• Furnances require adequate venting or dangerous carbon monoxide poisoning can occur.Jupiterimages/Comstock/Getty Images
  
  All furnaces except electrically powered models, including oil and gas furnaces, require proper venting through specially designed metal pipes. While the least expensive and most common furnace vent pipe is made from a single layer of metal, double and triple wall furnace vent pipes do have some benefits. Choosing better quality vent pipes is easier during the initial installation process than trying to retrofit them onto an older furnace.
  
  

Noise Reduction

• Metal tubes like furnace vent pipes can become sound amplifiers for the noisy fans and motors in your furnace. Double and triple wall furnace pipes cut down on the transmission of these noises, says Eco Duct Products, because the space between the walls of the pipes are filled with insulation or air, which can absorb the sound waves and muffle them. If you are purchasing a high-efficiency furnace, it may make more noise than you are used to if your last furnace was older or had a lower efficiency. Installing double or triple walled vent pipes can quiet some of the unwanted noise.
  
  

Heat Reduction

• Venting a furnace can be tricky if your home lacks a basement or large crawl space with concrete walls. The vent pipes can become very hot and burn the material around them if you run them through a regular wood and drywall wall. Double and triple walled vent pipes have a greatly reduced surface heat on the outside of the pipe, according to Hearth.com, making them much safer to run through or near combustible materials. The space between the two or three metal walls in the pipe trap most of the heat in your furnace's emissions.
  
  

Corrosion Prevention

• Double and triple walled pipes last a lot longer than single wall, according to Woodstove Outlet. Rust can slowly eat away at your furnace's vent pipe, either outside where rain regularly hits it or caused by a leak or high humidity inside your home. Holes that open in the vent pipe can leak dangerous carbon monoxide as well as soot and other toxic fumes, depending on your furnace's fuel type. Double and triple walled pipes seal the actual exhaust under layers of extra metal, reducing the likelihood that the vent pipe will leak before you notice the damage. Rust and corrosion will have to eat through at least two layers of the pipe for any of the exhaust to escape.
  
  

Insulation Protection

• Keeping your vent pipes insulated helps prevent both sound transmission and heat transfer, says Eco Duct Products, but the constant heat of a single wall vent pipe often destroys even heatproof insulation after constant exposure. All double and triple walled pipes have air trapped between the layers of metal, creating automatic insulation. Some pipes also feature heat-resistant fiberglass insulation between two walls for extra protection. Being encased on both sides by metal walls helps protect the insulation.