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  • #16
    Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

    Originally posted by fresnoplummr View Post
    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.
    Initial costs and reoccurring cost are major factors for me. Being that the gas heater will be about $1,200.00 more that the electric – cutting venting through brick wall etc.. Two heaters are out of the question due to costs (understanding the reasoning for the suggestion).

    There are usually just the two of us (empty nesters).

    Looking at my calculations – do they make sense or am I missing something?

    Will the gas heater cost over a few years make up for the $1,200.00 difference? That just seems like a large cost gap to my layman’s mind.

    Regards.
    Regards,
    K. Nezz

    Comment


    • #17
      Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

      Originally posted by fresnoplummr View Post
      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.
      Where are you finding 20 degree water? Who figures a 100 degree rise? An electric water heater has less standby loss....no flue...thats not insulated and no pilot. Electrics cheaper here by far to buy,install,maintain and to operate.

      With gas the make up air is all too important.....electric doesn't have those problems or considerations. The new FVIR water heaters have made me quite a bit of money in service calls due to dirty enviroments or just plain malfunctions in general.
      Last edited by TheMaster; 04-20-2011, 06:26 PM.

      Comment


      • #18
        Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

        Originally posted by TheMaster View Post
        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?
        Thanks for explaining your logic.

        There really isn't enough detail about the installation, for example the capacity of the jetted tub, to make a capacity recommendation. I see your point, but it's expensive to go with two heaters... and there's clearly a budget at issue here. I would make sure it was needed first. I presumed that OP came up with a 50 gal considering his jetted tub and usage pattern. If his 5' jetted tub is huge in volume, then you have a good point and more hot water would be needed.

        Don't see that OP mentioned that getting a 50 gal through the door would be a problem. Again, a good point, but only if that's the case.

        If too heavy for one guy, installer should bring a helper, no? As opposed to intalling two heaters at Customer expense? As a Customer I wouldn't be happy if I was sold two tanks instead of paying a little more for a helper to assist with the heavy lifting. Just sayin'.

        Appreciate your comment about element life. Not losing hot water completely is definitely a feature. However most residences have a single heater, so this a "nice to have" but not really necessary, especially if one is on a budget. On the other hand, two heaters means twice as many leaks, twice as many anode rods to replace, etc.

        Recovery time is a good point. If it's a concern, a gas heater with large burner might be a more cost effective solution than dual electrics. And considerably chea[er in terms of utility bills in most areas.

        One thing's for sure - If OP really needs more hot water, he should increase the capacity somehow. But it won't be cheap.

        EDIT: But can you comment on plastic venting for gas WHs? I've never seen it and it sounds goofy to me. But then again there are many things I haven't seen.
        Last edited by Andy_M; 04-20-2011, 08:00 PM.

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        • #19
          Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

          It's a powervent model, like a pvc flued furnace.

          Originally posted by Andy_M View Post

          EDIT: But can you comment on plastic venting for gas WHs? I've never seen it and it sounds goofy to me. But then again there are many things I haven't seen.
          No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

          Comment


          • #20
            Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

            Originally posted by Andy_M View Post
            Thanks for explaining your logic.

            There really isn't enough detail about the installation, for example the capacity of the jetted tub, to make a capacity recommendation. I see your point, but it's expensive to go with two heaters... and there's clearly a budget at issue here. I would make sure it was needed first. I presumed that OP came up with a 50 gal considering his jetted tub and usage pattern. If his 5' jetted tub is huge in volume, then you have a good point and more hot water would be needed.

            Don't see that OP mentioned that getting a 50 gal through the door would be a problem. Again, a good point, but only if that's the case.

            If too heavy for one guy, installer should bring a helper, no? As opposed to intalling two heaters at Customer expense? As a Customer I wouldn't be happy if I was sold two tanks instead of paying a little more for a helper to assist with the heavy lifting. Just sayin'.

            Appreciate your comment about element life. Not losing hot water completely is definitely a feature. However most residences have a single heater, so this a "nice to have" but not really necessary, especially if one is on a budget. On the other hand, two heaters means twice as many leaks, twice as many anode rods to replace, etc.

            Recovery time is a good point. If it's a concern, a gas heater with large burner might be a more cost effective solution than dual electrics. And considerably chea[er in terms of utility bills in most areas.

