OT- Hot Water Tank vs. Tankless -OT

danv23

Sorry if this upsets OT haters.  I'm finishing my basement, approx 1200sqft. I will have a total of 5 showers when complete, family of 4 (me, wife, 13 & 15 year old) and have stay over guests a few times a year. Currently have an approx 7 year old 50 gallon. I have a fear that when the basement is done it will decide to leak to piss me off and ruin the floors, etc. The plumber's offer is a 75gal for $2900 or a tankless Navian 240A for $3500 (includes removal, adding 3/4 gas line- it's a beast based on reviews). I currently have a hot water circulator pump which the Navian has one built in so I will keep hot water at all spigots on demand. I don't want to spend the extra money right now but as I am a fortune teller of bad events I've convinced myself I'm doomed if I don't.

So is tankless really the way to go or am I being an idiot (wouldn't be the 1st time).

danv23

I saw that there was a discussion in January and seems tankless had the most fans. Opinions on cost/need still welcome and BTW, the Navian is approx $2000 on its own in the box for reference.  Thank you!

nolaegghead

if you didn't run out of hot water with the 50 gal, I would stick with the tank.

danv23

nolaegghead said:

if you didn't run out of hot water with the 50 gal, I would stick with the tank.

It's become an issue recently during the winter in GA. Dam near got it maxed out for a few months but then can dial it back as the ground heats up. Tells me there's probably crud on the bottom, like they all get.  Thanks Nola!

nolaegghead

NP.  You can also get a larger tank. 66 or 100 gallon. 

I have a tankless and we love it, but if you have a busy household, you don't save that much money on gas, maybe $100/year, but you basically get unlimited hot water. 

If you have a bunch of people using hot water at the same time, a tank might be a better solution. 

Tankless last much longer, so figure your installation cost over 20 years will be 2x the tank cost or 1x the tankless cost.

Hub

I recently built a house and had a very similar dilemma.  I read tons of reviews and was more confused then when I began.  I decided to roll the dice and go with the tankless option.  It was my first tankless water heater ever.  I've always had the traditional water heater.  Just over a year later, I can tell you that I am VERY happy with my decision.  Forget the short term costs.  Go with what will give you the best long term results.  Tankless is awesome, but absolutely, 1000% make sure you get the recirculation kit.  It makes a HUGE difference!!

stv8r

First off if you have gas then it's actually a discussion. If all electric than not even worth discussing. If gas the an instantaneous heater could be an option but the installation modifications required usually negate the cost savings for the first 8-10 years.  If planning to stay longer than maybe worth considering. You mention you have a recirculation pump installed which takes advantage of a tank type heaters storage capacity.  IMHO a properly sized tank type water heater is your best option. 

nolaegghead

There's nothing wrong with electric on-demand heaters other than most people don't have the electric capacity to run them.  You need 100-150A of current to run a busy house.  If you have the capacity (and you will need 4-8 slots on your distribution panel), you've won half the battle.  Running a small fortune in copper is the other part, basically it can get expensive.  But if you have the capacity and the on-demand heater is near your distribution panel it's not bad at all.  No ventilation needed, for example.  It can save you the most money, in installation and cost of operation.  *can*, depends on your circumstances.

If i was building a house I would consider point-of-use electric heaters.  No wait for hot water, no waste in the re-circulation circuit.  Doing that after the house is built is nearly impossible unless you have a basement or attic to run the wires.  Also, copper is really expensive right now.  The heating elements won't last nearly as long as the gas heat exchanger, but they're really cheap.

Corv

You could replace your present water heater with a decent 40 gallon one and add a second 40 gallon one in series with it. You'll get 80 gallons of hot water and new tanks.

I have a tankless one without any hot water storage and there's a period where it kicks on and heats the water before I get any hot water, kind of annoying. The annual cost is a wash: I pay less for gas but I use more water now.

Mattman3969

I had the Navian that you mentioned above in my last house. It replaced our 70ish gallon tank. I am in a house now with a standard tank and miss my Navian. If you have huge tubs/whirlpools these thing kick butt with endless hot water. My house had recirc lines so I always had hot water relatively quick.  I think it would circulate ever 20mins or so when sitting idle. When I build/buy it will be source of hot water.  

Mickey

Very little to contribute except here in the middle of Texas last month (very bad winter storm)  they were blowing up all over the place. 

texaswig

Is it because I do things myself that $2900 for a water heater replacement seems super expensive? I have a tank heater. But would like to have a tankless mounted outside to free up some space. Maybe one of these days. 

mEGG_My_Day

I am not an expert in these things - but we did an addition about 15 years ago that added bathrooms.  We opted for two 40 gallons running in parallel.  It was the most cost effective solution at the time.  Several times one of the hot water heaters has malfunctioned but we still have hot water from the other.  Redundancy can be a wonderful thing when needed. 

