You can block it. The unit won't heat or cool that room anymore though. The return air does effect supply air temp. And heat pump efficiency. With a 60 degree return air temp, the heat pump is more efficient then with a 70 degree return air temp.
We are simply getting contaminated causing otherwise healthy folks to lose the function of their kidneys and for a senior citizen who is already suffering sarcopenia this can be a death sentence because of the complexities associated with Renal Failure.
Sarcopenia is the degenerative loss of skeletal muscle mass (0.5â1% loss per year after the age of 50), quality, and strength associated with aging. Sarcopenia is a component of the frailty syndrome. It is often a component of cachexia.