Even if you’re feeling ready to get settled into your space and add a few sets of curtains to your online shopping cart, we encourage you to take a few moments to brush up on the how-tos of curtain shopping. Selecting the proper length of curtains is key to ensure that your room looks intentionally designed and sophisticated, after all. Not sure what factors to keep in mind before making a purchase? We consulted a handful of design pros who offer their expertise below.

Check Your Ceiling Height

You’ll want to have this important measurement on hand before you begin curtain shopping, designer Rosanna Bassford notes. “Generally, if your ceilings are eight feet tall, you should still be buying curtains that are eight feet, hanging them a few inches above the top of your window and then hemming them so they just graze the floor,” she explains. “I like to split the difference from the top of the window trim to the ceiling and install the curtain rod at that point.” As a frame of reference, note that nine feet is said to be the standard height for most ceilings in residential homes.

Decide How Closely You Want Curtains to Touch the Floor

Bassford mentioned having curtains graze the floor, but there are a few different routes you can go when it comes to length, according to designer Cortney McClure. “The rule is always to have the drapes ‘kiss’ the ground or just above, but I love when the fabric is longer and bunches just a bit at the bottom,” she says. Jason Miller, design consultant at Stoneside Blinds and Shades says that the latter approach is ideal “for a more elegant and luxurious look,” if that’s what you crave. Figure out which result most appeals to you, and then purchase the appropriate curtain length based on your preference!

Think About Optics

If you wish to add some extra oomph to a space, you may wish to go for curtains with extra volume, designer Allison Knizek notes. “Typically, my fabric width would be approximately double the window or door size,” she shares. “In this formal living room, I took the lighter weight printed linen width to three times the door size.” Note that this approach does involve paying some extra attention to detail. “This requires multiple vertical seams so close attention must be paid to pattern matching,” Knizek cautions.

Take Radiators Into Account

Long curtains are not always the answer, though, designer Annie Elliott notes. “I generally use short curtains only in bedrooms, but they’re an option if you have pesky radiators also,” she explains. However, just as is the case with longer curtains, there are some important length rules to keep in mind when working with shorter ones, too. “The curtains should come exactly to the sill or they should completely cover the apron (the piece of wood below the sill),” Elliott advises. “Anything in between looks unintentional.”