How do you vent a gas dryer? read this to stay safe8 min read

Gas dryers are more efficient than electric dryers, dry faster and only require 110v of electricity. However, failing to properly vent a gas dryer can be dangerous and can lead to fires and even death due to carbon monoxide poisoning. 

Gas dryer installation should follow the International Residential Codes of exhaust ventilation covered in section M1502. This includes rules on vent material, duct size, duct length, exhaust termination, clearance to combustible materials, and the vent hood. Failing to vent a gas dryer properly is dangerous and can lead to carbon monoxide poisoning. 

Whilst venting a gas dryer is sometimes best left to professionals, it’s actually a simple process. In this article, I explain the specific principles of gas dryer ventilation and guidance on how to effectively ventilate a gas dryer. 

Your safety is my top priority. For accurate, expert advice on dryer venting, I’ve had this article reviewed by Andy Fulenchek, a professional with 10+ years in appliance repair and owner of Grace Appliance.

How to vent a gas dryer

When setting up your gas dryer, it’s crucial to keep in mind the main safety elements behind proper venting. I always remind my readers that safety comes first so within this section, I cover the perquisites to safe venting, whilst adhering to strict building codes.

Gas dryers are some of the best performing and most efficient dryers you can get, but they can also be some of the most dangerous situations when things go wrong. Don’t be scared to use them, but do be vigilant when it comes to maintenance and use.

Andy Fulenchek

1. follow government building codes for venting your gas dryer

Most homeowners and construction guidelines will focus on the International Residential Code M1502 which covers the rules and regulations on how to vent your dryer. 

In summary, the code covers vent material, duct size, duct length, exhaust termination, clearance to combustible materials, and the vent hood.

This isn’t just me being cautious; it’s about ensuring proper operation and adhering to the government laid out safety guidelines.

I’d recommend you read the codes before planning your ventilation system and also bear in mind that building codes can vary by jurisdiction, so it’s essential to consult the specific requirements of your local building code authority or relevant regulations to ensure compliance with the applicable standards.

2. you need to ensure your gas dryer vents to the outside of the house

You should always vent your dryer, regardless of whether it’s gas or electric, to outside the building. Venting inside the building can cause health problems as well as being a fire hazard, and the consequences of not venting a gas dryer properly are more severe than electric.

I’ve seen some gas dryers vent into the garage, into the basement, or into the crawl space and homeowners will assume that this is as good as venting outside the house. However, venting internally causes the following problems: 

  • Fire Hazard: Gas dryers produce lint, which is highly flammable. If the dryer is vented into an enclosed space like a basement or garage, the accumulation of lint can increase the risk of a fire. 
  • Carbon Monoxide Buildup: Gas dryers produce carbon monoxide, a toxic gas that can be harmful or even fatal if inhaled in high concentrations. Venting the dryer into an enclosed space can lead to a buildup of carbon monoxide, posing a serious health risk to individuals in the area. 
  • Poor Air Quality: Venting the dryer into a basement or garage can lead to poor indoor air quality leading to mold growth and unpleasant odors.
  • Condensation and Structural Damage: The moisture expelled by the gas dryer during the drying process can condense on surfaces within the basement or garage. This condensation can lead to dampness, mold growth, and potential damage to walls, ceilings, and stored items. 
  • Compliance with Building Codes: Venting a gas dryer into a basement or garage probably won’t comply with local building codes or regulations.

3. rigid ducting is safer

Gas dryers require venting to the outside of the building. The venting should be made of metal pipes four inches in diameter. 

Rigid metal vents are safer than their flexible plastic and metal counterparts, as they trap less lint, don’t need frequent cleaning, and allow for better air circulation. Flexible ducts are more prone to being crushed, hindering airflow and leading to the dryer overheating, and possibly starting a fire due to the lint build-up.

The rigid aluminium vent hoses, while safer, do bend easily and once crushed do not go back to their original shape. So, if a homeowner pushes the dryer back and crushes the vent hose unknowingly, they may have just created a restricted vent, unintentionally.

Andy Fulenchek

You can use a 4-inch flexible aluminum foil duct that is UL 2158A listed and marked for safe dryer venting. Look for a product made from heavy-duty, fire-resistant aluminum foil with a high-density, corrosion-resistant wire helix. 

the step-by-step process to Venting a Gas Dryer 

Venting a gas dryer is a relatively straightforward task that requires some elbow grease and some supplies. They include:

Here are some steps providing general guidance on how to vent a gas dryer. Note: this is meant as guidance only and should not be taken as a substitute for professional advice. 

