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  • My tankless experience summary

    I installed a Rinnai RLS75i natural gas unit at the end of July.


    Natural gas analysis:

    September was my first full bill of natural gas usage with the tankless. Below are my results when compared to last year.

    September 07 Bill: 16 therms billed.
    September 08 Bill: 12 therms billed.

    12 / 16 = 0.75

    Or, a 25% savings.

    For the month of October:

    October 07 Bill: 24 therms billed.
    October 08 Bill: 14 therms billed.

    14 / 24 = 0.58

    Or, a 42% savings.

    (I will note that October gets a little dicey as I could have turned the heat on last year. I did this year, but on October 10th, the last day of my billing cycle.)

    Combines savings to date (12 + 14) / (16 + 24) = 0.65 or 35%.

    I would think as the weather gets colder, the savings would continue.

    The tankless is energy guide labelled for 183 therms per year. Granted only two months have passed, but I seem to be on track for that estimate.


    Water usage analysis:

    Okay, so I see savings in my natural gas usage. What happens if I never used hot water this year compared to last year? I would not really then have a savings.

    I am billed bi-monthly. My September bill would have covered from July 12 to Sept 12. My natural gas bill for September was from Aug 12 to Sept 12 (about).

    My water consumption for Sept 07 was 1970 cubic feet of water. It was the same for Sept 08.

    It is therefore pretty safe for me to conclude that the 25% natural gas savings I experienced in September was completely due to the tankless.


    Analysis Notes:

    Now that my heat is on, I can no longer distinguish the natural gas used by my furnace and the tankless. Therefore, my analysis has to basically stop. I can however log my usage and compare. I will add however that I added about 300 square feet of living space to my 1800 square foot home in September along with another child which will increase my heating and water consumption. Thus, it will make any future comparisons skewed. If I can break even, I will be happy ...


    General Experiences:

    As far as the experience goes ... pretty typical of other tankless units I think.

    I can run two showers without a hitch. I do not notice any fluctuation in temperature at all. I think the tankless does a really good job of keeping the temperature the same regardless of the load. Temperature consistency has been great. Don't notice cold "sandwiches" during use at all.

    There has been a time or two where I have run into low flow situations where the flow was too low for it to kick in.

    Getting ready in the morning is great. Back with the tank, usually by the end of the 3rd shower we were out of hot water. That was tough when you have at times 6 people that need showers and baths. We typically would have 2 or three people shower, wait 30 minutes to an hour, followed by the rest. Now, we just shower. The hot water heater no longer runs our life. I would definitely recommend a tankless if you have a large family.

    Also, back with a tank, when another person started to shower in the other shower, you would also have to "fight" for your share of the hot water by upping the hot water every minute or two until you were done or ran out of hot water. Now, when someone jumps in the other shower, I do nothing but shower. The temperature of my shower stays the same with the tankless. It is really nice.

    Prior to the tankless I had a 50 gallon "basic" natural gas tank prior. Nothing fancy, no special venting, etc. It was 8 years old when I replaced it. It still was working fine enough and probably could have lasted another 8 (who knows). As a family though, we were just tired of living as the water heater "told us" and so I decided to "convert".

    And so, the big bang for me is the continuous hot water. The additional savings is just icing on the cake.


    Maintenance:

    From what I have found, most tankless manufacturers recommend that you periodically check the inbound water filter. It is a small circular filter found on the cold water side. I talked to a local home owner that had a tankless. He commented how his hot water flow had starting to decrease. The installer came and looked at the filter and noted that it was pretty plugged up. Once the filter was cleaned out, hot water flow returned to like new. I have checked my filter about half a dozen times now. Once after the initial installation and once after I had additional plumbing work done (added another bathroom to my house). Both times had debris in the filter. There was also another time where there were about a half dozen small rocks, just barely large enough to be stopped by the screen, in the filter. The other times the filter has been clear. I checked just because I could, not because I noticed a reduction in flow or hot water abnormalities.

