How to enable feature in ember to use htmlbars when not using ember cli or app kit

I have been getting this error :

template must be a function. Did you mean to call Ember.Handlebars.compile("...") or specify templateName instead?

after I upgraded my ember version(1.10.0). Upon searching for this issue, it seems like I have to enable feature

EmberENV: {
  FEATURES: {
    'ember-htmlbars': true
  }
},

but we are not using ember cli at this moment. I read up on http://ift.tt/1KGbSM6 and then tried this :

var EmberENV = {FEATURES: {'ember-htmlbars': true}};

//Ember.FEATURES["ember-htmlbars"] = true; //tried this too

window.AS = Ember.Application.create({
..
});

but this still didn't help. So what is the correct way to enable feature?

Thanks, Dee