What exactly do you mean by "current floor vents"? Do you have ducts under the house? What do you currently have for heating?

If you have existing ducting and floor vents, why not use a heat pump? One of the best parts of a heat pump is that they are very quiet in AC mode. Cooling the house doesn't make your outdoor areas unpleasantly noisy.

If you have ductwork in place you should consider a ducted mini-split heat pump. If your objection to ductless is the look of wall-mounted indoor units, note that a number of manufacturers offer ductless indoor units that are floor mounted. Have a look at them before dismissing a ductless system. Be sure to check with your local utility provider (or the group that represents them) to determine if there are any applicable rebates or tax credits for upgrading your system.

A ducted heat pump system is an air handler with cabinet and an outdoor unit. It uses reversing valves to use the indoor evaporator as a condenser and the same for the outdoor component. Simple. Just don't let somebody price it for thousands more than what it is. Central Ducted Hyper Heat – MRCOOL

Other manufacturers offer similar products. This can be diy if you have other uses for 8-10k.

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