It seems you almost can not build a house over 5000 SF any more without including a multi-slide door. What used to be a luxury is now almost a requirement.
This being the case it appears that more and more consumers want to update their existing homes with these products. Their popularity can not be denied so I feel the best way to discuss these doors are in terms of pro's and cons. Then, you the homeowner can decide whether the decision is right for you or not.
Cons
1. Poor Energy Efficiency – Usually multi-slide doors are such large openings that they need to be made of aluminum to be able to manufacture such large openings. As you probably know, aluminum is not very energy efficient. Also having such large sections of your home being glass will also require more energy to heat and cool as opposed to if there was just wall space there. However, luckily glass is getting more energy efficient all the time, and there are several low-e glasses available that perform surprisingly well.
2. Difficult to Install – This is one of the projects that I would seriously recommend you hire a licensed contractor to install. Most manufacturers only sell the product as an installed unit because of the difficulty of installing them; they require all installers to be factory trained employees. Even manufacturers that do not install, usually require vendors to be licensed glaziers.
3. Difficult for remodeling situations – Most multi-slide doors are designed with pockets and large spanning opening, they can be sometimes difficult to rearrange your existing framing to accommodate what you may be looking for. The home usually needs to be designed with the multi-slide door in mind to accommodate your exact design wishes. However, usually if you're flexible with the design and configuration, there is typically a way to make it work.
4. May require a general contractor – Most times when installing a multi-slide door, it may require framing changes. Depending on where you live, if the change is made to a load bearing wall, you have to pull a permit and have an engineer sign off on the change. This will usually require a GC to handle the details for you. A simple French door or window installation can be done by a licensed window or door company.
5. Cost – These doors can be quite expensive. Most time when I give a remodeling customer / homeowner an estimate on these doors, it usually becomes price prohibitive. They see a French door or sliding glass door at a home store for 800 dollars and figure these doors are three times as big, so they should be three times as much right? Wrong, you see standard size doors are made with stock sized tempered glass. Multi-slide doors are custom sized and the price grows exponentially when you go to custom sizes.
Pros
1. Dramatic effect – No other home improvement will such a dramatic effect on the design, look and feel of your home. Removing what used to be a wall and replacing it with what amounts to a moving glass wall can really improve the lighting, look, feel and design of your home.
2. Indoor / Outdoor – These doors are the best way to create a space where the lines between inside and outside are not so clear. Some people like to barbecue and invite lots of people over but do not quite have the space inside their home to entertain the way they would like to. Well, choosing the correct sill tract and continuing your flooring from inside to the outside and the lines between inside and outside disappear. The glass disappoints into the wall and voila, you have doubled your living space without actually adding any space.
3. Automation – If you are going to the expense of installing these types of doors, you might as well have them automated as well. You can set them up with a motion sensor so when you walk up; they automatically open for you or your guests when you are entertaining. This feature is easily disabled when the need is no longer required.
4. Resale Value – nothing will catch the eye of a prospective buyer from a large expansive opening across the back wall of your home. Your competitive neighbor may have nicer landscaping or a larger pool, but if you can not see it from inside the home, there is not the same perceived value.
So there you have the pros and cons of multi-slide / pocket doors. The fact remains that these are a luxury item and they are going to be expensive but like most things that are expensive, they are worth it.