“The Voluntary prayer of a man done where people can’t see him outweighs his prayer done where people can see him by twenty five (degrees).”
Benefits for this topic:
Shaykh Rslan (may Allah preserve him) considers offering Sunnah prayers in the home an abandoned sunnah. 
Al-Ameer As-San’anee (may Allah have mercy on him) said, “The Voluntary prayer of a man” was said here because most men pray in congregation. However here the same ruling applies for women, who pray sunnan prayers in their homes.
“Where people can’t see him…” what is evident from the wording is an empty masjid and a person’s home are both included.
“Outweighs his prayer done where people can see him by twenty five” This refers to the degree of the prayer or twenty five prayers. The reason for this status is because voluntary prayers were legislated to draw nearer to Allah. Hence, if an act of worship is done in secret, then it’s farther from showing off and seeking fame than acts done publicly.
On the other hand, obligatory acts of worship were legislated to be carried out in public. Subsequently, these acts and rites help establish the religion when everyone sees them done.
Shaykul Islam Abu Yahya Zakariyah Al-Ansari (may Allah have mercy on him) said,” Only the supererogatory acts of worship were legislated to be practiced in the homes. Reason being, this is the farthest away from Riya. Along with this the Angels descend with mercy. The Sunnah acts which aren’t included are; Sunnah Al-Jumu’ah, Tawaf, Ihram and Taraweeh in congregation
Translated and compiled by the one in need of Allah’s mercy,
bu Aaliyah Abdullah ibn Dwight Lamont Battle Sr.
Doha, Qatar 1433 ©
 Collected by Ibn Hajr in Muttalib Al-Aaliyah (547) from the chain of Abu Ya’la .Al-Albani graded this hadeeth as being Saheeh.( Jami 3821)
 Abandoned Sunnan pg 38
 Tanweer Sharhul Jami As-Saghir vol 7
 (Minhatul Bari Bi Sharhi Saheeh Al-Bukhari vol 3