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  • Electric Hot Water Heater vs Natural Gas Hot Water Heater

    Greetings:

    3 story (1,900 sft) -125+ year old brick row home on the East Coast. I have two full baths (showers are separate from the tubs. I also have one 5 foot Whirlpool jet tub and the other tub is a standard 5 foot tube. Other than that I have dishwasher.

    I originally had a gas hot water tank. Because I removed the old chimney from the basement to the roof (to gain precious space inside) I now have to replace the hot water heater. I was considering gas and would need a heater that can be vented using plastic.

    I read a posting here and a few other places (to my surprise) that an electric heater is more efficient than a gas heater and would save me on my monthly costs? Does this hold water…?

    I did consider tankless but my reading say the ROI isn’t there (unit cost as well as installation costs). I’ve also seen that there could be intermittent hot water at times. What I’m gathering is they are best when multiple units are used and are installed directly next to your water needs.
    I’m looking at getting a 50 gallon tank? Moving from a 30 gallon gas tank. I had the 30 gallon because my house was originally divided and I only have 2 floors and 1 bath (without Whirlpool). Now I have 3 floors and two full baths.

    Is that true that electric can be just as efficient cost wise as natural gas?

    With the limited information does a 50 gallon sound correct?

    Any recommendations on brands as some manufactures are better at electric than gas?

    Thanks in advance.
    Last edited by Knezz; 05-01-2011, 09:07 AM.
    Regards,
    K. Nezz

  • #2
    Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

    are you sure about the 19,000 square foot home

    more like 1,900 square feet

    a 50 gallon direct vent would be your best bet.

    electric are very efficient. very little energy is lost in the heating process compared to gas. problem is electricity energy cost are much more expensive than natural gas. at least out here.

    other than that, your assessments are correct

    now do you live in a castle or a house

    rick.
    phoebe it is

    Comment


    • #3
      Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

      Down here on the 27th parallel, we don't have natural gas and LP
      is more expensive than electric. So, about 95% of the water heaters
      are electric. You will just have to compare the cost of what gas is
      available in your area to electric. I like to see at least a 65 gal. unit
      if you're going to be filling a whirlpool tub. Stay away from the
      big box brands.

      Comment


      • #4
        Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

        Originally posted by PLUMBER RICK View Post
        are you sure about the 19,000 square foot home

        more like 1,900 square feet


        now do you live in a castle or a house

        rick.
        It's more like a shoe box... 1,900 square feet it is...
        Regards,
        K. Nezz

        Comment


        • #5
          Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

          Originally posted by PLUMBER RICK View Post
          a 50 gallon direct vent would be your best bet.

          electric are very efficient. very little energy is lost in the heating process compared to gas. problem is electricity energy cost are much more expensive than natural gas. at least out here.

          other than that, your assessments are correct

          rick.
          What I'm understanding is that all things being equal electric is more efficient? Do to the cost of electric compared to gas the monthly costs will make gas a better choice in your area (I'm sure gas is cheaper here also)?

          Now- how can I calculate gas compared to electric (btu vs kwh)? Any online calculators that can help me.

          The contractor wants to charge $2300 for gas (direct vent) and $1,100 for electric.
          Regards,
          K. Nezz

          Comment


          • #6
            Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

            Here is a calculator you can try:

            http://www1.eere.energy.gov/femp/tec...ters_calc.html

            Gas is considerably less efficient than electric. Both lose some heat from the tank itself. With gas though, like anything with an exhaust pipe, a certain amount of heat is unavoidably lost up the flue. With an electric, the heating element puts virtually all the thermal energy into the water. Because of this, the electric is more efficient. However, efficiency for most people isn't usually as important as total operating cost. Natural gas is most often cheaper, where it's available.

