I want to install a tank-less natural gas water heater for my 2-1/2 bathroom home.?

Question

My only concern is the venting system. I want to vent out of my chimney the same way my conventional water heater does. From what I understand, the unit has to have a dedicated vent and air intake. I am wondering why the unit cannot be vented out of the chimney with my furnace like my conventional water heater?

Answer 1

Instead of asking the question here call the company who makes the equipment and ask them, They have a good reason why they tell you to do it that way and i would listen to them before anybody here!  

Answer 2

it depends on the type of instant on water heater you buy , some use a conventional "B" vent type chimney and others use a power vent that goes through the wall and yes it can be vented with your furance as long as the chimney is large enough for both (which it was for the hot water tank ) and both appliances are on the same floor , combustion air can be brought in anywhere or not at all if you have an air exchanger

Answer 3

It can be vented with your old vent system. Just make sure that you have a good air intake, but your old system should have had that also.

I Say go with what you have it will work out ok!

Answer 4

What efficiency is your new water heater? If it's in the 90% efficiency range, it will use pvc for venting. You have to run both the intake and exhaust pipes outside and not in the chimney due to condensation. If you vent a condensing appliance into a chimney, you will cause yourself major problems.

If it's not a condensing appliance and uses metal pipe for the exhaust, the unit may have to be vented all the way outside to keep flue gas velocity up.

If it's in the installation instructions, it would be a good idea to follow them to keep you and your property safe.

Answer 5

Read the instructions that come with the unit before buying it.  Lots of people think tank less heaters are the answer to all their problems. Most good units require them to be professionally installed to keep the warranty intact. Many Plumbers will install them, but will not do service work on them since they are complicated. If you have hard water, don't get one.