I just installed some air-tight trim kits for recessed (can) lighting in my house. Though my house is only 10 years old and has IC (Insulation Contact) cans, there was a substantial draft on windy days. The new trim kits are pretty much as advertized: AIR TIGHT. It's like night and day -- a real energy (i.e. money) saver.
They install in a few minutes with no tools. You'll need to know the exact make and model of your can to select the correct trim kit.
Here is the one that fit my cans. I have no affiliation with the vendor or manufacturer.
http://www.antonline.com/antonline.php?op=inventory&st=6IN+AIRTITE+TRM+WHT+BAFFLE
W.
They install in a few minutes with no tools. You'll need to know the exact make and model of your can to select the correct trim kit.
Here is the one that fit my cans. I have no affiliation with the vendor or manufacturer.
http://www.antonline.com/antonline.php?op=inventory&st=6IN+AIRTITE+TRM+WHT+BAFFLE
W.