            One thing's for sure - If OP really needs more hot water, he should increase the capacity somehow. But it won't be cheap.
            I didn't comment on element life....I commented on tank life. An undersized water heater will fail at a higher rate than a properly sized tank. A 65 gal electric costs more than two 40 gal tanks to buy and depending on the installation location is can be more expensive to install. So two heaters does not mean twice as many leaks...theidea is to have too much so the tanks dont sweat as much...sweating tanks eat from the outside in....the bare tak has no rust protection. If he buys a 50 and runs it out of hot water on a regular basis he could literally go through 3 or 4 heaters compared to the life of the two electrics or gas heaters or a properly sized one tank.....but then the price jumps as I said...I can buy two 40's cheaper than one 65.

            Yes I'm saying a 50 is too small...especially if he has a low incoming water temp.

            Comment


            • #21
              Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

              Other options:

              Option 1 -- Two heaters, two isolated systems

              My father put in two water heaters. He did this to set a lower temperature for bath and sink where the kids might get burnt and a higher temperature for dishwasher, laundry, and laundry room. (Dishwashers and laundry detergents required higher temperatures back in the 1950's.) The tanks were 30 gal and 40 gal. Each ran its own system of pipes, like two seperate systems.

              If there is a long run to one bath, a dedicated electric water heater placed right next to that bath might be cheaper to run than having to run water for long period to wait for the hot water to get there.

              You may choose to split the system so that the high-usage jetted tub (or that bathroom) is on it's own heater.

              Option 2 -- Gas and Electric in series

              In my house, I have both a gas and electric heater, connected in series with the gas unit first. These were installed by a very paranoid previous owner who didn't believe you should count on a single untility supplier. (We also have a gas furnace and baseboard electric heaters in some rooms, and even had a few gas lights, left over from the 1910's, which I disconnected or converted to electric.)

              By setting the gas at about 145, and the electric at about 125, the water simply flows from the gas tank to the electric tank. Temperatures do not drop that much in the electric, and it doesn't even turn on unless the water isn't used for 18 hours or so. If it does go on, it is only used a little to kick up the temperature a few degrees. The gas water heater, which is more ecconomical to run in our area does the "grunt" work to initially heat the cold incoming water.

              We went through a wind storm and power outages in the area last night. Our electricity is out at the house. But we still have plenty of hot water. The electric heater stands most of the time as nothing more than a storage tank.

              We rarely experience gas outages, but did go through a period when a contractor installing new gas lines in the area made a mistake and "forgot" to connect an existing main to the new piping. The whole system to our neighborhood was out for a period of 2 days. Again, we had hot water (but in more restricted amounts) while the gas was out, thanks to the electric heater.

              Option 3 -- Electric using lower night heating costs

              Where my sister lives, they sell electricity at lower rates if used in the night. The utility installed a special meter for the purpose with seperate dials for daytime and night electric usage. Because of the special equipment, you are charged more for the electric connection fee.

              If you qualify this might be an option, but you may need to make lifestyle changes, install either larger than normal heaters, or add some form of storage tank, so the "grunt" heating occurs only during the nighttime hours. In my sister's case, both she and my brother-in-law work evenings, so when they get home, they can use all the hot water they want and be heating it only during the lower cost period.

              A note on "storage tanks". I needed to buy one once for a place I worked and found out it was cheaper to buy an electric heater and simply not connect it to the electric lines, than to buy a tank listed as a "storage tank".

              Comment


              • #22
                Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                Originally posted by TheMaster View Post
                I didn't comment on element life....I commented on tank life. An undersized water heater will fail at a higher rate than a properly sized tank. A 65 gal electric costs more than two 40 gal tanks to buy and depending on the installation location is can be more expensive to install. So two heaters does not mean twice as many leaks...theidea is to have too much so the tanks dont sweat as much...sweating tanks eat from the outside in....the bare tak has no rust protection. If he buys a 50 and runs it out of hot water on a regular basis he could literally go through 3 or 4 heaters compared to the life of the two electrics or gas heaters or a properly sized one tank.....but then the price jumps as I said...I can buy two 40's cheaper than one 65.

                Yes I'm saying a 50 is too small...especially if he has a low incoming water temp.
                You can't conclude that a 50 is too small based on what OP has posted. A five foot jetted tub such as OP has said he has can hold a lot water volume, in which case he may well need more capacity... but some of the five footers are barely more than a regular tub, in which case a 50 would work fine.

