Q. My husband and I are trying to decide if we should buy a \$330,000 home in our neighborhood that, at 2,300 square feet, is twice the size of our current home (the monthly payment would be only about \$50 more a month than our current payment), or renovate our old house using a home-equity line of credit, then refinance at a lower rate and pay off the equity line.

The extra money we would need for the larger home's down payment would be around \$25,000, and the renovation we'd like to do would cost the same. The renovation would up our square footage by 750 square feet and allow us to stay in our home longer. We bought the home for \$280,000 three years ago and have a private buyer who will give us what we paid for the home. Do you have any advice on whether buying new or renovating is wiser?

A. The decision to buy new or remodel depends on a number of factors, some financial and some not — and ultimately, only you can decide what answer makes the most sense for you. That said, I'm leaning towards the new purchase.

Let's look at some of the issues to consider:

1. Cost per square foot: Although figuring the cost per square foot is an imperfect exercise at best, since it doesn't account for variations in floor plans and materials, it's worth doing the math (price divided by square footage). The bigger house is less expensive at \$143.47 per square foot, versus \$147.36 per square foot for the smaller one (after it's been expanded to 1,900 square feet).

2. Transaction and moving costs: You need to compare the costs of refinancing — and perhaps renting a place to stay while the remodeling takes place — versus the costs of buying new and moving. An online calculator can help you compare these expenses. An interesting one that not only allows you to compare costs but also asks questions to help you sort out your "gut feelings" towards remodeling versus moving can be found at RemodelOrMove.com.

Keep in mind that costs for loans and moving tend to fall into line with budget projections, while remodeling costs often exceed them, swelled by change orders, delays in delivering materials and unexpected problems that crop up during construction, like leaky pipes that are discovered when the drywall is removed.

3. Age and obsolescence: Although you don't say how old each house is, you need to take their relative ages into account, because that can make a difference in the eyes of future buyers. How much depends on the actual age of each house. For instance, if the larger house is 15 years old, and your current house is 20 years old, there may not be much of a qualitative difference between the two in most buyers' eyes. But if you only plan to put an addition on your home, it won't be competitive with a house that's five years old or less, and won't appreciate as quickly. A house that's new will have an updated floor plan, a current kitchen and bath, and materials, fixtures and finishes that have yet to see much wear and tear — well worth the \$50 extra you'll pay per month on the loan.

Home affordability calculator

4. The economy: You may get bargain rates from remodelers trying to keep their businesses in the black during a tough economy (though \$33 a square foot for a 750-square-foot addition seems awfully low). But as home prices continue to fall, many people are seeing their home-equity lines of credit shrink or get cut off — so don't expect them to be reliable sources of money for a renovation. What's more, most of the measures the government is currently considering to stimulate housing, including mortgage rate buy-downs and tax credits, are targeted towards people who are purchasing homes, not those who are refinancing or remodeling.

The bottom line: If you remodel your house instead of moving, you'll be able to get exactly what you want and will have total control over the final result. But given the costs, uncertainties and hassles of remodeling — and the fact that you have a buyer in hand for your current home — if I were you, I'd trade up.

By June Fletcher, The Wall Street Journal