The requirements of doors are influenced basically by their application, the human aesthetic approach, and the economic factors.

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The important factors that are normally considered for door selection are:
Style And Appearance
The doors at entrance are the initial observations that create an impact regarding the building.Often, the entrance door style is reflected in the other house doors.
Thermal Efficiency
Thermal effects of doors are considered while selecting door materials, and door styles. Modern doors have R value ratings that represent thermal efficiency. It is an evaluation of the material thermal resistance. Normally, it is ratio of temperature variation across the insulator and heat flux.
Ventilation
The real placing of windows and doors has a huge effect on the house ventilation. Poor design will increase the energy bill. Some doors include inherent openings for suitable ventilation even with the door in a closed position. This is feasible on the external doors.
Fire Safety
The door placing mitigates the door fire hazards. There are building regulations that require specific distances to be maintained to an exit. This is the distance required to be run when fire breaks out. Public buildings have doors and frames with specific fire ratings. Furthermore, these doors open outwards.
Illumination
The doors should be adequately illuminated to obtain maximum advantage of the natural light. Therefore, doors may have glass panels, or may be constructed totally from glass.
Strength
Closely linked to security is the door and frame strength. Expensive locks will not be effective on the external doors if the door panels are not correspondingly strong.