                Sorry I misinterpreted your comments on the tank failure. Sweating, though, can only be an issue if the tank temp goes below the dew point. Since we don't know anything about the install, eg, is the space heated space or unheated, and what is the supply temp, as well as the tub sizing, neither of us can really make any intelligent comment on whether this will be an issue. But it's a good point for him to discuss with his plumbing contractor, who presumably is familiar with the local conditions of climate and main temp, as well as the volume of the jetted tub.

                65 gallon WHs are very pricey. A single 50, if it will do the job, is going to be cheaper to install, run and maintain than dual 40s. It all comes down to the tub... I have no idea how you can conclude that 50 gal is insufficient knowing nothing about the tub. I have a 6 foot soaking tub, also two bathrooms and two people.... and have been doing fine on a 40 gal gas that was installed in 1995. It seldom runs out of hot water and has lasted pretty long. When it does finally die I will get a 50 gal, 12 year warranty GE (Rheem) gas at H-D for $650, which will be more than adequate. That's just my experience. Dual 40 gallon tanks would never run out, but would cost a lot more to run and are not necessary in my application. Because my situation is similar to OPs, I don't see that dual tanks are needed for him either, unless that tub is large.

                Brookline: I use a 4 gallon Ariston electric mini tank under the kitchen sink, in series with the main WH. I did this because the wait time for hot water was very, very annoying, and I'm not a fan of the recirculating systems. I love the mini-tank. It is cheap to buy, easy to install, couldn't do a better job and I the energy use is so low that I don't notice it on my bill. You do have to be a contortionist to get under there to change the anode, though... small price to pay compared to the benefit.

                Comment


                • #23
                  Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                  I was remised in including the whirlpool tub specs – very small tub - 60” x 43” x 20” 60 Gallon capacity. In that bath room there is a separate shower, one sink. In the 2nd bathroom there is another standard 60” tub, separate shower, sink. The only other hot water considerations are the kitchen sink, dishwasher, clothes washer and basement utility sink.
                  Regards,
                  K. Nezz

                  Comment


                  • #24
                    Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                    Originally posted by Andy_M View Post
                    You can't conclude that a 50 is too small based on what OP has posted. A five foot jetted tub such as OP has said he has can hold a lot water volume, in which case he may well need more capacity... but some of the five footers are barely more than a regular tub, in which case a 50 would work fine.

                    Sorry I misinterpreted your comments on the tank failure. Sweating, though, can only be an issue if the tank temp goes below the dew point. Since we don't know anything about the install, eg, is the space heated space or unheated, and what is the supply temp, as well as the tub sizing, neither of us can really make any intelligent comment on whether this will be an issue. But it's a good point for him to discuss with his plumbing contractor, who presumably is familiar with the local conditions of climate and main temp, as well as the volume of the jetted tub.

                    65 gallon WHs are very pricey. A single 50, if it will do the job, is going to be cheaper to install, run and maintain than dual 40s. It all comes down to the tub... I have no idea how you can conclude that 50 gal is insufficient knowing nothing about the tub. I have a 6 foot soaking tub, also two bathrooms and two people.... and have been doing fine on a 40 gal gas that was installed in 1995. It seldom runs out of hot water and has lasted pretty long. When it does finally die I will get a 50 gal, 12 year warranty GE (Rheem) gas at H-D for $650, which will be more than adequate. That's just my experience. Dual 40 gallon tanks would never run out, but would cost a lot more to run and are not necessary in my application. Because my situation is similar to OPs, I don't see that dual tanks are needed for him either, unless that tub is large.

                    Brookline: I use a 4 gallon Ariston electric mini tank under the kitchen sink, in series with the main WH. I did this because the wait time for hot water was very, very annoying, and I'm not a fan of the recirculating systems. I love the mini-tank. It is cheap to buy, easy to install, couldn't do a better job and I the energy use is so low that I don't notice it on my bill. You do have to be a contortionist to get under there to change the anode, though... small price to pay compared to the benefit.
                    A water heater will condensate when it goes from lets say 120 degrees to lets say an incoming water supply of 55 degrees. When you fill a hot tank with cold water......it will condensate between the bare steel and the insulation.

                    As you see the tub has a 60 gal capacity......you do realize that a 50 gal heater will not deliver 50 gal of thermostat setting of hot water dont ya? Its diluted by the cold incoming water...I believe you actually get 38 gal out of a 50 gal tank of actual thermosat setting......it all is dependent on the incoming water temp. Plus with a low incoming water temp the more hot you will use to fill a tub or take a shower to temper the cold your using on a pressure balanced faucet.

