Water Heaters - One Heater or Two?
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Ma999
12-26-04, 08:19 PM
I have a 48 gal Bradford White Power vent gas water heater and in the winter months we [ family of five] are running out of hot water before we are all showered. I am in the middle of a basement remodeling project and was thinking of adding additional capacity. What makes the most sense, Getting a larger heater, a tankless system or another 48? Secondly if I get another 48 can I connect the power vent of the second to the first? Its just PVC pipe about 3" dia.
Thanks
Thanks
rav12
12-27-04, 01:46 AM
If I were looking at this I would say the first step would be to establish how many gallons of water you are using off the hot line. It would have to be an estimate but assuming you mix it at say 3:4 ratio hot to cold and knowing the flow rate(s) of your bath(s)/showers (you can measure this using a bucket) you can figure out your hot water usage. You can use this to decide if you should either get a bigger heater or couple a second 48 gal tank. At the moment your calculations should show more than 48 gallons of water to confirm you will be running out of water - ie you are using more water than the tank can reheat.
Tankless is another option but here a different calcuation is needed. You will not run out of hot water, but if you will need multiple baths/showers simultaneously then the heater will run out of capacity so you need to make sure you size the heater correctly in terms not of the length of time of usage but of how many appliances will be used simultaneously. Other considerations include the possible resizing of the gas line (if using natural gas) as well as requiring different diameter vents . Some tankless heaters cannot use B-vent which is commonly used by tanks. If you plan to switch to tankless I would suggest trying to get hold of the installation manual and see if the work involved is something worth undertaking or even feasible.
Another consideration is cost - tankless tends to be more expensive to buy than a tank but should be cheaper to run (referring to NG - not sure about electric). The nice thing about a tankless is that it does not waste energy keeping water hot.
And for the combining the vents - it is possible and the figure needs to be obtained from the gas tables but it is likely the diamter will need to be enlarged.
Tankless is another option but here a different calcuation is needed. You will not run out of hot water, but if you will need multiple baths/showers simultaneously then the heater will run out of capacity so you need to make sure you size the heater correctly in terms not of the length of time of usage but of how many appliances will be used simultaneously. Other considerations include the possible resizing of the gas line (if using natural gas) as well as requiring different diameter vents . Some tankless heaters cannot use B-vent which is commonly used by tanks. If you plan to switch to tankless I would suggest trying to get hold of the installation manual and see if the work involved is something worth undertaking or even feasible.
Another consideration is cost - tankless tends to be more expensive to buy than a tank but should be cheaper to run (referring to NG - not sure about electric). The nice thing about a tankless is that it does not waste energy keeping water hot.
And for the combining the vents - it is possible and the figure needs to be obtained from the gas tables but it is likely the diamter will need to be enlarged.
mcjunk
12-30-04, 01:03 PM
The problem with tankless electric heaters is the amount of current they draw. I was thinking about getting one to heat the water for my 70 gallon jacuzzi tub and I believe it pulled 90 amps!
The solution I came up with might work for you. I have a 40 gallon low-boy which is fine except for filling the jacuzzi or when we have several house guests. I simply installed a second low-boy beside the first one and connected them so the water runs into the new one and out to the original heater. That way, I have constant water flow through both heaters without having to "use" both heaters. I put a disconnect switch in the house, and whenever guests are coming to spend the weekend or when we want to use the tub, we cut the heater on about an hour beforehand. I changed the elements from 4500 to 3500 in the new heater so I could put it on a 20 amp circuit.
In your situation, you could use an electric heater (3500W elements, 20A 240V) and either turn it on and off like I do, or adjust the temperature depending on the season.
The solution I came up with might work for you. I have a 40 gallon low-boy which is fine except for filling the jacuzzi or when we have several house guests. I simply installed a second low-boy beside the first one and connected them so the water runs into the new one and out to the original heater. That way, I have constant water flow through both heaters without having to "use" both heaters. I put a disconnect switch in the house, and whenever guests are coming to spend the weekend or when we want to use the tub, we cut the heater on about an hour beforehand. I changed the elements from 4500 to 3500 in the new heater so I could put it on a 20 amp circuit.
In your situation, you could use an electric heater (3500W elements, 20A 240V) and either turn it on and off like I do, or adjust the temperature depending on the season.