Tankless hot water heater / hot water on demand

[BLOODSWEATSTEEL]

What's the deal with these systems? Anybody have any first hand experience? It sounds like a pretty good idea - especially considering my gas bill last month was $177.

http://www.foreverhotwater.com/index.shtml

[focus]

My grandparents had one of those systems temporarily while we were building their house. It never got particularly hot, and would start to run colder the longer the faucet ran. It's since been reinstalled down at our camp, which seems to be a better fit for it.

More of a quick fix thing than a solution, I think...

edit: upon further review, it was a different system that they'd had installed. Same concept, but prolly not as elaborate.

[bagtagley]

Nahm Abrams was pimpin those things on one of those fixer-upper shows recently. Seems they've come a long way, and are just as effective as tank-style heaters.

Assuming the water's hot enough, and it doesn't get cold, it's a great idea. Keeping a tank of water hot all day long is far from efficient.

Edit: The one they tested was made by BASF I'm pretty sure.

[Snow Dog]

What's the deal with these systems? Anybody have any first hand experience? It sounds like a pretty good idea - especially considering my gas bill last month was $177.

http://www.foreverhotwater.com/index.shtml

Big deal. My gas bill was $355.

A gas fired demand heater requires a larger flue than a hot water tank (up here) so you can't easily retrofit.

An electric tank is more efficient (better insulation, no center exhaust stack) so sometimes it's cheaper to operate.

edit: as a bonus my house has 2 tanks (upstairs and down) -- one gas, one electric. Pretty silly for one person.

[Blatant]

my hot water is heated by a manster coil in the center of the an oil furnace....it's hot as all hell an has what seems to be an endless supply of hot water. Not the oil bills a different story wasn't too bad in dec and jan cause we had the wood burning stove in the basement going, along with the fireplace on the weekends....marches bill was 4hundy....uggh...

[Snow Dog]

The part they leave out is that the waste heat usually heats your living space so in the winter months it's not really wasted. If you're cooling in the summer then double penalty for you -- paying to heat and paying to cool.

[Arty50]

My sister just had one installed in her house and if fuggin' rocks. She now has an endless supply of really hot water.

[Viva]

I had one installed in my new house solely to clear up a little extra space (it's a little house).

Get the Japanese units. The Japanese have been making these suckas for years and have worked out a lot of the bugs.

These can be mounted on a wall outside- that's what I did. No flue issues.

Digital temp control is included, so if your H2O ain't hot enough, crank it up a bit.

Problems- My unit needs 2.5 GPM (gallons per minute) flowing through it to activate fully. This means turn the tap on full blast initially and wait until you get hot water. Also, when the system's been off for a while (e.g., overnight) taps further away from the unit will take longer to receive hot water. So, placement may be critical lest you waste water. I may end upo moving my heater to to wall outside of the bathroom. this way, instead of waiting 30-40 seconds to get hot water, I'll only have to wait 10-15 seconds, or less.

[BLOODSWEATSTEEL]

Significant decrease in gas/electric $ since?

[Conundrum]

I've been interested in this for awhile so I just called the local salesman. He said for the product BSS linked to, it ranges from $2,800 to 3,300 installed for my type of house_ have a 3 bedroom, 1.5 bath, 1,750 square feet and the $500 difference was for how he would have to run the venting duct work and that he may have to up the input on the gas line. Apparently a normal gas water heater runs at around 40,000 btu's and this system peaks at 180,000 btu's but only for short periods. He did say it would cut my gas bill and the unit was about 22"x15"x5". I'm in the process of fixing up my house and if the water heater needs to go, this looks like a pretty good option.

[wildstyle]

I've had these in europe since at least 1980. They rule.

Instant cheap piping hot water. Try and get a combi boiler to do the central heating at the same time. Can't be beat.

When i get my next house though, i'll get one of these. Wood burning multi fuel boiler stove.

http://www.stovesareus.co.uk/catalog...roducts_id=201

It gives you the option of wood if gas prices go through the roof ... i like that.

[riderspro]

I have a modern tankless unit. I guess they are all the rage in Europe...The model I have is name Infinion I believe. I'll try to find beta on it later.

They can be electric or natural gas. Mine is gas, and has coils that get flamed when you turn on a water flow. Gets super hot, is adjustable to prevent burns. Continuous supply, meaning you can do three loads of wash and still take a hot shower. however, with my unit, you can't really do all at once. You feel the reduction in capacity when the washer is running if you are in the shower. Would probably be the same with a tank? I can't really remember. Also what someone mentioned above, it needs a certain amount of flow to activate. This makes it hard to have a trickle of hot water going. It needs to be about the amount you would use to wash your hands to keep the flames on. Warm up time is about 30 seconds, which is about the same for people that have a conventional water heater in the basement.

Big advantage is that size. About the size of a large backpack, and much lighter. I have mine installed in the attic. If I had a tank up there, I would have had to cut a larger access hole into the attic, and be concerned about weight load on the rafters.

I'm about 90% pleased. The trickle of hot water thing bugs me sometimes (shaving etc) I think the cost is relatively equivalent. I paid about $600 for my unit and installed it myself.

Edit: I think if you lived in a super cold place, the cost might turn out to be less as not keeping the tank warm. CO has been very mild last couple years, so hard to get a good judgment on the question...

[powpig]

Doing a remodel on my condo this summer and have been doing some research on these. This is the best and cheapest one I've found.
http://www.tankless-water-heater.com/index.html

[wildstyle]

The main reason you get just a trickle of hot water is down to the mains water pressure entering the house.

