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Direct Vent Gas Fireplaces

I remember back when the first factory fireplaces came out about 30 years ago. I thought they would be a fad because they just didn't look too realistic. Well, the fireplace manufactures worked hard and rose to the challenge. Add to that advancements in technology, and you have the new breed of direct vent fireplaces.

Visually Appealing Furnaces

After all, that is what these direct vent fireplaces really are. They are so efficient that you can absolutely heat a major portion of your house with one. If you have a smaller home, you can heat practically the entire space. Why? Some of these direct vent fireplaces can deliver (output) close to 20,000 BTU's per hour. This is a tremendous amount of heat.

The most common complaint with direct vent fireplaces is that they work too well. That is, they create too much heat. This gives you an indication of how much heat really escapes up a traditional fireplace. Some direct vent units capture and deliver up to 70 percent of the fire's heat.

The heat loss for an entire house (depends upon size) can range anywhere from 40,000 to 120,000 BTU's per hour. If you purchase a large, high efficiency direct vent fireplace that pumps out 20,000 BTU's or more per hour into one room, you can see the problem.

Many people like to see the fire's flames dancing and rolling. This usually means you have the fireplace running on high or near the high setting. Herein lies the problem.

Keep these BTU numbers in mind when you buy. To stay comfortable in a room, it may pay to purchase a smaller model or one that is not so efficient.

Installing These Beauties

For the most part, you don't have to be a highly trained technician to install a direct vent fireplace. The only aspect you might have to sub-contract is running the gas line. Many people just don't have the tools to run gas piping. All of the other tasks fall within the capabilities of a serious DIY'r.

The most important aspect is to completely read through the instructions TWICE before you even break out any tools. You need to be sure you follow the precise order of assembly AND that you follow each manufacturer's directions to the letter. Not all installations are the same.

You must pay very close attention to clearances around the exhaust pipe. If the manufacturer says 1 inch clearance, they don't mean 3/4 inch! There is nothing wrong with making the clearance a little more in the interest of safety.

Don't even think of modifying or exceeding the design limitations of the venting components. The proper combustion of the fireplace relies on you following the designs listed and maintaining the maximum distances as required in the instructions.

Be careful about moving the fireplace or vent components during the installation procedure. Many direct vent fireplaces require you to use stove cement and gaskets where the first vent pipe component leaves the fireplace. Common sense should tell you that once installed, you don't want to jeopardize the tightness of this joint. Moving, bumping, knocking vent components during the installation can cause problems. Pay attention to this critical detail.

Minimum Clearances

Pay attention and maintain the minimum clearances between the vent pipes and any wood or paper products. Don't take a chance or think that a 1/4 inch deviation will make a difference. Moving from 1 inch to 3/4 inch towards a piece of wood means you are now 25% closer! That is a huge percentage.


As the vent components pass through ceilings, walls, etc., you have to install metal firestops. Note that these often have to be placed on both sides of the wall. These usually nail in place very easily if you have created the correct sized rough opening.

Some firestops will have curved heat shields. These always need to be placed towards the top of a hole in horizontal firestop applications.

Each manufacturer will have different firestop requirements. Pay attention to these details!


Be sure to check into all spots where something might fall into or alongside the fireplace metal boxing. Why? If a combustible foreign object, piece of plastic, or whatever gets hidden, it can cause a fire or bad odors as the fireplace burns. It can be a nightmare to tear it apart and find the offending source of the odor. This has happened before!

Related Articles: Fabulous Fit Anywhere Fireplaces, Interesting Locations for a Direct Vent Gas Fireplace, Gas Furnace & Direct Vent Manufacturers


One Response to Direct Vent Gas Fireplaces

  1. Sparrows keep nesting in gas fireplace vent (exterior, 15 ft. above ground). I bought some copper mesh, but I need a better way to secure it. The birds have figured out a way to rearrange it. I want to be sure airflow stays sufficient. Thank you!

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