There is no doubt that a lot of homes set up their furnace and water heater to share the same exhaust vent. When properly installed, this can work out with the gas furnace venting at 80% and the rest for the gas water heater. Read this post if you’ve ever asked yourself: can furnace and hot water heater share vent sytems?
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Is it safe to share a vent with a water heater and a furnace?
It is generally unsafe for you to vent your water heater and furnace at the same time because this can cause a fire hazard in the home. While venting consistently helps proper heat distribution, doing this wrongly would also have adverse effects such as heat getting out from unvented pipes.
Setting up a vent for both the furnace and the water heater requires making sufficient space and finishing the vent right to avoid another risk. However, if you use a demand-type water heater, then there is no risk sharing a vent with the furnace in your home.
First, bear in mind that venting your furnace and water heater at the same time can lead to outdoor air pollution. This makes it environmentally unsafe even though it also reduces the air pollution indoors.
Also, the vent of a demand-type water heater is a lot smaller than that of a furnace. This implies that the tankless water heater will do a lot of work to force hot air out and to draw in air as well.
Although this might seem like a good idea in order to save space, there are potential set-up risks such as a clogged furnace or no hot water.
Can you vent a hot water heater outside of the house?
A water heater with power vent systems has an inbuilt blower or fan which is quiet in most cases. They are fixed at the top most part of the water heater and can have a horizontally or vertical vent duct.
It is recommended to position the vent duct horizontally outside the house because the vent doesn’t depend on the action of hot air.
However, when the ventilation in your installation space in your home is not sufficient, then it is advisable to use a direct vent gas water heater. That’s because it draws in air for heating from outside rather than inside.
How do I vent my furnace and water heater?
Typically, it is ideal to have the vents from the water heater and furnace fixed from the machine to a solid single pipe on the wall.
Also, attach it to a solid double wall pipe. This would vent the gases through the exterior.
Much like a furnace, a water heater that uses a gas burner releases carbon monoxide. Harmful fumes in the form of carbon monoxide are a byproduct of the fuel used to power the burner to heat the water in the storage tank.
This fuel can be oil, natural gas, or propane. This is why it is essential to have appropriate venting to exhaust the toxic fumes from the water heater outside.
Does the furnace affect the water heater?
There will be a pipe attached from the furnace or boiler to the water heater. The function of this pipe is to enable the flow of hot water from the boiler into a heat exchanger within the water heater. The heat exchanger proceeds to heat up the water in the storage tank and provides about 30-100 gallons of water for use when needed.
This is much like how it works with indirect water heaters powered by gas, electric, propane or oil.
What is a tankless water heater?
As the name implies, tankless water doesn’t have a tank and doesn’t require a capacity to operate. It is also known as demand-type or instantaneous water heater because it provides only hot water when needed. Demand-typewater heaters are cost-effective and very efficient option as compared to the traditional tank models.
It also protects natural resources in the environment. They are eco-friendly and do not store much electricity by operating bulky equipment all day long. This implies that they do generate standby energy losses as seen in storage water heaters which makes it much more cost-effective.
Demand-type water heaters are able to store large amounts of hot water within a short period of time, and this makes them more efficient than the regular tank models. The cold water flows the heat exchange point once the faucet is turned on and a natural gas burner or an electric element heats up the water. You don’t have to wait for the heater to preheat or go through a cycle before you can use the pipes again.
It can supply hot water at a rate of 2 to 5 gallons which is an equivalent of 7.6 to 15 liters per minute, but a tankless water heater’s output may affect or restrict the rate of flow.
How far can you vent a tankless water heater?
When it comes to venting a demand-type water heater, the design permits multiple venting choices. You can vent the tankless water heater from the roof or from the side wall depending on how much flexibility you want to create as well as the type of venting system. Venting your demand-type water heater through the sidewall creates more placement options for you.
However, it is important to note that demand-type water heaters with a direct venting system can only be vented in a vertical position via the roof, whereas a demand-type water heater with a power venting system can be vented in a vertical position via the roof and also horizontally to a sidewall.
What kind of vent does a tankless water heater use?
There are three known ways to vent a demand-type water heater.
- Power vent — In a tankless water heater with a power venting system, there is a blower or fan installed in it to serve two different purposes.
The first is for intake of air. It draws indoor air into the combustion area pushes out exhaust gases from a vent pipe. It is usually installed in the basement and the pipes of a power venting system can be installed vertically or horizontally.
- Direct vent — There are two venting pipes. One is responsible for the intake of air, while the other is for exhaust.
In general, a direct venting system doesn’t take up a lot of space and doesn’t require so much air from the environment. This makes it possible for a demand-type water heater with a direct venting system to be installed anywhere in the home, even in the closets or in the basement.
- Concentric vent — A concentric vent work in the way of a direct venting system. In this case, the intake and outtake pipes are separate but housed in one place. Instead of two pipes venting gases from the roof and somewhere else, there will only be one pipe.
Can you vent two water heaters together?
This might not be possible, especially if the installer never stated that you can. In that case, you should make sure the follow the instructions and requirements strictly.
However, there are also cases where you can vent a dual gas water heater by doubling the size of a single vent to ensure that both are heating water at the same time.
Is it possible to vent a gas water heater through the wall?
To take off byproducts of combustion, it is recommended that an all-natural gas water heater be vented outdoors. The vents go out right through an outside wall and can also bring combustion air to a gas burner. They can be set up in a smaller area because they do not need clearance at the sides and the rear.
Is it possible to vent a demand-type water heater through a chimney?
It is not advisable to try to share the vent piping off a tankless water heater with any other appliance. Also, using a masonry chimney flue when venting a tankless water heater is not a workable idea.
In place of a chimney flue, use a steel pipe. Those pipes are called special stainless for venting.
It is a must for the vent pipe to be made from stainless steel produced for venting corrosive gas and vapor. If you try to vent your demand-type water heater through a typically galvanized vent, it will simply get rusted.