The only time it bothers me is in the shower so i fit small compressors to make up the pressure difference ......

These are only cost effective ( sort of ) for gas fuelled boilers, the flow rate would be too much for an electric boiler.

http://www.mirashowers.com/onlinecat...y_overview.jsp

If you're just after a fast flowing hot shower then a Mira combined electric shower with a flow compressor built in works really well.

edit: http://www.mirashowers.com/onlinecat...ectric+Showers

[BLOODSWEATSTEEL]

Good stuff here, keep it coming. I'm considering the electric model. With my solar conversion this summer, I will be that much more self-sufficient.

[cooltsi]

I retro'd the upper portion of my house with one of the larger Bosch units which is actually build by the japanese. N****something. The smaller bosch units are built by bosch. Hot water as long as you can stand it on multiple sources. Up to three sources at 1.5GPM at 125 degrees as I recall. Downside is that it takes a bit longer to get hot water to the other end of the house. Gas bill has gone down since the install. Runs me $10-20 less per month. Gas bill peaks at no more than $140 in our house. No level pay as the electric seems to be a reciprocal.

Installation is a bugger though. I had to have a 6" flue per code. My brother does HVAC so his labor was near free. We were replacing a electric 50 gallon unit. Piping etc....ran $150 his cost.

[1wsguy]

I had a Boiler Mate installed bout 6 years ago. Its awsome. You need to have hot water heat (base board, radiators) already in the house for this system. There is a small "tank" with the system but it is not a storage tank like typical hot water heaters. When you turn on the hot water faucet it fires up the boiler and an additional zone valve allows the heated water to go to the faucet. Non stop hot water,-as long as the faucet is on, hot wter comes out at constant temp. I love it. It was well worth it, when installed, but perhaps a little less worth it now. I wont change a thing though. Downside is you never run out of hot water so you tend to take longer showers. Still wont change a thing.

[wolfy]

good thread/discussion- these are great units especially, as noted, for new construction due to the larger than normal flue sizes. if anyone wants to get serious i have a new Paloma PH-12A-DP (propane, could be re-jetted for nat gas) sitting in my garage wrapped in plastic. it's probably 15-18 yrs old but was a backup unit for a project and was never installed, never fired. still have the manual, instructions and warranty car. needs a 5"fluepipe, should handle a 2 bath house. i'm trying to raise funds to hand over to Splat, but would consider trades for something decent/recent (90-100mm, 180-188cm, yea, i'm old) or good 16" tires for toyota. unit is in truckee, shipping would be a pain. pm if interested.

[riderspro]

The main reason you get just a trickle of hot water is down to the mains water pressure entering the house.

Not sure if you were replying to my comment or not. If no, never mind, if yes, then actually no, my water pressure is fine. The trickle thing relates to the fact that I cannot have a trickle of hot water rolling. Like if I was rinsing dishes, shaving etc. This is because the on demand heater model I have requires that you have a minimum of water going through the unit, or the burners will turn off. Then the water will go cold. Then you have to crank the water back on to get it going again. I would call it medium, you have to have the water flow on medium, if you turn it to low at the faucet, the heater turns off.

But again, that is really to only thing I dislike about the unit.

[Arty50]

As has been mentioned before, you can mount these on an outside wall of your house if ducting is a problem.

[bossass]

I had one in an attic apartment. Don't know the model, was at least 8 years old. It worked, but I think you need good water pressure to make it work correctly. It was a trick on the kitchen sink and shower to get hot water all the time. They were the kind with one knob to control it. So, if I had it open and it wasn't over to "hot" far enough, the faucet wouldn't be demanding enough hot water from the unit for it to stay on. Basically, I couldn't get lukewarm water at these faucets. Now, in the bathtub, which had two knobs, you could turn the hot on full blast and regulate temps with how much you had the cold open.

I think the big limiting factor in my situation was living in the attic of a 1890s house. I was essentually on the 4th floor. Water pressure wasn't great up there and when a neighbor downstairs would run their shower, I sometimes couldn't get hot in mine, due to a lack of pressure to activate the unit.

Aside from this ideosyncrasy, it worked gud.

[altagirl]

Anyone else have any more beta on these?

We run out of hot water FAST in our new house and have been thinking this might be the way to go instead of just getting a new water heater. Our current location for the water heater is on a shared wall to the garage, or we could run ducting through what's going to be the new bathroom in the basement, but is currently just framed.

Any other comments on brands or features to look for or avoid?

[Spats]

If you're using the electric on-demand heaters, nothing says you can't have more than one. For instance, one for the kitchen/laundry, and one for the bathroom(s). This avoids the delays, and the lukewarm water when you're doing laundry or running the dishwasher. And you can use smaller heaters, which are cheaper.

This isn't as much an issue with the gas versions, which can make as much hot water as you need.

Both will be much more efficient than a tank heater. Think about it: how many hours per day are you actually running hot water? On average, probably less than one. No need to keep it hot the other 23 hours.

[RootSkier]

Do you people seriously use hot water in the washer? Why?

[altagirl]

Do you people seriously use hot water in the washer? Why?

I don't, but a lot of people do. Not installing hot water for the laundry would probably be an issue when you're selling the house. And for us, the water heater is going to be in the laundry room, so that really isn't an issue one way or the other. Plus the distance from the laundry room to the bathrooms/kitchen is pretty much just directly upstairs - distance shouldn't be an issue either.