Solar vs. Gas heating for hot water

bargain lover on 21/05/2013 - 22:37

Went to the HomeShow in Sydney last weekend and saw how much solar there is these days. Got talking to some reps and other than saying that a Net use meter is the best they also said that in NSW you only 8c per unit for feed-in, which compares poorly with how much it costs to buy energy.

Anyways, I also saw some systems that can use either solar or gas to heat you water such as http://www.dux.com.au/p/environmental-hot-water. What I'm wondering is if per equivalent unit of energy gas is cheaper or more expensive than 8c?

In other words if I am on net metering is it better to use gas for my hot water and sell my solar for 8c, or, use solar as much as possible because gas is more than 8c?

If it helps, from my last AGL gas bill it seems last quarter I used 55 units which they say is 2073MJ to give a usage charge of about $60.

Cheers!

Electrical & Electronics

Comments

  • ESEMCE on 22/05/2013 - 06:48

    Solar hot water wont use your PV solar panels at all.
    it uses evacuated tubes to directly heat the water.
    Your only question then is how often will I need to use the booster?
    and that will depend on how much hot water you use and where you live.

    Unless I misunderstand and you're thinking of using the electricity generated by solar panels to power an electric hot water system?
    In which case that option (provided you have a big enough system) and your bill is calculated only by the net inflow to your house (which is what that meter sounds like), then that would be the best option.

  • RockyRaccoon on 22/05/2013 - 07:05

    An alternative option is to look at using a reverse cycle hotwater heater rather than a solar hotwater system. Its a new maths game, and I dont have the figures, but worth researching.

    But then all this depends on what you already have installed and its existing life spam. ie is it worth the investment in new equipment.

    eg if you have gas hot water water already, spending big money to replace something that only uses $60 a quarter as compared the savings vs interest on capital.

    Now if you are having to buy the new equipment because the existing is due for replacement, then the maths are different.

  • bargain lover on 23/05/2013 - 19:56

    I think I've got myself confused. If there is not enough solar to warm the water, then presumably there won't be enough solar to sell back to AGL. Which means I will be using either electric or gas to heat the water.

    So gas augmented solar water should be best.

    • ESEMCE on 24/05/2013 - 10:14
      +1

      Explain what you want to do precisely.
      Cause I think you're wrong.

      Ignore any profits from selling back to the grid, they're negligible.
      You should be looking at the saving from effectively not buying electricity or gas to heat the water.

      I assume you have solar panels already.. If I'm wrong, then the balance shifts towards gas.
      If you have a big enough system to effectively negate any electricity you buy, then your hot water (and everything electrical in your house) is "free" (ignoring the cost of the solar panels).

Login or Join to leave a comment
Login Join