My wife and I once bought a hundred-year-old hunting lodge in the mountains, and I got a taste of what a home without much light felt like inside—in three words, dismal, dark and depressing. The old hunting lodge had one small window in the living room, and we realized we had to let some light in, or go nuts. Time for more windows, skylights and a sliding glass door or two.

When you spend a cold night in the mountains in an old cabin or lodge, you realize why they didn’t have many windows. The old, thin single-strength panes let in so much frigid air that builders minimized the amount of glass to save heat.

Today we’ve conquered that problem. With new glass technologies, with double- and triple-pane doors and windows, and with modern manufacturing techniques that make glass doors and windows ultra-efficient insulators, living in a glass house isn’t just a dream—it’s entirely possible.

One of the best ways to add glass area and get more light into your home? Add a sliding glass door, or replace a standard door with a double-width slider, and you’ll really open up your room, adding an enormous amount of natural light. Sliding glass doors are efficient, space-saving ways to retain your room layouts, too, since they don’t require the normal “sweep area” that standard or French doors do when they open and close. They provide an added measure of security, allowing you to see what’s going on outside without going outside; and they visually expand the size of every room, too.

I know one couple who decided to open up their kitchen, dining area and adjacent family room with a bevy of four sliding glass doors to their backyard. They found a good contractor, picked out the doors they wanted and had them installed in a week. They loved the way the doors united the inside and outside environments, let a massive amount of light into the home and brightened everything up. An unanticipated payoff: their sliding glass doors allowed so much light to enter a formerly dark area that they saved a considerable amount on their electricity bill every month.

We tend to think of sliding glass doors as confined to those kinds of patio-adjacent spaces, but their versatility and use has expanded far beyond that traditional use. Think about it this way—sliding glass doors can work pretty much anywhere you would normally put a standard hinged door. New uses include sliding frosted glass separating master baths from their adjacent master suites; in use between in-home offices and other living spaces; or even opening into indoor atriums, spas or garages.

Some of the newest sliding glass doors, minimalistic and ultra-modern in their execution, have even transcended the standard door-frame by utilizing hidden tracks or exposed-hardware, barn door-style hanging tracking systems. When combined with the vast array of glass finishes and textures available today, sliding glass doors can make a powerful design statement just about anywhere in the home.