It is amazing to me how people who know nothing about HVAC have such
strong opinions concerning goofy devices that affect the air in their
houses. Yes, the dryer vent diverter will add heat to your house. It
will also add a lot of moisture in a small space, which can cause
problems, like mold. If you exhaust the dryer into a large room in a
large house, probably OK. But there is no control on the dryer to
detect when you get too much humidity in your house. You find out when
the wallpaper starts peeling or the inside of the windows sweat.
If it is a gas dryer, you are also adding CO2. Some CO will also be
added, which can be dangerous in concentrations over 5 PPM.
Unless you have instruments constantly measuring these things, qith
alarms for high concentrations, I do not suggest doing it.
OP please note: PVC dryer exhaust duct violates codes in most areas.
However in our area they allow it ONLY if it is burried in a concrete
slab. The inspectors allow it but the code does not. (Inspector wins).