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Procom Vent-Free Heaters and Fireplaces

Frequently Asked Questions

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What exactly does vent-free mean?

Vent-free, or ventfree, simply means that the gas heater or fireplace is not vented to the outside.  Vented heaters bring in air from the outside, and then exhaust the combustion byproducts to the outside.  Vent-free units burn inside air and do not require a vent.


If they aren’t vented, where does all the carbon monoxide and fumes go?

Vent-free heaters are safe to use without venting.  You may already have other vent-free gas appliances in your home now, such as a gas stove, oven, or dryer.  They don’t need to be vented because LP gas (propane) and Natural Gas are very clean-burning.  Yes, there are tiny, tiny amounts of carbon monoxide and other gases that are released into the air, but these amounts are regulated by the EPA.  Procom units are tested by the CSA (formerly called the American Gas Association) and proven to operate within the safety limits established by the EPA. 


Will my carbon monoxide detector sound an alarm?

No.  The amount of carbon monoxide produced by a vent-free heater is so small that a detector will not sound an alarm.  And the normal “breathing” of your home, where outside air gets into your house through cracks, crevices, doors, windows, etc, means that the chemicals will not “build up” inside the house. 


What are the main benefits of Vent-Free heaters?

  1. Initial Cost – compared to vented heaters, vent-free heaters are typically 65% to 75% cheaper. 
  2. Installation Cost – Vent-free heaters and fireplaces require no venting, so you don’t need a chimney, a hole in the wall, vent kits, termination kits, etc.  All you need to do is run a gas line to the place you want to put your heater or fireplace.  Any plumber or heating/air-conditioning technician can do this for you. 
  3. Operating Cost – Vent-free heaters are 99.9% efficient.  That means that for every 1000 btus of gas, 999 btus are turned into heat and only 1 btu is lost.  Vented heaters are typically 75-82% efficient.  So you get 22% to 33% more heat from a vent-free heater for the same cost
  4. Flexibility – Vented heaters must be vented through a wall, up a chimney, or through the ceiling and attic.  This is costly, and once you’ve put it there, you can’t move it.  To move a vent-free heater, all you do is disconnect the gas line, move the heater anywhere else in your home, and hook it up to another gas line.  (You may have to run a new gas line to the new location, of course.)


I’ve heard that Vent-Free heaters produce a lot of fumes?

Nope.  If it does, it is not operating correctly and should be checked out by a gas technician.  When a gas appliance is used the very first time, there may be some fumes for a few hours until the oils and gunk from the factory are burned off, but after that, you shouldn’t smell it at all.  If your heater collects dust from a long period of not being used, there might be a little smell as the dust is burned away.  If there is a smoker in your home, or if you have recently used paint, stain, scented sprays or cleaning fluids, odors can be produced as the appliance burns the contaminated air.  The “fume story” is something you might typically hear from someone in the hearth industry who sells $3000 to $4000 fireplaces.  The vent-free industry has cut into their sales a lot, so they sometimes exaggerate or even make up stories to steer you away from the lower cost options you have.


What about people with Asthma or Allergies?

People with severe asthma, allergies, or hyper-sensitive sense of smell may be sensitive to vent-free heaters.  It has been estimated that 2-3% of the population will find vent-free heaters objectionable.


What about Moisture?

When gas is burned, water vapor is released into the air.  Approximately one ounce of water is produced for each 1,000 btus of gas burned in one hour.  So, for example, a 20,000 btu heater would produce 20 ounces of water vapor if it burned continuously for one hour.  If it burned an average of 6 hours during a 24 hour period, it would add 120 ounces (3.75 quarts, which is almost one gallon) of water vapor to the air each day. 


In the winter, some extra moisture is usually a good thing.  But if you put a vent-free heater in a room that already has a humidity problem, the additional humidity can lead to window fogging or even mildew.  Improving the air circulation in the room, and/or using a dehumidifier, can fix this problem.

Can I Replace My Central Heating System with Vent-Free Heaters?

Vent-free heaters are intended to be “supplemental” heat.  Most states do not permit the use of vent-free heat sources as the only source of heat in a home.  But if you have an addition to the home, or a cold room, or if you want to cut your overall energy costs by turning the main house thermostat down and adding supplemental heat to the rooms you use the most, vent-free heaters are an excellent choice.


Are Vent-Free Heaters Legal in All States?

Vent-free heaters are legal in almost all states.  California, Minnesota and Wisconsin have restrictions on their use, as do parts of Massachusetts.  Some cities and counties have restrictions even though the heaters are legal in the rest of the state.  Before purchasing a ventfree heater or fireplace, call your local zoning board or Building Inspector – they will know if there are restrictions for where you live.


Can I Use a Vent-free Heater in a Bedroom or Bathroom?

Most states allow the use of vent-free heaters in bedrooms, but the size cannot exceed 10,000 btus.  Even if your bedroom is 1000 square feet, the limit is still 10,000 btus. Bathroom heaters are limited to a maximum of 6,000 btus by most building codes. 


Natural gas vs. Propane - What's the Difference?

If you live in a densely populated area, you may very well have natural gas available to your home. Natural gas pipes are buried in the ground and feed gas to a gas meter inside your home. If you have a gas meter, you probably receive a monthly bill from the gas company. If you live in an area that does not have natural gas, you need to get a propane tank (also called LP, for Liquid Propane). Tanks are usually white and usually sit in the yard, close to the house. Look in the phone book for Propane companies. They will bring a tank to your home, help you determine the size tank you need, and then they will periodically fill up the tank. Most propane companies charge an installation fee for running the gas line from the tank to your home, but they usually do not charge you for the tank, since they make their money by selling you the propane to fill the tank. 


What Safety Features are Built In to Vent-free Heaters and Fireplaces?

Vent-free gas appliances burn the air inside your home.  As they do this, they burn the oxygen in the air and replace it with carbon dioxide and water vapor.  This can cause a drop in the oxygen content of the air.  Your house, though, is constantly “breathing”, meaning the air inside is escaping through cracks, crevices, windows and doors, and is being replaced with outside air.  Because of this, the oxygen content of the air inside your home is constantly being replenished.


All Procom heaters and fireplaces contain a device called an ODS (Oxygen Depletion Sensor) that monitors the oxygen content of the air.  If the oxygen content of the air were to drop to around 16% (which is still very safe), the unit will shut off the gas and the flame and pilot light will go out.  Likewise, if the pilot flame were to blow out, the unit would also shut of the gas supply automatically.  The invention of the ODS, several decades ago, has made vent-free appliances very safe to use.