application_controller.js

App.ApplicationController = Ember.Controller.extend({
	observePath: function() {
		if (this.get('currentPath') !== 'index') {
			$(window).scrollTop(264)
		} else {
			$(window).scrollTop(0)
		}
	}.observes('currentPath')
});

application_view.js

App.ApplicationView = Ember.View.extend({
	didInsertElement: function() {
		$('#menu-affix').affix({
			offset: {
				top: 264
			}
		});

		if (this.controller.get('currentPath') !== 'index') {
			$(window).scrollTop(264)
		} else {
			$(window).scrollTop(0)
		} 
    }
});