Dairusire:

 

So, we're sort of in the middle of the same as yourself.

 

We're in Hastings, 180m square ish and basically the exact same roof angle and direction. 
We've got a wood burner for heating the house, but we're getting ducted heating/cooling done, as well as Hot water heatpump, which will then have us getting disconnected from Mains gas as we currently have infinity hot water.

 

All in for the ducted system, solar, and hotwater heatpump, we're looking around 45-47k.
We're lucky in that we can afford to do it all in one go. 

We've found most Heatpump HWC quotes for a 250L-300L came back around $8-10k incl GST fully installed. 
This is the one thing I've been wondering if I 'actually' need to do this. Our Infinity hot water is working perfectly fine, it's a lot of money to replace, for the only benefit being that we're no longer having lines charges and know that we're not getting a massive energy price increase at a providers or markets whim. 

Ducted has been pretty variable in terms of costs. Averaging around $15.5k. That's for 4 bedrooms, a really large kitchen/dining space, and a big lounge. So 6 different zones. 

 

The Solar system, we're just getting documentation on from Micromall for the Deye system, installation instructions etc. After having looked through all the solutions, considering the price and the fact it's got 20kWh of battery for 18k, which was 4k cheaper than a SigEnergy solution with 10kWh, it is worth it to me. 

The below doesn't include installation, which is being done by two of my friends who are certified to do so, so account for that. I've found install quotes to be around 5-6k where you've provided the kit. 

 

 

You should not be paying $10K unless you are going for a high end CO2 system. If it is a high end CO2 system it will easily out perform an Infinity in energy savings. For a monobloc style system coming off an infinity I would be charging around $7 to $8 max for a 330litre Hot water heater pump in Napier or Hastings.