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How to Vent Gas Water Heater in Basement Area? – 7 Steps

Fact checked by Stephen Conklin

how to vent gas water heater in basement

All homeowners must know how to vent gas water heater in basement to prevent back-drafting and carbon monoxide-related issues. Although basements are a secluded area from the rest of the home, exhaust gases can still undermine a family’s health and safety if not properly vented.

Most households have a gas water heater vent through the roof. However, alternatives exist to help families who prefer venting water heater exhaust gases laterally.

Continue reading to learn the steps for venting a gas water heater through wall.

Table of Contents

Step-by-step to Vent Gas Water Heater in Basement

What to prepare

Venting a gas water heater without a chimney requires the following tools and materials. We assume you already have the gas water heater. If not, you can include it in this list.

  • Tape measure
  • Non-flammable foil tape/duct tape
  • Draft hood
  • Vent pipe
  • Vent elbow
  • Vent cap
  • Storm collar
  • Drill and bits
  • Screws and screwdriver

Step 1: Prepare the wall to accommodate the water heater vent pipe.


Grab your drill and insert the correct bit to create an opening in the basement wall large enough to accommodate the gas water heater exhaust vent pipe.

Ensure the wall opening is wider than the vent pipe’s diameter. For example, a 4-inch hole should be perfect for a 3—inch-diameter vent pipe.

You will not want the vent pipe to touch the wall, especially if the basement panel features flammable materials. Exhaust gases are hot. They can heat the vent pipes and ignite combustible wall substrates.

You’ll also need to take the storm collar and vent collar into account. To make sure they can fit into the hole, it’s important to measure these items before getting down to drilling.

Step 2: Install the draft hood over the gas water heater.


Examine the draft hood before proceeding to vent a hot water heater. Count the number of legs, including the fastening method. Most draft hoods have four legs, while others have three. Some have screws for fastening, while others feature hooks or pins.

Ensure the draft hood legs are straight and not wobbly; otherwise, you may break its leg, which will require a replacement of the whole unit.

Measure the draft hood’s vent port diameter and compare it to the exhaust vent’s diameter. It should be the same size or slightly smaller than the vent pipe. Otherwise, you risk back-drafting of flue gases and undermining the hot water heater vent pipe installation.

Position the draft hood over the gas water heater’s vent opening, ensuring alignment between the two holes (draft hood and water heater vent).

Secure the draft hood’s legs by fastening the screws to the water heater’s top plate or inserting the hood’s hooks into pre-installed slots.

Step 3: Connect the exhaust vent pipe to the water heater draft hood.


This step for installing a hot water tank ventilation requires you to consider your vent pipe-draft hood connection options. Most experts use sheet metal screws to create a robust bond between the vent pipe and the draft hood.

You might want to avoid aluminum tape because a construction inspector might give the gas water heater vent pipe installation a failing grade. This material covers small pricks and can make it challenging to assess corrosion. Duct tape is also a no-no.

A Type B gas vent (or B-vent) requires a different installation technique owing to the pipe’s double-walled construction. Moreover, these vent pipes have proprietary locking systems, requiring only screws to hold the pipes before securing them with the locks.

Step 4: Link the exhaust vent pipe to the vent elbow.


Get the exhaust vent elbow and examine it for cracks and other signs of damage or deformity. You will want the vent elbow to form a continuous system from the draft hood, vent pipe, and the outdoors.

Assess the vent elbow’s articulations. Can you move them freely? This attribute is necessary, allowing homeowners to adjust the vent elbow’s angle relative to the vent pipe.

Insert the vent elbow over the vent pipe’s snap ring. Rotate the vent elbow until the materials lock into place. You are almost ready with the propane water heater venting.

Step 5: Install the storm collar.


Get the storm collar and inspect it for any defects. This device is crucial because it prevents rainwater, melted ice, and the elements from entering the basement through the wall. It can also inhibit air drafts, allowing the propane heater for basement units to function optimally.

