Gas tankless vs tank water heaters

[Michael Ndjondo makadi]

Hello community,

I have been debating whether switching to gas water heater makes sense over swapping the old tank WH with a new one?  Tankless WH cost has dropped significantly, they tend to last longer and are less prone to leaks but the initial switch might require upgrading the gas line with potential higher installation price tag. Those are for small units less than 960 sq ft. Any feedback will greatly be appreciated.

[Nicholas Coulter]

I love ours but in San Diego the hard water took out our first unit. I would make sure you are flushing the unit at least once a year for maintenance. If possible a water softener would be ideal.

[Chris Seveney]

Quote from @Michael Ndjondo makadi:

Hello community,

I have been debating whether switching to gas water heater makes sense over swapping the old tank WH with a new one?  Tankless WH cost has dropped significantly, they tend to last longer and are less prone to leaks but the initial switch might require upgrading the gas line with potential higher installation price tag. Those are for small units less than 960 sq ft. Any feedback will greatly be appreciated.

 we have been using tankless for 10+ years. They are great. The good ones also have a shutoff in them for leaks so you do not have to worry about it. The newer ones also allow for a recirculation line as well. Definitely prefer tankless for us

[Dan H.]

Quote from @Chris Seveney:

Quote from @Michael Ndjondo makadi:

Hello community,

I have been debating whether switching to gas water heater makes sense over swapping the old tank WH with a new one?  Tankless WH cost has dropped significantly, they tend to last longer and are less prone to leaks but the initial switch might require upgrading the gas line with potential higher installation price tag. Those are for small units less than 960 sq ft. Any feedback will greatly be appreciated.

 we have been using tankless for 10+ years. They are great. The good ones also have a shutoff in them for leaks so you do not have to worry about it. The newer ones also allow for a recirculation line as well. Definitely prefer tankless for us

 I tried the recirculation function on my Rheem tankless and the water heater burner was on constantly.   It does have a feature that you can set the time for recirculating, but our schedule is too chaotic for that being a good option. 

Have you tried the recirculation feature?   Was your burner on constantly?  

I really want the recirculation to work but I don’t want the burner on constantly.   I have planned to investigate further, but it has been over 1 year and I have not as of yet investigated further.  

@nicholas Coulter is correct that the tankless require more maintenance than tanked heaters and the effort is more.  In San Diego I recommend descaling tankless annually and this is significantly more effort than draining 5 or 10 gallons from a tanked heater and changing anode every 5 years (by the way always use impact wrench to extract old anode as breaker bar can move water heater messing with other connections).  

I personally would not choose to swap a tanked water heater to tankless at a rental due to increased maintenance.   Tankless is fine for your own house and if descaled annually will outlast most tanked even if flushed and anode changed.

good luck

[Michael Ndjondo makadi]

Thanks for your inputs @Nicholas Coulter, @Chris Seveney and @Dan H. I already a have installed a couple in the past and I spend about $225 on each for annual flushing and cleaning. This time it's in 4plex and thus 4 units in total and 4x the maintenance cost. But interior space is more important as units are not as big. Unless a costly plumbing pipe upgrade is required, I will go with tankless since $18 monthly maintenance isn't that big of deal. 

[Dan H.]

Quote from @Michael Ndjondo makadi:

Thanks for your inputs @Nicholas Coulter, @Chris Seveney and @Dan H. I already a have installed a couple in the past and I spend about $225 on each for annual flushing and cleaning. This time it's in 4plex and thus 4 units in total and 4x the maintenance cost. But interior space is more important as units are not as big. Unless a costly plumbing pipe upgrade is required, I will go with tankless since $18 monthly maintenance isn't that big of deal. 

You will likely need a bigger gas line (assuming gas).  Cost will depend on how easy this is.  

Not sure of size of unit, but have you considered smaller tanked units?   I have two 1140’ (2/1.5) units that each have 26 gal water heater.  It is not much larger than my tankless, but my tankless is fairly large compared to many.  

For me the cost of the descaling is not as impactful as another maintenance item.   In this case a maintenance item that I cannot get the tenant to perform.  

Good luck

[Colleen F.]

@Michael Ndjondo makadi  also consider who pays for water. If it is you costs could go up. 

[Bruce Woodruff]

Bear in mind that Tankless units must be drained and de-scaled each year (by a licensed Plumber), or you will void the warranty.

When I was building a lot, most people in the SD beach area wanted the tankless (generally only because they were cool and groovy). We had lots of problems with them. Maybe that is not the case today, but I have always favored tanked WHs, especially on my own homes.

Most people may not care about this, but.....in the event of a disaster, if you have a tanked WH, you will have 40-50 gal of stored accessible water at your disposal.

[Dan H.]

Quote from @Bruce Woodruff:

Bear in mind that Tankless units must be drained and de-scaled each year (by a licensed Plumber), or you will void the warranty.

When I was building a lot, most people in the SD beach area wanted the tankless (generally only because they were cool and groovy). We had lots of problems with them. Maybe that is not the case today, but I have always favored tanked WHs, especially on my own homes.

Most people may not care about this, but.....in the event of a disaster, if you have a tanked WH, you will have 40-50 gal of stored accessible water at your disposal.

 >We had lots of problems with them. Maybe that is not the case today

In general, I believe the problems with the tankless are due to not descaling.   I had an AO smith with long warranty,   It died at near year 10.   The heat exchange showed it failed due to not enough descaling which I believe (I suspect it was descaled twice).   Here is something to keep in mind, how many of us drain 5 to 10 gallons from our water heater annually?   How many ever change the anode?   These are both simple (use impact wrench on anode) compared to descaling.    I can flush in 5 minutes and change an anode in 10 minutes.   The first descale took over an hour and subsequent take over 30 minutes. 

I have 2 large tankless for my home.  Both are past one year since last descaled.   There are a lot of items that take time.   this is past due knowing my last one failed due to not descaling often enough.  

tankless are great.  Small, efficient, if properly maintained will last a long time.   But they require more maintenance than tanked water heaters and most people are not good with their water heater maintenance.  

I stay with my assertion that I would not choose tankless for rental units.    Also I believe descaling is more impactful than flushing a tanked heater.   I believe anode has more benefit than flushing.   A plumber told me that the primary difference between rheem product warranties was the size of anode supplied with the water heater.  Failure to descale will void warranty and significantly shorten the tankless water heater’s life    

Good luck

[Wesley I.]

@Michael Ndjondo makadi

Ive been thinking about the same thing for my primary here in San Diego.

The only thing that is stopping me is that I will most likely need to upsize my gas houseline to a bigger pipe since tankless wh require more BTUs, and my water heater is at the other end of my gas meter.

Another thing to note is if your existing gas service can handle the additional tankless water heater loads. Some gas services in San Diego are joint services(shared with another property) sometimes as small as 1/2” PE and they have an excess flow valve at the street which will trip if you exceed a certain flow.

And dont get me started with gas meter upgrade requirements if its near a source of ignition or under an operable window.