solar water heater in attic or conditioned space? Charlotte, NC.

rollandelliottrollandelliott Solar Expert Posts: 834 ✭✭
I got a Velux solar water heating system off craigslist for $400. I think I spent $1200 for just the pump station on my last solar water system purchase.   Normally they are Thousands of dollars. It is a single tank system with a glycol tubing heat exchanger with electric back up heat and separate pump station and two water panels for the roof. 

Any pros/cons to installing the tank in the attic vs in conditioned space? I think if I put in attic then the cold line will get condensation on it a lot and eventually rust out, so better to keep in conditioned space with thick insulation blanket around it. 
link below details the over all system. It will also be easier to maintain yearly with a flushout.$FILE/X20219-0112_SWH_Brochure.pdf

anyone ever use a powered anode vs a regular aluminum anode. seems like the powered ones are better in the long run. 


  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    I wouldn't put a tank in the attic, as pretty much any tank eventually leaks.  In an attic, the resulting damage could be significant.  In a basement next to a floor drain on a concrete slab makes much more sense to me.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Roadrunner0Roadrunner0 Registered Users Posts: 3
    A low pressure drain back system with a heat transfer tank is the safest and easiest water heating system.. For $400 or so you can build one and have little worries as there is no high pressure or glycol/freezing to worry about.. 500 foot roll of 1/2 inch PEX red = $125.. Small boiler pump $100.. 50 foot coil of 1/2 inch copper pipe $100 and $75 for fittings , valves , a 55 gallon plastic barrel etc.. My attic gets to 100 deg. F most days when it is above 60 deg. and sunny.. This will preheat the well water that is 45 to 50 deg. to 80 deg.+ which should cut electric use of the hot water tank in half.. Running full tap pressure thru the 500 feet of PEX in the attic and having an expansion tank and check valve is even simpler but far more dangerous with leaks and freezing..
    Outback Mate 3s
    Radian RS4048a
    GS load center
    2x Flexmax 80
    24x Solarworld 300w panels
    8x Trojan 415a Solar L16
  • Marc KurthMarc Kurth Solar Expert Posts: 902 ✭✭✭✭
    edited June 2021 #4
    This is a thread from 2019, but since it is alive:

    Based on my experience personally and professionally, I will not allow anything in my attic except for a very few feet of Romex wire. No, plumbing, no ducting, air handlers or tanks.
    For piping, it's not a matter of "if" - it's "when" the leak will occur.
    For ducts and air handlers, the heat gain/loss is horrific enough to destroy efficiency far beyond what most people assume.

    I always have more questions than answers. That's the nature of life.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,087 ✭✭✭✭✭
    And know where the thru hull valves are  ;)
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

Sign In or Register to comment.