energy efficient residential storm doors

Residential storm doors may not add much to the energy-efficiency of well insulated entry doors, but they can be useful for ventilation and energy savings if added to old and bad condition exterior doors.

Goals of storm doors. Adding a storm door to an existing entry door can diminish air leakage and also heat loss (or unwanted heat gains). Storm doors can also be an important element of ventilation in hot climate and hot weather conditions, which is also a way of reducing the energy bills with air conditioning.
Other goals include natural lighting, security and aesthetics…

Cost-Benefit analysis

Very cheap residential storm doors are useless for energy savings. Cheap storm doors do not have double-panel glass and well insulated elements, or thermal breaks and, due to it, they will not block air leaks or protect the primary door significantly.

Only reasonable or good residential storm doors that can due that job.

Features you may look for...

Storm doors come with very different features, that can make the difference. Pay attention to...

Ventilation: some types of storm doors have movable glass panes providing bottom and top ventilation, or both.

Protection: some patio doors offer additional protection; they have thick aluminum or other metal frames with security grilles, and special locking systems.

Type of glass: glass is crucial in most storm doors; the type of glass determines much of the door efficiency.
Note: the energy-efficiency of residential storm doors with large glass panes should be assessed as windows. See on this issue: Types of glass for windows (and doors)

Frames: insulation of the frame and thermal breaks are very important for energy-efficiency. See: Windows/Doors Frames and Sashes

Maintenance: most storm doors have low maintenance needs, and some can be easily removed for cleaning. Follow the manufacturer’s instructions.

Installation: installation is typically easy; follow the manufacturer instructions. Top manufacturers offer videos and detailed installation instructions.

Size: storm doors come in different standard sizes; you have to measure your door opening to determine its exact size and the size of the storm door. Top manufacturers offer detailed instructions on the how to get accurate measurements… See, for instance Larson or Emco/Andersen for instructions on how to choose the right size of a storm door.

disadvantages

Adding a storm door to a new foam core-filled entry door may not worth the expense; the energy savings will be too small, unless the ventilation provided by the door and savings in air conditioning are significant (compare potential savings with the price of a storm door: often in the range $150-$250).

Be also aware to overheating damages. If a glass storm door gets too much direct sun during large periods, trapped heat can damage the main door…

Companies

Pella and Larson (sold at Lowe's) and Emco/Andersen (sold at Home Depot) are very well known storm door manufacturers. But there are others that also can also ensure durability, quality customer service or ease of installation.

Choose a good company, but also well rated glass doors (do not forget: glass storm doors should be assessed and rated as windows) with a large warranty.