Step 1: Choose the Shortest Route for the Vent

The first step when installing a new dryer vent is to map out the shortest possible path for the ductwork. Ensure the route is horizontal and has a pitch of ¼ -inch per foot to the outside.

For basement installations, use 90-degree elbows to create a vertical ascent that leads to an outside wall. This will help prevent moisture from settling in the pipe or flowing back to the dryer.

If your washer and dryer are situated in an upper-level room, it might be possible to vent through the roof, depending on the model of the dryer. You can check the manufacturer’s guidelines to make sure.

Step 2: Drill a Test Hole In the Rim Joist

Fnd the center point of the rim joist — that’s the large beam framing the floor of your house. Using a ¼-inch drill bit, carefully drill a small test hole. This hole is your initial guide to check the vent’s path to the outside.

Once you’ve drilled the hole, go outside to locate it. Make sure there are no obstructions like wires or pipes where you plan to put the vent. If you discover the hole isn’t quite in the right spot, or if the vent cap doesn’t sit well against your house’s siding, don’t worry. It’s easy to patch up the hole with some wood filler or caulk and choose a new spot to drill.

This step is all about precision and ensuring your vent will have the best possible exit route from your home.

Step 3: Adjust the Hole to Fit the Siding and Drill the Vent Hole

Before drilling the main vent hole, it’s important to understand where to position it in relation to your home’s exterior. If your house has lap siding (which are horizontal boards overlapping each other from top to bottom to shed water effectively), you’ll want to align the top of the vent cap with the upper edge of one of these boards.

This alignment is crucial for a snug fit and to prevent water infiltration. After finding the right spot, detach the vent cap from its duct to make measuring and marking for your hole easier. Now, use a 4-¼ inch hole saw attached to your drill to create the main vent hole. This size is typically perfect for standard dryer vents, ensuring a tight fit and neat finish.

This image shows what a hole saw looks like.

Step 4: Drill Through the Rim Joist and Install the Vent Cap

Stop drilling and pry out siding and sheathing from the saw as you progress. Carry on with your cut through the rim joist. Insert the vent and screw the cap to the house. Push a foam backer rod into deep gaps, then seal around with acrylic caulk.

Step 5: Cut the Vent to Length

I can’t stress this enough – never reuse old flexible connectors. I’ve seen too many cases where this has led to leaks and, frankly, dangerous situations. Always opt for new flexible connectors when installing your gas appliances. It’s a simple step, but it’s essential for your safety and the appliance’s longevity.

You should use only 4-inch rigid metal ducting for the home exhaust duct. And here’s a key tip from my experience – never terminate your dryer’s exhaust in a place where lint can accumulate unnoticed, like a chimney, wall, or attic. That lint build-up is a hidden fire hazard waiting to happen.

Use tin snips to trim the straight sections to the right size before joining the pieces together. Put on leather gloves before cutting the metal edges because they’re sharp.

Step 6: Close the Seam on the Vent

Line up the seam edges of the duct, then starting from one end, press the edges together while gently pushing them down.

Step 7: Tape the Elbow Joints and Attach the First Vent Section

Connect the crimped end of the first elbow to the first straight section of the dryer and secure the joint with metal foil tape. Put the first piece of ductwork on the dryer and press it up against the wall. Measure the other components, cut them to size, and connect them.

Step 8: Install the Other Vent Sections

Insert the last elbow into the ductwork piece running up the wall, secure the crimped end of the elbow into the duct cap section, then fasten it with tape.

Step 9: Secure the Vent to the Wall with Straps

Secure the duct to walls or ceilings every 6 to 8 feet using a pipe strap. Wrap the strap around the duct rather than screwing the strap to it.

Step 10: Safety and precautions

Before wrapping up the installation, there’s something I always double-check: the exhaust system. Your clothes dryer must exhaust to the outdoors. And when I say ‘must’, I mean it’s non-negotiable for safety.

Step 10: Turn On the Dryer

Plug the dryer in and switch it on. Go outside and check if the vent flap is opening and the vent is functioning properly.

After you’ve successfully installed your gas dryer vent, regular maintenance is key to ensuring long-term safety and efficiency.

I always advise my readers to schedule a yearly inspection of their venting system. This isn’t just about keeping the dryer running smoothly; it’s about preventing fire hazards caused by lint buildup.

Remember, a clean vent means a safe home. Also, be vigilant about any signs of wear or damage to the venting materials. If you notice anything unusual, don’t hesitate to call in a professional. It’s better to be safe than sorry when it comes to gas appliances.