                    What temp is your 40 gal gas set to? 120 degrees? Tempering valve and set higher?

                    ADD> Look at the original posters location....seems like it would be cold there. Now consider the home. Two nice full baths with seperate showers and a jetted tub.......probably 3 or 4 bedrooms at least. The house seems to be built for up to 4 or 5 people...easy. So you have a family of 5 with 3 kids. Do you think a 50 gal water heater would be good or do you think two 40's in parallel would be better?

                    Heres the bottom line.....the tub is the deciding factor with me. If the lady or man of the house uses the jetted tub at his or her pleasure then a 50 gal heater will not be satisfactory.

                    I have basically the same tub and a seperate shower and a 50 gal electric heater and I live in a warm climate. I have my heater set at 130 degrees and I have an extended diptube.......If I take a shower while I fill my jetted tub and then add some more hot water to my bath as I soak......I dont have any hot water to shave with.
                    Last edited by TheMaster; 04-21-2011, 08:25 AM. Reason: ADD>

                    Comment


                    • #25
                      Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                      Originally posted by TheMaster View Post
                      A water heater will condensate when it goes from lets say 120 degrees to lets say an incoming water supply of 55 degrees. When you fill a hot tank with cold water......it will condensate between the bare steel and the insulation.
                      Uh, no. Condensation occurs when the temperature of the surface tank drops below the current dew point, which is the temperature at which the vapor pressure of the air reaches saturation, or 100% relative humidity. As the temp drops further, the relative humidity can't go above saturation... so atmospheric moisture precipitates out from the air and forms moisture on the surface.

                      The incoming water has to drop the tank temp below the dew point for there to be condensation. If the tank temp stays above the dew point, then you don't get condensation. If you don't know the local atmospheric conditions - that is, the barometric pressure and the level of entrained moisture in the air, then you don't know the dew point and there is no way that you, me or Einstein can predict that you will or won't get condensation.

                      The air trapped in the insulation won't be always at precisely the atmospheric dew point, but it won't be different enough to matter much. The exception is in the case where the insulation is getting soaked (say, due to a leak at the inlet or exit connections or some other such problem). But in those cases, you have bigger problems. I bet water dripping from leaky connections is responsible for more external rusting of tanks than condensation, but I'm just guessing.

                      So... you can't really claim that you'll get condensation just because the tank is filling with cold water. When you fill a glass with cold tap water do you always get condensation? No. But add some ice and you'll get condensation.. because the temp drops below the dew point. If you don't know the installation details you can't say if you're going to get condensation or not.

                      Originally posted by TheMaster View Post
                      As you see the tub has a 60 gal capacity......you do realize that a 50 gal heater will not deliver 50 gal of thermostat setting of hot water dont ya? Its diluted by the cold incoming water...I believe you actually get 38 gal out of a 50 gal tank of actual thermosat setting......it all is dependent on the incoming water temp. Plus with a low incoming water temp the more hot you will use to fill a tub or take a shower to temper the cold your using on a pressure balanced faucet.
                      Well, yes, I understand the relationships pretty well. Do you? You don't get 38 gallons or any other fixed number. You may not even get one one gallon at the set temperature. It's not a constant. The temp starts to drop immediately as soon as you turn on the hot water tap. The burner will come on as soon as the tank temp drops below the thermostat's dead band, but generally can't ever keep up with the demand from the tub fill valve, so the temperature will continue to drop during the entire fill. The actual temp of the fill of your tub depends largely on the incoming water temp but also on the size of the burner and the flow rate of the tub fill valve. A gas burner has more output than an electric element, which is why most engineers will spec out an electric WH with more 15-20% or more tank volume compared to a gas heater.

                      The sizing question is *not* about how much water you can get at the WH set temp. No sane person wants to bathe in a tub at the full 130F water heating setting. That's why the heater tank size isn't the sole determining factor in how much demand a WH can supply. Most people prefer full-body imersion temperatures in the range of 99 to 104 degrees. 104 is a limit for outdoor spas, and may be a legal limit for jetted bathtubs with heaters as well. In any case, that's the sort of temp area you will be in with a tub. A 50 gal WH with a good-sized BTU rating will be able to fill this 60 gal tub. Kohler recommends that the WH tank size should be 70% of the tub volume, which in this case would be 42 gallons. Kohler doesn't distinguish between electric and gas WHs, so it's safe to interpret this recommendation as applying to electrically-heated water. With a gas WH you will have extra margin.

