A direct vent system pulls in.
Can tankless water heater and furnace share vent.
The tankless heater cannot share vent piping with any other appliance and it cannot use a masonry chimney flue for venting.
This is because most homes have water heaters and furnace sharing the same exhaust vent.
Facts about tankless water heater venting.
Tankless water heater venting must be done correctly to ensure safe and efficient operation of the unit.
The vent pipe must be made of stainless steel designed for venting corrosive gases.
Always follow the manufacturer s installation instructions exactly.
Special stainless steel pipe.
Best case scenario you kill your furnace.
Before you decide against a tankless water heater for your next project consider these tankless water heater venting requirements.
It would be a potential fire hazard.
Traditional gas tank water heater require venting through the roof.
The furnace in the photos is a category i appliance a negative pressure draft vent appliance.
The furnace is likely sized correctly with no room to add another appliance.
Tankless water heaters use fans to blow exhaust from the unit horizontally allowing vents to terminate on the side of a house.
However the key here is to install the vent pipe in the size required by the water heater.
While there are high efficiency gas water heaters tank less units for one that utilize pvc for vents you will run into trouble trying to get the size correct for both.
The difference is that a power vent water heater pulls in combustion air from the space around the appliance then uses a fan to propel the exhaust through the vent.
Gas tankless water heaters don t have to use indoor air for combustion.
You furnace vent pipe is probably type b vent and not suitable for this use.
Tankless water heaters can be vented in two ways.
Tankless water heaters can vent through the roof or a side wall creating more flexibility and options for placement.
If you were to tie the vents together the exhaust from the tankless water heater would be pushed through the furnace and into your indoor space.
This unit is a condensing unit and requires a pvc vent so no you can t connect it to the common vent you describe.
Your tankless requires it s own individual vent.
A high e furnace has separate venting which leaves the existing vent pipe to serve only the water heater.
Vent to the outside.
Typically they require stainless steel triple wall venting.
Most homes have a shared vent serving both the furnace water heater when the furnace efficiency is up to 80 which is today s standard efficiency gas furnace.
Tankless heaters put out a lot of heat.