I have placed electrical plate insulators on my outside wall outlets,
and I still have cold air coming thru the actual electrical plug holes!
Although the cold air is piercing thru these small slits/gaps, would
this still be too negligible to have an affect on my heating costs? If
so, I certainly won't bother with anything else past the insulators,
which are surely helpling somewhat, or, perhaps they are simply
blocking one route and therefore the air coming out of the electrical
holes themselves is now escaping with slightly more force, making the
whole effort a waste of my time?

I have Water based heat running thru copper with small radiant fins,
which I really like for quickly heating my house.

Just wondering what I can do at this point, if the airflow in NOT
neglible for my heating costs, then I'll consider continuing my crusade
for energy efficacy ;-).

Thanks in advance.

bd