Can You Extend a Generator Exhaust – How?

If you use a portable generator, then you’re probably worried about the exhaust issue too. When generators run in an enclosed space, the fumes, unless disposed of properly, can turn the inside air toxic. At that time, you will need to extend a generator exhaust.

Can you extend a generator exhaust? You can definitely extend a generator exhaust. Here are step by step guides!

  • Measure the dimension of the generator
  • Find the right extension
  • Clean the generator exhaust
  • Attach the extension tube
  • Use the clamp
  • Secure the extension tube
  • Shift it to a suitable location
  • Test the installation

Without further ado, let’s discuss ‘how can you extend a generator exhaust?’

DIY: Extending a Generator Exhaust

This will require determination, creativity, and some effort on your part but the results are unparalleled by anything else.

Measure All Dimensions of Generator with Accuracy

There cannot be a good DIY without accurate measurements, don’t worry there aren’t many, just two. You’ll need the accurate dimensions of your generator’s exhaust diameter and the required extension length.

Generator’s Exhaust Diameter: There can be no mistakes in this area as any miscalculation could end up ruining the whole venture. If the extension turns out to be too loose or so narrow that it doesn’t fit, the whole effort would be a waste.

You can use a simple ruler to obtain the measurement, but the results of a vernier caliper would be far more accurate. Record the reading and be sure to leave an allowance of 0.7 centimeters or so, to ensure that the extension pipe does not fit too tightly. Don’t worry, though; we will be using a clamp or a similar object to secure the pipe to the exhaust.

Exhaust Extension Length (Required): This length will be variable and will depend on your specific needs.  You need to ascertain where the generator would be kept and how far the nearest ventilated area is. The distance between those two points may vary, just take a measuring tape and measure all the possible lengths, select the longest one. 

Finding the Right Extension

The most common extension choices are flex tubes because they are durable, and as the name suggests, flexible. They are available in variable lengths and will endure hours of use without any damage to its structural integrity.

They are mostly metallic, but flexible nonetheless; however, they do vary in diameters, so you should be careful when buying one. You can get one from an auto store near you, or you could go online and search for one on amazon.

The Walker 40001 Universal Fit Exhaust Pipe is a decent option, if it suits your need, you can give it a swirl, or look for similar products.

Cleaning the Generator’s Exhaust

All of us who’ve used a generator are well aware that they can get coated with dirt and grime. You don’t want that to come in the way when you fit the extension flex tube on the exhaust.

That’s because it will loosen it up and may cause it to come off at the slightest force. Simply wiping the surface with a cleaning cloth should take off all the dust, grime, and lubricant residue, making it perfect for the attachment of the extension.

Attaching the Extension Tube

If your measurements were right, there should be no problem here. Just remember to opt for a pipe slightly bigger (just a fraction of a centimeter) than the exhaust’s diameter.

Use the Appropriate Clamp

A clamp will secure the extension tube with the exhaust of the generator so that it doesn’t fall off after some time. You will come across two types of clamps in the market (or online), pipe clamps, and hose clamps. Ideally, you should go with the former, as they are better suited for flex tubes, and also buy a simple socket for the fastening of the tube.

Fasten & Secure the Extension Tube

This part is simple, any clamp has two screws, one at each end. Simply loosen them up until the clamp is loose, and then place it over the exhaust.

Place the extension flex tube on the exhaust and then tighten the screws so that the clamp fits perfectly.

Note that the clamp should not be fixed too tightly, so as not to damage the exhaust, or too loosely.

Move the tube a bit to check if the clamp loosens up (which it shouldn’t).

Orient the Extended Exhaust to a Suitable Location

For this step to be perfect, you should have ascertained the distance (and the location) to which you want to extend the flex tube. If you had considered multiple measurements (for variable distances) and selected the biggest length, there should be no problem at this point. Just note that the place should be well ventilated and outdoors (otherwise it beats the whole purpose, doesn’t it?)

Test the Installation

The test run is important, it will help you avoid any problems in the future. Just run the generator for 10 minutes, and notice the following:

  • Are there any leaks in the flex tube?
  • Do the fumes dissipate in a well-aerated area or accumulate inside the office or building?
  • Does the extension stay on firmly or does it loosen up after some time?

If everything turns out to be fine, then there is nothing more for you to do. You’ve successfully added an extension to your generator.

You Shouldn’t Keep the Extension On at All Times

This may not apply to everyone, but in most cases, you will want to take the extension off when you leave the office or building. Since the generator is to be placed away after use, having a long extension attached can make the storage process cumbersome. Also, the tube may get damaged if not placed safely in a safe spot.

Extending & Silencing Your Generator

Portable generators pack a powerful punch of voltage but, at the same time, produce deafening noise. And no, this is not an exaggeration, as someone who’s been with generators for a pretty long time, I assure you, the noise is a potential health risk. While some consider silencing a by-product of exhaust extension, this is not always the case. Granted, adding an extension can reduce the decibel score somewhat but simply extending the exhaust will not silence the generator.

For quietening your generator, you should place it away from where people work, or install sound deflectors to minimize the damage.

Placing the generator on rubber feet, tightening its loose parts, or placing it in a sound-absorbing baffle box are also viable options.

Just as directing the exhaust fumes away from people is important, minimizing noise pollution should also be a concern as it too can have severe health-related problems.


The best way to extend the generator exhaust is by DIY.

Short of asking a technician to add the extension to your generator for you, the DIY method is by far the most convenient. Although it will require time and effort on your part, the results will be worth it and much more economical than anything else.

Just remember to place the exhaust extension to a well-aerated area, ideally where there are lots of plants so that environmental pollution can also be minimized.

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