Energy efficient aircond R410-A?

average comfort is considered 75 deg F at 50% humidity but for energy efficiency its recommended for 78 in summer and 68 in winter.

I have made units to work at 60 for computer rooms but they require special controls accessories as well as the rooms are double insulated to hold out the heat transfer.

The refrigeration systems job ins to remove heat. Since heat always moves towards cold heat is always trying to get back in so the system is only 1/2 of the job. the other is trying to slow the heat from getting back in. most residential houses are built to keep a 20 deg f difference so at a 100F Texas day you can efficiently cool to 80. The Ac system works on temperatures and pressures to absorb the heat. They are designed to operate at a 40 F coil at 75 F room temperature. Bye the time you drop that below 70 the coil is on the verge of freezing, There is also less heat at that point to absorb and you will have unevaporated liquid flowing back to your compressor. since your compressor cant pump liquid it slugs back, also the liquid refrigerant starts eating on the wiring inside the hermetically sealed compressor.

It's not because of the refrigerant, it's because they are newer with more efficient motors and compressors. The new refrigerant requires a higher pressure and therefore is more dangerous for technicians to work with. Also, although it's less damaging to the ozone layer, it's a much stronger greenhouse gas. The Montreal Accord predates any concerns about global warming so only ozone depletion was addressed.

efficent motors