    What is also recommended is a yearly flushing of the unit using a "utility pump", a few hoses, and some clear vinegar. I as of yet need to get one. Googling, I have found these pumps at Lowes and Home Depot for around the $80 range. Most seem to be self priming. The purpose of the flushing is to remove any build up in the unit. Even tanks are subject to build up; however, due to the fact that the diameters of tanks are much much larger than the pipes that go through a tankless unit, tankless units are naturally more sensitive to buildup than a tank would be.


    Installation:

    I had 4 contractors come out and give me bids. Three were in the mid to high $2000 dollar range. One was way out there at $4000. I have seen posts, I believe even in this forum of a quote in the low $2000 range. It could be that tankless install costs are coming down. It could be a sign of the economy too. Tankless installations are typically 1.5 to 2.5 times more expensive than a tank install. Don't be afraid to ask for tankless references from your contractors. My experiences here in Idaho may be completely different from what one may experience in New York.


    Other notes:

    There are many other pros and cons to tankless water heaters. This is not meant to be exhaustive, just simply my humble observations with my specific application. Others may have contrary experiences.

    If you are considering a tankless water heater, do your homework, and seek the opinions of qualified professionals and those who have had tankless water heaters.

    Tankless water heaters in my opinion are not do it yourself projects. Have them installed only by those who are qualified.


    Conclusion:

    If I moved and had to replace my water heater, assuming the home could support one, I would do it again ...


    Monthly Updates

    Below are brief summaries of the results month by month. Because 1 post can only contain so many characters I can not give the full summary for each month in this post; however, I will provide the numbers. For a full summary of the month you will need to go through the thread as they are posted.


    Nov 2008:

    At the meter this year: 49 Last Year: 59

    Or a 17% reduction.

    But ... the billing factor killed me and that 49 got bumped up to 55 after all was said and done.

    This works out to a 7% (55/59) reduction in therm usage.


    Dec 2008:

    Natural Gas

    This year: 86 therms.

    Last year: 97 therms.

    11.3% difference.

    Combined therm savings to date: 15%
    Combined dollar savings to date: 16%

    Water Usage

    Water Usage Nov 2008: 1860
    Water Usage Nov 2007: 1600

    I used 260 more units of water, or about 16%, this year for this time period, than last year.

    Jan 2009:

    Natural Gas


    This year: 143 therms
    Last year: 121 therms

    A -18.2% difference.

    Combined therm savings to date: 15%
    Combined dollar savings to date: 3%

    Water

    This year: 1580 therms
    Last year: 1610 therms

    Feb 2009:

    Natural Gas


    This year: 120 therms
    Last year: 135 therms

    A 11% difference.

    Combined therm savings to date: 5%
    Combined dollar savings to date: 5%

    March and April 2009:

    March

    Natural Gas


    This year: 92 therms
    Last year: 88 therms

    A -5% difference.

    Water

    This year: 1250 therms
    Last year: 1530 therms

    April Natural Gas

    This year: 71 therms
    Last year: 82 therms

    A 13% difference.

    Combined therm savings to date: 5%
    Combined dollar savings to date: 5%

    May 2009:

    Natural Gas


    May 2008 Therms: 67
    May 2009 Therms: 39
    Therm Savings: 28 therms or 42%

    Total Therm Savings: 8%
    Total Dollar Savings: 9%

    Water

    May 2009: 1590
    May 2008: 1690

    June 2009:

    Natural Gas


    June 2008 Therms: 27
    June 2009 Therms: 13
    Therm Savings: 14 therms or 52%

    Total Therm Savings: 10%
    Total Dollar Savings: 11%

    July 2009:

    Natural Gas


    July 2008 Therms: 19
    July 2009 Therms: 10
    Therm Savings: 9 therms or 47%

    Total Therm Savings: 11%
    Total Dollar Savings: 12%

    Water

    July 2008: 1790
    July 2009: 1270

    Total Water Tank: 10190
    Total Water Tankless: 9520

    7% difference.

