Author Topic: Would you recommend tankless water heaters  (Read 1388 times)

shanaling

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Would you recommend tankless water heaters
« on: June 10, 2018, 11:36:42 PM »
We currently have a 10-year old 40 gallon electric water heater that requires repairing or replacing.

Thanks!

Kyle Schuant

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Re: Would you recommend tankless water heaters
« Reply #1 on: June 10, 2018, 11:40:20 PM »
The instant hot water ones? Yes. They're simpler so there's less to go wrong, and because 90% of the water they heat is used straight away, energy isn't wasted heating water to just sit there.
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Fishindude

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Re: Would you recommend tankless water heaters
« Reply #2 on: June 11, 2018, 07:26:40 AM »
No.
They cost more money, require a big electric service and based on he few I've been around they don't last long.
A modern tank type water heater is pretty efficient and cheap to purchase.   If you are going to be gone for an extended period, just shut the heating element off so you're not wasting electric.

MaikoTsumi

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Re: Would you recommend tankless water heaters
« Reply #3 on: June 11, 2018, 07:29:33 AM »
Unless things have changed recently, it only makes sense with the gas tankless heaters.  Electric just doesn't have the capacity of a gas unit.

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Re: Would you recommend tankless water heaters
« Reply #4 on: June 11, 2018, 07:34:44 AM »
I once stayed in an Airbnb that had a tankless water heater and it was LOUD, so you may want to research that aspect before proceeding.

Rufus.T.Firefly

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Re: Would you recommend tankless water heaters
« Reply #5 on: June 11, 2018, 08:05:09 AM »
I have a gas tankless water heater. For a household of 2, we used 3 therms in the month of May. It's warm here, so we have less use for hot water, but that gives you an idea of the efficiency.

My bill was $13 because they charge a base of $10/month regardless of usage.
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nereo

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Re: Would you recommend tankless water heaters
« Reply #6 on: June 11, 2018, 08:09:49 AM »
"It depends"
Tankless will run 2-3x what you were quoted for your standard tank heater, but they use less electricity provided usage remains the same.  How much you will save and what your 'return on investment' will be depends on how you use hot water in your household and what your energy rates are (electric or gas). If you are a lower-use household where no one is home during the day it makes sense - if you are a larger household that uses a lot of hot water throughout the day you won't see as big a savings on your energy bill.  Ironically, households that use LESS hot water (and long periods with no hot water usage - eg from 9-5pm each day) see a larger energy efficiency gain by going tankless.  For households that use a lot of hot water there's very little energy savings involved.

One thing to consider if you decide to go tankless is the output of the tankless water heater. While hot water never 'runs out' each unit has a limit on how much it can heat at once.  If you expect multiple showers and a washing machine to be operating simultaneously you'll either need a larger unit or you will need to install multiple tankless heaters.

Minor bonus of going tankless - you free up most of that space currently occupied by the water tank.  you'll still have the tankless unit mounted on the wall but you'll gain another broom-closet sized space.
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Bracken_Joy

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Re: Would you recommend tankless water heaters
« Reply #7 on: June 11, 2018, 08:16:19 AM »
I was told, when we were looking into it, that temperature of your ground water matter substantially. This tallies with my experience of them- even with gas ones, the 3 families I know with tankless their water never really gets hot. When we were considering an install, the guy told us he often recommends a 2 section tankless with a 'booster.' The design does better with a small footprint house (either 1 or two levels) rather than a more spread out single level (what we have) because the water doesn't get hot enough to travel the pipes without losing a ton of temperature.

Long story short: definitely ask around for your specific areas. I was told sub-55F groundwater is the point where tankless have a hard time keeping up.
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solon

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Re: Would you recommend tankless water heaters
« Reply #8 on: June 11, 2018, 08:18:39 AM »
There are two main features of these water heaters: 'tankless', and 'endless'.

If you have low hot water usage, you'll benefit more from the the 'tankless' feature. You don't have to keep lots of water continuously hot.
If you have high hot water usage, you'll benefit more from the 'endless' feature. 6 kids showering every morning, plus 3 loads of laundry, and 2 cycles of the dishwasher, and you still won't run out of hot water.

We had one in a previous house. It used gas, we had it for five years before we sold the house, we never had any problems with it. We bought it because of the 'endless' feature, and it didn't disappoint. It wasn't loud. You could hear it running if you were right next to it, but even standing right next to it, I wouldn't call it loud.

