Ventless Gas Heaters

Ventless gas heaters are heaters desinged to heat a room without needing to have an exhaust system leading to the outside of the building.

Ventless gas heaters are much more efficient and hence cost effective than heaters that take air from the outside for combustion. This is because there is no air exchange where vented heaters lose a lot of their heat.

Any type of heater cannot escape the fact that oxygen is needed for the combustion process. However instead of drawing oxygen from outside, ventless gas heaters draw their oxygen from the room in which they are placed. Other types of heaters that do not completely burn their fuel release smoke that must be vented outside. This is not a problem for ventless gas heaters which release their exhaust directly into the room. In other types of gas heater this would be a problem but in ventless models burning either propane or natural gas, they are so efficient that they burn almost 100 percent of the fuel and so exhausting into the room is not a problem.

Of course their are perceived dangers with this type of heater and they are actually banned in California and Massachusetts. This is for two reasons. The first is the fact the ventless gas heaters, as has been mentioned draw their oxygen from the room they are located in. Over time this can conceivably cause the oxygen levels to drop to dangerous levels. However this is a very remote possibility unless the room is extremely tightly sealed. In addition most modern ventless gas heaters have automatic cut off features that switch the unit off if the ambient oxygen levels fall below acceptable levels.

The other perceived problem is the carbon monoxide emission. Even though these heaters are very efficient and burn almost all of the fuel, tiny amounts of carbon monoxide will be released and over a long period of time, in a highly sealed room these levels may become dangerous. However it should be noted that an open fire will produce more carbon monoxide. If you are really worried about this you can buy a cheap carbon monoxide detector and site it in the same room as the heater. The other possible drawback is that ventless gas heaters emit water vapor which can raise the humidity in a room. This may damage soft furnishings in the long-term. Again if you are worried about this you could always just buy a dehumidifier. 

Because you are relying on the ventless gas heater to burn almost of all of its fuel for the efficiency gains and also, most imortantly the safety of the unit, these heaters must be serviced regularly. If you fail to properly maintain this type of heater you will lose the 99.9 percent efficiency that is possible and you may get an unacceptable build up of combustion by products like carbon monoxide and aldehyde. You also run the risk of internal damage of the heater which will cost a lot more than the service bill down the road.