    August 2009:

    Natural Gas


    August 2008: 13
    August 2009: 7

    Therm Savings: 6 or 46%.

    Total Therm Savings to date: 12%
    Total Dollar Savings to date: 12%

    Final summary is found here.
    Attached Files
    Last edited by theoak; 08-17-2009, 11:44 AM.

  • #2
    Re: My tankless experience summary

    I did a clogged kitchen sink job today and the customer told me him and a couple of his buddies installed a tankless heater.


    Asked him what brand, bosch, from lowes. Paide around $1300 for it including the 14' of stainless steel duct.



    Here's his statements:


    Continuous hot water

    Gas bill went down

    BUT


    Hot water cannot be regulated in the summer time. They have to run a lavatory sink when taking a shower because the water gets so hot.

    Also, they haven't done any maintenance on this unit....and he seemed to act a little curious as to what I was talking about....?

    I'm thinking yeeeeeeeep! That's where everything will go wrong.....especially that bosch.



    What impressed me? Damn thing was so freaking quiet, couldn't tell it was on.


    Quieter than a standard gas water heater.


    He would of dropped 3 grand if he had a plumber do the job, easily. But that can't be good that they have to caution themselves that they can't properly regulate the hot water temperature.

    Device shows 105 degrees, no way it's that temp when it can literally melt the skin off your bones. But he said in the winter, the extreme heat problem goes away.


    When it breaks......he'll be without water for days. If the electric goes out, he'll be without hot water.

    I talked to him about delime/descaling.....? Went over his head and I promise it will never get done by the way he acted. Where does that leave efficiency at that point.
    Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

    Comment


    • #3
      Re: My tankless experience summary

      "They have to run the lav while taking a shower"

      Dunbar,
      Love ya like a brother.You've impressed upon me as someone who is articulate.

      But if someone I didn't know told me this they would forever branded as
      "DUMB AS A BOX OF ROCKS !!!!!!"

      Or he better be replacing the valve.

      Adam

      Comment


      • #4
        Re: My tankless experience summary

        Added the following above:


        Maintenance:

        From what I have found, most tankless manufacturers recommend that you periodically check the inbound water filter. It is a small circular filter found on the cold water side. I talked to a local home owner that had a tankless. He commented how his hot water flow had starting to decrease. The installer came and looked at the filter and noted that it was pretty plugged up. Once the filter was cleaned out, hot water flow returned to like new. I have checked my filter about half a dozen times now. Once after the initial installation and once after I had additional plumbing work done (added another bathroom to my house). Both times had debris in the filter. There was also another time where there were about a half dozen small rocks, just barely large enough to be stopped by the screen, in the filter.

        What is also recommended is a yearly flushing of the unit using a "utility pump", a few hoses, and some clear vinegar. I as of yet need to get one. Googling, I have found these pumps at Lowes and Home Depot for around the $80 range. Most seem to be self priming. The purpose of the flushing is to remove any build up in the unit. Even tanks are subject to build up; however, due to the fact that the diameters of tanks are much much larger than the pipes that go through a tankless unit, tankless units are naturally more sensitive to buildup than a tank would be.


        Installation:

        I had 4 contractors come out and give me bids. Three were in the mid to high $2000 dollar range. One was way out there at $4000. I have seen posts, I believe even in this forum of a quote in the low $2000 range. It could be that tankless install costs are coming down. It could be a sign of the economy too. Tankless installations are typically 1.5 to 2 times more expensive than a tank install. Don't be afraid to ask for tankless references from your contractors. My experiences here in Idaho may be completely different from what one may experience in New York.

        Comment


        • #5
          Re: My tankless experience summary

          Originally posted by drtyhands View Post
          "They have to run the lav while taking a shower"

          Dunbar,
          Love ya like a brother.You've impressed upon me as someone who is articulate.

