2 bands - 2.4 ghz and 5 ghz.
2.4 is lower and more crowded, but the signal reaches out further.
5 is higher and less crowded, but the signal strength is not that great, so it won’t go as far in your home.
Actually, the maximum power transmitted into the antenna is the same for both bands: 1 watt. The maximum radiated power (EIRP) for 5 Ghz is greater: 53 dBM vs. 36 dBM for 2.4 GHz.
You can raise the EIRP for 2.4GHz with additional antenna gain, but must lower the input power to the antenna, limiting the maximum EIRP to 52 dBM.
http://www.afar.net/tutorials/fcc-rules
I think what you meant is that the 5 Ghz signal is more heavily attenuated (reduced) by obstacles like walls. So, equivalent 2.4 GHz and 5 GHz EIRP will have different effective ranges in a typical house.