Thoughts on tankless propane water heaters

Discussion in 'Off Grid Living' started by Tempstar, Jun 18, 2017.

  1. Tempstar

    Tempstar Old and crochety Site Supporter+

    I have installed a lot of these for clients in the past, but never really got feedback other than they worked great. I installed Rinnai and Bosch brands. Now, it's time to replace my KW sucking electric water heater and I'm going with propane tankless. I'm sure some of the Monkeys have these and can make some suggestions and usage observations. I'm interested in propane consumption, longevity, and of course a good deal.
    Tully Mars and sec_monkey like this.
  2. T. Riley

    T. Riley Monkey+++

    I have a Rinnai at my farm (aka BOL). I have had it for 5 years. Since I am only there part time or so I did not want to heat water for days at a time when I was using none. Mine is outside and has only frozen up once. No big deal, all the water was frozen. Takes a little longer to get hot water but it can provide an endless supply 120 degree water to two showers at once. Washing a load of clothes and showering is no problem, no sudden temperature drops. I have had 8 teenage girls showering one after the other which is not something I could do at the big house. I have two gas water heater at the in-town house which will be replaced with Rinnai's one day. The electric on demand are worthless from what I have read. I purchased mine on the internet when I built the farm house and had the plumber install it.
  3. OldDude49

    OldDude49 Just n old guy

    do they make a multi fuel variety? or just propane?
  4. Dunerunner

    Dunerunner Brewery Monkey Moderator

    Here's one you can make at home...

    DKR and Tully Mars like this.
  5. T. Riley

    T. Riley Monkey+++

    Propane, natural gas and electric are all I have seen.
  6. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Filter WELL before for H2o, to save the DHWH unit , keep the sludge out. & filter the propane as well .
    I have one also.
    sec_monkey likes this.
  7. oil pan 4

    oil pan 4 Monkey+++

    If you need to save water don't use a tank less. Mine has to run at about 1gpm for 6 to 10 sec before it even kicks on.
    Or use a water recirculating pump to warm up the lines.

    By compairson conventional tank hot water heaters flow water as soon as you open the tap.

    If you need a lot of hot water, get a tankless.
    Tank less heaters make nearly endless hot water. I filled my 260 gallon little hot tub with my tankless. I calculated it was outputting 73,000btu/hr for an hour, that's like a heavy duty commercial water heater.
    Cruisin Sloth and sec_monkey like this.
  8. T. Riley

    T. Riley Monkey+++

    So, there are about 92,000 BTUs in a gallon of propane, so in my neck of the woods about $.50 or less for a 15 minute shower. I have tested mine running on solar power for ignition and using my backup water system and it worked fine.
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  9. Merkun

    Merkun furious dreamer

    That could be related to the length of pipe full of cold water.
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  10. oil pan 4

    oil pan 4 Monkey+++

    The instruction manual says it has to detect continuous flow before it will kick on.
    So it has to detect water flow, kick on, come up to temperature, all told it takes about 3 times longer to start getting warm water with a tank less than compared to the tank water heater it replaced.
    Cruisin Sloth likes this.
  11. Tempstar

    Tempstar Old and crochety Site Supporter+

    Thanks so far. I put in one system with solar evacuated tubes and a storage tank that fed to a Rinnai. The Rinnai hardly ever ran. This was in a home with water heated bathroom floors and a spouse who liked very hot garden tub sized baths. I can't afford all of this at once though.
    sec_monkey likes this.
  12. T. Riley

    T. Riley Monkey+++

    Yes, it does take a while to get hot water compared to traditional hot water heaters. Since there is no tank where water it heated, it has to be heated as it passes through the heat exchanger. Therefore it can only increase the water temperature to a certain point. My unit will increase the water temperature up to 65 degrees as it passes through the heat exchanger. If the water coming into the exchanger is 35 degrees it can’t get over 100 coming out. It also takes a moment for the temperature of the heat exchanger to rise. In the summer when the water coming into the exchanger is 75+ I don’t notice the delay. When it 40 outside, I do. Water is cheaper than propane in my area. Since I have a deep well it’s a lot cheaper. You just learn to turn the water on sooner.
    Last edited: Jun 19, 2017
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  13. arleigh