U_tarded

texaswig said:

Is it because I do things myself that $2900 for a water heater replacement seems super expensive? I have a tank heater. But would like to have a tankless mounted outside to free up some space. Maybe one of these days. 

I thought the same thing quick google puts a 75 gallon tank at just over $1200 so nearly 1900 to install.  I get it labor is expensive but something doesn’t add up. 

Hoster05

Also in the same dilemma as the OP but mine is merely looking at cost savings.  We are in an electrical co-op and pay way to much in monthly electric costs.  The main source is the 100 gallon water heater we have. 

stlcharcoal

If saving money/energy is your concern, then dump that recirculator.  Electricity or gas is a hell of a lot more expensive than water.  For a bathroom far away you can get that "chilipepper" that you can use a remote for.  Otherwise, keeping hot water in all the pipes 24/7 is expensive.  Even if you have insulated pipes, turn that thing off for a month and see how much you save.

I have a 80 gallon water heater with an unpowered 50 gallon "buffer" tank that a desuperheater from my geothermal preheats.  In the morning with 4 kids taking showers I can get at least 45 minutes out of the big tank.  If it's a really hot or cold day when the geothermal is running, then it's an hour plus since that 80 pulls from a holding tank that's already 100-120F.

The buffer tank is in series, but I put bypass valves in and ran power to it.  That way I can turn it on manually to have an extra 50 gallons hot water if I need it, or if the main 80 gallon tank fails, then I can bypass it and still have hot water. 

The tankless ones are nice for smaller houses and smaller families, but with long runs of pipe and long showers, they are not what they are cracked up to be......that's why they never took over the industry.

You could go bigger on a tank, then use your old one as a buffer/backup.  Takes up a lot of room in your utility room though.  If you're worried about them leaking like I was, put them in the plastic pans they sell at Lowes, and pipe it to the floor drain.  I think you'd be surprised what you can do with a 80 gallon high efficiency.  

alaskanassasin

My water heater is sitting in a galvanized pan that has a drain running to the floor drain shared with the furnace condenser line, should something happen. For me I like the tank unit, never had a problem with one, no flame sensor or error codes it just works.

Thatgrimguy

I have a 3500 square foot home, with 4 showers and 3 adults and 2 kids. We LOVE our Navian tankless water heater. Never run out, all of us shower at the same time.

poster

wow, some of you guys have some serious systems. I haven't even heard of a tank over 60gal. until here

EzraBrooks

texaswig said:

Is it because I do things myself that $2900 for a water heater replacement seems super expensive? I have a tank heater. But would like to have a tankless mounted outside to free up some space. Maybe one of these days. 

I agree the quote for the water heater replacement does seem super expensive.  Our water heater died a couple of years ago, and while I don't remember the numbers exactly I want to say it was $700 for tank replacement and like $3500 for tankless.  We weren't planning to stay in the house for long so went with the tank.  Just my opinion, but you might shop that tank replacement around and see if you can get a better deal before you decide.

danv23

All great information, and just like anything else there's pros and cons. In the midwest where I lived in IL there were floor drains in the basement, but here in GA my sewer line is about 5 feet up the wall. Got to rely on pumps to get the water out, just another mechanical worry. I've decided to go tankless as everything I've read says the Navian can keep up with a lot of demand. Also, we're left with just the mechanical room for storage so getting that additional space is a bonus. Love this board and all those in it. Thanks all!!!!

Mark_B_Good

Tankless 100%. I changed mine out 4 years ago. We NEVER run out of hot water, like NEVER. I've had 10 people in this house, showering whenever they want, and NEVER run out.

The only issue is it takes time to heat up the water ... probably about 30 to 40 seconds, as there is no reserve. 

That can be fixed by adding a recirc line in, which keeps the flow running through the heater, and forces it to always stay on (but running idle) ... this keeps the water in the distribution pipes hot ... and it's a fairly popular thing to do. I installed the return line, but not the pump (I can retrofit it later if I want). In the morning, I turn on my shower, brush my teeth, and by the time I'm done, it's hot ... so no skin off my back.

Scott805

Have been tankless for five years and LOVE IT!  Unit sits above the Master Shower and has unlimited instant Hot Water.  However, the old Master on the other side of the house takes about 2 minutes to get hot.

nolaegghead

There's really not much difference in the time to get hot water between a tankless and a tank.  The distance the water has to travel, material of he pipe, ambient temp of the whole system makes much more difference than if the water source is on-demand or a heated tank. 