            If you're concerned about efficiency in the environmental sense, it might seem that electric has the edge. This isn't really always true. Most electricity in the US is generated from burning fossil fuels, so if you're motivated by environmental "green" considerations you should take into account the efficiency of electricity generation. In this sense, electric water heat isn't necessarily more efficient or "greener" in the total picture, just like electric cars aren't necessarily any more efficient or "greener" than internal combustion cars when you consider the electric generation.

            A third alternative is the hybrid water heater offered by several manufacturers. Stielbel-Eltron, Rheem and GE, among others offer these. The GE and Rheem are, I think, similar and both made by Rheem. They are based on a design developed at Oakridge National Laboratory that helps little heat pumps achieve decent, though unspectacular, performance. A traditional electric heater uses a simple resistive element. The hybrids use a small heat pump, with a secondary resistive element to provide good recovery time. These can reduce the cost of electric water heating by 1/3 or so (in the real world) depending on usage. They're expensive ($1500+), and more complicated (that means probably less reliable) but if I was in a spot where electric was needed, I would consider one. They generally don't reduce energy costs enough to make them competitive with a natural gas water heater. The other catch with these is that you have to install them in a heated space maintained at 40F minimum... the higher the temp, the better it will work and the more money it will save. Putting it in a cold place kills the heat pump performance, so the thing will run on the resistive heater, eliminating the advantage.

            You could also go with a gas or electric tankless.... but I don't see either of those as very cost effective for most people/families.

            In your calculations, most households use 60 to 80 total gallons of water per person per day but keep in mind that the hot water use per person is considerably less, even considering dishwasher and laundry. Size of the house isn't too important... it's not a space heater. Neither is how many bathrooms and all that. The driver is how many people are actually living there, creating demand for hot water.
            Last edited by Andy_M; 04-19-2011, 12:28 PM.

            Comment


            • #7
              Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

              check with your electric company, some of them sell vaughn water heaters to their customers. they're stone lined and hella effecient.
              No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

              Comment


              • #8
                Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                Go with two 40 gal electrics piped in parallel. I say two 40's if you have a busy family and use the tub alot.

                Go with a 50 gal electic wired for simultaneous element operation or a 50 with the temp cranked up to 140 with a tempering valve added........or just go tankless and forgettaboutit

                Comment


                • #9
                  Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                  If you go with the two water heaters piped in parallel I would remove the drain valves and install tee fittings and use this for my cold water inlet. You do realize that typical residential water heaters have a restricted cold inlet,the diptube does this for you. I like full flow bro

                  Comment


                  • #10
                    Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                    Originally posted by TheMaster View Post
                    If you go with the two water heaters piped in parallel I would remove the drain valves and install tee fittings and use this for my cold water inlet. You do realize that typical residential water heaters have a restricted cold inlet,the diptube does this for you. I like full flow bro
                    Two heaters to expensive for my current pockets.
                    Regards,
                    K. Nezz

                    Comment


                    • #11
                      Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                      My main concern at this point is cost over 6 years (tank and installation cost along with reoccurring monthly utility bill for 72 months).I’m using 70 gallon per day for two people (140 gallons per day for total water - 1/3 of total water will be heated as a guess). I’m also going with the FEMP recommendation.

                      My Electric Company is charging 0.1588 per kWh (includes all fees except the $7.25 monthly customer charge)

                      My Gas Company is charging 2.264345 Ccf (not including a monthly Customer charge of $12.00). 2.264345 Ccf x 1.024 therm conversion factor = 2.31868928 therm

                      $558 annual for electric + ($7.72 x 12 months – customer charge = $87.00) = $645.00 per year

                      $411 annual for gas + ($7.25x12months- customer charge = $144.00) = $555.00 per year

                      ***Am I correct in my understanding of comparing the two?***

                      Because the contractor is saying that the gas heater is $1,200.00 more to install than electric it would take me 13 years to recoup those additional dollars of installing gas if my understand of comparing gas to electric is correct?

                      Is it true that electric tanks usually have issues prior to gas as the elements in the electric go bad more? Or is that an old wives’-tale?

