We had a rented house that had a tankless water heater in the laundry room, on the first floor. (Propane gas) Our bedrooms were upstairs and as I remember, since hot water is instantaneous with a tankless water heater, the water was hot when it reached the upstairs and you never run out of hot water. In this house we have a tank water heater in the basement and you have to run the water for awhile before it gets hot for our shower on the first floor.

We have a tankless heater in the basement and our shower on the second floor. In the dead of Canadian winter it takes only a minute or so (I start the shower while brushing my teeth and it’s ready by the time I’m done), and that’s when winter is at its coldest.

As stated above, tankless takes a few seconds longer to get up to the
target temperature from a cold start (gas burner has to fire and the
heat exchanger get heated ... or electric elements get heated).

However, the physical distance from the water heater to the usage point is the primary factor for delivery time for ANY and ALL types of hot water systems.

So far, it sounds very similar to our tank water heater, we have to wait about a minute to heat up. Thank you!

There are a ton of posts about this subject already. "Search" is your friend.

I am a proponent of tankless heaters. That said, it will take several more seconds for hot water to get to your faucet than a tank heater (as in about 15 more seconds).

To start with, the heater has to purge and then heat the water. Then that hot water has to travel to the faucet - whereas a tank heater keeps the water hot in the first 6-10 feet of pipe.

Pipe insulation will reduce the wait between uses by keeping the water in the pipes warm.

Consider a heat pump (hybrid) electric heater instead.

When you remove the chimney, would it be possible to run a vent pipe from the basement up to the roof? If would be cheapest solution to vent the existing hot water heaters. The installation of two tankless hot water heaters is going to expensive. Be prepared for sticker shock.

Hi mike_home, That is a great question. Unfortunately for us, both of our water heaters broke down within months of each other so we had to replace them...it was this past winter so less than 6 months ago for both and winters in Boston without hot water is not good. I had someone come out to discuss venting the ones I have out and I was told that I would have to purchase a different kind of tank water heater to have them vented out. Are you saying that the ones I have could be vented through the roof? Thanks so much for your input! Also, the plumber that came out did not recommend the tankless but everyone I know who has recently renovated their homes has changed to the tankless wall water heaters.

I'd get two Direct Vent (not power direct vent) water heaters vented out through a sidewall.

Thank you sktn77a! I believe the plumber recommended purchasing new heaters that could be vented out through the sidewall. I'm not sure if they were direct vent but I will find out. The other reason I was thinking of the tankless water heaters is that we are planning to remodel the basement and make it another apartment and it will save on room. As mike_home mentioned the tankless are expensive and I had not looked into pricing.

If your two new hot water heaters are currently venting through the chimney, then they could also be vented up through the roof through a steel vent pipe. The pipe could through the space currently occupied by the chimney. The pipe could be a 4 inch double wall pipe which should allow you to have a minimum inch clearance around it. That means you will need at least a 6 inch width enclosure for the pipe to travel from the basement to the roof. Your local building code may require more clearance so you will need to check with the code official.

The challenge will be where to locate this pipe in the kitchen so it does not take away the space you are trying to gain.

I like tankless heaters, I installed them in the last two houses. But there are things to understand about them:

1. Tankless heaters are very expensive to install when done as a retrofit.

2. They take an extraordinary amount of gas at one time - so you have to have the gas supply. Having the supply to run two of them would be unlikely.

3. They do take longer to supply hot water.

4. they do need regular maintenance

So again, let me suggest a hybrid electric heater. These don't require venting at all. They cost less to use than even a tankless heater. They will cost much less than a tankless to install and there are often large rebates from the power company. In addition they will dehumidify your basement. They will give you hot water faster.
There is an 80 gal available rather than installing two.

This is a two family house. If there is a tenant with a separate electric meter then a single electric hot water heater may be an issue. Even it is not, a hybrid electric hot water heater is still an expensive solution.

Diane invested in two gas hot water heaters 6 months ago that should last 10-15 years. It would be a shame to throw these out.

So - is this two separate units? I didn't catch that. But two hybrid tank units are still much less to install than two tankless heaters - and would cost a few hundred more than a power-vent per unit (and no vent to install - so installed costs could be lower) A utility rebate is common - so that could change the equation more.

I got it that she just bought the gas water heaters. Redoing the vent won't be cheap - and she's back to taking up the space she's trying to recover. Nobody said anything about throwing them out... could e-bay them or possibly donate them (we have a place that accepts donated building materials) and then would be a tax deduction.

Jake The Wonderdog, yes it is two separate units. And we may add a 3rd unit. We have a very large above ground basement with almost 8' ceilings that we are thinking of finishing.