What Jonathan said about the recirc system is very true - you will loose a ton of energy running that type of system.  If water is expensive (not for us), then the point-of-use heaters or a "button press" pump recirculation circuit will help you out.

Mattman3969

One thing I forgot to mention is that when we leave for vacation I shut the water off to the house and have to turn the water heater off. We would have to wait a good bit to take showers after getting home with a tank model because of heat up time but with the tankless we had hot water in the amount of time it took to flush the cold water from the lines. Trivial I know but I did consider it a perk.  My tanked heater had gravity recirc lines and @nolaegghead is correct about no difference in timing of tank vs tankless in that regard but I did see about $12 savings a month in gas (again trivial) and with the water being a closed loop there was no difference in water usage  

smak

Mattman3969 said:

One thing I forgot to mention is that when we leave for vacation I shut the water off to the house and have to turn the water heater off. We would have to wait a good bit to take showers after getting home   

You could use something like an Aquanta (https://aquanta.io/) to solve that problem.  I have one on a dumb tank heater at a vacation house.  Cancel "away" mode when I start my drive and I have a full tank of hot water when I arrive.

If you use it at your main house, it is supposed to learn your patterns and only heat when needed (therefore saving money).  I cannot comment on how well that works.

RyanStl

I don't think it has been mentioned. If you have hard water or a lot of minerals you may have problems with a tankless.  I did some basic research awhile ago and came across that concern.

Mark_B_Good

RyanStl said:

I don't think it has been mentioned. If you have hard water or a lot of minerals you may have problems with a tankless.  I did some basic research awhile ago and came across that concern.

This is true ... the heat exchange tube will scale fast

Hoster05

Mark_B_Good said:

RyanStl said:

I don't think it has been mentioned. If you have hard water or a lot of minerals you may have problems with a tankless.  I did some basic research awhile ago and came across that concern.

This is true ... the heat exchange tube will scale fast

that is a scare for me to trying to switch from electric to gas.  we have very hard water here. 

stlcharcoal

It's different for every house, but I think the average monthly utility bill is 40% hot water.  Heating and cooling are not much in the milder months, but hot water is always the same.

I figured this out when I ran the entire month of December with my wood stove insert and a kerosene heater burning jet fuel.  I have geothermal, so I don't pay much for heating and cooling as it is, but I wanted to see anyway.  The next month's bill was within about $10 and the KWH used was about the same for previous years with the same average temp.  I was shocked it was so close, but it was because my water heater had to work normally since I wasn't getting "free" hot water from the geothermal.

There are all kind of "cost saving" systems, but until you have someone come in and analyze your house and your usage, don't believe anything.  It's like programmable thermostats.....they would actually cost me MORE money to dial the temp back on my geothermal because then the compressor is running in stage 2-3 to get the temp up vs just running stage 1 to maintain.  Every house is different.....get an expert that DOESN'T sell the systems if you want the true answer. 

stv8r

stlcharcoal said:

If saving money/energy is your concern, then dump that recirculator.  Electricity or gas is a hell of a lot more expensive than water.  For a bathroom far away you can get that "chilipepper" that you can use a remote for.  Otherwise, keeping hot water in all the pipes 24/7 is expensive.  Even if you have insulated pipes, turn that thing off for a month and see how much you save.

I have a 80 gallon water heater with an unpowered 50 gallon "buffer" tank that a desuperheater from my geothermal preheats.  In the morning with 4 kids taking showers I can get at least 45 minutes out of the big tank.  If it's a really hot or cold day when the geothermal is running, then it's an hour plus since that 80 pulls from a holding tank that's already 100-120F.

The buffer tank is in series, but I put bypass valves in and ran power to it.  That way I can turn it on manually to have an extra 50 gallons hot water if I need it, or if the main 80 gallon tank fails, then I can bypass it and still have hot water. 

The tankless ones are nice for smaller houses and smaller families, but with long runs of pipe and long showers, they are not what they are cracked up to be......that's why they never took over the industry.

You could go bigger on a tank, then use your old one as a buffer/backup.  Takes up a lot of room in your utility room though.  If you're worried about them leaking like I was, put them in the plastic pans they sell at Lowes, and pipe it to the floor drain.  I think you'd be surprised what you can do with a 80 gallon high efficiency.  

Please elaborate on what that "chilipepper" is?  I have a recirc system because if I didn't It'd take 5 mins for the shower to warm up.  Is there a better option?