Heian Shrine is located in eastern Kyoto and compared to the rest of the famous temples and shrines in Kyoto, it is very new, being built in 1895 for the 1,100th anniversary of the Heian Capital Foundation. Part of the shrine is a replica of the Imperial Palace of the Heian Period but not all of it is the same scale.
The best time to go here is during cherry blossom season, which is usually around the first week in April. Heian Shrine is one of the most famous places in Kyoto to see cherry blossoms, personally I prefer the Path of Philosophy though. To see the cherry blossoms here you have to pay an extra fee to go into the garden.
If you are short on time during your trip to Kyoto, it wouldn’t be so bad to skip the Heian Shrine (especially if it is not cherry blossom season). Below is a photo of a huge tori gate and in the background you can (kind of) see the entrance of Heian Shrine.