tankless hot water heater

13 years ago

anyone have any opinions or reviews on their tankless hot water heater? we have a small utility room and need to be space conscious. There are a lot out there so looking for some advice on how to choose. thanks

Featured Answer

S. Thomas Kutch

13 years ago

last modified: 13 years ago

There are pro's and con's to both systems........the cold hard facts are that both systems require maintenance (something which most home owners simply ignore).......if you check your warranty fine print on your standard hot water heater (tank type) you'll find that regular draining and flushing of the system is recommended to achieve the advertised years of service.........(how many of you actually drain and flush your systems.......?). Depending on the water quality, I've seen standard units that required a filter system in front of the supply point..

Yes, the utility consultants were correct, tankless system (hot water on demand) do consume more energy at the demand event.........what they didn't tell you was that in between demand events, they don't use any energy keeping water hot in the tank, unlike the standard hot water heater does during the day when you're not home.........so I'm betting that the energy usage is just about even in the long run.

As far as hot water pipe insulation..........every install should have pipes insulated regardless of the system.......that's just common sense. I have had the argument with more plumbing subs than I can remember........I don't care if it is in protected spaces or under slabs....insulate them.....and guess what, I won every argument........being the GC has it's advantages.

If space is a premium go with the best tankless system you can buy and size it slightly larger than you think you'll need. In my own house remodel, I'll be going with 2 tankless units, both gas fired. One for the main bath, outside shower and laundry area and a smaller unit for the kitchen at the other end of the house. One will be in the attic and the other will mounted on the exterior end of the house.......and I'm not looking forward to wrestling that beast of a tank heater down out of the attic, believe me.

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Comments (14)

onthefence
13 years ago
I'm a fan. After doing a lot of research we ended up with a Rinnai. Obviously you want something with a good warranty and good reviews. At the time we bought (about 5 years ago) Rinnai was the leader.

IMO the biggest issue is to find someone who KNOWS how to install them and has done it before successfully. We also chose one that provided above our needs. It's just DH and I. We do have guests though and considered house resale. We wanted to have a unit that was suitable for 3-4 people.
PRO
Interiors International, Inc.
13 years ago
I love them! If you have gas they are not a problem. If they are electric make sure you have enough amps to handle the size you need to service your house or put in more than one. This is a good idea if your plumbing needs are spread far away from the source.
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PRO
Cancork Floor Inc.
13 years ago
The "heat on demand" is standard practice in Europe. Water and energy are so precious that every drop/amp counts. If you are going to do this (and I think anyone with the budget should look at it) you might want to work with big names that are out of Germany! If you can find a dealer who carries it, you can probably find someone who installs it. Germany is famous, not only for their products, but for their technical support once a dealer decides to work with their product. German companies do "on-site" in-services/month long training for any dealer who picks up their models. They train and certify their own support services...etc.

Go with world renowned names (German, Swiss, Austrian) and you shouldn't have a problem...literally...your furnace might just out last you and the house!
evierh
13 years ago
I had a Navien installed just over a year ago. I went to their website & did the calculations to size the unit (I live alone), but should have gotten something larger! If I'm filling the bathtub, you won't get hot water anywhere else in the house .. only a trickle! No way would this size work for a house with more people in it!
PRO
Ironwood Builders
13 years ago
We constantly upgrade out jobs to on-demand water heaters, though I have installed most different manufacturers, my personal choice is the Eternal. It is a hybrid unit, i.e. it has a small tank as part of its guts, making the use of a pumped hot water loop easy and cheap...so the hot water is really on demand. The hot water loop takes the stored water to the farthest fixture so that the hot water is on instantly, saving not just energy, but the next crucially important natural resource, water. The units are manufactured in Texas...so we are keeping folks here in the US employed (sorry Cancork, gotta play for the home team). We have stringent energy analysis done here in California as part of our permit process and I rack up major points with this one. BTW, the hot water loop, in fact all the hot water lines need to be insulated. if the walls are open, we insulate right up to the valves. Every bit of energy saving helps. I'll be installing this same unit at my home next month...I expect to recoup half the cost of the unit in energy savings and tax credits the first year. One additional benefit is that the Eternal takes a PVC flue...not the stainless..ahem $1500 flue that the Rinnai does. Hope this helps!
Alice
13 years ago
I just had the local utility come in to give us an estimate on both a larger hot water tank and, alternatively, a tankless system. They recommended against the tankless. They said it was only a benefit if space was at a premium ie no room for a hot water tank. They said that tankless systems are not as energy efficient as advertised, as they draw a stupendous amount of btu to get the water hot instantly (ie 180,000 to 200,000 btu, vs, for example, the furnace which draws about 80,000 btu). They said this draws a lot of power (gas) and also means that the system inherently needs more servicing and has a shorter life span than a tank. They also said that our water source (a Canadian Great Lake) is so cold and mineralized that it takes that much more energy to heat and that the process charges the iodine in the water and causes the molecules to adhere to the copper pipes, resulting in build up. They said they have as many service calls to remove tankless, as they do to install! Anyways, I was left quite stunned, I really thought tankless was without serious negative implications beyond start-up investment cost. I can find no nay-sayers on Houzz. Any thoughts?
evierh
13 years ago
I think tankless hot water heaters must also be more "finicky", because they're installed with a water filter, that has to be replaced about quarterly .. and I never needed one on my conventional unit! I did think the tankless ones were supposed to last longer, which was a selling point .. but I guess that remains to be seen!
mmilos
13 years ago
If you have natural gas and space, I think I'd stick with the old tank type. Natural gas is cheap these days...especially with more fracking in the US going on, there is a huge supply glut. The savings are not usually enough to warrant the higher capital costs for a tankless.
kathy
13 years ago
Beware - tankless is not instant unless installed right next to outlets/faucets!

