Skip to Content

Gas Furnace Venting Options: Which to Choose

A gas furnace is a highly reliable heating option for your home. But without proper venting, your house can become a deadly breathing space. 

Replacing a furnace vent can be a hassle. But choosing out of all the varieties is even tougher. So, what gas furnace venting options do you have?

There are four venting options in the market. The sidewall/direct, power, natural and concentric venting. Every one of them goes with a distinct situation or infrastructure. Thus, choose one according to your needs.

We have also added information on the basic functions of the gas furnace. Furthermore, we compared among the least and most efficient furnaces.

Without further ado, let’s check them out-

Why Are Gas Furnace Vents Important?

If you’re thinking about whether you even require venting for your furnace. Let me stop you right there. 

You absolutely require a gas furnace vent. 

The furnace sends the toxic air outside of the house. It keeps you and your family safe from getting carbon monoxide poisoning. If you didn’t have vents, there would be no place for the fumes to go.

Now there might be times your furnace might not vent properly. The tell-tale sign of this is dew on your windows inside the house. This usually occurs in the morning since that’s when your furnace starts working.

Another indication of a faulty furnace vent could be rust forming on it. At that point, you’ve got no choice but to replace your venting.

Otherwise, your household might be at risk.

Gas Furnace Venting Options

There are several options available for gas furnace venting. Each one is better than the other. However, we’ve pointed out which one would be suitable for your condition.

Let’s explore those options briefly-

Sidewall/Direct Venting 

The most efficient and safest venting option is sidewall venting. Most of the time, there are 2 pipes for this type of venting; the exhaust and intake pipe.

Both of the pipes are positioned separately. They can be set through any wall. This also makes a place for a new furnace to adjust and install. 

High-efficiency furnaces use this type of venting the most. These furnaces face some common issues and aren’t always perfect. However, they are the best in the market till now.

Remember, you do have a choice of venting through your roof. But we won’t recommend doing so. 

There can be unforeseen issues with vertical vents. Because they can’t be easily maintained. Thus, always set separate pipes for venting.

The furnace takes the combustion air from outside and the waste gases are sent outside. This ensures the intake of fresh air which is an advantage of direct venting. 

Power Vents

This type of vent is considered an upgraded version of the direct vent. An added fan is the biggest asset of a power vent. The fan drives the waste gases out of the system.

Generally, the fan is connected to the furnace. As long as they’re connected, there will be no waste gas stuck in the vent. 

This will increase your utility bill by a lot. Since both of the power units are quite expensive. In the end, this is the most effective and efficient venting option. 

You also get the flexibility of installation with power vents. You can place those on any wall and anywhere you wish. Here are our top choices of furnace power vents-

Our Recommended ProductFeatures

Now that you’ve got your own power vent. It’s time to set them up.

After the installation, the vents can rattle frequently. The wind from the outside can often cause such things. But it’s nothing to be worried about. 

Natural Venting

For a long time, natural venting has been the most popular type of venting. It’s also the most cost-efficient option with a gas furnace.

Natural venting requires an attached pipe to your furnace. The pipe will be set vertically through your roof. The plan is to let the waste fumes go through and exit from the pipe.

Well, there’s nothing complex here. Naturally, the waste fumes are the lightest and should rise above other fumes. Due to the outdoor environment, this doesn’t always end up happening. 

Backdrafts are the most common cause in this case. The carbon monoxide that was about to leave your home, might enter if it’s windy outside. This can turn out deadly for you and your family inside. 

Concentric Venting

This type of venting is a bit uncommon among most people. Here, two similar-sized venting pipes are connected together. 

In other words, both the air intake and waste gas pass through a standard passage. 

You can place it both vertically or horizontally through the wall. But as always, we won’t suggest vertical placement. This makes it hard to maintain. The best method is to have a separate pipe for their distinct operations. 

Venting for Less Efficient Vs Super Efficient Furnaces

Choosing an efficient furnace is more important than choosing a vent. An efficient furnace will ensure how easy the venting would be. 

There are basically two types of gas furnaces depending on their efficiency; less-efficient and super-efficient. 

Less efficient gas furnaces are trending since ancient times. They often overheat and create a good amount of heat (275-350 Fahrenheit).

Overheating can even harm PVC venting pipes. For venting, they need metal pipes with surrounding insulation. 

Then there are super-efficient furnaces. They don’t create a massive amount of heat like the less efficient ones (85-150 Farhenheit). With these, you won’t require metal piping.  

Super-efficient furnaces produce a minimal amount of waste. However, a small volume of liquid acid is borrowed in with the waste. This acidic waste can damage metal surfaces.

For the super-efficient furnaces, you need a small plastic pipe. Also, you don’t need a vertical straight-up vent now. You can run it through your wall horizontally. 

Overall, it has become more cost-efficient. Super-efficient ones will reduce both your repairing and energy cost. So, choose wisely.


Question: Do natural gas furnaces need a chimney?
Answer: For today’s gas furnaces, a chimney is not necessary at all. We have more advanced and useful furnace venting systems than before. 

As the new gas furnaces have become highly efficient, they need a better venting system. A chimney is useless in this case.

Question: How do you tell if your furnace is venting properly?
Answer: To know if the furnace is venting properly, you need to know what happens if it doesn’t. You see, gas furnaces create moist fumes. If your windows seem to “sweat”, the venting system isn’t working properly. 

In most cases, the vented air gets inside the house rather than going outside. This results in condensed moisture on cold glass.

Question: Are high-efficiency furnaces worth it?
Answer: Yes, high-efficiency furnaces are worth it. Although they do come with a higher cost. But they do provide a higher quality service. If you wish for the best and long-term service, there’s no other option. Even if the utility bills get heavy, you won’t need any extra cost periodically. 

Final Verdict

You should be well aware of all the gas furnace venting options. You can’t always have everything at once.

If you’re looking to cut costs, go with natural vents. But no matter how heavy the bill is, investment in venting won’t go in vain. For a safer experience, choose sidewall or direct venting.

For an upgraded version of direct venting, try out power vents. If you want that single vent experience, install the concentric vents.

After setting up your chosen vent, they do last a long time. So, frequent inspection might also ensure the best performance.