NathanP

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Re: Would you recommend tankless water heaters
« Reply #9 on: June 11, 2018, 08:22:31 AM »
I have a gas tankless water heater. For a household of 2, we used 3 therms in the month of May. It's warm here, so we have less use for hot water, but that gives you an idea of the efficiency.

My bill was $13 because they charge a base of $10/month regardless of usage.

I have the same setup and it annoys me to pay $120 a year just for the ability to use gas. Originally my home had a gas furnace, but this was replaced with electric heat pumps, so we use gas only for the hot water. If my electric panel was near to the water heater I would replace it with an electric tankless.

SunshineAZ

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Re: Would you recommend tankless water heaters
« Reply #10 on: June 11, 2018, 08:35:00 AM »
I think it depends on the climate where you are.  When I was researching them for our house in Honduras it was perfect because the water it will be heating will probably never be below 65 degrees.  The cost and electricity required is based on how much you want the water heated.  I was able to get the lower powered ones because I only needed a +40 degree temp change, which I believe required a 15 amp circuit breaker.  We actually bought 2 and had one installed on each floor.  (It has been 10 years since I did the research.)  And they lasted for a lot longer than I thought, we only had to have them replaced a few years ago.  I think if you are in a cold winter area, you would need a much higher heating capacity, which might make it a bit more complicated and expensive. 

kanga1622

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Re: Would you recommend tankless water heaters
« Reply #11 on: June 12, 2018, 01:30:22 PM »
Our plumber did not recommend them for our area. We have some pretty significant minerals in our water that cause them to break down sooner than the life expectancy listed on the box. With the increased upfront cost, they said it wasn't recommended for our area. We end up replacing the big "standard" water heaters early due to our water makeup so it would make sense.

Have you checked in with a plumber in your area about how often they have to repair them or what they would recommend?

My FIL loves his and uses it to run his infloor heating elements as well. His water is a lot softer than my town.

Rufus.T.Firefly

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Re: Would you recommend tankless water heaters
« Reply #12 on: June 13, 2018, 09:38:21 AM »
I have a gas tankless water heater. For a household of 2, we used 3 therms in the month of May. It's warm here, so we have less use for hot water, but that gives you an idea of the efficiency.

My bill was $13 because they charge a base of $10/month regardless of usage.

I have the same setup and it annoys me to pay $120 a year just for the ability to use gas. Originally my home had a gas furnace, but this was replaced with electric heat pumps, so we use gas only for the hot water. If my electric panel was near to the water heater I would replace it with an electric tankless.

I'm a fan of the efficiency of natural gas, but you're correct, the fixed cost makes it less economical than electric until you have more things hooked up to it. I have my gas connected to the furnace and hot water. Within the next few years, I want to connect the stove and fireplace. Then the savings should be significantly better.
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tweezers

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Re: Would you recommend tankless water heaters
« Reply #13 on: June 13, 2018, 10:13:14 AM »
We have had a tankless water heater for the past 15 years (in two houses; both natural gas, and installed during significant remodels).  I don't recall the model details (one was a Rinnai), but we don't have an issue with noise at all and can run two showers and the dishwasher without heating issues (still no heat reduction beyond that, but the decline in water pressure is annoying).  We've been very happy with them, appreciate the space savings of not having a water heater (especially in the 800 sq ft house), and the fact that we never run out of hot water during high use periods.

ETA: we're a family of four, but frequently have guests that bring the household to 8-10.

Dicey

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Re: Would you recommend tankless water heaters
« Reply #14 on: June 13, 2018, 10:18:24 AM »
There is also the fact that you have to cut a hole in the roof. DH refuses to compromise the integrity of our roof, so it's off the table for us for the time being.
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solon

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Re: Would you recommend tankless water heaters
« Reply #15 on: June 13, 2018, 10:20:23 AM »
There is also the fact that you have to cut a hole in the roof. DH refuses to compromise the integrity of our roof, so it's off the table for us for the time being.

Our vent went out the side of the house. The installer said that was better, in fact, because the length of the vent was much shorter.

CNM

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Re: Would you recommend tankless water heaters
« Reply #16 on: June 13, 2018, 10:25:56 AM »
No.  I have been told that they do not work very well at altitude.  (I live at 7000+ feet).

