Will a stair lift fit your stairs?

Stannah, a stair lift company, says stairs about 28 inches wide suit most straight lifts in most homes, and about 30 inches suit most curved ones. Lifeway Mobility, a company that installs lifts, plans on 28 to 30 inches for straight stairs, depending on the model.

Tight stairs do not mean you are out of options. Acorn says its 130 runs on stairs just 26 inches wide, and its 180 on stairs 27.5 inches wide, leaving the rider room to swivel the seat round. Stannah also sells a slim Siena chair that suits stairs as tight as 27 inches.

Here is a count of how many of the 16 lifts compared on this page work at each stair width: by a published minimum, or only by the usual guide, where the installer's measurement decides.

Every manufacturer sets its own smallest stair width, so check the exact model you are considering. Folded depth means how far the lift juts out from the wall once the seat, the footrest, and the arms are all folded away and no one is riding. A lift with a small folded depth leaves more passing room for anyone using the stairs.

Some models offer a heavy-duty option with a higher weight limit, shown in the table. Looking at all 16 models together, 350 pounds is the middle weight limit. The heaviest rating, 600 pounds, goes to the Harmar Pinnacle SL600HD, and the lightest, 265 pounds, to the Acorn 180.

Stair width, staircase shape and the rider's weight are useful starting points for comparing models, rather than a guarantee that a lift will fit. If your stairs run straight with no landing or turn, a straight lift will do, and it costs less. Stairs with a bend need a curved lift, and most of those need at least 30 inches of width, though the Acorn 180 needs only 27.5.

Start with width, since it immediately rules models in or out. Stannah says a folded lift typically takes up about 7.5 inches of the stair width. The folded depths in the table measure how far the whole unit sticks out from the wall, and they run from 10.5 to 16.5 inches, so if others use the stairs, look for a smaller number.

Weight comes next. All 16 models have weight limits of at least 265 pounds, though stair width also affects your options. For riders over 400 pounds, the Handicare 1000 heavy-duty option supports up to 440 pounds, and the Harmar Pinnacle SL600HD supports up to 600 pounds.

Two measurements help you check which models might fit before anyone comes to the house.

1. Measure the width of your stairs, so you can compare it with the narrowest stairs each model needs.
2. Count your steps, because the rail length depends on the length of your staircase.

The rail is the track the seat travels along. Our cost tool estimates use a 15.5-foot standard rail and allow about $75 for each extra foot, and these are estimates, not terms that apply to every straight lift.

According to the National Council on Aging, having a new straight lift installed runs roughly $2,500 to $5,000, a curved one costs about $8,000 to $12,000, and a secondhand straight model goes for around $1,500 to $3,000.

Acorn provides quotes in your home. Other prices listed here are estimates, starting prices or prices from individual dealers.

Sometimes installation is included, and sometimes it costs extra. A single Harmar dealer quotes $725 for fitting the Pinnacle SL300, and a Savaria dealer asks $345 to $445 for fitting the K2. The AmeriGlide Rave 2 can be fitted yourself or installed by a paid installer. Curved lifts like the Harmar Helix are priced to your stairs.

The lifts covered on this page come from seven brands: AmeriGlide, Acorn, Bruno, Handicare, Harmar, Savaria, and Stannah. This page compares 11 straight lifts and five curved lifts.

Straight lift prices start at $2,249 with the AmeriGlide Rave 2 bought online and climb to roughly $7,505 for the Harmar Pinnacle SL600HD, both before installation; the model-by-model table gives the installed prices. Curved models begin near $8,000 and can top $25,000 for the Bruno Elite Curved. Warranty terms vary just as much: Acorn lifts carry a 12-month manufacturer's warranty, while the Bruno Elan is backed by a limited lifetime warranty.