The freestanding flueless Oxygen fireplace by EcoSmart can be moved from room to room, or apartment to apartment.

A. Almost any fireplace can be rehabilitated, though if every element, including the chimney, needs an overhaul, it can get expensive.

 What are the elements? Your fireplace and chimney have a hearth, a firebox, a smoke chamber, a damper, a flue, and lots of brickwork-both interior and exterior. When you call professionals to assess your fireplace, they will inspect these parts and determine if they are up to modern code or in need of repair. (Not all fireplace companies will inspect the exterior brick on your chimney, so be sure to ask.)

To get a general idea of costs, we asked Paul Loar, president of Fireplace and Chimney Authority (1702 Ogden Ave., Lisle, 630-969-8800; chimneyauthority.com), for an estimate. He said repairs to a firebox and smoke chamber range from $100 to $1,500; relining a flue, from $1,200 to $2,500; refacing or replacing a brick surround, from $25 to $40 per square foot. This puts you in the area of $6,000, not including a chimney, for an average-size fireplace.

Repairing a chimney can be relatively inexpensive-or can easily run into many thousands of dollars, depending on accessibility and the condition of the chimney, says Robert Reese, owner of AAA-1 Masonry & Tuckpointing (773-622-7300; www.aaamasonry.net). He has done repair jobs that cost as little as $500 and chimney rebuilding projects for as much as $35,000.

Loar points out that many homes in Chicago that predate 1920 have fireplaces built to burn coal; their fireboxes are too shallow for wood. In order to burn wood, these fireplaces need major restoration and would cost in the range of $5,000 to $10,000, he says.

There are alternatives, of course, to burning wood. Gas fireplaces and units that use other fuels are very cleverly designed these days, in both traditional and modern styles, and many of them actually radiate heat into a room. You can find anything from realistic-looking faux logs to something that resembles an eternal flame in Arlington National Cemetery.

One company that sells and installs alternative fireplaces-as well as rehabs existing wood-burning fireplaces-is Alltypes Fireplace, Patio & Grill (1215 W. Belmont Ave., 773-348-9111, and other area locations; fireplaceideas.com).

Another is American Heritage Fireplaces and Accessories (3054 N. Western Ave., 773-862-8200; fireplaceproducts.com), which sells vent-free and direct-vent gas fireplaces with the traditional log-in-the-grate look; both require installation of a gas line, and the direct-vent type also needs an exhaust outlet. They range in price from about $500 to $3,000. Fireplace and Chimney Authority sells vent-free log sets that are fueled by gel alcohol for $200 to $300.

And now we come to the eternal flame. This vent-free open fire, which can be installed almost anywhere, is made by a company called EcoSmart Fire (ecosmartfire.com). Available at Casamonte (1355 W. Concord Pl., 773-278-4100; casamonteusa.com), it is simply a stainless steel burner that is also a reservoir for liquid fuel. The fuel is denatured alcohol or ethanol, both clean, renewable energy sources you can buy at Menard’s or Home Depot.

EcoSmart Fire offers several sleek, modern designs, some of which are portable, so that you can actually move your fireplace from room to room. You can also buy the burner set in a grate and put it in your existing fireplace for a more traditional look. Prices range from about $3,300 to $8,800.