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How to Vent a Hot Water Heater Without a Chimney? – 7 Ways

Fact checked by Stephen Conklin

Learning how to vent a hot water heater without a chimney seems like Mission Impossible for some homeowners. After all, a chimney or similar structure allows water heater exhaust fumes to escape into the outside environment.

Most homeowners would be surprised if we tell them there are at least seven ways to vent a water heater without relying on a chimney. If you are doubtful, continue reading and learn seven neat tricks.

Table of Contents

7 Methods to Vent a Hot Water Heater Without a Chimney

What to prepare

Venting requirements will depend on the method you choose. For example, you can prepare an attic fan or a power vent if you pick these tricks for venting a gas-powered water heater.

Method 1. Power Vent


If venting hot water heater through chimney is not possible, a power vent will do the trick.

Power venting is one of the most effective hot water tank ventilation systems, moving air horizontally instead of vertically.

A blower helps facilitate the air’s natural (lateral) movement into the home and pushes hot exhaust fumes outdoors through the vent.

With this setup, you’ll be venting a gas water heater through wall structures instead of the roof.

One issue with a power vent is its space requirement. For instance, a 30-inch wide water heater might require at least 32 inches of space for the power vent.

Installing a power vent also requires choosing the ideal location. The best spot should be near the water heater, with adequate airflow, and flat.

Next, follow the power vent manufacturer’s installation instructions to connect it to the water heater.

Method 2. Attic Fan


Attic fans pull hot exhaust air from the water heater and move it outside.

They are the closest you can get to a chimney-based water heater vent. These appliances “suck” hot air upward, following the air’s natural vertical movement.

Installing an attic fan requires several materials, including: a drill and bits, hammer, wrench, screwdriver, jigsaw, cable clamps, electrical cable, wire connectors, and the attic fan.

  • Experts say attic fans are an excellent alternative to chimney-based water heater ventilation for homes with an existing gable or roof vent. It will save you effort and time cutting a new hole in the attic and through the roof.
  • The hole should be big enough to fit the fan, and there should be sealant on top of the screws securing it. Nail the shingles back down as well for extra security.

Method 3. Roof Vent

A roof vent for water heater venting is almost similar to an attic fan – they move hot air from inside the home to the outside environment.

Their only difference is that attic fans require electrical power, while roof vents rely on natural convection currents (airflow). Some roof vents have turbines, allowing them to function like attic fans.

These systems rely on air movement and its natural dynamics. Everyone knows cold air moves downward as hot air rises.

The heat from the water heater moves up the air column, and the roof vent’s rotation facilitates hot air evacuation from the house.

Installation should be similar to an attic fan, and homeowners will do well to read the manufacturer’s instructions.

Drill holes for the vents away from the rafters, and make sure to put the lower shingles under the vent before installing it. Seal the holes with tar or caulk as well.

Interestingly, most homeowners choose this method when using an electric tankless water heater.

Method 4. PVC Pipe

Water heater venting without a chimney is possible with a PVC pipe. It is inexpensive and straightforward enough for a DIY installation. However, homeowners must observe a few guidelines.

  • Position the PVC pipe at an angle, ensuring it slopes about a quarter of an inch per foot to prevent water entry and back-drafting. You will not want flood in basement units.
  • Ensure the water heater is sufficiently far from the room or basement’s ventilation intake. Otherwise, homeowners must modify their horizontal ventilation pipe by adding an air admittance valve.

This valve allows air to come in and balances the pressure in pipes.

Method 5. Exhaust Fan


An exhaust fan for hot water heater can also solve your chimney-less venting problems. The device is similar to the exhaust fan in the kitchen or bathroom, drawing hot air inside and moving it outside.

The best position for an exhaust fan is right next to the water heater, preferably near the bottom. You can then install a makeshift pipe and drill a hole on the wall to channel the hot air away from the water heater.

Like roof vents, exhaust fans work best for venting hot air from tankless water heaters.

Method 6. Stove Hood

This method might be the last on your mind when thinking about how to install a gas water heater vent without a chimney.