    arleigh Goophy monkey

    I don't know how they are now, but they are built so unique, and companies going in and out of business that getting parts is not an easy task.
    My brother had been through few different brands, this last one is only 2-3 years old .
    Hard to have confidence when there have been a few lemons .
    If you add solar, and a heat exchanger to any water heating system, there will be a significant savings.
    Solar in freezing territory absolutely requires heat exchanger because antifreeze needs to be run through the solar portion being exposed to the atmosphere /weather .
    Night an Day water heaters almost went out of business because of their failure in there solar water heater system, back in the 1930s.
    You have to respect what freezing does to plumbing, you might get away with it once, but consecutive freezings will eventually cost you dearly.
    Years ago I did my own experiments with solar water heating.
    At the same time I built a flat panel with 1/2"copper tubing and then a box with a 10 gallon tank , both glassed and insulated .
    In one hours time the panel reached 160 degrees and the boxed tank was at 130 degrees .
    draw back n the flat panel was it only held about 2 gallons of water .
    My conclusion was to use a tank as it heated adequately in one hour and provided sufficient water.
    Using the flat panel to preheat the tank made an even more impressive system. but the tank gave us some hot water at night .
    We did not have any other means for hot water than to use the wood stove at the time .
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  14. Cruisin Sloth

    Cruisin Sloth Special & Slow

    I built my system & it works great !! When the SUN is out & the chem trail BS don't kill the sky . ..
    Now the PNW is a cloud haven for 7-8 months , so the wood stove is used in the winter , summer solar ,,between grid power on a timer .
  15. hot diggity

    hot diggity Monkey+++ Site Supporter+++

    I'm sure these modern name brand tankless water heaters are hot stuff. I had a not-so-modern tankless propane water heater in my first tiny apartment in Japan. The water heater was right outside the bathroom window, and very low-tech. I could hear the switch close when I turned on the hot water. After a brief delay you'd hear the WOOSH! as the gas lit off inside the unit. The most wonderful thing I remember about this system was that I never ran out of hot water. Coming down south after a couple weeks in the jungle mud and water, it was great to just sit under the hot water with a beer and relax.

    My trip down memory lane got me thinking about the potential of a gasoline blowtorch based gravity fed hot water system. Not instant hot water, with the preheat time, but better than chilly water from a roof top tank on a cloudy winter day.
    Gator 45/70 and Witch Doctor 01 like this.
  16. Southbound

    Southbound Monkey

    I have had a propane tankless for 5 years now and won't be without one again. I can run a shower, dishwasher and laundry at the same time and it doesn't miss a beat. I live in any are with lots of snow in the winter and have even went out and melted snow and ice off the deck with hot water. Love it!
    T. Riley likes this.
  17. DKR

    DKR Raconteur of the first stripe

    We looked at the tankless to replace both the heating 'boiler' (wallboard hydronic) and for hot water. Took a pass as both units require a fan to remove the CO - the exchanger is good enough to leave only semi-warm air. A fan is used to vent the heater. Neat stuff, that.

    The last thing I wanted was to have a fan failure and the house fill with CO.

    We went with an on-demand type with a loop thru the hot water tank - so we get hot water as a bonus for running the heater. Our gas usage dropped almost in half (-48%)

    The city water coming in is cold enough here that most tankless H/W systems just don't work very well.
  18. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    I am building a Hot Tub for Momma and I, in the Back Yard... Plan is to Half Bury, a BIG Insulated Tote, right next to the Well House, and then use a 12Vdc Diaphragm Pump to circulate the water from the Tote up thru a 6KW TankLess Electric Water Heater, and then back down into the Tote.... I have enough overhead on the Gensets to run the TankLess Heater, or the Clothes Dryer, but not both at the same time... So we will have Laundry Day, or HotTub Day, but not on the same day.... I will keep the Hot Tub from Freeing with a 1.5Kw Stock Tank Heater.... I have all the Parts & Pieces, just need to get the BackHoe out back, and Dig the hole for the Tote...
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  19. Gator 45/70

    Gator 45/70 Monkey+++

    You animal!
    Tempstar likes this.
  20. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    I've installed quite a few in residential a and commercial structures. Most customers have been happy with them. I'm not part of the fan club though. I feel they have their place in the industry but they aren't a one size fits all.

    They are a complex piece of equipment and I'm an advocate for simplicity and practicality. They work well and do what they are intended for. If you need endless hot water and don't need water storage then it'll fit and suit your needs.

    I've installed a lot of Rinnai"s and a few Navien's.
    Homer Simpson, Gator 45/70 and BTPost like this.
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