We did it several years ago and since we had (non working bht still present knob and tube) we couldn’t get the insulation and the rest of the stuff they did at the end of the day re air flow didn’t make a difference (whatever they tested using scientific instruments didn’t change). So we have a basement with lots of weird insulation (the foam stuff) piped in places that apparently doesn’t do anything. So find out if you have any knob and tube anywhere inside and don’t bother if it does until you get it removed.