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.
It is desirable for a Muslim to perform supererogatory prayers as much as he can and at his home. The Prophet said: “A person's prayer in his house is better than his prayer in the mosque except for the obligatory prayer.”
The Prophet also said:
“Perform some of your prayers in your homes and do not turn your homes into graves.”
Performing obligatory prayers in the mosque in congregation is compulsory for every man who hears the Athaan (call to prayer) and who is able to go to the mosque. It is not permissible for him to offer an obligatory prayer at home without having a sound excuse. This is the most correct opinion of the Muslim Scholars. Many sound Ahadeeth support this opinion:
Abu Hurayrah narrated that the Prophet said:
“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]
It is narrated in Saheeh Muslim 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, the Prophet called him and said: “Do you hear the Athaan?” The blind man said: “Yes”. Thereupon, the Prophet said: “Then respond to it!” (By coming to the mosque).”
Hearing the call is not a rule because sometimes one could not hear it because of the noise of air conditioning or other reasons, which might hinder hearing the Athaan. So, what is considered is the distance that is between where the person is and the mosque. Allah has ordained Muslims to offer the prayers in congregation even though they are in the state of fear and travel. If this is the case, then just imagine how one could abandon congregational prayers while he is at home at a time of peace.
Shaykh Ibn Taimiyyah held that performing the prayer in the mosque is a condition for its validity for the different proofs. So, whoever considers the above pieces of evidence, and understands the wisdom behind building mosques and appointing Imams and Muath-thins, perceives that absence from congregational prayer is a characteristic of the hypocrites. If one looks to the benefits of praying in congregation, he will surely understand why praying in congregation is an obligation.
But whoever offers a prayer in his home without a legitimate reason, his prayer is valid, but he commits a sin for not praying in the mosque.
Whoever does not habitually offer the prayers in congregation is no doubt in great danger.
If there is a legal excuse, then one is allowed to perform the prayer in his home, and he may also make the Athaan.
If one performs the prayer without making the Athaan, his prayer is valid.
If one calls the Athaan, he should raise his voice at a range that only the persons around him can hear it. But if he is in an open space, it is desirable for him to call the Athaan with a loud voice.
The Prophet said:
“I see that you are fond of sheep and the desert. So whenever you are with your sheep or in the desert and you want to call the Athaan for the prayer, raise your voice in doing so, for no human, jinn or thing hears the Mu’aththin's voice without being a witness to it on the Day of Resurrection.” Abu Sa‘eed added, “I heard this from the Messenger of Allaah, sallallaahu ‘alayhi wa sallam.” [Al-Bukhari and others]
Allah knows best.