Our research took place in 2016. Thank you so much for assigning a positive, knowledgeable, and efficient technician for our furnace time-up! he represents everything we love and have grown to expect from holt! We always begin with a consultation and cost estimate so you'll feel comfortable. I think some folks here may just be impatient....when i use with warm water and let sit overnight, it does a great job on my sinks and bath. The best.