Gas tankless hot water heaters

[franksdad]

When my 15 year old Whirlpool electric low-boy hot water heater goes out I'm considering replacing it with a gas tankless hot water heating system.  Several years a representative from our gas company came out and discouraged me from going tankless.  However, a friend of mine who is a plumber said it would be okay and not a problem.  Do any of you all have the gas tankless hot water system?  If so, would you share your thoughts, pros and cons?  Thanks.  Jim 

 

[circlew]

My sister has one, and I hate the thing. It's OK for when you're going to be running hot water for a sustained period, like for tub or shower, or filling washer or dishwasher. However, for shorter time use at the sink or washbowl, it's very annoying, because once you get hot water and then shut it off, it turns cold after you start running it again. Also won't heat if you don't have the faucet running full blast.

The one they have is propane. They though about getting an electric one, but they would have had to installed a new 400 amp electric service to accomodate it. That was going to cost them more than the new larger gas tank.

 

[jamman_98]

I installed one

I had a 28 gallon electric hot water heater and replaced it with a tankless hot water heater. It produces 6.6 gallons   a minute of hot water. I love it! Best home improvement. I also got the tax break which ran out last year, $400 check from my state and $300 credit off my electric bill. As far as having cold water when you shut off the hot, that happens with any hotwater heater due to the distance from the heater to the spigot. Just be sure to do your homework. External gas ones are easier to install than internal ones.

 

Joe

jamman_98

 

[circlew]

The problem with mys sister's is that even though the unit is right below the bath room (with a short length of pipe), after hot water is turned off and then turned back on within a short period of time, it takes an inordinately long time for it to get hot again. It's like the burner waits a couple minutes to come on again.

 

[DADoES]

 

The "sandwich" effect of cooler water running between hot water tasks is not related so much to distance as to the tankless unit's burner shutting off between uses when the faucet is turned off.  Faucet off, burner shuts off, heat exchanger cools.  Faucet turned on, burner turns on, water flow runs cooler until the burner fully reheats the heat exchanger.

 

How fast the water must run to activate the unit depends on the individual brand/model.  All tankless units require a particular minimim flow-rate to activate, usually around 0.5 gal-per-min.  Gas units usually seem to need a higher flow than electric.  My electric activates at 0.3 GPM, and will stay on at 0.2.  One reason for requiring a minimum flow is so the unit doesn't turn on in response to dripping faucets.

 

A common complaint is showers running alternately hot and cold.  Running too-hot of a setpoint can make the problem worse.  One turns down the hot water flow to get a comfortable shower temp, which may drop the hot water flow rate below the unit's activation point.  Shower gets cold, the hot flow is turned up to compensate, gets too hot, turned down .... repeat.  Better performance can be obtained by setting the unit AT (or just slightly above) the desired temp and running only the hot tap (or less cold mixed-in).

 

Retrofitting gas units can also be more expensive than expected if the gas supply line is too small for the high-BTU burners that are involved.

 

[thomasortega]

If the tankless gas water heater is well choosen according to the pipes and the installation is according to the manufacturer instructions, they are safer, more economical and you'll have plenty of hot water without problems.

Here in Brazil any kind of water heater is considerably rare because most of the houses don't have hot water pipes. Rheem recently launched a model that even being tankless, has a constant flow temperature check (the water is delivered exactly at the selected temperature, no matter if the faucet or the shower is half or full open) and as optional, they also have a recirculation system that keeps the water in the pipe always hot so you have hot water since the first drop after you open the faucet.

I'm almost sure it's also available in the US because there are many more models than we have here.

 

[hunter]

Rinnai

When we bought our house, we replaced the (dying) 80s vintage furnace and hot water heater. 

 

We replaced them with a 95% efficient Trane Furnace and a Rinnai hot water tank.

 

It was expensive, yes, BUT:

 

1.  We now DO have continuous hot water.

2.  As stated above it can be annoying that it takes a little while for the hot water to get to the tap but honestly I don't think it is any longer than it was before.

3.  My gas bills are about $15 in summer and about $100 in winter. Even mid winter.

 

I would say 'go for it.'

HOWEVER:  If you rely on the water in your hot water heater as an emergency supply in case the mains water is contaminated you will have to store water as you don't have that anymore.

 

 

 

[franksdad]

Thank you all

for your comments.  And thank you Hunter for your comments about the Rinnai.  That is the brand my plumber friend has recommended.  One of my co-workers had a Rinnai installed and loves it.  Jim 

 

[foraloysius]

Hunter

Overhere in Europe water heaters heat cold water to hot. Now what on earth is a hot water heater?

 

[maytagbear]

If I owned, instead of rented, I would have these

One serving my bathroom, always set at 104F (Just a little over body temperature, my favourite temp for showering) and the one serving the dishwashers and washers would be set at least 145F, if not higher.

To me, tankless water heaters are the way to go for the future.

Lawrence/Maytagbear

 

[toggleswitch]

Tankless hot-water heaters have their advantages and their disadvantages.

Won't work in an electrical blackout.

Calcium and other contaminants can hamper the unit's ability to heat water or even light the burner.

Now if one were to put a gas-fired intantaneous heater "in front of" a gas or electric storage-type hot-water heater, one has the best of both worlds and could run MANY topload washers at once, even in winter..........