                      As I mentioned, my 6 foot soaking tub does fine with a little old 40 gal gas WH. I keep the thermostat turned up to "hot"... probably about 130F, but I've never measured the actual outlet temp.

                      Again, a 50 gal gas WH will be able to fill this tub at bathing temperatures. Sure if someone jumps in the shower right after filling the tub, they could start to run low on hot water. Don't do that! Wait 15 or 20 minutes. Having to wait on the rare occasions when the residents want to use the tub and shower at the same time is, when you're on a budget, a more cost effective alternative to installing and operating 80 gallons of electrically-heated hot water!

                      Look, I'm not saying that your proposal is wrong or doesn't have merit. It could be could be 100% necessary -- if the reasons you gave are relevant to OP and his situation. My point is, you don't really know, and so I don't see how you can tell a budget-driven guy to install dual 40 gallon electrics without knowing a lot more details about the installation. Like, where it's going to be installed, the actual incoming water temp, the usage, etc. to justify the expense you're suggesting. Some of the answers to these questions might well lead one to install dual electric 40s. On the other side of the coin, this is an average sized home with two adults and one moderate demand applicance. If I were in OP's position of trying to work to a budget, it would take some serious convincing (i.e., facts and actual analysis rather than supposition) to get me to pop for the installation and operation of dual electric 40s. Personally I'm thinking that OP is coming from a 30 gallon gas heater, so I would be inclined to think in terms of a 50 gallon gas with a large BTU burner, and turn up the t-stat if needed. 50 gallon heaters are still in the sweet spot, price-wise.

                      But even so, if I were OP I would definitely raise the points you've highlighted with the plumbing contractor. Where initial money and operating costs are concerned, there is no place for guessing, hoping... or overkilling.

                      By the way, when shaving, if you rinse your razor with cold water, you'll get much less skin irritation. Especially on hot sticky days.

                      Comment


                      • #26
                        Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                        Originally posted by Andy_M View Post
                        Uh, no. Condensation occurs when the temperature of the surface tank drops below the current dew point, which is the temperature at which the vapor pressure of the air reaches saturation, or 100% relative humidity. As the temp drops further, the relative humidity can't go above saturation... so atmospheric moisture precipitates out from the air and forms moisture on the surface.

                        The incoming water has to drop the tank temp below the dew point for there to be condensation. If the tank temp stays above the dew point, then you don't get condensation. If you don't know the local atmospheric conditions - that is, the barometric pressure and the level of entrained moisture in the air, then you don't know the dew point and there is no way that you, me or Einstein can predict that you will or won't get condensation.

                        The air trapped in the insulation won't be always at precisely the atmospheric dew point, but it won't be different enough to matter much. The exception is in the case where the insulation is getting soaked (say, due to a leak at the inlet or exit connections or some other such problem). But in those cases, you have bigger problems. I bet water dripping from leaky connections is responsible for more external rusting of tanks than condensation, but I'm just guessing.

                        So... you can't really claim that you'll get condensation just because the tank is filling with cold water. When you fill a glass with cold tap water do you always get condensation? No. But add some ice and you'll get condensation.. because the temp drops below the dew point. If you don't know the installation details you can't say if you're going to get condensation or not.



                        Well, yes, I understand the relationships pretty well. Do you? You don't get 38 gallons or any other fixed number. You may not even get one one gallon at the set temperature. It's not a constant. The temp starts to drop immediately as soon as you turn on the hot water tap. The burner will come on as soon as the tank temp drops below the thermostat's dead band, but generally can't ever keep up with the demand from the tub fill valve, so the temperature will continue to drop during the entire fill. The actual temp of the fill of your tub depends largely on the incoming water temp but also on the size of the burner and the flow rate of the tub fill valve. A gas burner has more output than an electric element, which is why most engineers will spec out an electric WH with more 15-20% or more tank volume compared to a gas heater.

                        The sizing question is *not* about how much water you can get at the WH set temp. No sane person wants to bathe in a tub at the full 130F water heating setting. That's why the heater tank size isn't the sole determining factor in how much demand a WH can supply. Most people prefer full-body imersion temperatures in the range of 99 to 104 degrees. 104 is a limit for outdoor spas, and may be a legal limit for jetted bathtubs with heaters as well. In any case, that's the sort of temp area you will be in with a tub. A 50 gal WH with a good-sized BTU rating will be able to fill this 60 gal tub. Kohler recommends that the WH tank size should be 70% of the tub volume, which in this case would be 42 gallons. Kohler doesn't distinguish between electric and gas WHs, so it's safe to interpret this recommendation as applying to electrically-heated water. With a gas WH you will have extra margin.

