The improvements that pay you back, and the ones that mostly do not

There are two reasons to improve a house: because you want to live in it that way, and because you want it to be worth more. Both are good reasons. The trouble comes when someone promises the second while selling the first. Here is how the numbers usually fall, drawn from the yearly cost-versus-value surveys and from what agents and appraisers say when nobody is selling anything.

Usually pays back most of its cost

• A new front door, especially steel. Small money, and the first thing a buyer touches.
• A new garage door. Same logic, larger surface.
• Exterior paint or new siding where the old is failing. Curb appeal is a real thing in a listing photo.
• A roof that is at the end of its life. Buyers and their inspectors price a tired roof at full replacement, and lenders can refuse to lend on one that is failing. Replacing it does not add value so much as stop the subtraction.
• A minor kitchen refresh: paint or reface the cabinets, new counters, new appliances, same layout. The full gut-and-move-the-plumbing kitchen returns far less per dollar.
• A manufactured stone or brick accent on the street-facing wall.
• Landscaping that makes the front look kept. Not the koi pond.

Usually returns much less than it costs

• Anything that adds rooms the neighborhood does not have. A fourth bathroom in a street of two-bath houses is priced by the street.
• Swimming pools, in most climates. Some buyers subtract for them.
• High-end finishes beyond the neighborhood's level. Buyers pay the neighborhood's price and take the marble as a bonus.
• Sunrooms and enclosed porches.
• Converting a garage to living space. Many buyers want the garage back.
• Elaborate outdoor kitchens, home theaters, wine rooms. Wonderful to own; the next owner may not care.

The ones that pay in a different way

Insulation, air sealing, a heat pump, new windows where the old are single-pane or rotten: these rarely return their full cost at sale, but they return it every month in the utility bill while you live there, and there are federal tax credits and often utility rebates that cut the price. Judge them against the bills, not the appraisal.

How to think about it

If you are selling in the next two years, spend on the outside and on fixing what an inspector would flag. If you are staying, build what you want, at the quality you want, and treat the resale number as a happy accident. The one thing not to do is build the expensive version of a project because someone told you it would come back at sale. Ask an agent in your area what it would do to the price before you sign, not after.

And whichever kind of project it is, get the permit. An unpermitted addition is worth nothing on paper and can be worth less than nothing at closing.