                      I used this site for conversion http://www1.eere.energy.gov/femp/tec...ters_calc.html (Thanks Andy M)

                      Edit.... error in my considerations. Andy M specifically underlined the fact that 140 gallons is total water usage - hot water is considerably less. With two bathrooms, dishwasher and the other normals would 1/3 of total usage be a reasonable gauge? If so, it might take me about 13 years to realize a savings in gas?

                      Does any of this make sense or am I barking up the wrong tree?

                      Regards.
                      Last edited by Knezz; 04-20-2011, 09:46 AM.
                      Regards,
                      K. Nezz

                      Comment


                      • #12
                        Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                        Originally posted by Knezz View Post
                        Two heaters to expensive for my current pockets.
                        Two 40's would be cheaper than one 65 gal......just talking about the water heater itself...not to install or operate. When you go above a 50 gal the price jumps alot.

                        Comment


                        • #13
                          Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                          Something to keep in mind. An electric water heater will recover a lot slower than a gas water heater. Something like just 18 gallons an hour 100 degree rise on a 4500 watt element. If your electric is billed like mine it is billed in tiers. In summer time when or if you have air conditioners running its easy to get into the third tier where your paying a lot more per kilowatt hr. Gas is generally your best choice. At least in California.

                          Comment


                          • #14
                            Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                            Two 40 gal? Doesn't that seem like a lot of water to keep hot for two people? I would think a 40 or 50 gal gas or 50 gal elec would do the job.

                            Your costs should always be lower with one large heater compared to two smaller ones. Surface area to volume ratio of the tank decreases (less heat loss per gallon) with the larger tank.

                            Two water heaters take up significantly more space than one larger one.

                            Two heaters buys you twice the failure rate.

                            I don't know what's in the installation costs OP cited. The cost for gas install could be high due to difficulty in venting?

                            And what's with venting in plastic?? Is this common? I've only seen conventional metal exhaust vents with gas... maybe one of you pros could comment on plastic for a gas WH? I'm guessing that the venting difficulties are contributing heavily to what seems like very large install costs for gas.... which is too bad.... I like gas where it's available for its better recovery performance and operating cost advantages.
                            Last edited by Andy_M; 04-20-2011, 01:56 PM.

                            Comment


                            • #15
                              Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                              Originally posted by Andy_M View Post
                              Two 40 gal? Doesn't that seem like a lot of water to keep hot for two people? I would think a 40 or 50 gal gas or 50 gal elec would do the job.

                              Your costs should always be lower with one large heater compared to two smaller ones. Surface area to volume ratio of the tank decreases (less heat loss per gallon) with the larger tank.

                              Two water heaters take up significantly more space than one larger one.

                              Two heaters buys you twice the failure rate.

                              I don't know what's in the installation costs OP cited. The cost for gas install could be high due to difficulty in venting?

                              And what's with venting in plastic?? Is this common? I've only seen conventional metal exhaust vents with gas... maybe one of you pros could comment on plastic for a gas WH? I'm guessing that the venting difficulties are contributing heavily to what seems like very large install costs for gas.... which is too bad.... I like gas where it's available for its better recovery performance and operating cost advantages.
                              One 50 gal gas set at 120 may not even get him a shower and her jetted tub filled.....depends on their habits.

                              I've seen instances where two smaller heater will fit through a door way or up through an attic pull down staircase but a larger tank will not fit. Plus one man can handle two water heaters easier than one big tank.

                              Having two 40 gal tanks can actually prolong the life of both water heaters as running the tank cold on a regular basis can and will cause the heater/heaters to fail at a faster rate....an with two heaters piped in parallel with isolation valves your chances of both heaters going bad at the same time is not likely and this would avoid an emergency situation of having no hot water.

                              With two 40 gal electrics the recovery would be faster than one water heater because you would have two seperate power sources working together.....and if you wanted you could wire them so that all 4 elements would fire at the same time.

                              Any questions?

                              Comment

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