          But if someone I didn't know told me this they would forever branded as
          "DUMB AS A BOX OF ROCKS !!!!!!"

          Or he better be replacing the valve.

          Adam

          Yeah he didn't want me messing or diagnosing the tankless which I wasn't asked to do...I just heard that statement and seemed like a problem for sure with kids in the house.

          Funny how he was protective of his install that he didn't want any critics, even though it was wrong. I guess he felt he was doing the plumber's job and that was that.


          He's got a bad BAD situation on a kitchen sink drain; has a 3" belly in 1.5" over 12'.

          If he can put a tankless in, he'll most likely take care of this drain issue, instead of me now that he knows why I was there.
          Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

          Comment


          • #6
            Re: My tankless experience summary

            Results for November are in.

            At the meter this year: 49 Last Year: 59

            Or a 17% reduction.

            But ... the billing factor killed me and that 49 got bumped up to 55 after all was said and done.

            This works out to a 7% (55/59) reduction in therm usage.

            Remember though ... I added about 15% more square footage to my home a few months back. Now that my furnace is running it makes sense that it is going to work longer because there is more house that it has to heat.

            After all is said and done though ... this seems about right ...

            Last month with no heat and just water I used 14 therms. Lets say I used the same amount for water this month, that would leave 41 (55 - 14) therms used by my furnace.

            For Oct of 07 I used 24 therms for water. Using the same logic as above, that would give me 35 (59 - 24) therms used by my furnace. With that being said though I have a feeling that some of the 24 therms last year actually went to heat, so a more realistic value would be 20 therms used by my water heater or 39 (59 - 20) therms used by my furnace. Therefore, my furnace this year would have worked about 2 (41 - 35) to 6 (41 - 35) therms harder for my added space, which seems reasonable. It also makes sense that my inbound water temperature might be a little lower too which might account for a therm or two which would close the gap.

            Another observation ... in the kitchen at least, when I turn the water off and on in short spurts I am feeling the cold sandwiches . It was not the drastic scolding hot to freezing cold that some reports seemed to suggest however. It goes more hot, warm, cold, warm, hot. I attribute this to colder water. I rarely noticed this in the summer.
            Last edited by theoak; 11-13-2008, 03:08 PM.

            Comment


            • #7
              Re: My tankless experience summary

              Best maintance for a tankless is maintaining water before it hits the heater. I always recommend a softner and a whole house filter(http://www.filtersfast.com/ProdImages/ob1.jpg) just before the heater.

              Comment


              • #8
                Re: My tankless experience summary

                What is a "therms"? In Canada we use "Cubic metres" or "Cubic feet" of natural gas. In any event, forget "Therms" and "cubic metres" I want to know in DOLLARS...how many DOLLARS did you save last month with the tankless? $5? $25? $100? My summer natural gas bill in Toronto is $25 for 30 days with a regular $188 gas water tank (I bought it at Home Depot 4 years ago for $188, 40 gallon, a Rheem) At $25 per month for natural gas I would need 120 months (10 years) to pay off a $3000 tankless...ummmmm, no thanks.

                Comment


                • #9
                  Re: My tankless experience summary

                  Originally posted by Chemeng View Post
                  What is a "therms"? In Canada we use "Cubic metres" or "Cubic feet" of natural gas. In any event, forget "Therms" and "cubic metres" I want to know in DOLLARS...how many DOLLARS did you save last month with the tankless? $5? $25? $100? My summer natural gas bill in Toronto is $25 for 30 days with a regular $188 gas water tank (I bought it at Home Depot 4 years ago for $188, 40 gallon, a Rheem) At $25 per month for natural gas I would need 120 months (10 years) to pay off a $3000 tankless...ummmmm, no thanks.
                  Thus far over the 3 months I have reduced my therm usage by about a combined 20%. I would naturally then see about a 20% reduction in my natural gas bill. You can do the math from there and figure out the payback in years from looking at what your installation cost would be divided by 20% of what you spent last year in natural gas.

