Most Cyms need a period (a couple months) of cool night temps (low 50s or lower), warm day temps are fine. In spike Cyms should be protected from frost or freeze. Many people bring them in just before threat of first frost. When inside, they will be happier if you have a slightly coolish spot for them, and definitely keep them away from warm air from furnace.
Other orchids it depends ... Most probably won't require a chill.
Nobile type Dens need a dryish, cooler winter with no fertilizer.
Common Oncidium alliance usually don't require cool temps.
Den-Phal types DON'T want to get chilly at all.
Catt alliance can depend, but common hybrids won't probably need a chill.
Outside of Cyms and nobile type Dens, I would probably not let things get too chilly for more than short periods without knowing exactly what the plants are. Other than Cyms and nobile Dens, most orchids from stores are house plants. There are sometimes exceptions, but I'd go with not too cold without knowing more