Hi Dave, I recently replaced my knob and tube wiring. I couldn't find an electrical company to give me a total bid. They would only do it on an hourly basis. Then a electrician friend said he would guess $22,000 to $25,000 on a two story 4400 sq. ft. house. So I (my family and I) did it myself except for the breaker boxes and a few other complex things. We basically pulled wire, put in outlets and a few switches and lights. I found that the hole for the ceramic tube wasn't quite big enough.....at least for 12-2, additionally your new wiring pattern is not going to be the same as the k and t. Of course the bulk of the cost is labor. My electrtician/advisor charged $25/hr.