 

[3beltwesty]

Language

In the USA folks use both phrases of "water heater" and "hot water heater" too.

Both phrases are in legal code books used in building houses, and literature, and markings on actual water heaters too.

Usage of both "ways" is older than any person alive, it goes back to steam boilers.

Todays 2009 International Residential Building code under chapter 20 in Boilers uses the phrase "hot water boiler" too, maybe to stress the difference where "steam boiler" is used.

Many folks say "hot water heater" since the water heater makes hot water. "hot" may not be really required, but I have never until this board heard anybody say mention that it is odd!

Folks in the USA too often say "lawn mower" too; and use the term "mower" too.

Thus yesterday a customer of mine said : "I will be back in a few hours, I need to take my lawn mower to my girlfriends house". If I told him that "lawn" was redundant he would think I was a nut.

In the USA folks can have water heaters for a pool too. Thus the added term "hot" often means it is the hot piping's supply for inside showers and sinks, not the pool.

ON house plans "WH" with a circle around the WH is often used.

SOME real old folks call our tanked hot water heaters "boilers" too; even if wrongly they never boil water st all.

If one worked at Home Depot or Lowes building supply stores as an employee and tried to correct customers not to use the added "hot" in front of "water heaters" one would be warned at first, then if done again fired as one who drives off customers with silly correctness.

 

[3beltwesty]

Tankless

As far as friends who have tankless systems, some love them and some totally HATE THEM.

Responses vary all over the map, from great money savers to massive time wasters of waiting on the hot water.

***THERE are massive variations of installs, and many experts besides total morons with tankless hot water systems.

Since many are "new" to tankless, sometimes poor settups are done snd folks have issues.

tankless in the USA is older than anybody on this board, but like FL washers it really is mostly a newer thing to many folks.

 

[markk290]

Tankless

Growing up my neighbors had a tankless water heater. Living in northern Ohio it did have a tank to preheat the water before it went into the heater. To the best of my knowledge it out lasted about 50 years and served a family of 5. It was gas.
I also watch a "This Old House" show where they installed a tankless in a home in Texas that had a recirculation system that was triggered by a motion detector in the bathroom so when someone entered the room it would start to heat the water. They did this so there was no waiting for hot water for a shower or the sink.
I asked the clerk at a local plumbing supply company about installing one in my house. He recommended using a water softener as our water is hard and would greatly shorten the life of the heater. Minerals would build up in the heater.

 

[passatdoc]

@foraloysius

My grandparents, who were old enough to remember iceboxes, used to call any refrigerator a "Frigidaire"....even the one my parents had, made by General Electric. Many years later I learned that Frigidaire made the first refrigerator in the USA intended for home use (not built-in like commercial units, you just placed it where needed and plugged it in).

Likewise, in 1962, my parents remodelled the kitchen of the 1930's era home they had just purchased. In addition to state of the art steel electric cooktop and built-in oven by Frigidaire, they also installed a Kitchen Aid garbage disposal in the sink, and a Kitchen Aid KDS dishwasher. It was like a space age kitchen. (the coffeemaker was a Farberware percolator, we didn't have Philips drip machines yet....). However, my father never called it a "garbage disposal", he pronounced it "dispose-ALL" with accent on the last syllable.

Years later, I learned that either GE or Hotpoint had pioneered the first in-sink soft waster disposer, possibly before the wall, and I've seen ads in which it was called a "Dispose-all". Once again, an advertising term went from being a proper noun to a common noun covering all brands of the same type of device, whether it was a Frigidaire or a Dispose-All"

PS the space age kitchen had no provision for storing either hagelslag or vlokken, so we weren't as advanced as we thought. We do have hagelslag here, but as a cake decoration and not for breakfast.

 

[passatdoc]

ps

I did once see Nutella on a table in Holland in 1973, but at that time, it was far less popular than authentic Dutch hagelslag and vlokken from Albert Heijn.

 

[revvinkevin]

My first experience with tankless...

The first time I visited Hong Kong (and my ex's brother, etc) was my first exposure to tankless. Each location that needed hot water (bathrooms and kitchen) had it's own tankless unit. This was the first time I'd seen one and first experience using one.

Each time hot water was needed, you turned the unit on manually. Once finished you had to turn it off again, you did not just leave it on. Of course these were not the automatic "whole house units" like they are selling today.

Kevin

P.S. Yes I agree with Louis, why do you need to heat hot water? 

 

 

 

[labboy]

I have some friends that absolutely love them and a few that regret they put them in. I think much of it has to do with where the heater is located in the house and the source water quality.

If your water is very soft/soft you will probably have fewer problems. Friends who installed them in hard water areas say that scale buildup has been a problem. The manuals for most of the units I have seen recommend a descaling procedure on a periodic basis. When we replaced our gas water heater last year, I decided to get a more efficient tank version because of the scale issues with the tankless systems.

 

[sudsmaster]

A few years back the local Orchard Supply Hardware had a special on smaller size tankless hot water heaters. Like $300. I was tempted, and I was thinking of buying one and installing it in the workshop. Then I read that the gas line requirement would be more than the existing gas service to the workshop. It might have worked anyway, but I figured it wasn't worth it. I do have washers installed in the workshop but the only ones I use are the Mielies which of course have internal water heaters and can run perfectly fine on just cold tap water.