The speed and the fluctuations in the speed of the service you receive at home will be dictated by the distance from the local exchange, the quality of the cabling to the building and the number of users on the system at any one time. Bear in mind that home internet speeds are usually reduced by the supplier during the evening to discourage the download of very large files due to the time it will take to do this. It would effectively lock out other users on the same cabling.
This can be overcome if you are prepared to pay for a business connection. This type of internet supply will give you a high fixed speed irrespective of the time of day or night or who else is using the connections. In most cases only 4 or 5 others users have access hence the reliability of the speed.