New custom home build, need feedback

[Dana]

Thinking about it a bit, I'm left wondering just how much math the "...plumbing engineer ..." applied to the actual problem? (That is, as opposed to adding up the billable hours or the component costs of the non-solution "solution" that was proposed. )

This isn't rocket science, but it's more than just drawing pretty pictures of plumbing layouts. Hopefully any reviewers will scrutinize the plumbing diameters against the equivalent lengths and anticipated flows. If they get the BTU/hour budget right, it makes the rest of it a bit suspect.

 

[Stuff]

Since it is a new home you can't count on only having low flow shower heads. From http://www.fergusonshowrooms.com/support/buying-guide-custom-shower-systems: "While a standard shower faucet may use 2.5 GPM of water, a custom shower system may use 12-15GPM or more." This is the case where a heat recovery system makes sense.

Imagine what happens when you have one of these massive showers and someone wants to fill a tub at the same time?

 

[Sponsor]

 

[Dana]

Since it is a new home you can't count on only having low flow shower heads. From http://www.fergusonshowrooms.com/support/buying-guide-custom-shower-systems: "While a standard shower faucet may use 2.5 GPM of water, a custom shower system may use 12-15GPM or more." This is the case where a heat recovery system makes sense.

Imagine what happens when you have one of these massive showers and someone wants to fill a tub at the same time?

Exactly!

This house doesn't sound like it's designed to be an energy sipping ultra-green hippie's Net Zero Energy or PassiveHouse hangout, which is why I asked right up front about deluxe multi-spray showers & soaker tubs. Hanging a tankless on those types of bathrooms is a recipe for extreme dissatisfaction. (And hanging drainwater heat recovery on that type of shower is a no-brainer investment.)

But as long as they have the plumbing engineer backing it all up it's going to be just fine, right?

 

[BadDad]

What about electric water heaters?
are there any new technologies out there?
Our old house had a gas fired wh, but our current temporary house has an electric wh. to be honest, our power bill was soo low, i'm considering going with electric on our new house, mostly because we are on a 250g propane tank and i dont want to find out on a cold night that we are out of propane, we only use it for the range.

 

[Dana]

What about electric water heaters?
are there any new technologies out there?
Our old house had a gas fired wh, but our current temporary house has an electric wh. to be honest, our power bill was soo low, i'm considering going with electric on our new house, mostly because we are on a 250g propane tank and i dont want to find out on a cold night that we are out of propane, we only use it for the range.

Heat pump water heaters (HPWH) need a substantial amount of room to draw heat from and can be noisy (you probably don't want one right under your bedroom) but use 1/3 to 1/2 the total electricity. Recovery times are pretty slow (even in "hybrid" mode when the resistance element helping out), so you'll probably need more than 80 gallons to manage 5 full bathrooms, but two might do it (especially with heat recover heat exchangers helping limit the draw down from showers.) There is probably some CA state rebate subsidy for them too.

The Stiebel Eltron Accelera 300e (300 liters, about 80 gallons) runs about $2500 each has a higher reliablity reputation than some. It's a hefty sucker- about 300lbs when empty, but so are other HPWH that size. An 80 gallon AO Smith Voltex is quite a bit cheaper, and has comparable first-hour specs, but not much data on reliability.

One benefit of HPWH is that it reduces the cooling load of the house a bit, taking some of that heat and putting it inside an insulated tank rather than pushing it into the outdoor air. For southern CA at lower altitude it's always a net benefit. During the heating season it's drawing some heat from the heating system, but not enough to force an increase in heating system sizing.

To do 5 baths with straight up resistance electric water heaters you're probably looking at a couple of 105 gallon Marathons. It's cheaper still, but has fewer reliability issues (no moving parts, no refrigerant loops to leak, etc.)

 

[BadDad]

Thank you for the suggestions @Dana that stiebel eltron is really nice. i'd rather have two of those than 3 tankless water heaters.

 

[hj]

The recirculation line should be a SMALL as possible and still maintain temperature back to the tank. The pump should also be very small or restricted to limit the velocity of the water in the system.

 

[OldSalt]

I see that this thread is a couple of months old, plus you have a lot of experienced plumbers chiming in, so you probably have already made your decision. I'll respond as a consumer (albeit, knowledgeable and skilled).

I have the RUR98e unit, which is your proposed Rinnai in a propane version.

1. No problems with the Rinnai technology. It does what it's supposed to do. We flip on recirc mode, and we have hot water throughout our 2400, two story house in less than two minutes. (We could schedule the tank to run on/off throughout the day, but two minutes until hot is fine with us most of the time, since we're running on relatively expensive propane, vis-a-vis natural gas.) It's the biggest utility hooked to a 500 gallon propane tank (we'll hook up 30K BTU fireplace later), and we've used less than half a tank in a year. Very efficient. Water temp at 115 degrees is as hot as you can stand it on your skin in summer, and plenty hot enough (but cooler) at zero degree temps outside.
   