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Re: Would you recommend tankless water heaters
« Reply #17 on: June 13, 2018, 01:46:38 PM »
I have a tankless and a tank-ful in my little house. The tankless is great. It is installed outside on the wall outside the main bathroom, so showers are hot almost instantly. The tank-ful heater is much slower, and there is something funky going on whereby it gives hot water and then suddenly goes cold for a while. If I ever get around to remodeling the second bath/laundry corner of the house I will replace that sucker with a tankless.

I am in a mild environment and use natural gas to hear water.
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Re: Would you recommend tankless water heaters
« Reply #18 on: June 13, 2018, 02:44:14 PM »
I have a tankless and a tank-ful in my little house. The tankless is great. It is installed outside on the wall outside the main bathroom, so showers are hot almost instantly. The tank-ful heater is much slower, and there is something funky going on whereby it gives hot water and then suddenly goes cold for a while. If I ever get around to remodeling the second bath/laundry corner of the house I will replace that sucker with a tankless.


Here's what is most likely happening your hot water tank:  You have to immersion heaters and one has burned out OR (possible) the pipe bringing water into the tank has corroded away internally.
under normal circumstances your the top element heats the water in the top of oyur tank followed by the bottom element heating the bottom.  Hot water is less dense, so it stays on top.  As you draw hot water out of the tank it is replaced with cold water which enters the tank from the top but travels through an internal pipe to a defuser at the bottom of the tank.  That way the new cold, dense water does not mix with the nice hot water in the tank, and instead just pushes it up (where the pressure pushes it out through your hot-water pipes and into your shower).

Now either your bottom heating element is busted and instead of ~40 gallons of hot water you have just 10-15 gallons at the very top, OR when the new cold water comes in instead of entering at the bottom of the tank it's mixing with the hot water at the very top, so you get shots of cold water followed by warm, follwed by cold...


Replacing the heating element is cheap (~$15) and an easy DIY fix. replacing the internal inflow pipe is similarily cheap but can be harder if your heater is pigeon-holed into a tight space (many are). 
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peeps_be_peeping

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Re: Would you recommend tankless water heaters
« Reply #19 on: June 13, 2018, 03:10:53 PM »
Yes. I replaced my gas furnace + hot water tank with a gas tankless heater several years ago and I've been happy with it. With the old gas furnace there was always a (small) risk of CO leaking into the living space of the house, especially with the furnace in the middle of the house instead of in the garage. The tankless heater has a sealed combustion system so there is much smaller risk of CO leakage (only if the vents are installed improperly). With the old system I was advised not to tighten up my house further in order to maintain air exchange for safety. With the new system I could seal windows/doors/crawlspace and add insulation to make my house more heat efficient. That was a selling point for me. I live in a cold climate where groundwater is just above freezing and we have two seasons per year - winter and road construction. On the plus side, natural gas here is cheap.

px4shooter

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Re: Would you recommend tankless water heaters
« Reply #20 on: June 13, 2018, 08:21:49 PM »
Look at distance to most common use of the hot water too. That may play into it. We installed one right next to the bathrooms and put another near the laundry and spare bathroom.

And don't forget to install a recirculator to reduce water waste and help improve the efficiency argument of installing them.

Since you are looking at electric, make sure your wiring can handle the increased load.

BDWW

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Re: Would you recommend tankless water heaters
« Reply #21 on: June 14, 2018, 03:44:46 AM »
Definitely yes for gas. No experience with electric, but with the price of electricity around here, I probably wouldn't do it.

It sounds to me like a fair bit of the issues people above are claiming are hearsay, screwed up installs or maybe based on information from 3 decades ago.

Altitude, not a problem, every modern heater has settings to control for that generally up to 7500ft+. Most manufacturers offer high-altitude models. I'm at about 5200ft.

Noise? A mild humming should be the only sound coming from it, maybe slightly louder than a desk fan. If it's load or shakes, it's not installed correctly (insufficient air supply, gas pressure/volume, etc.).

Doesn't get hot? My groundwater is ~ 50F and my current unit/house has no issues running full-bore(5.5gpm) at 140F (I suspect it would taper a bit trying to run full-bore at the max temp of 180). Easily supplies enough water for 2+ showers at once. I even installed a hot water spigot on the exterior wall to refill the hot tub(cheaper than using the inboard electric heater to bring up the temp) and to take the edge of the kiddie pool in the summer.

Significant savings over the old waters heaters I replaced, but those were due anyway.