                        As I mentioned, my 6 foot soaking tub does fine with a little old 40 gal gas WH. I keep the thermostat turned up to "hot"... probably about 130F, but I've never measured the actual outlet temp.

                        Again, a 50 gal gas WH will be able to fill this tub at bathing temperatures. Sure if someone jumps in the shower right after filling the tub, they could start to run low on hot water. Don't do that! Wait 15 or 20 minutes. Having to wait on the rare occasions when the residents want to use the tub and shower at the same time is, when you're on a budget, a more cost effective alternative to installing and operating 80 gallons of electrically-heated hot water!

                        Look, I'm not saying that your proposal is wrong or doesn't have merit. It could be could be 100% necessary -- if the reasons you gave are relevant to OP and his situation. My point is, you don't really know, and so I don't see how you can tell a budget-driven guy to install dual 40 gallon electrics without knowing a lot more details about the installation. Like, where it's going to be installed, the actual incoming water temp, the usage, etc. to justify the expense you're suggesting. Some of the answers to these questions might well lead one to install dual electric 40s. On the other side of the coin, this is an average sized home with two adults and one moderate demand applicance. If I were in OP's position of trying to work to a budget, it would take some serious convincing (i.e., facts and actual analysis rather than supposition) to get me to pop for the installation and operation of dual electric 40s. Personally I'm thinking that OP is coming from a 30 gallon gas heater, so I would be inclined to think in terms of a 50 gallon gas with a large BTU burner, and turn up the t-stat if needed. 50 gallon heaters are still in the sweet spot, price-wise.

                        But even so, if I were OP I would definitely raise the points you've highlighted with the plumbing contractor. Where initial money and operating costs are concerned, there is no place for guessing, hoping... or overkilling.

                        By the way, when shaving, if you rinse your razor with cold water, you'll get much less skin irritation. Especially on hot sticky days.
                        If your water heater is set to 130 degrees and its full of hot water and you run all the hot water out and fill it with 55 degree water the outside of the tank will sweat between the insulation and the tank. On a gas fired heater you can actually hear the condensation dripping onto the burner from the flue.....the manufacturers warn about excessive condensation and also tip the homeowner off that it could be condensation rather than a leaking tank.

                        So kohler says 70% of the tubs volume.....thats the minimum sir. Thats for people who just want to fill the tub and not use anymore hot water to speak of.....or you will be totally depleteing the tank and it will cause condensation.

                        Condensation cant escape from between the foam insulation and the steel tank very readily....this ever so slight condensation(or heavy) will eat away at the tank.

                        Under-sizing a water heater is a surefire way to failure. A pressure vessel only has so many cycles.....the larger the cycle the quicker it will fail. Thats why its best to have more than needed....the tanks temp doesn't fluctuate as much.

                        An electric tank has less standby loss than gas. A gas heater has a flue that cannot be insulated.....so standby loss is not really a factor if you use the heater everyday with an electric.

                        The typical 40 gal gas water heater would not even pass code here if you have a jaccuzi tub and only have one water heater. Whys that? How do they know a 40 wouldn't be "good enough"? Because we do this for a living.....thats why.

                        Skin irritation is not a problem from hot water and me shaving...infact it softens the hair to make the shave more comfortable. Thanks for the tip tho sweetheart.


                        When using my jetted tub I often drain 10 or 15 gal out and refill with straight hot water....the bath cools down before I'm ready to get out. Thats a selling point for cast iron.....it holds the water hotter for longer....but most jetted tubs are fiberglass. Many of my customers do the same.

                        You can "what if" to the end but ultimately a 50 gal water heater with a thermostat setting of 120 degrees is not sufficient unless you want your water heater to dictate when you can take a bath because your husband or wife just took a shower. God help ya if you have company over and all need to get ready to go out to dinner etc. etc.....or have teenage daughters.....yes women use more ot water than men do. In commercial sizing applications a womens locker/shower room gets upsized.

                        If the original poster said he lived alone and didn't have a bathtub would it be ok for him to install a 20 gal water heater? I mean if thats all he needs it must be ok right? Based on your logic of just having whats needed that would be fine. Go ahead and install a 10 gal on a switch.....turn it on 30 min before you need to take a shower and turn it off when your done....save that money.
                        Last edited by TheMaster; 04-21-2011, 03:30 PM.