                  Again, for me, I have a large family and so the continuous hot water is what I was after which in my opinion, adds value above and beyond the 20% ...

                  Comment


                  • #10
                    Re: My tankless experience summary

                    Originally posted by nomoreleak View Post
                    Best maintance for a tankless is maintaining water before it hits the heater. I always recommend a softner and a whole house filter(http://www.filtersfast.com/ProdImages/ob1.jpg) just before the heater.

                    I would take this advice with a grain of salt I have seen salt softners eat through the best Bradford White Water Heaters in less than a year.


                    IF this is something you may be interested have your water evaluated by an independant testing company (not the guy selling the softening / filter equipment.)

                    Just a few thoughts...

                    Okie

                    Comment


                    • #11
                      Re: My tankless experience summary

                      And so that baby will pay for itself.......never

                      Wait a couple years when the thing starts to have problems. Then get back to us.

                      By strict interpretation of the code, these things should not be installed. The code says you must provide continuous how water to all the fixtures in the house. There is no way in hell these things will do that. then there's the issue of the water temperature which though it ain't supposed to, it does fluctuate quite a bit during normal operation.
                      I may be old school but then again these things are nothing new. Paloma, and ELM Aquastar come to mind. We all jumped on that band wagon the first time oil and gas prices went sky high and we all hated the damned things. Funny how memories fade over time. For what they cost to purchase and install they are no bargain and will in most cases never pay themselves off in a lifetime of operation which if memory serves me is about 7 years or so then the flow valves screw up and the exchangers burn out and and and and........ Waste of money.
                      sigpic

                      Comment


                      • #12
                        Re: My tankless experience summary

                        Originally posted by OkieBill View Post
                        I would take this advice with a grain of salt I have seen salt softners eat through the best Bradford White Water Heaters in less than a year.


                        IF this is something you may be interested have your water evaluated by an independant testing company (not the guy selling the softening / filter equipment.)

                        Just a few thoughts...

                        Okie
                        Softeners as I understand it Kill tank water heaters because they eat the anode rod then move on to the tank. But with a tankless there is no anode and the heater exchangers are more often than not copper which a softener will leave a coating on making it harder for deposits to stick to. This is all just what I have gather in my short 3.5 years in the field so I most definitely ma have been mislead. I do know some tankless companies won't honor the warranty unless there is some form of water treatment to the unit. please correct me if I am wrong

                        Comment


                        • #13
                          Re: My tankless experience summary

                          OK, so 20% savings of my summer hot water gas bill...hmmm I normally spend $25 x 20% is 5 bucks....not bad ....I install a $3000 tankless unit and save 5 bucks a month...I'm SOLD....where do I sign up for one?

                          Comment


                          • #14
                            Re: My tankless experience summary

                            Originally posted by NHMaster3015 View Post
                            And so that baby will pay for itself.......never
                            ...
                            Originally posted by Chemeng View Post
                            OK, so 20% savings of my summer hot water gas bill...hmmm I normally spend $25 x 20% is 5 bucks....not bad ....I install a $3000 tankless unit and save 5 bucks a month...I'm SOLD....where do I sign up for one?
                            During the summer months I actually ranged from 25% to 40%. The 20% was a combined rate total to date.

                            With that being said, again, "payback" is a subjective thing where for some, is just dollars, for others more. To each their own ...

                            Comment


                            • #15
                              Re: My tankless experience summary

                              Originally posted by theoak View Post
                              During the summer months I actually ranged from 25% to 40%. The 20% was a combined rate total to date.

                              With that being said, again, "payback" is a subjective thing where for some, is just dollars, for others more. To each their own ...

                              No, no...payback is not subjective at all. It is an actual dollar amount. It can be calculated fairly accurately.

                              However, if you are happy with it then naturally that is what matters. In fact, I thank god for folks that have talked themselves into buying things that are impractical. It keeps the economy strong..... well, it used to anyway
                              sigpic

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