Insert the storm collar through the exhaust vent elbow. Rotate it until it locks into place. Secure the storm collar on the basement wall to ensure optimum weatherproofing for the gas water heater.

Step 6: Install the exhaust vent cap.


Go outside your house where the water heater vent pipe goes out. Check the other water heater venting requirements you have yet to install.

Check the vent cap for deformities or damage to replace or fix it as necessary. This will ensure the whole system functions optimally.

Secure the vent cap on the outside-facing wall with the correct fasteners. Ensure airtight connection of all parts.

Step 7: Apply sealant.


Seal water heater vent pipe screw holes, edges, and other joints or sections connecting to other vent elements. Although the gas water heater is in the basement, away from your living spaces, flue gases can still escape through small holes in the system.

Most homeowners use foil tape because it forms an airtight seal and is more durable than a pipe thread sealant. For vent ducts and draft hoods, you can use duct tape.

Be choosy in the sealant you use, ensuring it is nonflammable owing to the hot nature of water heater vent pipes.

Other Tips for Venting Gas Water Heater in Basement


Venting a gas water heater in the basement is a straightforward and safe endeavor. You can also improve water heater venting efficiency and safety by observing the following tips.

  • Observe the minimum clearances for your gas water heater relative to surrounding structures and objects in the basement. Read the manual for the brand- and model-specific clearances and make your vented natural gas heater for the basement to function optimally.
  • Remove or relocate combustible materials from within the water heater’s immediate vicinity. You might also want to consider vacating the basement of any substance that emits ignitable vapors or causes corrosion.
  • Ensure the exhaust pipe vent has the same diameter (or slightly larger) as the insulation holes.
  • Periodically drain and flush the gas water heater tank to remove sediments, minerals, and other deposits. These substances can overburden the water heater, causing it to produce more flue gases.
  • Schedule a professional water heater inspection and maintenance check (including cleaning and servicing) yearly to ensure optimum function, including venting integrity.
  • Always assess the water heater and exhaust vent system for signs of condensation or corrosion.

Types of Vent Water Heaters


Gas-fired water heaters produce harmful flue gases as combustion byproducts, which can affect your safety and health if inhaled. Vent systems channel these exhaust fumes away from the home interior. So, what types of vent water heaters should you know?

  • Atmospheric Vent

Most gas water heaters have vertical vent ducts that empty outdoors. This vent leverages air dynamics, allowing hot flue gases to rise along the pipe’s vertical column and exit the house. Hence, it is one of the best vents for preventing back-drafting.

  • Direct Vent

Direct vent systems are ideal for water heaters with insufficient ventilation. These vents have two separate pipes: one for drawing fresh outdoor air to facilitate efficient water heater combustion and another for pushing exhaust gases outside the home.

  • Power Vent

This water heater vent is almost similar to a direct vent, except it does not draw fresh outdoor air to promote efficient water heater burner combustion.

Instead, a blower atop the water heater pushes hot flue gases outdoors while channeling some exhaust gases to the heater. This action makes these systems more energy efficient than direct or atmospheric-vented units.

Cost to Vent Gas Water Heater in Basement


Venting a gas water heater in the basement can cost you $500 to $1,100, depending on the vent type.

For example, direct vent installers might charge you an extra $500 to $1,000 for the vent system alone. This cost excludes the water heater unit price and its installation. On the other hand, power vents are $100 costlier than direct vents.

Hence, if you spend $700 for a gas water heater tank and $900 for its installation, adding a power vent can cost you $2,200 to $2,700. Choosing a direct vent for the same heater can lower your expenses by at least $100.


You now know how to vent gas water heaters in basement areas. The steps are straightforward, although they require elbow grease. The most challenging aspect is creating a hole through the basement wall, ensuring it is the correct size.

It should be a piece of cake connecting the draft hood, vent pipe, storm collar, and vent cap to complete the water heater exhaust system. If not, you can always review the steps we shared here.

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