Can you use propane?

It's not something I've ever researched but intuitively heating water on demand without a flame sounds like a tough thing to do. My guess is if electric tankless units exist, flow rates are going to be low. I would think propane would be a better idea. You might get more responses in Plumbing.

There are many makers of tankless electric units, FWIW. I know several people in apartments who are very happy with them, but I don't know anyone who has one in a single family house, so can't comment on that.

You might want to check around in your area to see if there are electricians who are experienced in installing them.

Incidentally, just a caution--this is evidently a real hot button topic in the Plumbing forum, so expect a lot of vehement replies if you post there.

Typical whole house electric tankless require a service of 100 to 150 amps. Typical modern homeowner electrical services are 200 amps. You will have to upgrade the feed to your home from the pole and install a new service to retrofit an electric tankless.

Retrofitting tankless usually involves a lot of upfront costs that don't really see an economic feedback in your lifetime.

You should look at the Plumbing Forum where you will find many threads on tankless water heaters. As Writersblock mentioned, it's a hot topic there, but you should be able to get a great deal of information to help you.

One very important consideration is the climate you live in. Where I live, wintertime incoming water temperature to my house is around 40-45 degrees. The amount of electricity you would need to bring 40 degree water to 105 degree water "instantly" would be very high. Since traditional tank water heaters these days are so well-insulated and efficient, your electricity to keep water hot in a tank 24/7 would not be nearly as bad. On the other hand, if you live in a warm climate, an electric tankless may be more feasible if you are OK with the high upfront costs for the tankless heater itself, and the various installation costs like the electrical upgrade Live Wire Oak mentioned. If "endless hot water" is very important to you, you may feel electric tankless is worth the higher cost, but I cannot imagine it being a good choice in a cold climate.

Here is a link that might be useful: Search Results for Electric Tankless on Plumbing Forum

We have been renting a condo during our new build process. Our old home was lost to the 2004 hurricane season here in Florida. The condo has a tankless hot water heater and I hate it. It will suddenly turn from comfortable to freezing cold for no reason. Once it goes cold it must be turned up to full blast hottest shower setting for what seems like 10 minutes before it gets comfortable again. Remember, this is Florida. While this is an inconvenience here I think I would be seriously thinking of suing the manufacturer or installer if I lived in a colder climate.

flseadog, a common mistake with tankless is setting the temp on it too high. Tankless requires a certain minimum flow rate to activate, and stay on. If the hot faucet is turned down too much during a shower for example, the hot water flow rate may drop below what's required to keep the tankless running, and your shower will turn cold. In response, you'll turn up the hot water, which triggers the tankless to turn back on. By setting the tankless AT (or nearer) the desired usage temp, no cold water needs to be mixed in at all (or very little), which keeps the hot water flow rate up and the unit won't shut off. I set my electric tankless at between 102° and 105°F as the normal temp and run only the hot water faucet for showering. I've never had a shower turn cold in the 4.5 years I've been in this house.

Yes, as dadoes said, you have to learn to use hot water differently with tankless. I should have mentioned before that I seriously looked into going tankless for a place I was considering buying (the space saving would have been well worth the installation costs and I'm in a warm area so that part was okay), but I wouldn't have been able to upgrade the electricity enough to make it feasible, since it was an older townhouse and the whole building feeder would have needed upgrading, not just the particular unit.

dadoes and writersblock, we have tried a range of temperatures. The problem is in how one defines a comfortable shower temperature. DH and DS lean toward steaming hot. Both of my daughters have very sensitive dry skin and mildly warm is the best for them and this really is a necessity. I'm somewhere in between and can tolerate either but I'm the one who ends up freezing cold when my attempts at moderation fail. It just seems to me that these tankless systems are geared more to a one size fits all mentality rather than being flexible enough to accomodate individual tastes and needs.

What you need to do is set the tankless specifically AT the temperature desired for the shower, and run ONLY the hot water tap. If the unit isn't easily accessible to adjust the temperature frequently, then, yes, I know it's an inconvenience. This is where units with remote control panels come into play.

Perhaps 115°F might be a reasonable work-around. I'd suggest checking the actual temp in the shower with an instant-read kitchen thermometer for whoever likes the warmest temp to determine what that temp really is.

Mine is adjustable from 50°F to 140°F, which seems flexible enough for anyone.

From what I understand the electrics do not qualify for the energy star tax rebates. However, there are heat-pump electric water heaters that do qualify.

dadoes, are you saying that each person should adjust the water heater temperature before they shower to their own individual taste? If so, that sounds like a lot of running around for everyone involved. In a small condo this might work but what if the heater control is downstairs and in a utility room? What if in a house with multiple bathrooms 2 people are taking showers at the same time and want a different water temperature? I'm not trying to be contrary. I'm just saying that we have really tried what you suggested over the course of the past year and I can't get a decent shower using this appliance.

We had tankless water heaters in a vacation house, which made sense because who wants to heat water in a traditional water heater while nobody is home?

Ultimately, we ripped them out and replaced with a traditional electric water heater, as they just didn't work right despite many service calls.

FLSeaDog, ideally, the temperature should be adjusted precisely for each person. However, realistically, no. Hopefully all the preferred bathing temps fall within about a 10°F range ... so perhaps adjusting the unit between a lower bathing temp (perhaps 108°F to 110°F) and a higher household use temp (120°F to 125°F) would be a workable compromise. Ten to 17°F difference doesn't seem like much, but for a tankless that must heat a flowing volume of water on-the-fly, it can be enough to justify. Of course, frequent adjustment certainly can be an inconvenience to the point of being unworkable if the unit isn't easily accessible. This is where remote controls come in handy. My unit is in a broom closet in my laundry room. I leave it set on 104°F as the "normal" setting, raising it as needed for washing clothes (open the closet, punch a button a few times, it automatically drops back down after 30 mins) ... or sometimes lowering it a little for a cooler shower in the summer heat. I don't raise it for dishes, as my dishwasher has built-in water heating.

Maybe I've become accustomed to my tankless and using it efficiently to the point of unconscious habit ... but I have no complaints. I have to wonder if the folks having trouble just are unwilling to modify their usage habits accordingly, or if there's something wrong with their installs, or the units involved just don't work very well.

I've been looking at tankless, but must reluctantly say that their higher cost of installation trumps likely energy savings -- and that's for gas where the savings can be as much as a third, and with having adequate gas service without an upgrade. In my area it would be a 20-year payout -- not a great deal in any case, but especially for a unit that is projected to last 20 years. Most estimates I've seen for electric are savings of about 5%. Rebates or tax credits might help but I figure we can the tax credits for other improvements and our utilities don't offer rebates. YMMV.

Even where the payout is better, there's still the cold-water sandwich phenomenon, where a slug of cold water comes through the hot water pipe in between uses -- that flow is the demand that turns on the heat. It's well known to be a problem between uses but may also be the cause of what flseadog is experiencing. It may not be a problem for non-shower-takers, or people who live alone, or for those whose hot water will be heated close to their showers, but for me it would be a problem.

We lived with a tankless water heater (AquaStar) in our 2-person 2100 s.f. home for about five years and loved the seemingly endless hot water for showers. It was propane-fired and reliable. However, our well water is extremely hard, and calcium deposits would form, which meant that my DH had to take the dang thing apart about once a month and clean it with vinegar to keep it running. Eventually the calcium caused so much "plaque" to build up in the copper "arteries" that the thing broke down completely. IMHO the hardness of your water supply is a critical factor to consider.

rc
in
VT