Preboiling can be effective when chlorine is the disinfectant, but is far less effective on chloramines. The effects on calcium carbonate precipitation is directly dependent on the temporary hardness level of that tap water. If the temp hardness is only modest, then the precipitation may be low. The other thing about precipitating temp hardness is that it takes more boiling time than you might expect. While the solubility of CaCO3 is at minimum when the boiling starts, it takes several minutes for that reaction to proceed. All of the texts that I've read, point to a need to boil about 15 minutes to get that reaction to proceed to its fullest extent. That is a lot of wasted time and energy.
The comment above on carbon filters is also important. The treatment capacity of those typical 10 inch carbon housings is limited. To remove chlorine, you need to limit the flowrate through the filter to about 3L per minute. To remove chloramines, that flowrate needs to be less than 0.3L per minute. As you can see, using a filter for chloramines is kind of ridiculous.