I've installed 3 in different houses so far, and the oldest is going on 18 years. 2 are solely hot water heaters, and 1 is currently acting as boiler (much like MMM's setup). I plan on removing my furnace in the current house and using the water heater for heat and hot water. Probably open loop to start, but debating whether I want to get another unit dedicated to heat, or use an indirect tank.

The ability of everyone in the household to shower/wash dishes/clothes without ever worrying about running out of water is great. I highly doubt I'll ever consider a direct tank heater again.

ysette9

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Re: Would you recommend tankless water heaters
« Reply #22 on: June 14, 2018, 07:01:45 AM »
I have a tankless and a tank-ful in my little house. The tankless is great. It is installed outside on the wall outside the main bathroom, so showers are hot almost instantly. The tank-ful heater is much slower, and there is something funky going on whereby it gives hot water and then suddenly goes cold for a while. If I ever get around to remodeling the second bath/laundry corner of the house I will replace that sucker with a tankless.


Here's what is most likely happening your hot water tank:  You have to immersion heaters and one has burned out OR (possible) the pipe bringing water into the tank has corroded away internally.
under normal circumstances your the top element heats the water in the top of oyur tank followed by the bottom element heating the bottom.  Hot water is less dense, so it stays on top.  As you draw hot water out of the tank it is replaced with cold water which enters the tank from the top but travels through an internal pipe to a defuser at the bottom of the tank.  That way the new cold, dense water does not mix with the nice hot water in the tank, and instead just pushes it up (where the pressure pushes it out through your hot-water pipes and into your shower).

Now either your bottom heating element is busted and instead of ~40 gallons of hot water you have just 10-15 gallons at the very top, OR when the new cold water comes in instead of entering at the bottom of the tank it's mixing with the hot water at the very top, so you get shots of cold water followed by warm, follwed by cold...


Replacing the heating element is cheap (~$15) and an easy DIY fix. replacing the internal inflow pipe is similarily cheap but can be harder if your heater is pigeon-holed into a tight space (many are).
Fantastic advice. I appreciate it.
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Dicey

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Re: Would you recommend tankless water heaters
« Reply #23 on: June 14, 2018, 07:22:16 AM »
There is also the fact that you have to cut a hole in the roof. DH refuses to compromise the integrity of our roof, so it's off the table for us for the time being.

Our vent went out the side of the house. The installer said that was better, in fact, because the length of the vent was much shorter.
Hmmm, maybe what he meant was that based on the way our house is built, the only option would be to vent through the roof. I'll keep this in mind for a future property. Thanks, solon!

I'm curious about something else: A traditional water heater is typically installed internally. Are there problems with tankless models being stolen since they're high dollar value and externally mounted?
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toganet

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Re: Would you recommend tankless water heaters
« Reply #24 on: June 14, 2018, 08:21:11 AM »
The mention of low temperature incoming water reminds me of several years ago when I was home shopping, and I looked at a house that was for sale by owner.  The owner was an older gentleman, who had been an engineer of some sort before he retired.  He had made many idiosyncratic modifications to the house, but the one that sticks in my mind was his "dual hot water tank" system.  One tank was connected to the water supply, but was not powered.  The second was connected to that one, and was used to heat water.  I asked him about it, and he explained it was to raise the temperature of the incoming water to "room temperature," decreasing the energy needed to heat the water in the active tank.

Perhaps a similar design would be useful for folks who want to go tankless, but are worried about their cold water temp?

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Re: Would you recommend tankless water heaters
« Reply #25 on: June 14, 2018, 08:27:56 AM »
There is also the fact that you have to cut a hole in the roof. DH refuses to compromise the integrity of our roof, so it's off the table for us for the time being.

Our vent went out the side of the house. The installer said that was better, in fact, because the length of the vent was much shorter.
Hmmm, maybe what he meant was that based on the way our house is built, the only option would be to vent through the roof. I'll keep this in mind for a future property. Thanks, solon!

I'm curious about something else: A traditional water heater is typically installed internally. Are there problems with tankless models being stolen since they're high dollar value and externally mounted?

Interesting. All of them I've seen have been in people's garages. I'm curious what other people's experiences are with this?

Definitely yes for gas. No experience with electric, but with the price of electricity around here, I probably wouldn't do it.

It sounds to me like a fair bit of the issues people above are claiming are hearsay, screwed up installs or maybe based on information from 3 decades ago.

Altitude, not a problem, every modern heater has settings to control for that generally up to 7500ft+. Most manufacturers offer high-altitude models. I'm at about 5200ft.