This Old House put out a fantastic video on how to install a gas clothes dryer that I thought you’d find helpful: 

Does a Gas Dryer Need a Vent?

Some people choose to use gas dryers due to electrical constraints within their house and the fact that they are more powerful and efficient compared to electric dryers. Whilst most dryers need ventilation, it’s particularly important to properly vent gas dryers. 

In addition to expelling heat, moisture, and lint, gas dryers release Carbon Monoxide as a by-product of combustion. I always recommend homeowners install a Carbon Monoxide alarm (on Amazon) as it can save lives.  

Note: Carbon monoxide is produced by your dryer, but is not the gas that your gas dryer uses. The gas used by the dryer has an additive to give it a foul smell to alert you that there’s a gas leak.

Carbon monoxide is odourless, tasteless, and colorless making it very difficult to detect.

It’s also dangerous and can cause carbon monoxide poisoning causing symptoms ranging from headaches to death. Roughly 2000 Americans die each year due to Carbon Monoxide poisoning.

I had a close friend who took a nap with her oven on low. The flame was blown out and the oven continually leaked gas into her living room where she was taking a nap. She fortunately woke up with a massive headache, but certainly in the right scenario would have died. A good reminder to not use appliances while you’re out of the house or sleeping.

In addition to health concerns, the consequences of not venting a gas dryer properly include reduced air quality and lint being strewn everywhere. Lint is highly flammable and roughly 15,000 dryer fires occur yearly in America with the majority of cases being down to a clogged dryer vent. 

Both dryer fires and carbon monoxide poisoning can be prevented with correct ventilation installation.  

Considering Your Options: DIY vs. Professional Installation

I understand that DIY projects aren’t everyone’s cup of tea, and when it comes to something as crucial as venting a gas dryer, you might prefer to leave it to the professionals. That’s perfectly okay!

When it comes to venting a gas dryer, the decision between DIY and hiring a professional is crucial and should be based on your comfort level, skills, and understanding of the task at hand. If you’re considering a professional installation, here’s what you need to know:

Cost of Professional Installation

Professional dryer vent installation typically costs between $200 to $800. This price can vary depending on several factors, including the complexity of the installation, the type of ductwork used, and the location of your dryer. For instance, installing a vent through an exterior wall at ground level will be at the lower end of the cost spectrum, while venting through a roof or a more complex route can increase the price.

What to Expect

A standard professional installation will include cutting a hole in the wall, installing the ductwork, and ensuring everything is properly sealed and meets local building codes. The materials used, such as rigid metal ducts, are generally more durable and safer than the flexible plastic or foil types, which can pose fire risks. Expect to pay around $10 to $30 for an 8-foot long dryer vent hose, with prices varying based on the material quality and type.

Qualifications to Look For

When hiring a professional, it’s essential to choose someone with the right qualifications and experience. Look for technicians who are:

Ensure that the service provider is licensed, bonded, and insured. This not only guarantees a level of professionalism but also protects you in case of accidents or damage during installation.

Questions to Ask

Before finalizing a professional, ask these key questions:

  • How long have you been installing dryer vents?
  • Can you provide references from previous installations?
  • What type of material will you use for the ductwork?
  • Are there any additional costs I should be aware of?

Remember, while DIY can save you some money upfront, professional installation ensures that your dryer vent is installed safely and complies with all local codes and regulations. This peace of mind, especially when dealing with gas appliances, can be well worth the extra cost.”

viable alternatives to a gas dryer

As I mentioned earlier, many people choose to use a gas dryer due to its superior performance, the lack of adequate electricity in their homes, and the fact that it may be cheaper to run. However, if, after reading this article, you have doubts about your ability to safely vent your gas dryer, I’d highly recommend looking at some alternative options.

Both condenser dryers and heat pump dryers offer the advantage of not requiring external venting. 

A ventless dryer doesn’t vent to the outside. Instead, it recycles the air inside the dryer and filters out lint.

Bosch Ventless Dryer
I found this 4 year old ventless dryer on Facebook Marketplace for $400.

The hot air from the clothes is condensed in an internal heat exchanger and converted into water. These dryers are highly energy efficient but usually take longer to dry clothes than regular dryers and have a smaller capacity.

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Hi, I'm Ed, and I run BuildFanatic! I enjoy providing the best possible information on a range of home improvement topics.

Andy Fulenchek
Owner at Grace Appliance | Website | + posts

Andy is a professional appliance repairman and business owner with years of hands-on experience. He co-authors and reviews appliance articles, ensuring accuracy and top-notch information for readers.

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