DIY Exhaust Extension for Your Portable Generator

One of the biggest challenges one might face when using a generator is with the exhaust, where green energy has become very popular in today’s society. As a result, people now pay more attention to dealing correctly with exhaust fumes that may cause carbon monoxide poisoning.

Venting your generator’s exhaust pipe, therefore, becomes a task you want to embark upon.

For an average-sized or standby generator, there are several ways to go about this. However, the odds that the same is the case with your portable generator are pretty low. Besides, do-it-yourself (DIY) alternatives to exhaust extension always prove more economical and sometimes get the job done even better.

Of course, you can go online and purchase something suitable after a rather lengthy search, but what’s the fun in that?

Suppose you have been looking for a means to extend the portable generator’s exhaust pipe to a more convenient location. In that case, you are most definitely in the right place.

Below are a few guidelines to walk you through that.

Steps in Installing an Exhaust Extension for a Generator

1. Get The Right Dimension

The place you want to begin is to, first of all, take the appropriate measurements that you would need in this process. There are only two of them. And they are both equally important. The first measurement to take is that of the generator’s exhaust.

It would help if you determined the diameter of the exhaust pipe of the portable generator. You cannot avoid this, especially if you seek a long-lasting solution. You most definitely do not want a loose connection that easily pops off under the slightest pressure.o

Having taken your measurement of the diameter, you want to record it. Of course, you can use a ruler to obtain this measurement. But in case you opt for an accurate result, a Vernier caliper is what you would need.

One other thing you might need to do is add a little allowance of about 0.7 centimeters. The allowance gives room to fit the portable generator exhaust extension properly. The looseness, if any, can be made up for using a clamp or something similar in the end.

The second dimension needed is the length of the exhaust extension. This is need-specific. Depending on the generator’s location and the more ventilated area where you intend to let off the exhaust, you should take appropriate measurements.

A measuring tape will easily take care of this. However, in practical situations, the distance between these two locations mentioned above might vary constantly. In this case, the smart thing to do is measure the lengthiest distance and go with that.

2. Acquire The Right Extension To Suit Your Needs

Portable generator exhaust pipe

This step is the major one to take in this whole procedure. The kind of extension material you employ determines how effective the emerging result will be.

The choice of material depends basically on your budget and, sometimes, taste. The truth is it is always more advisable to go for the more durable and malleable option. It might cost just a bit more, but it gets to serve the purpose efficiently and longer.

Generally, the most common and most reliable choice is what is called the flex tube. As the name implies, the flex tubing is flexible. It easily makes up for the situation of varying lengths. A high-quality flex tube will hold up well even after extensive use and length adjustments.

This tube must match the dimensions taken earlier on, both in length and diameter. Most auto parts stores have all sizes and lengths of an exhaust pipe, and you will most definitely find the one you need. Most flex tubes are metallic but allow for easy routing nonetheless.

3. Prepare The Surface Of The Generator’s Exhaust

It is expected that you have been using your portable generator before now. A lot of dust and smoke may have been left over on the exhaust. If attached directly to this sort of surface, the exhaust extension may have a looser fit. This is even more serious in the case of oil or lubricant residues.

The right thing to do, therefore, is to wipe the surface of the exhaust properly and ensure it is free from all these substances mentioned above. Many people neglect this step and the result is always not as efficient as should be.

4. Attach The Tube To The Generator’s Exhaust

This is a very straightforward process, and no difficulties whatsoever should arise here. If you measure the diameter of the exhaust pipe rightly, attaching the flex tube to the exhaust would be an effortless task. First, remove the existing spark arrestor from the exhaust. Then, slide the tube over the generator’s exhaust and tighten the band clamp with a screwdriver to secure the tube in place.

5. Obtain The Appropriate Clamp Needed

As mentioned earlier, when measuring the diameter of the exhaust, a pipe clamp is needed to ensure a perfectly secure connection between the exhaust of the portable generator and the exhaust extension tube used. In addition, you need more effort to ensure that the tube doesn’t fall off after a certain while after attaching the tube to the exhaust.

This is where the need for the clamp arises. In the market, one can easily find generic clamps of varying sizes. Talking about clamps, you would have to choose between hose clamps and pipe clamps.

While few flex tubes might permit the use of a hose clamp, the perfect choice is always the pipe clamp. You might also need a simple socket for the next step, which involves tightening the flex tube.

6. Secure The Tube Firmly To The Exhaust

Having attached the tube to the exhaust and obtaining a suitable clamp, the next thing to do is to secure the connection using the clamp. The clamp always comes with two screws, one at each end.

You can loosen the screws easily, and then the two parts of the clamp are placed on the connection of the tube and the exhaust. What you need to do next is tighten the clamp firmly.

The connection must be firm enough to ensure that it is leak-free and loose enough to ensure that the exhaust is not damaged.

You can do a little test of durability by moving the flex tube around. If the pipe clamp does not move in the process, then you have executed an excellent job.

This is the major part of the work at hand. The remaining steps are simple procedures that do not require much.

7. Lead The Exhaust Extension To A Properly Ventilated Location

After you have carried out all the preceding procedures, the next thing to do is route your already installed exhaust extension to a suitable location.

This will always depend on your surroundings. But you do not want this to be indoors. After all, permitting the exhaust fumes back into your workspace will defeat the whole purpose of installing an exhaust extension.

The exhaust extension includes a 90-degree elbow and ducting that allows you to direct the carbon monoxide out of the generator room and into the room or space where it will be vented into the outside air.

8. Test-run Your Installation

No matter how well and carefully you have done your exhaust extension installation, there is still a tendency for an error to have occurred. A portion of your flex hose might be damaged, or the clamp loosely fits. Whatever the case, maybe, a short test run wouldn’t hurt. What does a test run look like?

You need to run the generator for a short period (about 5-10 minutes). In this time, clearly observe all the connections and parts of your installation to see if everything works perfectly.

In the case of any error, you should refer to any of the previous instructions that correspond with the error. Otherwise, you can go ahead and do all the work you intend to do with your newly installed exhaust extension.

9. Disassembling Your Installation

Depending on the nature of your workspace, it is highly unlikely that you want to leave your new installation after using your portable generator.

Apart from your preference, there are quite a number of reasons why it is not advisable to leave the exhaust extension after use.

One of them is that storage is more cumbersome this way. Also, having a long extension hanging around when moving your generator is not so convenient.

And this also makes it relatively easy for the installation to be damaged. To avoid all these, the wise thing to do is to disassemble the whole connection after use. Then, unbolt the clamp and store the different accessories properly as you deem fit.

Also Read: Best Portable Generators [2022]

Silencing Vs. Exhaust Extension

It is not news that most portable generators generate electricity, exhaust fumes, and much noise. Therefore, many people consider installing an exhaust extension for their portable generator to help silence it.

The truth, however, is that this is not always the case. The task of silencing a portable generator differs entirely from that of extending its exhaust.

There are many ways to silence a generator. A search on the internet could help out but extending the exhaust is a good place to start. It, after all, ensures the safety of your co-workers and family.


We hope that this guide has been helpful to the reader. Many people like to know if all of this works. How possible is it to achieve a leak-free connection or installation?

If the guide above is followed to a tee, the much-needed results are easily attainable. Otherwise, the help of a technician might just be what you need.



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