That set Mullen in motion, as he tried to find a remote-control method of opening windows. After nine years, eight prototypes and investing more than $300,000, Mullen has created what he says is a viable electronic remote control window for home use. ‘‘I’ve been waiting and waiting and, now that the patent has been filed, hopefully things will start moving forward with this idea,’’ Mullen said.

Mullen’s system relies on a motor and other hardware for each window, and a switch, remote control or computer to activate them. In all, it adds close to $300 to the cost of a window. At that price, Mullen said, people might want to install the system on a couple of hard-to-reach windows, not every window in the house.

Mullen started and owns Electronic Window Systems and has three employees who each have a minority stake in the company. Deana Dichiaro, the project manager, George White, the software engineer and Ken Vachon, the mechanical engineer, have each played a role in developing the product.

‘‘I joined EWS four years ago and Tim has just put his heart and soul into this company and this invention,’’ Dichiaro said. Mullen has been in the construction business for 20 years and started his first company, Bostonian Window Specialists, 11 years ago.

‘‘I bought the property next door, tore down the old house and rebuilt this model home where all 34 windows are electronically capable,’’ he said.

Mullen wants to use the model to demonstrate his product to major window manufacturers. For each window there is a circuit board, which can be wired to a central computer.

By pushing a button, a motor that’s linked to a particular window is turned on and a quarter-inch shaft begins to spin. Two separate chains, which are connected to the ends of the shaft, run up both sides of the window frame.

As the shaft rotates, the chains do as well - and the window opens. The mechanism is hidden from view: The only noticeable difference between an outfitted window and a normal one is a small switch and sensor light under the windowsill. The window-opening hardware can be installed on any kind of window, Mullen said.

‘‘The idea was originally for the unreachable window, but now it can be installed into any type of window found in houses,’’ he said.

An average Anderson-brand double-hung window costs about $520, and the addition of Mullen’s electronic components would raise the price to more than $800 per window. That might not be an easy sell considering the price of houses these days. ‘‘Not every window needs to be installed with this, but maybe just a few windows in those out-of-reach places,’’ he said.

Mullen and his associates are already looking toward the future. He has been thinking about developing the same idea for doors, if the electronic window takes off.