Process
- Submit a pre-approval form and contact Flathead Electric Cooperative (FEC) for an inspection: (406) 751-5291
- Determine what windows you are going to order. The new windows must have a U factor of 0.30 or lower (0.29, 0.28, etc).
- Provide FEC with a copy of the proposed order sheet showing size of windows and specifications for proposed windows.
- FEC will provide a quote of the potential rebate amount.
- Order and replace the windows (see below).
- Highly Recommended (required by most window manufacturers):
- Install sill/pan flashing.
- Install window and rest of flashing.
- Required:
- Trim the outside: paint all surfaces (including end cuts in the field) and caulk all gaps. The new window flange must be covered and protected from exposure to sun and water.
- Air seal the inside between the window and rough opening with caulk, backer rod and caulk, or low expansions window foam. Make sure to document with photos.
- Highly Recommended (required by most window manufacturers):
- Save all window stickers: either leave them on the windows or take them off and place them on sheets of paper to save
- Call FEC to get a final inspection: (406) 751-5291.
- Provide FEC with copies of all the window stickers documenting the U Factor and a copy of the invoice.
Window Replacement Steps
Step A:
Install sill pan flashing with dam or slope and peel back water resistant barrier (water-resistant barrier = tar paper or house wrap) on top of window opening.

Step B:
Apply sealant to sides and top of opening.

Step C:
Install window and secure flanges.

Step D:
Flash sides and top (in this order).

Step E:
Fold water-resistant barrier back down.

Step F:
Tape corners of water-resistant barrier and install trim (or foam board and new siding).

Many materials are available for sill pan flashings and side/top flashings. Call for a list of options.