Noise? A mild humming should be the only sound coming from it, maybe slightly louder than a desk fan. If it's load or shakes, it's not installed correctly (insufficient air supply, gas pressure/volume, etc.).

Doesn't get hot? My groundwater is ~ 50F and my current unit/house has no issues running full-bore(5.5gpm) at 140F (I suspect it would taper a bit trying to run full-bore at the max temp of 180). Easily supplies enough water for 2+ showers at once. I even installed a hot water spigot on the exterior wall to refill the hot tub(cheaper than using the inboard electric heater to bring up the temp) and to take the edge of the kiddie pool in the summer.

Significant savings over the old waters heaters I replaced, but those were due anyway.

I've installed 3 in different houses so far, and the oldest is going on 18 years. 2 are solely hot water heaters, and 1 is currently acting as boiler (much like MMM's setup). I plan on removing my furnace in the current house and using the water heater for heat and hot water. Probably open loop to start, but debating whether I want to get another unit dedicated to heat, or use an indirect tank.

The ability of everyone in the household to shower/wash dishes/clothes without ever worrying about running out of water is great. I highly doubt I'll ever consider a direct tank heater again.

Does it get warm quickly for you though? That's the major concern I've heard and experienced- with cold ground water, the tankless takes *forever* to heat the water. And that really sucks especially for things like my inlaw's dishwasher- it can really only wash with cold water, unless you run the sink next to it for a while first, and even then the periodic water cycles throughout are then cold after.
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Re: Would you recommend tankless water heaters
« Reply #26 on: June 14, 2018, 09:03:13 AM »
I've never seen a tankless water heater installed on the outside of the house. Every one I've ever seen was inside the house. But if it was outside, you wouldn't have any problem with a vent through the roof.

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Re: Would you recommend tankless water heaters
« Reply #27 on: June 14, 2018, 09:15:32 AM »

Does it get warm quickly for you though? That's the major concern I've heard and experienced- with cold ground water, the tankless takes *forever* to heat the water. And that really sucks especially for things like my inlaw's dishwasher- it can really only wash with cold water, unless you run the sink next to it for a while first, and even then the periodic water cycles throughout are then cold after.
A properly sized, powered and functioning tankless should take practically no time at all to heat water. If I had to guess, I'd say it installed a fair distance from the point of usage (e.g. the dishwasher). Either that or it isn't powerful enough.  FWIW you'll have the same problems with a traditional water tank if it has a long run to your point of usages.

In my last home our tankless was installed indoors, in the same location as where our water tank used to be.  It was about a 5' run to the kitchen sink/dishwasher and about a 10' run to the bathroom.
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Re: Would you recommend tankless water heaters
« Reply #28 on: June 14, 2018, 09:26:39 AM »

Does it get warm quickly for you though? That's the major concern I've heard and experienced- with cold ground water, the tankless takes *forever* to heat the water. And that really sucks especially for things like my inlaw's dishwasher- it can really only wash with cold water, unless you run the sink next to it for a while first, and even then the periodic water cycles throughout are then cold after.
A properly sized, powered and functioning tankless should take practically no time at all to heat water. If I had to guess, I'd say it installed a fair distance from the point of usage (e.g. the dishwasher). Either that or it isn't powerful enough.  FWIW you'll have the same problems with a traditional water tank if it has a long run to your point of usages.

In my last home our tankless was installed indoors, in the same location as where our water tank used to be.  It was about a 5' run to the kitchen sink/dishwasher and about a 10' run to the bathroom.

Their kitchen is really close to the garage wall the heater is on. So a run of 10' tops. There is also a shower directly above the heater that never gets above lukewarm, and even then, it takes 5+ min to get to that temp.

So do you think it's just undersized? It is a slightly older one, but like 8 years or so, not ancient.
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ysette9

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Re: Would you recommend tankless water heaters
« Reply #29 on: June 14, 2018, 09:55:34 AM »
I've never seen a tankless water heater installed on the outside of the house. Every one I've ever seen was inside the house. But if it was outside, you wouldn't have any problem with a vent through the roof.
Mine is installed outside my bathroom and it never occurred to me that someone may want to steal it. It is behind the chimney, so you can’t see it from the street. Perhaps that is preventing it from growing legs and walking off? For that matter though, why don’t people lose their AC units to theft? These things just never occur to me.
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Re: Would you recommend tankless water heaters
« Reply #30 on: June 14, 2018, 10:59:56 AM »
And don't forget to install a recirculator to reduce water waste and help improve the efficiency argument of installing them.
I don't see how a recirculator would improve energy efficiency of any hot water system - in either case you'd have pipes full of hot water when you're done with use wasting some of the heat. If the recirculator is always on (instead of being turned on only when you need hot water) you'd be maintaining a loop of pipe with hot water radiating heat constantly - a big argument for the efficiency of a tankless water heater is that you don't maintain hot water when it isn't needed. If hot water usage points are far apart, separate tankless units might be a better idea.

