Microsoft SQL Query sum values over time periods

I have the following data:
Value      ReadingTime      EntityID      ServicePointChannelID
0.273      2017-05-17 00:15:00.000      76058805      1
0.272      2017-05-17 00:30:00.000      76058805      1
0.274      2017-05-17 00:45:00.000      76058805      1
0.274      2017-05-17 01:00:00.000      76058805      1
0.275      2017-05-17 01:15:00.000      76058805      1
0.275      2017-05-17 01:30:00.000      76058805      1
0.278      2017-05-17 01:45:00.000      76058805      1
0.278      2017-05-17 02:00:00.000      76058805      1

I need to sum the value for every hour, so it needs to add the 15 minute interval, 30 minute interval, 45 minute interval, and the hour interval together for an hour value.

In the case of the data above the output would look like:
Value      ReadingTime      EntityID      ServicePointChannelID
1.093      2017-05-17 01:00:00.000      76058805      1
1.106      2017-05-17 02:00:00.000      76058805      1

There will not be missing time periods.  These come in every 15 minutes and must be aggregated by hour.

Any help would be appreciated!