I have heard the tankless water heaters don't really give hot water. The water is really, really warm but not hot. But I don't have any first hand experience with this myself.

We're going with tankless. They give plenty of hot water if you get the right sized unit(s) for your needs and locate it properly. But they sure aren't the perfect fit for everyone's needs. There are just 2 of us and we are gone a couple of days every week. That along with a small house makes the tankless the better choice for us. If you can't figure out if the tankless will suit your needs consider this. If you go tankless and don't like it you have a problem. If you go with a standard tank you'll be satisfied even if a tankless would have worked. Be sure you talk with plumbers who have experience with tankless units. Tom

Tankless units will specify a maximum gallons per minute at a set temperature rise. If you were going 75 gallon, I'm guessing you have a large tub. Look at the flow rate for your tub filler and see if the tankless can keep up. Otherwise you get a warm bath not a hot one, or you have to fill it more slowly.

Also determine if you want to take two or more showers at the same time. Again, tankless may not be able to produce enough hot water, or it may if you get a big enough unit.

skagit_goat_man seems ideal for tankless. It is definitely situational to the house and the homeowners.

The plumbing supplier may have a sales incentive going right now from the tankless supplier. That could be why he's pushing it.

I've used tankless systems in Japan where they are common. The advantage is hot water as long as you need it. You set the temp with a control unit.

When we built, we wanted tankless, but decided that it just had to wait because of the initial cost of the tank. sgm and klabio are right on. We did a lot of research, talked to some very knowledgeable people. It is critical that you get a unit that is large enough for your needs.

We plan to change to tankless down the road (after the landscaping & other things are done). We figured that, for us, the break even, point was 2-3 years.

Thanks for all your input - I think we should go traditional for now and see how it goes. We do have a large tub and 4 bathrooms. We will need lots of water. We are also in Florida and I have heard people like haveing the fresh 75 gal. of water as a safety net in case of an emergency or storm.

What about brands Rheem? Kenmoore?? Does anyone know much about what to look for?

I think you will be happy with the 75 gallon tank. We are currently living with my in-laws until the house is built and they have a 75 gallon tank. We have never run out of hot water, not once. And we do tons of laundry, run the dishwasher non-stop and 6-10 showers a day. Usually people are taking showers at the same time, in different bathrooms of course :) ha ha.

My hubby doesn't know when to stop showering here. In our old house he was finished when the water got cold LOL

Tankless works fine if you can live with the temperature differential, which is the number of degrees the unit can raise water temps.

In a lot of the US, the ground water is too cold to make tankless effective [thus, the warm vs. hot thing depends on where you live]: if your unit heats the water by 40 degrees and you live in the SW desert where the ground water is going to be in the mid 60's, your fine. But here in MT the ground water most of the year is only about 40-- an additional 40 degrees would only get you to [barely] luke warm.

So check the gpm, but also check the degrees above ambient.

And compare the projected energy use to the tank unit: You may find they don't save as much as you think, as it doesn't take as much energy to keep the water hot as it does to get it hot in the first place.

Should add that there's a website out there that makes a pretty good case that these units will NOT pay for themselves over their projected useable lives. That depends a lot on energy costs, though, and we all know where those are going...

I disagree. We switched over to putting nothing but tankless in houses several years ago, and it paid off in spades. Size the unit correctly for the home and application and it NEVER runs out of hot water. Also, I'd suggest Rinnai; more expensive, but worth every penny. I'm in Michigan and ground water temperature is irrelevant if the correct unit is sized.

Here is a link that might be useful: Rinnai

Just passing on some of the points my own reading has made. Happy for those of you having good results, but not everyone is so lucky.

An article worth reading before going tankless:

Here is a link that might be useful: tankless-- a dissenting opinion

I've lived with a tankless for 12 years and would never go back. You get an endless supply of hot water. Endless. For folks with ginormous bathtubs, that's a big bonus. I have a smaller unit, as it's just 2 of us, and because the temperature of the groundwater fluctuates, we have to set the flow rate to a bit less in the winter so as to get more heat from it.

But, that reduced flow rate is still more than enough to satisfy a 2.5 GPM showerhead, especially if you make the mental adjustment necessary to understand that you're heating the water up to just above what a comfortable shower would be and barely using any cold water to temper it. That's the biggest mistake those folks new to tankless make. They want the water to be the same temperature as a tanked heater, when it's totally not necessary. Traditional water heaters are set at a much higher temperature so that users will temper the hot water with cold water and thus the tanked supply will last longer under use.

For new construction, it'd be an no brainer for me. I'd choose tankless all the way. It is a LOT more difficult to retrofit, because the flue size is larger, and needs to be stainless. The gas piping also has to be sized correctly, and that usually involves a dedicated 3/4" line. That's why the folks that are not in love with tankless will raise objections about cost. In a retrofit situation, where someone has to pay for the labor and materials rather than DIY, it's probably going to take a long time to pay for the cost difference. In new construction, where nothing yet exists that has to be modified, I'd be surprised if the additional materials and labor costs approached $500 even. And, many many municipalities are offering tax credits for the installation of tankless, so it may not even cost any additional on the front end.

Another big bonus to the tankless is the size of the unit. Ours is about the size of a suitcase hung on a wall. Compared to a 75 gallon water heater, that's a lot of room saved in our laundry room. If you live in a temperate climate, they can even be sited outdoors and still be fairly non obtrusive.

The energy savings are real. Although we're a family of just 2, we saved approximately $35 a month over the old water heater. Sometimes, in the summer, our gas bill is only the minimum charge necessary from the utility. That's $9. And, we use a LOT more hot water in the summer than we do the winter because of outdoor activities making us hot and sweaty. I love being able to jump into the shower and not have to worry about leaving enough hot water for hubby and the 3 loads of laundry that I need to do.

livewireoak,
Thanks for mentioning that larger flue size and dedicated 3/4 gas piping. During construction we had both put in for the sole purpose of going tankless in a few years. It cost us about $600 extra - not too bad for the ability to simply change tanks down the road.

I've posted on other threads what we've bought. Plans originally showed a standard water heater in my laundry. But I messed up on design by not asking for an exterior door in my laundry which is something I've had for 20 years. So, GC came up with the idea of going with a phone book sized tankless which allowed me to have the door. Our's is a "SETS" electric. We went with electric because we're on propane which is expensive in our area. And, because our home is very long, we've bought two units (we would have even if we'd gone with standard). I can't attest to it personally yet (home ETA June!) but again, this is "why" I chose the manufacturer that I did.

Here is a link that might be useful: NASA uses SETS tankless during WTC clean-up

We chose to go tankless too. Mostly it was hyped by my brother who is an engineer. But after talking to the gas man, he sold us. We will have two units on opposite side of the house (exterior). What i also like is no hot water heater taking up valuable space and potentially exploding which i hear does happen. I love the fact I will be able to predetermine the temp I want to use and then have endless supply of that hot water.

I'm in the same boat. Check out the Vertex 50 Gal Tank from AO Smith. This is the first 90% efficent tank water heater and you kind of get the best of both worlds. This uses PVC as it is a full sealed combustion unit.

It is not as efficient as the tankless but it has a nice buffer in case you have 2 people taking shower and doing laundry at same time.

Also I havent been in a house with just a tankless (have been with boiler + intergral potable HW heater) but there is a minimum flow that you need for hot water to come on. This may or may not be an issue.

We have just had our two Rinnai tankless water heaters installed on opposite sides of our house. For us in Florida they make perfect sense. Also family and friends in the UK have had extensive experience of tankless for many years and wouldn't have anything else. (It can get pretty cold in Britain by the way!)