I encourage "out of the box" thinking when it comes to saving money on bills. I used to work for a TV show doing HVAC and saw alot of different ideas over the years. Some were really great, and some worked, but didn't save money in the end. I could go on for hours about some of these ideas, and you guys will probably hear about them in a few years. but as far as the instantaneous HWH go....I love them. But, again, as mentioned....weigh the costs out and see if it's worth it. I see them work great time and time again, but if you have a small ranch with normal water usage....is it really needed/worth it ?? See my point ? As with any new technology, there are differences. Installing pros. should be aware of these before installation, instead of just assuming everything is the same as the older technology. Water treatment might be needed for proper performance and dependability.
I installed a Takagi TK2 in my house 2 years ago. My reasoning was because my old heater needed replacement and the wall mount saved a lot of space in my laundry room. Cost was about 3 times as much but was well worth it. It works great for me. The notable difference would be at very low flow, the heater won't turn on. It needs .75 GPM to fire up and then .50 GPM to stay on. Other than that, you would never know it was a tankless- besides endless hot water. I recommend the remote panel that lets you adjust the water temp, it also gives you codes for troubleshooting if needed. I believe the Rinnai comes with this. No problems with the heater at all and no maintenance. If you live in a cold climate make sure you use the backflow damper to prevent cold air from coming into the heater on the off cycle and freezing the coil. I have repaired one like this.
I work for a heating company in Pennsylvania and we've installed probably close to two dozen Rinnai tankless water heaters in the last three years. So far we've had no complaints. The only problem we had is we installed one for a car wash. They recycle their water and have no water filtration system installed, yet they also refuse to call us to get their system flushed.
Aside from that one issue, we have had no complaints, which includes a happy hotel/restaurant that has two installed. Some of our customers have also seen a 50%+ drop in propane use. Customers that have received deliveries every two months have had to be adjusted to a four or six month delivery schedule.
I'm personally having one installed in my house. I recently purchased a small single-level earth home. It's already an efficient house, but I'm trying to take the next step. I have an oil boiler with a 30 gal tank for water. I'll be changing the gun to LP and installing a Rinnai to replace the water tank.
I will undoubtedly see a drop in gas use. Granted LP has less btu's than oil, I'm also looking at paying a $2.00/gal difference. I'll see payback in gas use and $/gal. Our company and a heating contractor figures if prices don't stray too much (which is anyone's guess), I'll see a payback in 2-3 years.
It just frustrates me when I walk into my house and hear the oil burner running to heat the water.... when I haven't been there for eight hours! A drop in gas use, in my eyes, is absolutely inevitable. I generally would not recommend spending the money on a unit like this if your current unit is still in good condition. I'm not sure you'd see a payback. I've never really done the math. But I have no kids. I don't use a lot of hot water. It eats away at me knowing I'm burning oil for no good reason.
Like one other person said, this unit does not fire at 190,000 btu+ all the time. Like their DV ductless heaters, they have a modulating gas valve. They'll fire all the way down to about 15,000 btu. Regardless, worst case scenario, I might shower twice a day, run the dish washer once, wash a couple loads of laundry (this is WELL rounding up) and wash my hands a few times. I'd rather run the unit for a combined 1 1/2 hours than continually heat water off-and-on in a tank 24/7.
A fellow trade-alli contractor told me about Navien tankless heaters. They're certainly intriguing. They claim 95%+ efficiency, claim that their stainless exchangers are better than competitor's copper and have 3" PVC venting options. Unfortunately I have no experience with them, nor does the contractor. They're fairly new. I'm gun-shy to have a Navien installed, even though it might be a great unit.
Last edited by AdamB5000; 06-05-2008 at 11:50 AM.
Yah, Navien certainly look interesting. I'd like to try an install. Probably easier than a Rinnai, and certainly cheaper if you have to run your vent a ways.
Navien actually claim 98% efficiency from what I've seen, and they have a model with a built in re-circ w/ buffer tank which eliminates the "coldwater sandwich" effect.
I'll post back after I do an install....
I'd love to hear how the install goes. I already purchased a Rinnai to have installed, as they have a good reputation and we've done plenty of installs with absolutely no complaints (just praises).
That said, there is always room for improvement with technology, so I'd like to hear how the unit performs. They say 98% efficient on the condensing chamber (maybe less overall...?). I'm not exactly sure what that means. I have a good idea of how our products work, but I work in accounting, sales and customer service, not installation.
As far as efficiency ratings on units....companies do not "claim" to be a certain efficiency. Testing is done by independent, reputable testing agencies. These aren't just numbers that the manufacturers make up.
The Navien is one of the few high efficiency water heaters "condensing".
I prefer a Mod/Con and indirect, safe, reliable and truly efficient.
One of my guys has one installed in his personal home and says he isn't all that happy with it. (Rinnia) It works, but he has to flush it out with vinegar every two years to stop the buildup. He also says his last company experienced alot of HX replacements on them. He went on to point out the payback on them after paying someone to flush them out, and we started discussing how long they last compared to a regular HWH. I wonder if you take everything into consideration.....the whole picture.....if they are really worth it in the end ?
I guess i'm starting to second guess them a bit.
I only try to be the best.....though i'm not......but in my efforts to be, I hope to learn and achieve more than most !!
I can remember a ew years back when these types were called "instantaneous water heaters" No waiting. Well when their located in the basement where the old stand up was, your still maybe 20 feet from a second floor bathroom, you still gotta wait the same time to feel it hot. They now recommend that if its a second floor bath, install it in a closet near the bath, and use one for the lower level.
I'll stick with my Crown Bimini 96% and the 40 gallon Superstor.