My planned house is of single storey 29 squares with 4 bedrooms, 2 living areas and 1 open theatre . Total of 9 vents are present as per the standard design( 4 in bedrooms and 5 in living/theatre).
Below are the price list provide by the builder and I am bit confused with the options to go with.
Gas heating : regular one provided by the builder is Brivis 3 star, which cannot have zoning and upgrade to SP series - i.e. 4, 5 or 6 star would be required.
Zone upgrade option:
Zone Option 1 - Provide Brivis Zone Plus Heating System 2 zones to Single Storey $1,604.00
Includes 1No. Networker Controller (NC6) in lieu of standard programmable controller (included in upgrade to heating unit), 1No.temperature sensor, 2No. zone motors.
Zone Option 2 - Provide Brivis Zone Plus Heating System 3 zones to Single Storey $2,223.00
Includes 1No. Networker Controller (NC6) in lieu of standard programmable controller (included in upgrade to heating unit), 2No.temperature sensors, 3No. zone motors.
Zone Option 3 - Provide Brivis Zone Plus Heating System 4 zones to Single Storey $2,372.00
Includes 1No. Networker Controller (NC6) in lieu of standard programmable controller (included in upgrade to heating unit), 2No.temperature sensors, 3No. zone motors & 1No. 506 module
Unit options:
Unit Option 1 - Upgrade heating unit from a Brivis CC3 to SP4 (3 Star to 4 Star) unit, includes upgrade to networker controller in lieu of programmable $959.00
Unit Option 2 - Upgrade heating unit from a Brivis CC3 to SP5 (3 Star to 5 Star) unit, includes upgrade to networker controller in lieu of programmable $1,483.00
Unit Option 3 - Upgrade heating unit from a Brivis CC3 to SP6 (3 Star to 6 Star) unit, includes upgrade to networker controller in lieu of programmable $1,834.00
Evaporative cooling : Brivis Contour L66 unit to 8 points. $7,808.00
Refrigerated air conditioning: 14.80 kW (Nominal cooling capacity) single phase Brivis refrigerated air conditioning to 9 points including upgrade of the heating unit from the Brivis Compact Classic to 5 Star unit - $15,135 (so this includes Unit Option 2, which is builders $1,483.00)
I believe refrigerated air conditioning would be reverse cycle, so can be used for both cooling and heating. Yes, included 5 star gas heater would be another option for heating.
So the point is, if I upgrade to 5 star gas heater ( $1,483.00) and no zoning + Evaporative cooling ( $7,808.00), it would be $9291
With Refrigerated cooling (5 star gas heater and no zoning), it would be $15,135
Difference is - $5,844
Please note that most of the time around the year, only living and master bed would be used. Also, I will be using more of heating than cooling ( I can bear most of the summer heat, not the cold weather in the peak winter

My confusions are,
1) Is it worth upgrading to Refrigerated cooling by paying $5,844
2) Is it worth to upgrade to Brivis Zone Plus in a single storey 29 squares home by paying $1,604.00 for 2 zones. Read somewhere that zoning may not effective in single storey house and anytime at least 6 vents should be open for smooth working of the Gas heating.
3) Is it beneficial to upgrade the gas heating unit to 6 star ( $1,834.00 ) with no zoning and then have Evaporative cooling.
It is will be very helpful if you could provide your suggestions based on your experience.
Thanks,
Shi