2. It has it's own internal recirc pump, though, with a larger, spread out home, you will probably need the secondary pump(s) and tanks for the far end of the line.
3. Tankless technology is overall, a pain. For your purposes (large home, many baths) and budget (high end), go with a tank and re-circulation system. It is (as far as I am aware), the hotel standard system, which is why there is "instant" hot water in high end hotels.
   
4. Insulation is more important than either option. Your hot water supply system essentially becomes and extension of your hot water heater. Any money you might save at the tank, with a highly insulated tank or tankless, you'll lose in the lines. I paid for very good insulation throughout the house, i.e. it's Idaho winters here and the house is between 60 and 75 degrees in virtually all weather, with very little heat/cooling added), but the plumbers I hired did not separately insulate the pipes (and neither did the insulation company).
5. To rephrase the above, costs are all about BTU's, and how many of them you burn (i.e. the more water heated, whether to your tap or running a racetrack around the house, the more you pay). Design accordingly. Maintenance is also, of course, a factor.
   
6. Water quality: SoCal water? forgetaboutit. You need every bit of help you can get, including soft water and filtration. If your "designer" and "planners" haven't included that, they've utterly failed you. EVERY PIECE OF HARDWARE YOU ATTACH to your pipes will be destroyed within a year (i.e. finish, etc.). You need over 50 PSI continually for the Rinnai unit (should be OK in SoCal, but soft water and filtration could reduce your street pressure to make this a problem) and CLEAN, CLEAN, CLEAN water. We have rock chips coming through our city water, like grains of sand, which plug up the filter within a week (as well as faucets and shower heads). I wouldn't install a tankless system unless I at least put in a y-strainer, or better, whole house filter.
   
7. Specific problems I've had with the tankless unit, have all been related to the original, deficient install, plus a few peculiar on site conditions. (I ended up rebuilding/reinstalling the tank system myself to get it functioning properly, but of course, as a learning experience I also made mistakes, so I've torn into it about 3-4 times.) Make sure the guy you hire to run your tankless system, specialized in tankless AND the system you're buying. Plumbers are independent, resourceful, skilled guys, who think that they can figure out anything, and a good plumber generally can. However, there are many idiosyncrasies to a tankless system install that only a TANKLESS experienced plumber will understand. You're spending a fair chunk of change, and knowing California as I do, over two years in building a new house. Spend time getting the right guy to install a tankless system, if you go that route.

I like the Rinnai and tankless technology overall. I would install the same thing again, given the circumstances of our mountain/lake front home here in Idaho. However, in your circumstances, I agree with some of the plumbers, you'll be calling a plumber out to work on the system one way or another, twice a year. Tanked water heaters with recirc is old, tested, forgiving technology. You'll probably need a secondary water heater in a system as large as yours, which any good plumber could design.

If it were me, and my dollars, I'd consider a manifold system over recirc (kind of a hub and spoke system, versus race track), which puts single, pex pipes from a supply manifold directly to your faucet, i.e. shortest distance = faster heat + lower cost. Depending on how sprawling your layout is, I'd have two or three water heaters, a supply manifold connected separately to each, and pex going directly from manifold to up to a dozen faucets/tubs/showers/etc. It should be less costly to operate, simple technology with no pumps to clog up or fail, and provide very quick hot water. Maybe ask the pro's around here on advice about this.

 

[Danny Soroudi]

So interestingly enough, not 'too late' ... the feedback I received on this forum made me really dig into the issue in greater detail and consult with more contractors than I could have ever thought possible.

In the end, although I decided to stay with a tankless design, several other major changes were made to my system, including locations of things like the recirc pump, going from Rinnai to Noritz, expanding the utility room to accommodate the water softening & filtration equipment, changing size of piping (copper not pex) and some routing to be more efficient (although still going to be a loop/racetrack style, not manifold layout), and having a lot of the "details" worked out including insulation of both hot and cold lines (vs just hot before), etc.

I know the general consensus of this forum is against tankless... but I consulted with 4 different local plumbing contractors, all of whom gave me their suggestions, all of whom are experienced in tankless, and whom gave me references (including my father in law) to check how others have been satisfied in similar sized homes with tankless units. Not a guarantee things will go great, but I'm about as confident as I could hope to be at this point.

Of course if I start posting in 15 months about all the **** problems I'm having, then we'll all know for sure...

 

[Jadnashua]

In warmer climates, a tankless system can work pretty well aside from the initial cost to install and long-term maintenance required.

 

[OldSalt]

15 months? Try 15 days .... oh, that's right, in California you'll still be waiting on permits in 15 months ..

More seriously, I can't argue with copper. Copper and brass give me warm and fuzzy feelings. I bought a failed/abandoned build, pulled permits, renovated almost from foundation up, and it already had pex installed. We made substantial changes to the pipes, and I HATED the idea of cheap pex piping. However, the more I researched the issue, and considering the pinhole leak epidemic in SoCal with copper (cheap or high quality; the water there just eats through anything), I'd probably build any house with SoCal water with pex, albeit with copper connectors (I'm still not sold on the quality of poly connectors, as I've had a poly connector on a toilet split and flood a guest bath in SoCal, right after I finished remodeling it, and even when I was in the next room - gallons of water flooded but I got there in time to save it.)

