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keith3267
Re: Need new water heater option

Not completely true. All other things being equal, the 80 gallon water heater will cost slightly more to operate. The reason is that to hold 80 gallons, the exterior surface area of the water heater will be larger and that means more area to radiate heat from, that is to lose heat from.

But, the cost to heat that water is exactly the same. If this is a well insulated water heater located in a heated space, the heat loss for storage will not be very high, $2-3 per month. The biggest cost is in the hot water used.

But all things are not usually equal. For two people without a jacuzzi. a 40 gallon water heater would be more than enough. With a shower head limited to 2.5 gal/min, you would be a prune before the water got cold.

The jacuzzi kind of changes things, and it doesn't matter whether there are only two of you or not or if it is seldom used or not. Jacuzzi's need a lot of hot water. If you use it at all, you may need anywhere for 80-120 gallons of hot water just to fill it.

This is where the 80 gal could actually be cheaper. To have enough hot water to fill the jacuzzi with a 40 or 50 gallon water heater, you would have to maintain a tank temperature of around 150-160°F. The higher the storage temperature, the greater the storage losses. I based my estimate on a storage temperature of around 130-140°F, the higher the storage temp, the faster the storage costs go up.

With an 80 gallon water heater, you could drop the storage temperature to 120°F and still fill that jacuzzi, but since you rarely use it, your overall storage costs will be lower. The lower temperature has added benefits as well, the lower temperature slows down the reaction of the metal parts of the water heater with the water. It will last much longer. So will the heating elements.

BTW, we have an adult son living with us right now so three adults in the house. 2.5 baths but no jacuzzi, a 50 gallon electric water heater set to 120°F and we do not run out of hot water.

dmontrond
Re: Need new water heater option
keith3267 wrote:

Not completely true. All other things being equal, the 80 gallon water heater will cost slightly more to operate. The reason is that to hold 80 gallons, the exterior surface area of the water heater will be larger and that means more area to radiate heat from, that is to lose heat from.

But, the cost to heat that water is exactly the same. If this is a well insulated water heater located in a heated space, the heat loss for storage will not be very high, $2-3 per month. The biggest cost is in the hot water used.

But all things are not usually equal. For two people without a jacuzzi. a 40 gallon water heater would be more than enough. With a shower head limited to 2.5 gal/min, you would be a prune before the water got cold.

The jacuzzi kind of changes things, and it doesn't matter whether there are only two of you or not or if it is seldom used or not. Jacuzzi's need a lot of hot water. If you use it at all, you may need anywhere for 80-120 gallons of hot water just to fill it.

This is where the 80 gal could actually be cheaper. To have enough hot water to fill the jacuzzi with a 40 or 50 gallon water heater, you would have to maintain a tank temperature of around 150-160°F. The higher the storage temperature, the greater the storage losses. I based my estimate on a storage temperature of around 130-140°F, the higher the storage temp, the faster the storage costs go up.

With an 80 gallon water heater, you could drop the storage temperature to 120°F and still fill that jacuzzi, but since you rarely use it, your overall storage costs will be lower. The lower temperature has added benefits as well, the lower temperature slows down the reaction of the metal parts of the water heater with the water. It will last much longer. So will the heating elements.

BTW, we have an adult son living with us right now so three adults in the house. 2.5 baths but no jacuzzi, a 50 gallon electric water heater set to 120°F and we do not run out of hot water.

Ok so since it does not cost anymore to heat a 80 gal vs a 50gal I guess the 80 would be ok. If I decide (or ever have time to wait for the jacuzzi to fill up) I will have the extra 30 gals at my disposal. Right? He is quoting me around $400 for the Bradford White tank. Is that a good brand?

dj1
Re: Need new water heater option

Bradford White is a good gas water heater. Ask any 10 plumbers, and they will all tell you that BW is their choice.

80 gallon gas BW for $400? I'll take 10.

Just make sure to check: 1. the date it was manufactured (on the heater). 2. that it's brand new unit. 3. that the plumber replaces the cold water shut off valve, the cold and hot flex (if required in your city), the gas shut off valve and the flex gas line (again, if required).

dmontrond
Re: Need new water heater option
dj1 wrote:

Bradford White is a good gas water heater. Ask any 10 plumbers, and they will all tell you that BW is their choice.

80 gallon gas BW for $400? I'll take 10.

Just make sure to check: 1. the date it was manufactured (on the heater). 2. that it's brand new unit. 3. that the plumber replaces the cold water shut off valve, the cold and hot flex (if required in your city), the gas shut off valve and the flex gas line (again, if required).

