I am 10 minutes away from the Mosque and I used to pray in my home since I am busy.
I know that it is 27 times better to pray at Mosque but is it a sin (HARAM) to pray in my home?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Performing the prayer in congregation is an obligation according to the preponderant opinion of the Muslim scholars.

Allah Says (what means): {And when you are among them and lead them in prayer, let a group of them stand [in prayer] with you and let them carry their arms.} [Quran 4:102]

Allah has Commanded us to pray in congregation at the time of fear, then praying in congregation in normal situations is more proper.

Abu Hurayrah narrated that the Prophet said: “(I swear) By Him in whose hand is my soul! Certainly, I was about to order the prayer to be established and command a man to lead the people in prayer, then I would go with some men with firewood to the people who were absent from the prayer and I would burn their houses with fire.” [Al-Bukhari and Muslim]

As long as the man hears the Athaan (call to prayer), he has to respond to it since the Prophet did not permit a blind man to perform the prayer in his house.

Abu Hurayrah also reported that a blind man said to the Prophet : “O Messenger of Allah, I have no guide to guide me to the mosque.” He asked the Prophet for permission to pray in his house and the Prophet gave it to him. Then, when the blind man turned to go away, the Prophet called him and said: “Do you hear the call to prayer?” The blind man said “Yes.” The Prophet then said: “Then respond to it!” [By coming to the mosque] [Muslim]

Allah Says (what means): {So let those beware who dissent from his [i.e. the Prophet’s] order, lest fitnah strike them or a painful punishment.} [Quran 24: 63]

Ibn Mas’ood, may Allaah pleased with him, said: “I have seen the time when no one stayed away from the prayer except a hypocrite, whose hypocrisy was well-known, or a sick man. But if a sick man could walk between two persons (i.e. with the help of two persons with one on each side), he would come to the prayer. He (further) said: “The Prophet taught us the paths of right guidance, among which is the prayer in the mosque in which the Athaan is called.” [Muslim]

You did not explain to us what kind of business you deal in that prevents you from praying in the mosque so that we could consider its importance, to abandon praying in congregation or not?

You should know that there are many social benefits in praying in congregation. It also helps one achieve contentment.

Moreover, praying in congregation strengthens the relation among the members of the society and reconciles their hearts in obeying Allah; consequently, the whole society gets used to the obedience of Allah.

Allah knows best.