It's a good idea to put a valve in the heater circuit?

i have some problems with the temperature of the AC system too. The low pressure AC tubes are extremely cold (almost frozen) but the air in the inside of the car is fresh but not so cold (about 7-8 celsius) , when ac is off, the air is a little warm, so maybe the evaporator have to colf air that is hotter than it should be. I read that someone uses a valve to close in summer the circulation of hot water in the heather… is it a good idea?

It seems like a good idea.
https://forums.jag-lovers.com/t/warm-hot-air-from-left-airvents-driverside-airvents/434472/21?u=dr_gaz