Venting a hot water heater without a chimney can be challenging, but it certainly isn’t impossible.
We already know that it is important to vent the hot water heater regularly, which is why you should find the most adequate method for venting your particular hot water heater.
In this guide, we will offer the most efficient methods of venting a water heater without a chimney, most of which are beginner-friendly.
We will also explain why it is essential to regularly maintain the water heater and vent it from time to time.
Why vent a hot water heater without a chimney?
Venting a hot water heater without a chimney is essential for several reasons. One of the most common causes of fires in a home is housing water heaters that are not ventilated properly.
Having no vent for the heater can lead to carbon monoxide poisoning and other dangerous situations.
To ensure that your hot water heater is functioning safely and efficiently, there are several things to keep in mind when venting it without a chimney.
First, check the building codes in your area before installing any heating system or equipment.
Each part of a home must meet specific safety standards and code requirements, so follow all local guidelines and regulations before starting any installation project.
Next, remember that every air-tight space needs an adequate supply of fresh air to function correctly.
When venting a hot water heater without a chimney, be sure that the space around it is properly vented and has good airflow. You can install vents into the room on the side or top of your hot water heater.
Also, always have your heating equipment inspected by a professional before using it for the first time each year.
This will help ensure proper functioning and prevent any potential issues from arising in the future.
Following these simple tips, you can safely vent your hot water heater without a chimney and keep your home safe from fire hazards and other risks associated with improperly maintained heating systems.
A water heater that isn’t adequately ventilated can lead to structural damage in your home. Without supporting air, the combustion gases become hot and pressurized. They force their way into the crevices of your home and can erode building materials.
Structural damage like this is costly and may leave you without a place to live until those repairs are made.
In addition to structural damage, not venting your heater correctly can lead to poor indoor air quality (IAQ).
The burning process creates CO2, soot, water vapor, carbonic acid, toxic fumes, and other pollutants that are typically vented outside the chimney.
If these gasses are emitted into your home instead of outdoors via the chimney or an exhaust flue ducted out of your house, there will likely be health hazards.
These pollutants can cause irritation, coughing, and other respiratory problems for everyone in the home.
Finally, not venting your water heater properly can lead to higher energy bills and a shorter lifespan for the heater itself. Without proper ventilation, gas heaters (including electric ones that use natural gas to run) cannot burn fuel as efficiently.
This means less hot water before having to refill or reheat the tank and more waste heat being released into your home instead of outdoors where it belongs.
Poor combustion also puts much more stress on your heating system over time than regular operation, so you’ll have lower efficiency ratings than if you’d just let out those gases properly in the first place.
How to vent a hot water heater without a chimney
Properly venting your hot water heater when you don’t have a chimney is a must and should be added to your list of chores.
However, if you have no idea how this should be done, look at this list of the most effective methods of venting an electric or gas water heater to avoid combustion air issues and exhaust gas in your home.
1. Install an attic fan
The first method of proper venting if you don’t have a chimney is installing an attic fan. An attic fan will work by pulling hot air out and keeping your house cool.
You can purchase attic fans at most home supply stores for around $40 to $60. Attic fans are an excellent alternative to installing a chimney if you do not have one, as they perform the same function.
2. Install a power vent
Another method of venting a hot water heater if you don’t have a chimney is using a power vent. Power venting is the process that involves a fan pulling air from outside and pushing it through your hot water heater.
The power vent will come in different sizes depending on which type you need for your water heater.
Power vents use electricity or natural gas to power the fan. Power vents are most commonly used when there is no chimney available.
However, these vents also require more space than standard ones because they are larger. For example, if your water heater is 24 inches wide, you will need at least 26 inches to fit the power vent.
To install a power vent on your water heater, you need first to find an area where it can be located outside of your home. This should ideally be on a flat surface, so it gets as much airflow as possible.
Then, you need to attach the vent to your water heater using the manufacturer’s hardware.
3. Install a roof vent
A roof vent can be a good substitute for a chimney when you vent your tankless water heater. It has several benefits, including compatibility with almost all styles of homes and functionality in areas where a chimney is not feasible.
A roof vent is designed to channel heat and exhaust out of your home. Many homeowners choose to install one on the roof of their house when they have an electric tankless water heater instead of a traditional gas-powered heater.
4. Use an exhaust fan
You can also use an exhaust fan if you don’t have a chimney. Place the exhaust fan near the bottom of the water heater and vent it to the outside using a metal pipe.
This option works best for tankless hot water heaters because you can position at least one of them near a window without too much trouble.
5. Use air conditioning
Another easy venting method is simply using air conditioning. To use this method, you will need a window to vent the fumes through.
Open the window and close all doors in your house so that the air is stifled throughout the house. This will ensure that toxic gases are not released into other rooms of your home.
The air conditioning should be turned on and set to circulate the warm air in your house. Ideally, it would be best if you vented through a window that is not used often or where no other rooms are located.
6. Use a concentric vent
A concentric vent is the most common type used with water heaters. It usually consists of a length of 3-inch (7.6 cm) diameter pipe that runs concentrically inside an 8-inch (20.3 cm) diameter pipe and is also known as an “8/3” system.
The 8-inch diameter pipe is the vent exit at the top of the water heater. Smaller diameter pipes connect from the upper pipe to drain traps or condensate stacks and allow air to enter when draining or using appliances that produce combustion products.
Concentric vents are also used with boilers and furnaces, except, in this case, the outer pipe is a 6-inch (15.2 cm) diameter, and the inner pipe remains 3 inches. These large-diameter pipes must be pitched slightly for condensate to run toward the drain trap.
A typical installation of a concentric venting system would include one vertical pipe from the chimney chase connected to the top of the water heater, combined with a T joint to two pipes that run down through the roof. The inner pipe must always be installed first, followed by the outer pipe.
The advantages of concentric vents are that they vent poisonous gases outside and allow condensate drainage into sinks or drains. They comply with codes, are easy to install, and don’t require additional support.
The disadvantages are that the inner pipe is constantly exposed to condensation, which can corrode the metal over time. Also, if the water heater breaks down or becomes flooded, it will leak out at the top.
7. Use a PVC vent pipe
Proper venting could also be achieved with a PVC vent pipe. Generally, PVC vent pipes should be sloped at least 1/4 inch per foot downward to prevent back-drafting and water entry.
It would be best to create the proper slope using additional tubing or cutting and re-attaching the existing vent pipe. Finally, you must ensure that your hot water heater is not too close to the room’s ventilation intake.
If it is too close, and you are using a PVC pipe for venting, you will need to install an air admittance valve on one of your horizontal runs so that excessive negative pressure does not cause water entry into your home.
8. Install a stove hood
While using a stove hood can seem like a rather unorthodox venting method, it is safe if you follow a few steps. It is surely not as effective as a chimney, but it can be a decent replacement in certain situations.
First, check with your local building codes department or gas company. There may be laws about how you can and cannot vent your hot water heater.
Once you have clearance to use a stove hood, you need to decide what type of ventilation system is best for your needs.
Some people opt for a free-standing ventilation system that can be placed near the hot water heater and connected directly to it. Others connect their hot water heater exhaust directly to an existing vent system in their home.
Related: A.O. Smith vs. Rheem Water Heaters
David Kessler is a CSLB licensed contractor with over 25 years of experience. He is specialized in home building, construction, and electrical works; he also has a keen eye for interior design and, over the years, has collaborated with various architects.
