tankless water heater - install before kitchen remodel or after

11 years ago

Our home is a 1 story 1800 sq ft older home with a pier and beam foundation that was built in 1935 in Houston, TX. There has been a lot of work done - foundation, electrical, new sewer line, hardie board siding, A.C. ducts replaced, and other mainly exterior stuff. The interior looks pretty bad. A contractor will soon be starting on our hall bath and as part of the job, he will be replacing galvanized and pvc with copper. We hoped we would follow this job with the master bathroom remodel but after an inspection, we are wondering whether we should address the galvanized pipe issues first. We have lots of galvanized pipe including a bunch in the attic where the hot water heater is currently installed.

My question mainly concerns the sequence of work that needs to be done. We don't want to have it all done at once. Hoping to split into tasks but this is what makes things difficult.

I hope to interview a plumber with my questions but I'm concerned that it will be in his interests to do the whole job at once. I would like to know what I would be losing (or gaining) by splitting the job into separate parts and I would also like to know what sequence to do the parts.

Questions:

1. If we want a tankless water heater (gas), should we have it installed before the master bathroom and kitchen remodel? Can this task be separated out from the other jobs for the other areas (see list below)? If so, should the tankless water heater come first and then master bathroom and then kitchen? (Our gas pipe has the required diameter for most of the run but underneath kitchen, it needs "enhancement" I think, plumber will hopefully confirm.

List of jobs to be done (none of these tasks will be DIY):

1.) Move gas hot water heater out of the attic and replace with an external tankless water heater downstairs on side of house outside kitchen.

2.) We currently have a major hall bath remodel coming up soon that includes having all the galvanized (and PVC) in the hall bath replaced with copper, at least in this bathroom.

Washer and Dry are also being moved out of the kitchen and installed in the hallway outside the hall bath. Copper plumbing will be used with washer/dryer also.

3.) We had hoped to move next to the master bath remodel where a small shower will be replaced with a tub. And galvanized replaced with copper.

4.) Master bath is adjacent to kitchen which is also scheduled for total demo and remodel. Also have galvanized in kitchen to be replaced with copper plus a small sink added and misc other plumbing tasks standard for kitchen remodels. Will not be using gas stove.

5.) We also hope to have a new roof installed.

6.) Also convert current vented attic to unvented/conditioned attic - using spray foam.

7.) Floors need refinishing and lots of painting and bookcases installed in living room and study.

Any feedback would be greatly appreciated.

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Comments (5)

User
11 years ago
I think I'd rather move that tackle all of those projects. Or do a teardown and start over. It might be cheaper. Really. Retrofitting is always harder and more expensive to do than to do new while all of the walls are open.

I'd also not waste my money on copper unless your water is perfect. Do a search on pinhole leaks and copper piping. I'd do CPVC and save the several thousand to put into the 150K worth of projects you've got planned. Most of the plumbing projects can be done as standalone projects, but you will probably get a much better price if you have someone do it all at once.
lazypup
11 years ago
All that BS about pinholes and switching to CPVC is non-sense. I subscribe to about 5 different plumbing industry trade journals and they keep on top of the research on pinholes.....

