How to Choose a Gas Fireplace

There are three types of gas fireplace systems with each type having its own characteristics.  It is best to become educated on these characteristics to be able to make the right decision on which type system will work best for your needs and expectations.  The three categories of gas fireplaces are, (Vent-Less, Decorative Vented and Direct Vent) with a summary of their abilities outlined below

VENT-LESS / VENT-FREE
Vent-Less gas log systems have been available for the past 20 years and have become more popular since the manufacturers of these units have changed marketing strategy be renaming this category as “Vent-Free”.  Everybody wants to get something “Free” and the marketing people want consumers to hear the word “Free”.  A Vent-Free fireplace or log set generally has a very poor unrealistic flame and the by-products of combustion are fully vented into the home.  Essentially the house is used as the chimney or vent and the occupants of the home are living in the vent.
The Vent-Less combustion of gas in the home creates odors, soot, moisture, carbon monoxide, carbon dioxide, nitrogen dioxide, plus too many other oxides to list.  These units do have an oxygen depletion sensor next to the burner as a safety device to prevent room oxygen from being displaced with enough combustion pollutants that would cause a healthy human to black out from the lack of oxygen.  There are many documented cases of health problems with Vent-Free systems and it is generally not recommended for people with a compromised metabolism such as the elderly, infants, pregnant women, people with allergies, heart conditions, or respiratory conditions.  It is safest to operate a Vent-Free unit sparingly or with the damper partially open or with a window partially open to bring in fresh air.
The combustion of 1000 BTU of gas per hour releases one ounce of water vapor.  A typical Vent-Free log set is sized at 40,000 BTU/HR for a potential of 40 ounces of water vapor released in the home for each hour the fire is burned.  This excess moisture condensing on window sills, inside walls, and around doorways thresholds has caused problems for some Vent-Free users.  Rotten wall framing, window framing, and mold and mildew from the moisture are potential problems for the home.  Check with your homeowners insurance for moisture, mildew and mold coverage before buying a Vent-Free system.  A Vent-Free gas log set installed into a brick fireplace and chimney will also cause accelerated deterioration of the interior fireplace brickwork from this moisture accumulation. 
No fuel is 100% pure and clean.  Impurities in natural gas, propane and even the air in your home can help to create soot in your home with a Vent-Free system.  The soot build-up in a home generally takes between three and five years of using the Vent-Free system before the deposits are noticeable.  A Vent-Free log set installed into a fireplace once used for wood burning can cause an extreme accumulation of soot in the home if the original creosote deposits in the fireplace and chimney are not thoroughly swept out before the log set is installed.  The original deposits will fall out of the chimney and filter through the damper and fall onto the Vent-Free log set causing the creosote to burn and disperse into the home as soot and offensive odors.  Additionally carpet fuzz, house lint, animal hair and dander, vapors from paint, stains, cleaning solutions, vinyl  blinds, floor coverings, and odors from litter boxes are all burned and chemically changed in the combustion process of a Vent-Free unit and aid in the potential for soot and indoor air pollution.  Most people notice the soot problem when they move a picture from the wall and can see the soot outline from the picture frame.  Check with your insurance company on soot removal from the home before purchasing a Vent-Free system.  Vent-Free systems are available as a complete stand-alone fireplace unit or as a log set to be installed into an existing code acceptable fireplace capable of burning wood.  If your family is in good health and the curtains around your windows move when the wind blows, a Vent-Free gas system my work for you.  It is the opinion of Hearth and Home Service and Construction that Vent-Free products should not be used due to the potential problems.  Currently Hearth and Home Service and Construction does not sell or install Vent-Free products, however we replace many Vent-Free products that have caused problems.

VENTED DECORATIVE
Vented decorative gas log sets are designed to be installed into fireplaces that are safe for burning wood.  Just as the name implies the damper of the fireplace has to be open for the fumes to be vented outside of the home.  This type of gas log set usually has a large flame with a rather large consumption of gas typically from 55,000 to 90,000 BTU/HR.  This large flame with glowing embers is beautiful to watch but not very efficient to operate.  Approximately 90% of the energy produced is lost up the vented chimney along with a considerable amount of heated air from your home that the furnace just heated.  An open draft fireplace will pull from 300 to 400 cubic foot of air per minute out of the home which causes a negative pressure in the home.  Since the pressure in the house is less than outside, this pressure forces cold outside air into the home.  If the outside temperature is less than 30 degrees than a noticeable cold draft may be felt running through the house at floor level when the decorative gas log or open wood burning fireplace is used.  The rooms away from the fireplace will also become noticeably colder. 
A safety pilot valve set with pilot flame is required on all decorative vented gas log burners and a clamp is required on the damper to prevent the damper from closing.  You cannot close the damper with this type log set which means you will be losing heat out of your home even if you are not using the log set.  If a vented gas log set is installed in a fireplace that is not code acceptable for burning wood or a fireplace with drafting problems, then a very serious carbon monoxide safety situation could be created. 
Most new home builders are installed cheap inefficient wood burning (builder box) metal fireplaces in their homes and then installing vented decorative gas logs into the fireplace.  This type of system will not put any usable heat in the home.  If rising gas costs are not an issue with your household and you can live with a cold draft in the home then a large convenient flame of a decorative gas log set may be just what you’re looking for.  Currently Hearth and Home Service and Construction do sell a high quality line of decorative vented gas logs made by Hargrove.


DIRECT VENT
Direct vent fireplaces, fireplace inserts and freestanding stoves are the safest gas venting systems available on the market today.  Some models are designed for high efficiency heating that is more efficient than a full house furnace!  The direct vent firebox is a sealed combustion chamber so no air from the living area of the home is used for combustion or for the draft.  The combustion air is brought in directly from the outside through a special pipe that also vents out any by-products of combustion (i.e. carbon monoxide and moisture).  Many of the direct vent systems have the vent pipe that can exhaust through a wall or through the roof allowing great flexibility of installation location.  Since the fire is in a sealed chamber a large fire can be obtained consuming less gas than a vented decorative log set and since no house air is used for draft or combustion your furnace will work less!  This closed combustion system also prevents the risk of down drafting or back drafting  that could cause spilling fumes, soot, odors or carbon monoxide to enter the house.  There is a wide range of quality and efficiency with the direct vent fireplaces on the market.  As a general rule most builders install the cheapest and least efficient fireplaces available to maximize their profits.  Most of the cheap fireplaces have a firebox made of thin sheet metal held together with RTV silicone caulking and pop rivets and use a wall switch to turn the burner on or off. 
A high efficiency direct vent system will be furnace rated with an adjustable room thermostat and a published efficiency of over 78% with the option of using either a standing pilot flame or spark ignition system.  Since these high efficiency units can produce a great volume of heat they can be used as a primary heating source, zoned heater or as an emergency  backup  system  if  the electric utility service failed.  Direct vent systems are available as zero clearance fireplaces, fireplace inserts that can be installed into most existing fireplaces and freestanding stoves.  Hearth and Home Service and Construction has been selling, installing and servicing heavy duty high efficiency direct vent fireplaces and insert from Avalon and Fireplace Xtrordinair since 1992.  We have specialized and promoted high efficiency even before the term “Green” was coined!  These products feature the patented glowing Ember-Fyre  burner and log set that won the “Best of What’s New” award from Popular Science magazine for this highly efficient and incredibly wood-like gas burning technology! 
As a general rule if having a fireplace is important to you, then you then you should not let your builder pick a fireplace for you.  Do your own research and tell your builder what you want, what you want it to look like and where you got your information.  The wrong fireplace for your needs and expectations could cost you hundreds of dollars of waste in your energy bill each year.