As our parents get older and begin to decline in vitality, many of us consider letting them move into our home. After all, it's easier to care for an elderly mom or dad in a nearby room, rather than one who's across town or even in another state.

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But you should also be aware of the potential economic impact of such a move, particularly if your parents have limited resources. Experts say that the financial ramifications are often greater than most people anticipate.

Here are some key factors to consider — and to plan for — if you're contemplating such an invitation.

Remodeling or renovation costs

Your home in its current form may be just fine for you, but what about for Mom or Dad? If your home is modest, a lack of space is the first hurdle to overcome.

"Do you have the room to afford them the privacy they're accustomed to and to maintain privacy for you, your spouse and family?" asks Jack J. Hetherington, a certified elder-law attorney in Chalfont, Pa. "If there aren't enough bedrooms or bathrooms and only one kitchen, then those living arrangements can quickly prove inadequate."

The costs of fixing this problem depend on the solution you choose. Some people with homes that are too small buy entire new homes or build additions or in-law suites in the old one. The costs can be frightening: According to Remodeling magazine's 2011-2012 Remodeling Cost vs. Value Report, the national average cost for a midrange master suite addition is $106,196.

If you plan to have a parent move in with you, space is a factor to consider. — Photo by Getty Images

At the other end of the spectrum, having a home that's too large can be tricky, too. An aging parent with physical issues — like a bad back, faulty knees or a hip replacement — may not be able to climb the stairs in a two-story residence. Installing an electric stair lift for moving from floor to floor usually runs about $5,000 to $10,000, depending on the manufacturer.

Even if such major renovations aren't required, it's a good idea to plan on upgrading some basic areas, like your bathroom. Many older people require handicapped-accessible toilets, or showers and tubs with handlebars and grab rails.

Cost of hiring medical or professional help

All of us want to be there emotionally, physically and even financially for our parents when they need us most. But not everyone has the wherewithal to provide day-to-day care, such as bathing, feeding or dressing an aging parent who may be frail, forgetful or physically ailing.

Since the average cost of a home health care aide is about $21 an hour, experts at the MetLife Mature Market Institute put the average cost of a parent's in-home care with a home health aide at about $21,840 a year. For boomers on the cusp of retiring, or those already in retirement, spending several thousand dollars a month on a parent's care simply isn't economically feasible.

Perhaps that's why a recent survey by AgingCare.com found that an estimated 34 million Americans are personally providing care for older family members.

Many are paying for part of the care, too. The AgingCare.com survey revealed that 34 percent of caregivers spend $300 or more per month out of their own pocket for caregiving expenses. Typical expenses include anything from groceries and household goods to prescription drugs or medical copayments made on behalf of a parent.

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