BASIX Gas HW vs Heat Pump

Hi All,
I'm building a new home in NSW through Coral Homes and upgraded to a heat pump hot water system (instead of gas) and apparently now this change is affecting the BASIX and means we will have to make changes elsewhere. From everything I read re BASIX a heat pump is supposed to be better, what are peoples thoughts on this? I can't find anywhere the actual points or scores attributed to different appliance or design etc, does anyone know if there is likes a NSW government document with all that in it, or an online calculator etc?


  • BASIX is based on what’s more energy efficient, if you can work out a way to compare the specified gas and heat pump systems total yearly energy usage, which might be tricky as they both use different energy rating systems. There are definitely some very efficient heat pump systems on the market that will be much more efficient than any gas system, but maybe not all heat pumps are as efficient as gas. Or maybe your builder’s energy rating consultant is a bit useless.

  • +2

    Heat pumps generally are around 2x to 4x cheaper than gas or electric heating. But…

    Only 20% of energy on the grid in NSW is green, and over 50% is coal. Compared to coal, gas is green.

    So your heat pump may be more energy efficient and cost less to operate, but may generate more pollution if powered by the grid.

    • Yep heat pump is like magic. With 1kw power it can generate 2 to 3kw output.

  • If its like Victorian standards it will simply be because BASIX is way behind the times. Thirty years ago, when the original standards were set, gas was definitely cheaper (and greenhouse friendlier) for heating, cooking and HWS than electric. Its the reverse now.

    Here in Victoria you still have to get the gas connected on a new home wherever its available if you want your compulsory six star rating. My theory is that, as with the Fed's climate change committees, they've appointed gas company executives to the energy standards committees. No doubt after some lobbying.

  • +1

    We decided to ditch gas/heat pump and go solar panels with electric hot water -

  • Gas is the highest rated option in Basix for some unknown reason. Has been for years and likely will be for a few more to come. Failing Basix by changing hot water is a very common situation. I personally do not believe that heat pumps are good value for money however - the cost to strap the unit to the hot water storage is thousands more than gas instantaneous. Same applies to solar backup gas instant etc. All just wasted money for a very specific purpose.
    I encourage all clients to choose a standard alone cheap electric storage (1 element or 2 element) and a dedicated PV system for their roof that provides solar to their entire home (including the hot water). Adding 1.5kW solar will give you like a 99 point rating on your Basix above the required ~50 points.

    • Thanks, you do make a good point re not worrying about complex and expensive heat pump and just get more solar with simple electric HW. Was trying to avoid solar since the builder has a 4x markup compared to local solar installers, seems like won't have a choice.