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                        • #27
                          Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                          Before I installed a 65 gal electric or a 75 gal gas.....I would do two 40 gal. and never run out of hot water and have a quicker recovery time. I would always have a back up hot water supply as long as both tanks didn't fail at once and thats very very unlikely. They would last longer as a general rule because they would get taxed as much and the temp wouldn't need to be cranked up because i would have plenty of volume and would not need to compensate for lack of volume with a higher thermostat setting. Higher thermostat settings increase standby loss and the life of the heater in general. Cheaper to buy two 40's than either a 65 electric or a 75 gas.

                          With a thermostat setting of 120 degrees and a incoming water temp of 55 degrees.....with a mixed water temp of 105 degrees.....77% of the water will be HOT water.

                          A 40 gal water heater with a thermostat setting of 120 degrees will deliver approximately 36 gal of 110 degree water for a shower and with a showerhead that flowed 3 gpm the shower would last 12 minutes. A 40 gal is not impressive at 120 degree temp setting.

                          Only in America will a guy have a jaccuzi tub then worry about the cost to use it properly.
                          Last edited by TheMaster; 04-21-2011, 05:20 PM.

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                          • #28
                            Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                            Originally posted by TheMaster View Post
                            If your water heater is set to 130 degrees and its full of hot water and you run all the hot water out and fill it with 55 degree water the outside of the tank will sweat between the insulation and the tank. On a gas fired heater you can actually hear the condensation dripping onto the burner.....the manufacturers warn about excessive condensation and also tip the homeowner off that it could be condensation rather than a leaking tank.

                            So kohler says 70% of the tubs volume.....thats the minimum sir. Thats for people who just want to fill the tub and not use anymore hot water to speak of.....or you will be totally depleteing the tank and it will cause condensation.

                            Condensation cant escape from between the foam insulation and the still tank very readily....this ever so slight condensation(or heavy) will eat away at the tank.

                            Under-sizing a water heater is a surefire way to failure. A pressure vessel only has so many cycles.....the larger the cycle the quicker it will fail. Thats why its best to have more than needed....the tanks temp doesn't fluctuate as much.

                            An electric tank has less standby loss than gas. A gas heater has a flue that cannot be insulated.....so standby loss is not really a factor if you use the heater everyday with an electric.

                            The typical 40 gal gas water heater would not even pass code here if you have a jaccuzi tub and only have one water heater. Whys that? How do they know a 40 wouldn't be "good enough"? Because we do this for a living.....thats why.
                            Re condensation: Look, I am not claiming that you don't or can't get condensation with hot water heater tanks. It happens. But you are claiming that the OP is *going* to have this as justification for 80 gal of hot water heater, while you don't even know (a) where he's putting the tank and (b) what the inlet water temp is. You were arguing this before you even knew what size his tub was! Defend your recommendation if you must, but I think it's overkill to spec out dual 40 gal electrics for two folks before you know anything about the installation, or even how big the tub is.

                            It doesn't seem to be clicking with you that filling a tank with 55F water does not guarantee condensation. Water will only condense if the dew point - a function of the environment - is higher than the tank temperature. Look, I didn't invent physics, I'm just trying to explain to you how it works. If you don't want to understand, that's ok with me.

                            You make a decent point about the temp cycling. It's not really a pressure vessel problem though. The problem is that the glass, on the glass lined tanks, may eventually crack. I'm not convinced that OPs temp cycles are going to be frequent enough - or severe eonough - to matter. I have 16 years on the same 40 gal WH, which I set to the hottest position, about the same demand as OP. It runs out sometimes. Not too often.

                            What are you trying to say about standby loss?? If you're arguing that this makes two 40 gal electrics less costly to operate than one 50 gal gas... well, I think you're wrong... unless the gas v. electric rates are way far out of kilter with bulk of the country.

                            Or are you disagreeing with my statement that a gas WH can get by with a smaller tank than an electric? If so, please explain... I think it's pretty well known that with an electric you need a larger tank than you do with nat gas.

                            I don't want to go back and forth with you any more. You obviously have your opinion, and I really don't buy your logic... nor does the "I do this for a living" argument hold a lot of sway with me. In any case, I think it's moot. OP doesn't want the expense of a dual system. I hope he does go for good quality, large BTU gas 50 gal. Maybe he will report back in a few years how it has worked for him.