I've no real problem with tankless technology, but there are a lot of things on the install that you have to get just right to have a long term, problem free system. If you've got the right plumber, and are willing to pay to see him back once in a while (or can solder and turn a wrench yourself), you'll love tankless systems.

(Correction: I have a RUR98i - propane. the "e" is an external system, and "n" is for natural gas.)

Good luck with the build. It takes a strong constitution to see it through (regardless of the size of your checkbook). I'm installing wood flooring in my build now, and after that, the carpet. I SO want this to be over. It'll be years before I can watch HGTV with my wife again and without having night terrors about "the endless build". I think I'm going to burn all my tools when I'm done, just to make sure I don't try this again.

 

[cecil1966]

Wow, sounds good. I was about to suggest making sure to have enough room for water treatment equipment. On a big house like that in California a recalculating pump makes sense. It might even make sense for me, but I'm in Charleston and we haven't had any kind of water shortage or restrictions. I already use less than normal and also bogged down in renovation project, so manifold worked for me. I think you will like the unlimited hot water on tankless. I have more experience with pex so trust it more. But last thing contractor will want to do is install a problematic hot water system. I've done a lot of renovation work and could see how challenging installing one might be on existing house, as there could be other existing problems with plumbing, but if you do everything to factory specs, especially new construction, in temperate climate, tankless has some advantages. I think you will be glad you went tankless, and will also have nice clean water.

 

[Danny Soroudi]

So, here I am, back after finishing up the house which took WAY longer than I expected (shocker, I know). So, my initial feedback:

1) Went tankless and so far, so good. Time will tell, but I am happy as of now. We ended up going with 2 Noritz tankless units instead of Takagi or Rinnai after looking into options more and consulting with 2 local plumbing contractors, etc.

2) Ended up with a Grundfos recirc pump, again, after more consultations and lots of question asking. It works well, has a sensor at the end of the loop and doesnt over or constantly circulate, only when end of the line drops below set point, and only during allowable hours (ie, its not trying to recirc at 3am).

3) Installed water softener system for the whole house, very happy with it, and instead of doing full house R/O, just from the 2 specific taps we wanted filtered water, we put under cabinet units, also very happy with quality.

As of now, living with it all for a few weeks, seems to be working as designed/intended/hoped for. I need to see how it all goes for next few months, but I think the feedback I got from these forums was critical to making the tweaks needed to ensure I had a good plan implemented, so thank you all!

 

[Tankless Tech]

2 years later.... whats the verdict?

 

[Danny Soroudi]

2 years later.... whats the verdict?

Been living in the house a few months now.
Love it. Unlimited hot water, never takes more than 10 seconds for hot water to reach any faucet or shower, no issues when multiple showers or faucets running. Really happy we insulted every line so we don’t hear water running anywhere from inside walls.

The water softener took time to get used to, water feels so different when soft vs hard and everyone had to learn to use much less soap and shampoo.

The only plumbing issue I’ve encountered so far has been with the landscape system and the drip irrigation, nothing was in the house itself.

Very happy with the outcome, at least so far!

 

[Tankless Tech]

Would love to see some pictures of the install.

 

[Danny Soroudi]

Would love to see some pictures of the install.

Ask and you shall receive (months later).

On the left side of the room is the water softener system. On right right are my 2 tankless heaters. To right of those is the recirc pump. Expansion tank (not pictured) is below the tankless heaters), with a floor drain as well.

Living in the house now for about 8 months, continue to be very happy with my ultimate decisions (much of it, thanks to the folks on these forums). Of course we'll see how things go for a few years and whether I start having any issues or not, but for now, so far so good.

 

[Stuff]

Glad it is working for you but I hope your house leaks air like a sieve to provide make up air. Those two tankless should have the intake piped to the outside.

 

[Master Plumber Mark]

Glad it is working for you but I hope your house leaks air like a sieve to provide make up air. Those two tankless should have the intake piped to the outside.

That is a very good point.... if those two come on at the same time it will probably suck the doors shut trying to get air into them...
its wise to at the very least put a 3 inch hole out the side of the home in that mechanical room to allow fresh air into the room... and its much better to actually run both lines out the side of the home because you are throwing out air that has been heated or cooled out of the house... and its better to suck in un heated or cooled air to run the tankless heaters........

 

[Jadnashua]

When I looked into the possibility of a tankless system and not getting outside air for the burner, the installation manual specifically gave a minimum sized room that is required to take inside air.

I totally agree that by trying to use indoor air to feed those two significant burners is not a good idea unless you have a whole house energy recovery system that is sized with this in mine. Throw in bathroom exhaust fans, range hoods, a gas stove or dryer, if present, etc., and you're throwing a huge amount of conditioned air out.

FWIW, it looks like the gas line feeding them may be undersized, but that's hard to discern for sure not knowing the distances and actual pressure or pipe sizes installed. The gas meter must be sized correctly as must the supply line to it.