You have indeed asked a very interesting and relevant question from both Vastu Shastra as well as the generic Hindu Shastra point of view.

First of all as a Vastu Shastra consultant I would be answering this question from that perspective. Many are of the opinion that one should place the Horse Shoe either atop the frame of the Main Door or then on the threshold in order to ensure that no negative energy or malefic effects of Saturn ( Lord Shani ) negatively impact the occupants of the Vastu. However, this common trend has no basis or relevance at all. In all my reading and experience I have rummaged through various authoritative classical texts for a reference to this notion. But alas all my effort was in vain as there was no text which vouched for its placement on the Main Door.

On the contrary it is regarded as attempting to further invite Lord Saturn into the premise it is placed in. It also attracts Alakshmi ( loss of Wealth and Riches ) and hence in my personal opinion I would dissuade you from placing the Horse Shoe on your Main Door or just any door of either a commercial or residential premise.

The placement of the Horse Shoe is a Western concept and hence one does not find any reference in the ancient Indian scriptures.

I sincerely hope that this Blog has been a good eye opener.

Shivam Kalyanam

 Prof.Dr. Manoj Kalantri. Ph.D, D.Sc, D.Lit

Eshans Emporium.