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                            • #29
                              Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                              Originally posted by TheMaster View Post
                              Before I installed a 65 gal electric or a 75 gal gas.....I would do two 40 gal. and never run out of hot water and have a quicker recovery time. I would always have a back up hot water supply as long as both tanks didn't fail at once and thats very very unlikely. They would last longer as a general rule because they would get taxed as much and the temp wouldn't need to be cranked up because i would have plenty of volume and would not need to compensate for lack of volume with a higher thermostat setting. Higher thermostat settings increase standby loss and the life of the heater in general. Cheaper to buy two 40's than either a 65 electric or a 75 gas.

                              With a thermostat setting of 120 degrees and a incoming water temp of 55 degrees.....with a mixed water temp of 105 degrees.....77% of the water will be HOT water.

                              A 40 gal water heater with a thermostat setting of 120 degrees will deliver approximately 36 gal of 110 degree water for a shower and with a showerhead that flowed 3 gpm the shower would last 12 minutes. A 40 gal is not impressive at 120 degree temp setting.

                              Only in America will a guy have a jaccuzi tub then worry about the cost to use it properly.
                              Sheesh.

                              First of all, if you need a 65 gal electric, you can do fine with a 50 gal gas with a large BTU burner. You wouldn't need a larger gas heater.

                              The whole point of this is to stay with the sizes of heater that are in the sweet spot of pricing.

                              I would say , "Only in America would someone advise installation of an energy wasteful, 80 gallon system to support two people and a smallish bathtub".

                              Let's see how OP's installation turns out.

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                              • #30
                                Re: Electric Hot Water Heater vs Natural Gas Hot Water Heater

                                Originally posted by Andy_M View Post
                                Re condensation: Look, I am not claiming that you don't or can't get condensation with hot water heater tanks. It happens. But you are claiming that the OP is *going* to have this as justification for 80 gal of hot water heater, while you don't even know (a) where he's putting the tank and (b) what the inlet water temp is. You were arguing this before you even knew what size his tub was! Defend your recommendation if you must, but I think it's overkill to spec out dual 40 gal electrics for two folks before you know anything about the installation, or even how big the tub is.

                                It doesn't seem to be clicking with you that filling a tank with 55F water does not guarantee condensation. Water will only condense if the dew point - a function of the environment - is higher than the tank temperature. Look, I didn't invent physics, I'm just trying to explain to you how it works. If you don't want to understand, that's ok with me.

                                You make a decent point about the temp cycling. It's not really a pressure vessel problem though. The problem is that the glass, on the glass lined tanks, may eventually crack. I'm not convinced that OPs temp cycles are going to be frequent enough - or severe eonough - to matter. I have 16 years on the same 40 gal WH, which I set to the hottest position, about the same demand as OP. It runs out sometimes. Not too often.

                                What are you trying to say about standby loss?? If you're arguing that this makes two 40 gal electrics less costly to operate than one 50 gal gas... well, I think you're wrong... unless the gas v. electric rates are way far out of kilter with bulk of the country.

                                Or are you disagreeing with my statement that a gas WH can get by with a smaller tank than an electric? If so, please explain... I think it's pretty well known that with an electric you need a larger tank than you do with nat gas.

                                I don't want to go back and forth with you any more. You obviously have your opinion, and I really don't buy your logic... nor does the "I do this for a living" argument hold a lot of sway with me. In any case, I think it's moot. OP doesn't want the expense of a dual system. I hope he does go for good quality, large BTU gas 50 gal. Maybe he will report back in a few years how it has worked for him.
                                The enviroment would be approx 120 degrees between the insulation and the steel tank. Then it is immediately filled with 55 degree water. The original poster lives in the north.....common low incoming temps there.



                                Originally posted by Andy_M View Post
                                Sheesh.

                                First of all, if you need a 65 gal electric, you can do fine with a 50 gal gas with a large BTU burner. You wouldn't need a larger gas heater.

                                The whole point of this is to stay with the sizes of heater that are in the sweet spot of pricing.

                                I would say , "Only in America would someone advise installation of an energy wasteful, 80 gallon system to support two people and a smallish bathtub".

                                Let's see how OP's installation turns out.
                                Second of all thats just not true. You can get more hot water out of a 65 than you can a 50 unless it has such a high BTU burner and the draw down rate is slow....usually not the case...especially with 60 gal bathtubs.
                                Last edited by TheMaster; 04-21-2011, 05:59 PM.

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