walkie talkie at home

living in condo townhouse is not as convenient as living in single family house. in California, the popular single family is one flat floor, and condo townhouse normally is multiple floors. we live in 3 floors condo townhouse. recently we found that it is inconvenient for echo between person when they are in different rooms which in different floor in our case. one time, my wife is calling me for help from 2nd floor bath room, and I barely heard her calling since I am in the kitchen and kitchen fan is on. if I am in 3rd floor study room, she must make it real loud from first floor. sometime, she sent her royal army, i.e. my daughter, to carry message to me, this kind of service is off after 9:00p.m. since my daughter get into sleep. How to solve this inconvenient situation? We thought about walkie talkie. walkie talkie is definitely a good idea; however, today we just found a good alternative way: just carry the cellphone, and put it into speaker mode. Since talk time is free between family, we are enjoy this feature due to free!
I will always carry my cell phone, even in the house.