Actually its an electric. I hope the electric are just as good.

keith3267
Re: Need new water heater option
dmontrond wrote:

Ok so since it does not cost anymore to heat a 80 gal vs a 50gal I guess the 80 would be ok. If I decide (or ever have time to wait for the jacuzzi to fill up) I will have the extra 30 gals at my disposal. Right? He is quoting me around $400 for the Bradford White tank. Is that a good brand?

I'm not sure you completely understand me. All other things being equal, the 80 gallon will cost a little more to operate. First, in the initial heating, you are heating up 30 more gallons of water, but once that is done, you operating costs are makeup heat for the heat lost through the walls of the tank (storage cost) and to heat up water that comes into the tank to make up for the water used (usage cost). The bulk of the cost is the make up for water used.

But as I said, all things are not equal. There are variables here. With the smaller tank, you might have to maintain a higher temperature. This will affect the storage costs as there are really two variables associated with that cost, the surface area of the tank and the temperature difference between the hot water and room where the water heater is located. Well there is a third variable, the level of insulation but for now, lets assume the two tanks are the same, at least an R-6 but I've seen some that claim as high as R-20.

With the larger tank, you can easily set the water temperature down to 120°F or even lower. For most applications, you mix some cold water into the hot in order to keep from scalding your skin. Your skin won't take much over 105°F and around 99°F feels very hot to most people. 96-97°F would be typical for most showers.

About the only time you need a higher water temperature is when you use the dishwasher. But many dishwashers have a built in water heater to boost the temp up to the needed level. With an 80 gallon water heater, you set the storage temp as low as 110°F and save some money, but at 110°F, you probably won't be able to fill the Jacuzzi. But for it, if you plan ahead, you could turn up the water heater an hour before you plan on using it and have all the hot water you need, then turn down the heat afterwards. You will need your plumber to show you how to do this.

johnjh2o
Re: Need new water heater option

At this point I would say this thread has been talked to death.

John

dmontrond
Re: Need new water heater option
keith3267 wrote:

I'm not sure you completely understand me. All other things being equal, the 80 gallon will cost a little more to operate. First, in the initial heating, you are heating up 30 more gallons of water, but once that is done, you operating costs are makeup heat for the heat lost through the walls of the tank (storage cost) and to heat up water that comes into the tank to make up for the water used (usage cost). The bulk of the cost is the make up for water used.

But as I said, all things are not equal. There are variables here. With the smaller tank, you might have to maintain a higher temperature. This will affect the storage costs as there are really two variables associated with that cost, the surface area of the tank and the temperature difference between the hot water and room where the water heater is located. Well there is a third variable, the level of insulation but for now, lets assume the two tanks are the same, at least an R-6 but I've seen some that claim as high as R-20.

With the larger tank, you can easily set the water temperature down to 120°F or even lower. For most applications, you mix some cold water into the hot in order to keep from scalding your skin. Your skin won't take much over 105°F and around 99°F feels very hot to most people. 96-97°F would be typical for most showers.

About the only time you need a higher water temperature is when you use the dishwasher. But many dishwashers have a built in water heater to boost the temp up to the needed level. With an 80 gallon water heater, you set the storage temp as low as 110°F and save some money, but at 110°F, you probably won't be able to fill the Jacuzzi. But for it, if you plan ahead, you could turn up the water heater an hour before you plan on using it and have all the hot water you need, then turn down the heat afterwards. You will need your plumber to show you how to do this.

Keith, thank you very much for your time and information. I had the 80 gal installed today and hopefully it will force me to use the Jacuzzy now that I have the extra 30 gals. I will try to monitor the electrical cost and compare to the cost of oil with the boiler mate from years prior. Again thank you so much for your feedback. People like you make forums like these a success. Happy Holidays to you and yours.

dmontrond
Re: Need new water heater option
johnjh2o wrote:

At this point I would say this thread has been talked to death.

John

John, I'm sorry you feel this way. However there is a reason why people like myself come to these forums and ask many questions. As Keith stated there are many factors and most of them I did not consider because this is not my field of expertise. But with some patience and was able to better understand what I was dealing with and made the best informed decision I could. Only time will tell if it will save me money or not. But the main point is I have hot water and I may use my jacuzzy now.
So next time you don't feel like giving positive feedback or any information that is helpful to a member then just stay quiet. I was the non expert that figured out that my boiler does burn 1.1 gals per hr when you as an expert told me I was wrong! Happy Holidays to you as well my friend!

keith3267
Re: Need new water heater option

johnjh2o has given a lot of good advice in the area of plumbing to many people on this board, please try not to be too hard on him.

johnjh2o
Re: Need new water heater option

Thanks for watching my back Keith.

John

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