I will be getting rid of my tank heater soon and switching to tankless gas water heater. I was going to go with AO Smith, but seen some really bad reviews on theirs. Any thoughts on the best rated? I’d like 7.5-8 gpm and would like to use at least 3 water appliances simultaneously if need be. Central illinois area, 3 bds, 1.5 bath ranch. Who stands by their product, and what brand or model seems to have the lease service calls? Thanks for any input!
The best rated tankless gas water heater?
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FishScreener
Well-Known Member
Are you sure you have enough gas feed? They take a bunch, and if you need to upgrade, it can rapidly drive the cost up to the point you can never pay it back.
Bird Doo Head
Well-Known Member
One of my brothers has a Noritz and a Rinnai (2 separate houses).
He is happy with both, but the upkeep is tedious. He installed bypass & flushing valves & tees to clean the heat exchangers periodically. (Rinnai has a pre-made one available.) That takes too much attention for my tastes.
Plan B: Heat pump water heater? Expensive to purchase, but eventually it should pay back.
He is happy with both, but the upkeep is tedious. He installed bypass & flushing valves & tees to clean the heat exchangers periodically. (Rinnai has a pre-made one available.) That takes too much attention for my tastes.
Plan B: Heat pump water heater? Expensive to purchase, but eventually it should pay back.
Mitchell-DIY-Guy
Well-Known Member
Rinnai is popular around here (NC) above all others, but I've seen other brands too. Take @FishScreener advice and check on gas supply. Almost without exception, every residential gas water heater, tank style, has a 40,000 BTU burner. The largest available tankless has 199,999 BTU, or 5x the gas burning that you need to accommodate. See what is available and popular in your area.
You say you need 7.5-8 GPM flow. If your water temperature in January in central Illinois is 50 degrees (just a guess) and you want 120 degree water, that's a 70 degree rise. Check the charts but I don't think you can get this out of one unit...you may need two separate units, or "cascading" units.
You cannot get larger than 199,999 since anything larger is considered a "boiler" and that's a whole different kettle o'fish.
You say you need 7.5-8 GPM flow. If your water temperature in January in central Illinois is 50 degrees (just a guess) and you want 120 degree water, that's a 70 degree rise. Check the charts but I don't think you can get this out of one unit...you may need two separate units, or "cascading" units.
You cannot get larger than 199,999 since anything larger is considered a "boiler" and that's a whole different kettle o'fish.
I had a Navien at my old house which worked great for 6 years. Afterwards, we starting getting lots of error codes and we had to have the plumber/electronic technician on "speed dial." My latest house has a great, reliable tanked water heater.
Right! When you have a plumber on speed dial you are spending way more on service calls than it would cost to run a tank type water heater, they are virtually maintenance free, if you have reasonably good water and flush them occasionally. We have always gotten 20 or more years out of tank type heater with maybe one element change in 40 years.
Noritz and Navien are both brands I've gotten full day trainings.
We only offer Navien as it is the easiest to work on and diagnose as a technician.
Navien in the latest iteration NPE A2 series can't be beat as far as quality components and the internal mini tank and pump. Even if you don't have a recirculation loop, the mini tank stays hot...and they are very quiet.
They are highly efficient, and perhaps over 20 years will compare in cost of two tank WHs replaced at 10 yr interval...but when you add in descaling every few years, it is not a money saver...just a greener option for folks who have the money.
With new homerun gas line and not including electrical, average installed cost can easily be over $5k
We only offer Navien as it is the easiest to work on and diagnose as a technician.
Navien in the latest iteration NPE A2 series can't be beat as far as quality components and the internal mini tank and pump. Even if you don't have a recirculation loop, the mini tank stays hot...and they are very quiet.
They are highly efficient, and perhaps over 20 years will compare in cost of two tank WHs replaced at 10 yr interval...but when you add in descaling every few years, it is not a money saver...just a greener option for folks who have the money.
With new homerun gas line and not including electrical, average installed cost can easily be over $5k
Daulton Ruff
Member
I have a question;
I've thought about a tankless heater for the West end of my 2050"ish home, but I read these posts, and I realize I don't have the propane volume to run one, and would have to trench through a lot of concrete to get that volume. My propane tank is roughly, at least 90' from my bathroom. I'm wondering is a more practical idea is just to put in a small hot water tank on the west end and run it from a separate smaller tank, or just use electricity. My breaker box is on the West end. We have to run water way too long to get hot water back there. I do have a heat pump on my hot water heater, but doesn't seem to help much. Bathroom is about to be under construction.
