I received and email the other day from a reader who was upset that he didn’t get instant hot water from his tankless water heater. There are 2 things you have remember about tankless water heaters. First, it takes a couple seconds for the unit to get to full operating temperature and literally it is just a few seconds.
Second, and most importantly, is consideration how far away is the tankless water heater from the usage point of use. If there hasn’t been a call for hot water from the point of use for sometime, the water in the lines most likely has cold. The standing water has to be cleared before the hot water reaches the point of use. If the tankless unit is in the basement and the call is on the 2nd floor at the other end of the house, it is going to take sometime for the cold water to clear the lines before the hot water reaches the point of use. This holds true for tankless and conventional hot water heaters.
If you want to have instant hot water, you can have your local Denver plumber install a recirculating pump. Please note some tankless water heaters will not work properly with a recirculating pump. Here is a short video on recirculating pump