DIY Window Weatherization

Drafty windows can be a major source of heat loss during cold Colorado winters. The Energy Resource Center fields a lot of calls from homeowners and renters hoping for help replacing hopelessly old and drafty windows. Unfortunately, new windows are rarely a justifiable investment for our nonprofit organization.

That’s largely because there are much more affordable ways of sealing your windows for the winter and preventing heat from escaping through them. If you are income-qualified and sign up for a free Colorado home energy audit from the ERC, we might weatherize your windows for you. But it’s something you can do yourself right now if you don’t want to wait.

Identifying and sealing small drafts

If you have drafts coming through your windowsill, you might need to use some silicon caulk along the seams of the sill to prevent cold air from seeping in and warm air from escaping.


Use weather stripping in gaps around your window and the windowsill and between the various parts of your window. Some places you apply weather stripping might prevent you from opening the window. That’s OK because you won’t be opening the window during the winter anyway and should be able to easily peel the stripping off in the spring.

Replacing or sealing cracked panels

Cracked window panels will leak — no question. Replacing them doesn’t have to be expensive. If your window is broken into several small squares, you should be able to find a replacement panel easily and affordably. If you have a large window pane with cracks in it, it might be more affordable to use silicon caulk or other repair products to seal the crack.

Window insulation

You don’t have to buy all new expensive windows to save on your Colorado energy bills during the winter. In fact, new windows don’t offer nearly the return on investment that other more affordable energy upgrades like light bulbs and added wall insulation do.

Plastic window insulation typically costs about 20 cents per square foot and provides tremendous cost savings for people with drafty windows. Installing it is relatively easy to do on your own.

  • After you have caulked and applied weather-stripping, place the double-sided tape a couple inches away from the window on the windowsill.
  • Remove anything that protrudes from the window, such as a handle, that will poke into the plastic.
  • Premeasure the plastic so the piece is more manageable and you’re not wasting a lot of the plastic. Begin sticking it from the middle out.
  • Work with a partner. It makes the process much easier.
  • Use a blow-dryer to tighten the plastic.
  • Trim the edges.

Plastic-insulated windows can save significant money and energy and don’t look bad when they’re done right.

If you have any questions about weatherizing your home or want to find out if you qualify for the Energy Resource Center’s home energy audit, which is free for income-qualified families in El Paso, Teller, Fremont, Elbert, Douglas, Alamosa, Conejos, Costilla, Mineral, Saguache and Rio Grande counties, contact us today.


Our Loveland office has moved! If you are in the Weld, Boulder, Larimer country service area please contact our Sterling office at 970-463-7020 or email