We had a tankless system installed approximately 2 years agao - purchased from local gas utility company. It is in basement, so it took a LONG time for hot water to travel to my master bath - that was true before tankless, but noticeably worse after. But recently we changed and insulated the plumbing runs in the basement so that there is a shorter travel to 2nd floor. Much better! But it still takes a good minute to get water up there. So I brush teeth with hot water running, shut it off once running hot, and then its ready to wash face after teeth.

Other than that, we love it! No problems with multiple showers at same time. Installer told us 3 things running at same time would be fine, but not 4.

Hope that helps
PRO
nFORMAL design
13 years ago
Kathy is sort of right. I've researched and spec'ed many tankless water heaters, and there are TWO things you want to do. First, unlike HVAC units, you definitely want to "oversize" by a good margin. Next, Tankless aren't instant because people are hooking them up to a plumbing "tree" (system design in most houses), and they are meant to be hooked up to a manifold system. In a tree system, the furthest outlet from the tank takes the longest to heat because it has to go through ALL the pipes. In a manifold system, each fixture is plumbed separately. The other great thing about a manifold system is that if you have a water leak, etc., you can turn off that one fixture, repair it, and still use the other fixtures.

Tankless is what I'd buy.
creeser
13 years ago
Kathy is right. We put one in a few months ago and it takes forever for the water to heat up. Endless hot water is nice, but to be honest, with our kids grown, I don't know that it was worth it.
PRO
Ironwood Builders
13 years ago
In California, all new construction has to pass a green building code and Title 24 energy use evaluation. Most jobs specify a gas tankless water heater for compliance. On a recent job we had two tankless units specified but without a hot water loop for instant hot water at each faucet in the house (an oversight that caused some problems later). Insulation had been figured as spray in foam 5 1/2" thick with a 1" blue styrofoam layer on the exterior. The insulation package was cost prohibitive so alternatives were presented. The need for a hot water loop meant that the on demand unit would fire more frequently (hence my recommendation of the Eternal above) That nullified some of the energy efficiency (and oh yes, it is more energy efficient, we have the calculations to prove it) of the on demand units. Our plumber suggested a 96% efficient super insulated tank style heater to replace the on demand units...at a cost savings, as we no longer needed the stainless steel flues. Our Title 24 rater did the math and the higher efficiency tank style as a single unit outperformed the two tankless units...but only when coupled with the hot water loop. The hot water loop was part of our green building requirements...water use is also a concern here...In the end, we were able to reduce not only our energy consumption but water consumption and save the client money on their insulation package.

In conclusion....Tankless units are more energy efficient because they don't keep a large quantity of water hot constantly. They are small and easy to fit in less space and new models are available that allow the installation of water saving hot water loops. There are tank style heaters that give them a run for the money but only in specific circumstances.
PRO
Cancork Floor Inc.
13 years ago
Thank you nFormal Design! I think that is what was missing from the conversation. In Europe, every tap runs off of the tank - with its own connection. In N. America, we are used to having 1 or 2 outlet pipes that then have more branches running from the one set!

Good to know!

tankless hot water heater

S. Thomas Kutch

Comments (14)

onthefence

Interiors International, Inc.

Related Professionals

Cancork Floor Inc.

evierh

Ironwood Builders

Alice

evierh

mmilos

kathy

nFORMAL design

creeser

Ironwood Builders

Cancork Floor Inc.

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