Plumbing and Piping - tankless hot water heater

We are looking at builing a new home. A very exciting time for us as it will be our first home. I am interested about the new? tankless hot water heaters. I wonder if anyone has one and how well it works for them. Are they reliable? Do they supply an adequate amount of hot water? We would ideally like to use it for household demand and for radiant floor heating.

The new tankless water heaters are supposed to be very energy efficient and reliable, but the drawbacks that I've seen posted in here are that parts can be difficult to obtain and getting experienced plumbing service on them can be a problem.
If the dealer and installer (and servicer) for them is local for you, they might be the way to go. If not, you need to consider parts and service availability as a factor.
Talk to your general contractor and your plumbing sub-contractor about this first.
Maybe Ron (Plumber 2000) or one of the other pro plumbers (I'm not one) in here can add their thoughts on the subject.
Good Luck!
Mike

hello
i just installed my today. it works fine but now i've got low water presure. on the hot water only. if any one has a solution to this problem pls reply to my question under spankyme1..

good luck!!

I have done quite a bit of research, and would have liked to buy one, but the plumbing contractors in my area (St. Louis), seemed stumped by "tankless". Some had never heard of them.

Here is what I discovered that was the deal-breaker. I am not an expert, but...

Make sure your flue liner is sufficiently large to handle the enormous BTU output of tankless, especially if you are looking at the whole house tankless variety. To install at my house, I would have needed a new flue liner, pushing the cost break-even point for going tankless out to about 15 year payback. Ouch.

My recommendation is get the biggest one you can find. I have read that even though they don't run out of hot water, you may not get enough to create adequate water pressure.


I think the Tagaki is the best bet.

Here are some web-sites:

http://store.yahoo.com/lowenergysystems/tanwatheat.html
http://www.tankless-water-heater.com/products.html
http://www.notanks.com/lowenergysystems/paloma_specs.html
http://www.seisco.com/
http://www.globaltownewarehouse.com/HomeProducts/aquastar/aquastargastanklesswaterheaters.htm

that's my problem.. not enough water pressure..
now what's a flue?

Again, I am no expert. The flue is where poisonous exhaust gases are directed from gas appliances like furnaces, water heaters, etc.

The sum of the BTU ratings for all gas appliances dictate a certain size flue. The flue liner runs up your chimney to be vented outside, typically 3 or more feet above the highest point of your home (local housing codes may require more or less).

For the large tankless heaters, BTU output of 150,000 BTU or more is common. This compared to a standard gas water heater that is rated 40,000 to 60,000 BTU for a 40-50 gallon heater.

The flue only applies to a gas tankless, right? You can get an electric tankless if you have at least 200A service and it doesn't use a flue. Correct me if I'm mistaken, I just started looking into these.

I believe you are correct, but since I did not research electric tankless water heaters, I cannot state that with certainty.

I assume electric does not produce exhaust gases, a flue is not needed.