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Re: Would you recommend tankless water heaters
« Reply #31 on: June 14, 2018, 11:14:57 AM »

Does it get warm quickly for you though? That's the major concern I've heard and experienced- with cold ground water, the tankless takes *forever* to heat the water. And that really sucks especially for things like my inlaw's dishwasher- it can really only wash with cold water, unless you run the sink next to it for a while first, and even then the periodic water cycles throughout are then cold after.
A properly sized, powered and functioning tankless should take practically no time at all to heat water. If I had to guess, I'd say it installed a fair distance from the point of usage (e.g. the dishwasher). Either that or it isn't powerful enough.  FWIW you'll have the same problems with a traditional water tank if it has a long run to your point of usages.

In my last home our tankless was installed indoors, in the same location as where our water tank used to be.  It was about a 5' run to the kitchen sink/dishwasher and about a 10' run to the bathroom.

Their kitchen is really close to the garage wall the heater is on. So a run of 10' tops. There is also a shower directly above the heater that never gets above lukewarm, and even then, it takes 5+ min to get to that temp.

So do you think it's just undersized? It is a slightly older one, but like 8 years or so, not ancient.

If it takes anywhere near that long, somethings seriously wrong. The heat should only take as long to reach you as it takes to push the old (room temp) water out of the lines.

Our current house is a ranch with a two story addition on one end. The top of the addition is a master with bath, the furthest run in the house. From the water heater - in the basement of the original portion - to there is probably about a 30ft run, and it takes maybe 15 seconds to get hot water there. Part of that delay is also due to the 3/4in manifold system I put in that adds little length/cold mixing to the run.

robartsd

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Re: Would you recommend tankless water heaters
« Reply #32 on: June 15, 2018, 09:47:05 AM »
If it takes anywhere near that long, somethings seriously wrong. The heat should only take as long to reach you as it takes to push the old (room temp) water out of the lines.

Our current house is a ranch with a two story addition on one end. The top of the addition is a master with bath, the furthest run in the house. From the water heater - in the basement of the original portion - to there is probably about a 30ft run, and it takes maybe 15 seconds to get hot water there. Part of that delay is also due to the 3/4in manifold system I put in that adds little length/cold mixing to the run.
A bath filler tap (4+ GPM) can clear the lines much faster than a efficient shower head (<2 GPM) or wash basin tap with aerator (0.5-1.5 GPM). It is unusual to have much more than a gallon (~37' of 3/4 copper or ~50' of 3/4 PEX) to clear. Of course the first hot water out of the heater will also transfer quite a bit of heat to the pipe, thus requiring more water to flow before hot water comes out of the tap (for copper pipe, I'd estimate about 25-50% more water before noticing the water starting to warm and 2-3x the volume of the pipe before getting close to a steady temperature). Still this wouldn't account for 5 minutes to lukewarm water in any typical residential system.

FiftyIsTheNewTwenty

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Re: Would you recommend tankless water heaters
« Reply #33 on: June 18, 2018, 07:28:53 PM »
I've never seen a tankless water heater installed on the outside of the house. Every one I've ever seen was inside the house. But if it was outside, you wouldn't have any problem with a vent through the roof.

I installed one just outside the kitchen and adjacent bathroom.  (Small house.)  I could have put it in the back of a kitchen cabinet, where the previous small tank unit was, but then I would have had to deal with venting.  Outside was so much simpler.

I'm not sure how efficiency was affected.  It seems to me the input water temperature is what really matters, the air surrounding the unit not so much.

For someone seeking efficiency, the heat pump ones are probably best.

robartsd

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Re: Would you recommend tankless water heaters
« Reply #34 on: June 19, 2018, 10:20:43 AM »
For someone seeking efficiency, the heat pump ones are probably best.
Are their heat pump tankless units or are you just saying that heat pump tank units are more efficient than tankless units?

Heat pump water heaters are often loud (similar to window AC unit).