I've thought about a tankless heater for the West end of my 2050"ish home, but I read these posts, and I realize I don't have the propane volume to run one, and would have to trench through a lot of concrete to get that volume. My propane tank is roughly, at least 90' from my bathroom. I'm wondering is a more practical idea is just to put in a small hot water tank on the west end and run it from a separate smaller tank, or just use electricity. My breaker box is on the West end. We have to run water way too long to get hot water back there. I do have a heat pump on my hot water heater, but doesn't seem to help much. Bathroom is about to be under construction.
You say you have a heat pump, do you mean a pumped recirculation system or a heat pump water heater?
If it is not piped properly or has an air lock, then the pump may not be pumping or the piping doesn't go all the way.
I can say with certainty that a decent recirc. system will be hot at whatever the timer allows. Navien has a Hot Button option to have the pump only turn on when the button is pushed.
You should kick this around with a local plumbing contractor.
If it is not piped properly or has an air lock, then the pump may not be pumping or the piping doesn't go all the way.
I can say with certainty that a decent recirc. system will be hot at whatever the timer allows. Navien has a Hot Button option to have the pump only turn on when the button is pushed.
You should kick this around with a local plumbing contractor.
Daulton Ruff
Member
Thank you for the education. I installed it and we have water flowing back there to a bath about 80 feet away, and it does take time to get hot, but I am pretty negligent and ignorant about maintenance of the pumped recirculating system. I don't pay any attention to it, but if I install that back bath I will be showering and shaving back there. Unless it becomes a cost factor to bathe there.
I never pay attention because the shower I use now is right next to the hot water tank.
As far as the possible air lock- I don't know how to detect or remedy that. The "master bath" old shower, and sink plumbing, and toilet are plugged for now. Some work in the sink in the central bath, adjacent to the "master bath" because they have the same riser.
Thanks for your reply.
I never pay attention because the shower I use now is right next to the hot water tank.
As far as the possible air lock- I don't know how to detect or remedy that. The "master bath" old shower, and sink plumbing, and toilet are plugged for now. Some work in the sink in the central bath, adjacent to the "master bath" because they have the same riser.
Thanks for your reply.
We had a similar situation when we bought our current home 14 years ago, the master bath/shower that I use was in the new part of the house, 70 feet from the 50 gal. electric water heater. It took a long time to get hot water for a shower! I installed a 2 1/2 gal electric tank heater in the crawl space under the bathroom, in series, in the hot water line. It runs off 1 120 volt breaker, works great, hot water pretty quick, and no temperature change during shower.
FishScreener
Well-Known Member
The other thing to consider is that modern electric heaters are very well insulated and loose heat very slowly. And the Dept of Energy sent out the new drat rules for tank type heaters for final comments a few months ago. So tank type heaters will get more efficient in a year or two.
For long runs of hot water we are using 3/8-inch PEX, which has about half the water volume per length. So the hot water gets there twice as fast.
WE had 8 or 9 tankless units, 13-years ago. We now have 4 left, which are in a shower facility at a large camp, which houses 30 to 40 young adults, who work on trails. A team of ten go into the wilderness for ten day hitches. When they get back they generally want a long hot shower, and here physically isn’t enough room to fit enough tank top water heaters.
The other locations all had multiple failures and breakdowns, and they were replaced in kind once or twice, and we decided that we were wasting a lot of time and money trying to keep the tankless functioning. Most of our facilities get drained and shut down every winter, but unless we pumped a couple of gallons of RV antifreeze through them they would freeze over they winter. And, apparently the RV antifreeze was damaging the heat exchanger. So, we began to hate them…and I made a decision that they were not worth the slightly better efficiency.
For long runs of hot water we are using 3/8-inch PEX, which has about half the water volume per length. So the hot water gets there twice as fast.
WE had 8 or 9 tankless units, 13-years ago. We now have 4 left, which are in a shower facility at a large camp, which houses 30 to 40 young adults, who work on trails. A team of ten go into the wilderness for ten day hitches. When they get back they generally want a long hot shower, and here physically isn’t enough room to fit enough tank top water heaters.
The other locations all had multiple failures and breakdowns, and they were replaced in kind once or twice, and we decided that we were wasting a lot of time and money trying to keep the tankless functioning. Most of our facilities get drained and shut down every winter, but unless we pumped a couple of gallons of RV antifreeze through them they would freeze over they winter. And, apparently the RV antifreeze was damaging the heat exchanger. So, we began to hate them…and I made a decision that they were not worth the slightly better efficiency.
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