Out of the 7 leading causes of pinholes in copper, 6 are directly related to the installation practices of the installer....I would have absolutely no hesitation in installing copper and writing a 60 yr warranty on it.
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You actually want to run them in parallel. Right now, there's nothing to control where the hot water flow comes from at a given fixture, besides the piping losses (length/size of pipe, fittings). If you have a bigger line to/from the bigger heater, and it's closer to the cold water entrance to the house, hot water will want to come through it preferentially. You can get some brands (I know you can for Noritz) where they communicate between 2 heaters in parallel. But I believe that's really intended for where they're sitting next to each other. With them on the opposite sides of the house, you'll probably need to do what we did. We have a tankless on one end of the house for 2 bathrooms. The older gas tank heater is in the garage on the opposite corner of the house. In the crawlspace, there's a closed valve on the hot water line in between the 2 bathrooms and the rest of the house. Basically, this zones the hot water system. If either heater is out, I can open the valve and feed the whole house. But the 2 heaters don't fight each other under normal circumstances. To get your smaller heater to work, you need a closed valve somewhere. It might be on the extension/connection you mentioned in your OP. But that depends on how much stuff is on the 2 systems. I may be wrong, but I think zl700's check-valve solution would still lead to zero flow through one unit most of the time. That'd be the smaller one, since it sounds like it's running the least now.
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There is a LOT of disinformation on these forums about on-demand tankless units, ESPECIALLY the electric units. First, energy cost savings is NOT a reason in itself to make the switch. No reason alone is sufficient. It is the total package, in light of your particular lifestyle, that will dictate the pro-con outcome of the decision making process. First, tankless units save space -- a lot of it, especially electric units that do not need to be vented. In Texas we have no basements, so that can be an important issue. Second, an electric unit is unlikely to blow up, unlike anything using natural gas. Third, there is an endless supply of hot water, which in a successive-morning-shower household like mine, is a really important issue. And finally, yes there is some documented comp fuel savings (electric tankless over electric tanks, or gas over gas), that is really offset by the added initial cost of the unit plus upgraded electrical service or gas supply line sizing. Moreover, there ARE full-house electric units out there that provide plenty of water, unless you plan on taking two showers simultaneously while also doing your laundry and running the dishwasher! And if that's your bag, you can run 2 or more electicals together. Or get a really big gas unit. Bottom line, nearly every nay-sayer of tankless units ignore the pros and focus on a single con - cost, cost, cost. Well, we all don't drive a Ford Focus for a reason. Some of us enjoy our Buicks, Porsches or Camrys even though another car would get us from point A to point B cheaper while using less fuel etc etc etc. Full disclosure: I have a Steibel Eltron Tempra 36 whole-house electric unit. Love it. My electric bill went up nary at all.
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One thing to consider in your case is the location of the unit. I put my Noritz N-084M up in the garage attic because it was out of the way and I had easier access to gas and existing hot and cold water lines. However, the unit is probably 10 feet or more further from the kitchen now and the wait to get hot water there is longer... probably a good 45-60 secs total. Sounds like your outside install could be even further away... and it does make a difference. We've had the unit up and running since June 10th and so far I like it allot. Don't think I'll ever save any money since the gas piping, new gas meter and line out to the main were expensive... but the endless hot water is nice when you need it, and I love having the old tank unit out of the garage. Being able to dial the temperature you want is convenient too, especially if you have small children that take frequent baths and want to protect them against scalding. For the most part I just leave it at 120 F, but when it was colder early in June (summer doesn't start in Seattle until August!) I tried setting it to 125 F and this seemed to get the hot water to the kitchen a bit faster. I've since dialed it back to 120 F and that seems fine now and plenty hot for showering. Have not had ANY problems with the so-called "cold water sandwich" or times that the unit turns cold during a shower. Once activated I can set the flow down really low in the kitchen and still maintain hot water. I think the Noritz has a cold water bypass so that it can mix in some cold water with the hot if needed to maintain the set temperature during low flowrate conditions. Newer units that can regulate to a lower Btu/hr flame are probably even better. As to your question... it really depends on whether you want to spend your money or the utility's up front. If you can buy the unit for less and get it installed that might be the way to go, BUT I think a lot of contractors will not install a unit you did not buy from them. That's what I ran into so I did it myself. Better check before buying. I did not run a dedicated electrical line... just tied into the garage door opener circuit in the attic since the until only consumes 135 W max, 85 W nominal without the freeze protection heater on. Have fun.
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weedmeister
11 years ago
Are you living in the house while all this is going on? If not living there, I'd do 2, 3, and 4 together while the walls are open.

Save 5, 6, and 7 for later.

I suppose you could have the plumber rough in for the tankless while doing the first part and save the tankless for later.
elphaba_gw
Original Author
11 years ago
Thanks for the info.

Can we have an old style gas water heater (in the attic) AND tankless water heater downstairs servicing the same house and gradually phasing out the fixtures (room by room) with end result of eliminating the old gas water heater after remodel complete?

This post has helped me realize that my main desire is to try to do this in phases rather than one job (which I'm sure would be cheaper.) For one reason, the smaller jobs help us evaluate the contractor and decide whether we want to continue using him (he gets to evauate too). It also helps us keep from having so many "change orders" before job is done as we learn more about our 77 year old house.
(think I will cross post this in the "old house" forum as well)

background: I think we are committed to going forward because we LOVE our neighborhood but neighboring homes are old like ours so besides prices being quite high though footprints are small (in center of major metro area), we are afraid we would buy another old home that was in worse shape than ours and would still need to do work.
HeritageTexGal
11 years ago
WOW! So, we just moved into a pier and beam 1600 sqft home that is old in the metro houston area as well! We started our remodel with the kitchen, as the bathroom floor was too intimidating to even think about. (the classic 1940's tile laid over 5 solid inches of pure concrete that has to be jackhammered out) Im just dying to know what neighborhood your home is in, I haven't seem many Houstonians on this blog! Did you think about keeping the tank before you decided to phase it out with a tankless? Do you just need more space? We are trying to get rid of our tank thats currently in a pantry in our kitchen, but we don't know wether to go for the expensive tankless or move the tank to the attic. You've got a lot of projects, Im assuming cost in not an issue for the tankless?

tankless water heater - install before kitchen remodel or after

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tankless water heater - install before kitchen remodel or after

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