. This was not our sole source of heat, but we kept it going most of the time to cut down on our heating bills.

Although I enjoyed the atmosphere of burning wood, it was messy and a lot of work. My husband is the one who would chop and gather the wood.

I would bring it in from the deck and no matter how careful I was, I always left a trail. It just seemed like there was constant clean up.

Now we live in home that has a monitor kerosene heater. This is the first time we have used something like this and I really like it.

The whole house stays warm and it seems to be a very even heat all throughout the house. I have lived in other houses where some rooms were much colder than others. This isn't the case with our monitor heater.


Hey "here in Alaska", all Monitor heaters do not use diesel, they use #1 (kerosene) otherwise the #2 of which you speak of, would turn to jello in the tank!


No. 1: fuel only, works fine.


Here in Alaska all monitor heaters use diesel fuel.


Can you use diesel fuel to operate a monitor heater? I hear people say they do it and when you talk to a dealer they say it is not recommended.

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