I am a do it yourselfer on both auto and home projects. I'm looking for a leak detector to find the leak in my home A/C unit. I'll also use it for my auto. There is no way I would/could fix the leak myself so I will be calling a HVAC person to do the work. My home A/C runs pipes and tubes thru a crawl space and up to the attic. I think I can save a few bucks by finding the leak(s) first and then calling for service. My unit is old (20yrs.) so it might make sense to replace the whole system but I'd still like a leak detector. Is the Mastercool 55100 - Electronic Leak Detector something I would want? I really don't want to pay 3 or more times that for a professional unit. What do you think?