Just found this site and lots of information. I could spend days reading.

We are considering replacing our 1985 water heater before we wake up to a cold shower one morning and are considering a tankless water heater. From the initial trips to the box stores, they all require a 3/4 water inlet. We have 1/2" currently to our water heater.

From the main outside it's 3/4" but right where it enters the house, it reduces to 1/2". Will we even be able to put a tankless in or will be have to replace the water supply line to the tank to 3/4"?

I'll continue reading the board for other useful information.

JP

My opinion is if it's a short 1/2 inch line and you still need to cut it just go 3/4 form water service to feed the heater. You could chance a 1/2 in inlet but in honesty that would probably void the warranty and a do over "ouch" Maybe you could mount it closer to the main to shorten the change.

Signed 21 boat

If my answer has helped please rate my answer.

Why would anyone that has had faithful service form a twenty-three year old water heater of one type decide to switch to one of another type that there is so much controversy about. If you are thinking about efficiency, you may be surprised to learn that the difference is very little either way. The originial cost of the tankless is such that any savings, on the side of the tankless, that it would take you many years to break even. Plus the tankless water heaters are not one hundred percent trouble free.

Thanks guys for the thoughts. I was surprised as well that this waterheater has lasted so long, even with no maintenance. Running or putting a tankless close to the inlet is next to no practical, so we might just go the route of keeping the money in savings and when the ole' trustee finally dies, go buy a good efficient water heater where piping won't be an issue.

I'm sold on replacing with a waterheater and maybe a booster or a loop like I've read in some of the other threads. Both of those are very do-able and easy runs.

Thanks again!
JP

Maybe someday when they get the kinks and price worked out of the tankless, I will recommend them, but for now, I agree 100 percent with letmetellu.

Who says the tankless has to be close to the inlet?

If you just need the boost, you can combine tank with electric tankless. Infinite showers.

You can go gravity feed recirc.
Motion sense recirc or push button recirc is retrofit with no new pipes

Tankiless by itself introduces other problems like no hot water until a particular flow is reached.

Kiss makes a good point. All depends on what you are looking to achieve. Are you looking to have instant hot water at all fixtures in the house? Or are you happy with the system you have(but wondering if there is a better way to go when existing water heater fails) If happy with the current water heater, just put in another one of those bad boys when the old one fails.

Tankless heaters are way to go. They replace the inefficient heater that maintains its original, energy inefficient, design for over 100 years. Basically, what conventional heater is, is a big pot of water being reheated 24/7/365 regardless whether you are home or not, whether you sleep or not, and whether you use hot water or not. I am glad you are considering catching up with the times and saving energy in the process. We need more people like you...

Anyway...

Big Box Stores do not sell good tankless heaters. Go to more professional supply house like Ferguson Enterprises.. There are basically 3 top models to consider: Noritz, Takagi, and Rinnai. They come in different outputs and are priced just about the same: around thousand dollars. They can be Interior or Exterior heaters, meaning that interior has power vent (direct venting), and exterior has no vent. Vent may present you with problem since it is a specialty direct vent and has limitations. You cannot simply install tankless in heater using existing vent that is leftover from old heater installation. The best of these 3 heaters is Rinnai.

All of these mentioned heaters will give you hot water On Demand - not Instant Hot Water. Read it carefully - there is a big difference in terminology. They all have variable gas consumption ranging from 18,000 Btu's to 200,000 Btu's. This may be your biggest problem. You have to plumb it for its maximum demand, therefore, for 200K Btu's. Most of the times you have to run dedicated gas line directly from the gas meter up to the heater to satisfy the demand.

I must tell you from my own experience ( have 2 heaters installed in my house since 2002) that they work great and definitely live up to their expectations.

Milo, let me know how you feel when it comes time to replace these for 1000 bucks a pop, and if you think you would have saved that 600 to 700 in efficiency over the life span. Not to mention initial install(venting gas piping and or electrical). Are you sure you aren't Pual Harvey in disguise? LOL

But seriously, good advice. You have had enough experience with the tankless (not just the ones in your house, but you said in a previous post that you install many of these a year) to make me listen to your advice closely, someday I may even recommend them, just not going to hold my breath.