It would be a potential fire hazard.
Can tankless water heater and furnace share vent.
A high e furnace has separate venting which leaves the existing vent pipe to serve only the water heater.
Tankless water heaters use fans to blow exhaust from the unit horizontally allowing vents to terminate on the side of a house.
Worst case scenario you kill your family.
Yes venting tankless water heater with furnace is possible.
However the key here is to install the vent pipe in the size required by the water heater.
Gas tankless water heaters don t have to use indoor air for combustion.
Tankless heaters put out a lot of heat.
Traditional gas tank water heater require venting through the roof.
Typically they require stainless steel triple wall venting.
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.
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.
Tankless water heaters can vent through the roof or a side wall creating more flexibility and options for placement.
Tankless water heater venting must be done correctly to ensure safe and efficient operation of the unit.
Facts about tankless water heater venting.
Tankless water heaters can be vented in two ways.
Special stainless steel pipe.
Always follow the manufacturer s installation instructions exactly.
The tankless heater cannot share vent piping with any other appliance and it cannot use a masonry chimney flue for venting.
You furnace vent pipe is probably type b vent and not suitable for this use.
A direct vent system pulls in.
Your tankless requires it s own individual vent.
The vent pipe must be made of stainless steel designed for venting corrosive gases.
Before you decide against a tankless water heater for your next project consider these tankless water heater venting requirements.
The furnace is likely sized correctly with no room to add another appliance.
Here are a few things your installer should consider for effective tankless water heater venting.
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.
Best case scenario you kill your furnace.
This is because most homes have water heaters and furnace sharing the same exhaust vent.