# Going To Toss The Sidearm And Install An Electric Tank

• 02-24-2011, 05:45 PM
drizler
Going To Toss The Sidearm And Install An Electric Tank
I don't use my boiler for anything but heating hot water anyways and the sidearm tank just died. While expensive here in NY State it seems to make more sense to just put in an electric tank and install it upstairs where it is warm rather than the cold basement.

How many kilowatts does a family of 3 usually use with a shower a day each and no one being a shower hog? Nobody showers one after the other either.

The tank we currently have is a 30 gallon sidearm so I would assume a 40 gallon electric would replace it well enough. We have a 55 gallon whirlpool tub that rarely gets used but the sidearm 30 barely filled it.

I plan on just using the Peerless boiler during the winter as a backup and draining it for the majority of the year and do all my heat as I do now with the pellet stove.
Is there anything I am missing here?
• 02-24-2011, 05:59 PM
A boiler assisted tank can heat a lot more water than an electric. The recovery rate is higher as well, so a 40-gallon electric may not (likely won't) fill the tub. Once hot, it doesn't take all that much to keep it hot in an electric tank. A Kw=3412BTU. One BTU can raise one pound of water one degree. So, depending on how cold the water coming in is, and how hot you make it, and how much you use, you can figure it out. A gallon of water weighs about 8# (less, but that would give you some room for standby losses).

So, to raise 40-gallons of water from say 40-degrees to 120-degrees (about the minimum you want) means:
40*8 or 320# of water, *80 degrees, or 25600BTU /3412 = about 7.5Kwhr.

Then, add in any other hot uses during the day, and you can figure out approximately how much energy it will take; then, multiply by the local rates. Sometimes, it is a tiered rate, and the more you use, the higher the cost/Kw, so it might bump you up to a higher rate.
• 02-26-2011, 02:36 AM
drizler
Thanks for the explaination. I guess a 40 will fill the bill fine. One last thing. Any specific wiring schematics out there for one of these. I have replaced a few in my day but they were all many years between and already set up. Off hand I am assuming a 12/2 romex straight to it's own circuit at the box with no other special considerations. I am going to put this in an drain pan like no one ever does for that eventual day it leaks. Any big consideration on models / makes besides the warranty? I don't plan on getting anything magnificant as changing out an annode is no big deal to me every 5 years or so. Neither is draining and flushing.
• 02-26-2011, 02:52 PM