Selecting Good Recessed Downlights

By Daniel Mozey, LC, MIES

Can Lights go by numerous names. They are sometimes called High-Hats, and in Canada the term Pot Light is common.  These days Can Lights are often simply referred to as Recessed Downlights (but Can Lights are not the only type of luminaires within the Recessed Downlight category).

The very common “can light” can be found everywhere, from homes to commercial buildings. Properly designed Can style luminaires are great for many applications.  Unfortunately, a significant number of new and renovated properties – especially in the residential and apartment markets – use “cans” and other recessed lighting products that have horrible lighting performance.  Let’s take a quick look at what makes a good Can Light and what makes for a bad Can Light.    

Features of a good Can Light

  • Can Lights have three primary features: (1) the housing (can) is recessed into the ceiling; (2) the decorative trim is flush with the ceiling; and (3), the lamp/LED source is recessed to reduce glare.
  • Besides giving ceilings a clean look, the recessed nature of the light source of a Can Light allows the luminaire to throw out a considerable amount of light with low glare.

Can Lights come with integral recessed LED, or with medium based (E26) sockets.  The recessed housing is comprised of the “can” with mounting brackets, or a box with the can inside.  The housing is installed prior to the finished ceiling (from which the housing gets the nickname “rough-in”).  There are also Retrofit and Remodel Downlights which have different housings to accommodate installation in finished ceilings.

Features of a bad Can Light

Nobody wants to look at a bare lamp.  So in the 1880’s when lamps first became widely available for use it didn’t take long for luminaires to feature lamp shades or to recessed the lamp.  Sadly, in recent years it’s not uncommon to find a new breed of cheap “compact” style recessed luminaires in many new home, condo, and apartment projects.  These compact style semi-recessed luminaires have very bright emitting surfaces that are a significant source of glare.  These styles of luminaries are often misrepresented as “recessed” products, but while their housing may be, their light source is not.  Why do these products exist?  Well, their purpose is really meant for utility spaces where good optics is not needed.

After 140 years of consistent improvements, why are we now back to high glare, poor quality lighting?  One reason they are popular is that these compact style recessed luminaires are typically cheaper that their optically superior cousins.  Another reason is simply a lack of knowledge of what makes for good lighting.  If you are purchasing or specifying downlight products, avoid those that have a frosted flat style lens that is less than 3″ from the trim surface (for 6″ downlights), less than 2 1/2″ (for 4″ downlights), and less than 2″ (for 3″ downlights).  In other words, you want the frosted lens to be recessed deeply.  Unless it’s a shower, utility room or closet, don’t use any fixture with a frosted lens that is flush with the ceiling or trim, as this will also significantly increase glare.

All three of the above samples have frosted light emitting surfaces that are barely recessed, or not at all!  Great for closets, horrible for living spaces.  Their main attribute is GLARE !