For comparison, I just bought a house here in Japan. Installed 6 minisplit heat pumps across various rooms in the house. All together it cost me 750,000 yen ($5,000) for the hardware and 90,000 yen ($600) for the install.
In the US, they are struggling to break out of the eco-luxury product niche (where they have been stuck for a long time).
As for the indoor units, they can either be the "ugly" ones (the indoor head units visible on the wall), recessed "cassettes", or they can use traditional A/C air handlers in a utility room to distribute conditioned air via existing duct-runs and registers.
There are also companies like Quilt that are making heat pump systems with much more attractive indoor wall units.
This isn't exactly new or unique to heat pumps (and some older heat pumps lack both), but as the technology has gotten cheaper and more reliable, coupled with the drive for better efficiency, it has become commonplace.
I got HVAC drop-in replacement quotes ranging from $7k to $14k for what upon some quick research was about $3k in hardware.
[edit] i say that because my hardware is 2.5k euros, so ~3k¯dollars, so we probably have the same high end stuff, and i guarantee you it's not hard to install, and it can be quite fast if you have help from your SO.
Having just installed a mini-split in my office shed with a pre/charged unit. I told him it was easy and helped him. We ended up needing to buy an extra long line set to make the distance work, which needed more refrigerant.
I called 15 different places and finally found one that could come out and charge the line for under $350. Which was hard to stomach with the whole unit costing only $750 from Amazon.
Around here anyway, I was getting quotes of 20k for the install & equipment of a central air handler and the outdoor unit.
I'd be dead before the thing paid for itself in electricity cost savings. $20,000 ÷ (~90yrslife - 40yrsold) = $400 / year of neccesary savings to break-even as my casket is lowered into the ground.
Of course you have exactly one chance with your install this way until you have to call someone.
regardless, this is incredibly cheap
GP still got an amazing deal
After reading some other comments I realize one vital detail is that they were installed in a renovated house that already had suitable holes to the outside and power outlets where the units were going, so the install job was just mounting the units, pulling the tubing and gassing it, no cutting things up or doing electrical work.
The price would at least double if we needed all the holes cut open, and I have no idea what the electrical work would cost.
They’re remarkable, and I would go for a mini-split system over a central unit 100 times out of 100.
In my current home, I have two "heads" attached to a single outside unit, but they cannot operate independently beyond setting different fan speeds or closing the vent really. If one of the mini-splits is set to heat and the other switches to cooling, they will booth start cooling, or vice versa, the head units just blindly blow air over what ever is being pumped through the line and the last unit to send a command to switch mode "wins".
Maybe there are clever heat pumps that truly allow fully independent control of the head unit when connected to multiple heads, but given the flow of refrigerant has to reverse direction completely when switching between heating and cooling, I don't see how they can operate fully independently when they are sharing the same refrigerant lines.
There is only one reversing valve inside the outside unit for all the head units connected to one outside unit in my experience, but would love to see examples of systems that do permit this if they exist.
When the oven is done cooking it can dump heat into the water heater (and or furnace in the winter). The fridge and HVAC could dump heat into the water heater before pumping it outside in the summer.
As opposed to central unit’s all-or-nothing approach.