Energy losses from inefficient entry doors can account for a significant portion of your monthly utility bills,
because air leaks can cause you to adjust your thermostat – up in the winter and down in the summer. Fortunately,
there are some simple things you can try to make your old doors more airtight without replacing them.

On the other hand, installing new doors may be the best solution. The cost of some well-insulated steel and
fiberglass doors, especially ones without glass, are very reasonable – and installing a door pre-hung in its own
frame isn’t beyond the scope of being a do-it-yourself project.

If your doors are in very bad condition,
you won’t be able to improve their
efficiency by a meaningful amount. If
you have a wood door, make sure it’s
not rotting. Then check for warpage by
placing a straightedge across the face
and around the perimeter of the door.

The most common problem with
metal doors is rust, not warping. The
first place to check is along the bottom,
on either side. Rainwater tends to collect
there – and it’s not always painted
well – so rust easily can form along or
under the weather stripping.

If you find small holes rusted
through, you can repair them with
car body filler, followed by primer and
paint. But before you make any repairs,
make sure you determine and eliminate
the reason water is collecting there
and correct the problem.

If the doors are reasonably sound,
check for air leaks. At night, have
someone shine a flashlight from outdoors
around the seals, and check for
light leaks indoors. On a windy day,
you can move a lighted stick of incense
around the seals and watch the trail of
smoke to find the leaky areas.

Also, if you have double doors, check
the astragal – the raised, half-round
trim or gasket where the doors meet
in the middle – that acts as an air seal
between them.

With wood doors – especially ones
with compression-style weather stripping
– the main problem could be the
latch plate not holding the door tightly
closed against the weather stripping.
One solution is repositioning the latch
plate, which requires filling in the old
screw holes and latch cutout and making
new ones. Another option is replacing
the existing latch plate with an
adjustable one.

Steel doors should include magnetic
weather stripping. Unless it’s damaged
and needs replacing, make sure the
surface of the door and the weather
stripping are clean and smooth so they
contact each other as the door is closed.
(Paint on the door edge sometimes can
come loose and create small gaps that
leak air.)

Check the condition of the hinges
too, and replace them if needed. If the
hinges and pins are worn, the door will
not hang squarely in the opening and
won’t seal properly. There are many
sizes of hinges, so take an old one with
you to the store to get an exact match.
Finally, it’s almost certain the seal
on the bottom of the doors against the
floor threshold is worn. If it’s not worn
but there’s an air gap, try adjusting the
floor threshold higher. There are several
height adjustment screws across the
threshold, but after years of use, they
may be filled with dirt. Poke around to
find them. If the threshold isn’t adjustable
or the seal itself is bad, you should
be able to find generic replacements at
the store.

Another option is an add-on retractable
threshold seal that’s especially effective
if there’s carpeting on the floor
by the door. The threshold seal mounts
on the inside surface of the lower door
edge, and when the door starts to open,
a pin against the door frame is released
and the seal automatically lifts to clear
the carpeting. It’s easy to install and
adjust.

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