Our house has some large areas that are 24 ft talk in the family room and when you walk in. Our goal is try to be as energy efficient as possible. [5900 sq ft]

Build a smaller house with lower ceiling height... is predominantly the #1 rule when it comes to efficiency -- if efficiency is about operational $$$ it costs to keep house comfortable.

Sure you can put in quote / unquote energy efficient equipment in terms of higher SEER / SEER2 rating but kind of nonsensical argument when you have 24FT high ceilings and 5900 sq ft.

You give no clue about location -- climates are a big factor in efficiency too along with sizing etc. The more air volume you are trying to condition, the warmer the climate, the more it's going to cost you -- operationally, maintenance, repairs, up keep etc.

The bigger the house, the more equipment. The more equipment the less efficient in terms of what those operational and other costs will be. 14.3 SEER2 is entry level equipment. 14 SEER was the previous nomenclature prior to 2023. -- In the north the SEER2 requirement is less sticky. In Texas you can't "legally" install anything less than 14.3 SEER2 since Jan. 1, 2023.

A house this big to increase efficiency -- if you have this kind of money and actually need this big a house --- solar system would probably be in your future. (more money).

You should ask for the model numbers of all eqipment, how mony zones will be installed, and the heating and cooling load calculations.

Efficient operation is a perfectly legitimate goal for systems serving a home of any size including the HVAC system. An HVAC system not only maintains a comfortable and healthy indoor environment for the occupants, but helps to sustain the structure over time, too. Unfortunately, in residential construction, the design of HVAC systems is often relegated to whomever the least-expensive HVAC contractor has on staff. If the municipality in which the home is constructed doesn't require a mechanical plan and calculations to be submitted for review prior to a mechanical permit being issued, you get what you get-- and subsequent owners will inherit performance issues.

The most cost-efficient approach is to make sure the system is designed right from the start. To that end, I recommend you insist on a credentialled, professional HVAC designer on your design team. They'll work with you, your architect, and your builder to establish specific goals, consider alternative systems, and help you make informed choices about what best meets your needs.

Best wishes for a successful project.

4 systems is quite a lot, even for a 6000sq ft home! How big (tons) is each of the proposed systems? Where are you located? Is the home built super insulated?

My BIL house is 3500’ foundation with upper/lower levels so 7000 finished. he showed me the heat storage boiler/tank in hvac room but i cannot recall how he cooled house. he has sport court under 4 car garage but im unsure how he heats that space. $1.6 mill to build 14 yrs ago

It’s a great idea to do some research on other HVAC brands as well. Checking out reviews and comparing features can help you make the most informed decision for your new home's needs. In terms of price, it can vary a lot depending on your location and specific requirements. Also, don't forget to explore zoning possibilities – it could save energy. Besides installation, having a reliable maintenance plan in place is key to keeping your HVAC running smoothly. You might want to look into professionals who can handle both installation and maintenance. Personally, I've had a great experience with the specialists at dynamicheatandcool.ca. Their services have been stellar in ensuring my HVAC's efficient performance.

I agree with doing some homework as suggested above. You should investigate whether your local utility provider offers incentives or rebates which might affect your choices. Ditto for any tax credits or incentives offered by Uncle Sam.

OP:

“Our goal is try to be as energy efficient as possible. “

Then geothermal Liquid-to-Water heat pump & hydronic distribution of hot and chilled water for heating, Domestic Hot Water (DHW) and air-conditioning.

Only 1-heat pump for everything ! 1-integrated, zoned system for maximum efficiency, maximum comfort, lowest operating expense - but greatest up-front costs !!

IMPO

SR