What is accessible or universal design?

Basically a universal design is barrier-free design. It is a holistic approach to designing a space to suit anyone. These considerations include: eliminating steps or stairs, roll-in showers, wider doorways to accommodate walker or wheelchairs, lower or adjustable countertops.
Many people have to stay in their current home longer. Many of these homes are not designed with aging in mind. Steps into a shower or tub, stairs to the bedrooms, steps to get in and out of the house, all will be barriers as we get older. Any one may end up on crutches or a wheelchair due to an accident and builder never really take that into account.

Universal or accessible design allows ample room for maneuvering a wheelchair in every space. During a remodel, changes can be made to bring many of these features into an existing home: Replace the tub with a roll-in shower, create room under countertops to allow for a wheelchair to pull up close,  install attractive ramps outside next to steps, widen doorways, and many more. You should consult a design professional about these changes however before you take on such renovation.

An accessible bathroom will have enough clearance under the countertops to allow for a wheelchair, but elegantly hide the plumbing pipes. It is equipped with a roll-in shower with a seat and an area for dressing.

sustainable design makes a lot of sense to your health

Green or Sustainable Building is the practice of creating healthier and more resource and energy efficient models of construction, renovation, operation, maintenance, and demolition.

According to the US Green Building Council (USGBC), as of January 2006, the annual market for Green Building in products and services was $7 billion, a 37% growth over 2004 Over 531 million square feet of commercial building space has been registered or certified under LEED.
Green Design has significant benefits:

Contributes to better health
EPA studies indicate indoor levels of pollutants may be two to five times higher – and occasionally more than 100 times higher – than outdoor levels. Studies with 30,000 subjects showed that  there are significant relationship between low ventilation levels and higher carbon dioxide concentrations – a common symptom in facilities with sick building syndrome. Green buildings instead use alternative building materials that do not emit toxins, like formaldehyde or VOCs (Volatile Organic Compounds).

Saves you money in the long run 
A Well-designed green buildings will be more energy efficient and have lower utility costs. Recent studies indicate that with an upfront investment of 2% in green building design, can result on average in savings of 20% of the total construction costs in lifecycles– This is more than ten times your initial investment.

Increases your productivity
Factors considered in Green design include abundant daylighting, individual climate controls, and outdoor views increase employee and tenant satisfaction, which improves productivity. A study by Carnegie Mellon University measuring the relationship between increased lighting control and productivity showed an average increase of 7.1% in productivity.