With temperatures dipping into the 20s last night, it was absolutely freezing in my house. That’s because my Seattle home is a 1924 Craftsman, with windows that leak air.

insertswindows111Sam Pardue experienced a similar problem with his 1906 Portland Craftsman home, so three years ago he founded Indow Windows. Today, the Portland startup is announcing $1.3 million in funding, led by Vision Ridge Partners of Boulder, Colorado and including participation from the Alliance of Angels, Puget Sound Venture Club, Northwest Energy Angels and Keiretsu Forum. The new cash, which will be used for product development and sales and marketing, caps the series A round at $2.6 million.

Demand was so high for the deal, that the company had to turn down cash. There’s good reason for the interest.

Reuben Munger, managing director of Vision Ridge Partners, notes that there are a billion single-pane windows in the U.S. Many of them are letting the heat escape from the home.

“The company is experiencing strong growth and has put in place the team and infrastructure to scale up rapidly,” said Munger in a release, noting that Indow Windows’ inserts are more affordable and energy efficient than other solutions. (including mine of stuffing a towel by the air leaks).

The inserts, which are made in the U.S. and distributed through 26 dealers, are made of a sheet of acrylic glazing edged with a patented compression tube that allows home owners to easily place inside a window frame. The company says the inserts cost about 80 percent of what it would to replace a window. In addition to boosting energy efficiency, the windows also are designed to reduce noise.

Laser measurement insures a snug fit for the inserts
Laser measurement insures a snug fit for the inserts

An average size window insert costs about $250. The main dealer in Seattle is remodeling company Neil Kelly. They handle the laser measurements of the windows, and then submit the dimensions via specialized software to the company, which custom manufactures each insert at its facility in Portland.

Customers can get a federal tax credit for installing the inserts, and there’s about a 3-week turnaround time from measurement to shipping of the inserts.

Here’s a closer look at how the window inserts are installed.

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