You have two options for using a stove hood.

  • First, you can leave it as a free-standing stove hood ventilation system directly above your water heater.
  • Second, some homeowners connect the stove hood’s other end to an existing ventilation system, allowing them to move the hot air from the water heater outdoors.

Method 7. Air Conditioner

Using air conditioners is an unusual method, but equally effective as having a chimney to remove hot air from the water heater and cool the home’s interior.

Although effective, the AC method requires a few things to ensure efficient venting.

  • First, you must open only one window to allow exhaust fumes to move outdoors. All other entry points (i.e., windows, doors) must be closed so that the air isn’t simply circulated indoors.
  • Second, the air conditioning unit must have a setting for moving warm air.

Why is It Necessary to Vent a Hot Water Heater Without a Chimney?


Chimney-less homes are susceptible to many hot water heater venting problems. However, the two most serious concerns are residential fires and carbon monoxide poisoning.

It is worth noting that water heaters are a fire risk.

Gas-powered water heaters might cause residential fires when flammable materials are next to these appliances and within reach of flammable vapors.

Meanwhile, the heating elements of electric water heaters can overheat, while electrical components can short or experience other problems. An electrical fire could start with these events.

Unsurprisingly, proper water heater venting is necessary to prevent explosions.

Venting a water heater is also crucial to prevent carbon monoxide poisoning. Improper venting produces back-drafts of combustion gases, particularly carbon monoxide.

Things to Consider Before Choosing the Best Method for Yourself


Homeowners have several considerations when pondering a gas water heater vent pipe installation or choosing any alternative methods described above.

  • Local Venting Codes

We recommend checking your local water heater venting code before you start with any of these methods.

Venting codes reflect city- or community-specific safety regulations, guidelines, and standards. These rules are in place to protect you, your home, and everyone else in the community.

They also help you determine which alternative venting solution you can set up and which ones are “illegal.”

For instance, your local government might allow you to install an attic fan but not a stove hood to move hot air from the water heater.

  • Alternative Water Heater Venting Location

Consider the location for your water heater, ensuring adequate ventilation or airflow. After all, all water heaters require ample space around them to facilitate more effective heat dissipation and prevent the buildup of combustion byproducts.

  • Professional Inspection

Hire a professional to inspect your appliance, including its venting requirements and space, before you vent a gas water heater without relying on a chimney.

This activity incurs a fee, but it is worth it because you will feel more confident and secure about the optimum functioning of the water heater and vent system.

  • Installation Ease and Budget

Some methods require you to purchase some tools and materials, while others only need a few actions on your part.

For instance, using an air conditioner only demands opening a window and closing everything else. Meanwhile, an attic fan or roof vent requires purchasing the device and working on the attic or roof.

Frequently Asked Questions

Types of water heater vents

Water heater vents come in three main types, as follows.

  • Atmospheric vents – The vent has a vertical duct to move the hot air from the water heater outdoors.
  • Direct vents – This system requires two vent chambers, one for pulling cool outdoor air and another for venting hot exhaust from the water heater.
  • Power vents – This vent type is more flexible than atmospheric and direct vents (installed horizontally or vertically). It features a blower to force hot exhaust fumes from the water heater and move them outside.

What happens if I do not vent water heater?

Backdrafting can occur if you do not vent a water heater. This event can lead to carbon monoxide buildup in the home, increasing your risk of carbon monoxide poisoning, which can be fatal.

Cost to vent a hot water heater without a chimney?

The cost to vent a water heater without a chimney depends on the method. For example, an attic fan should not cost you more than $60. If you hire a professional, a direct or power vent installation can cost $500 or more.


You now know how to vent a hot water heater without a chimney. Some methods are more straightforward than others, requiring slight modifications and a bit of elbow grease. Others are more intimidating, demanding homeowners to create a hole in the roof or attic.

Nevertheless, these methods show it is easy to vent a water heater without relying on a traditional chimney. You will never worry about residential fires and carbon monoxide poisoning again.

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