Ducted mini-splits - cost & pros/cons

Ducted mini-splits are a relatively new addition to the residential HVAC industry. In many ways, they offer the best attributes of ducting and ductless systems in a single package.  The easiest way to understand these new systems is to compare them to the two traditional options – ductless mini-splits and whole house ducted systems.

Limitations of traditional mini-splits

Traditional mini-splits are effective, but they have two big limitations.  First, there’s no getting around the aesthetic draw backs.  Many customers are not enthusiastic about the idea of a large plastic box mounted on the wall of every room.  Second, the don’t distribute air beyond a single room.  If you want to comfortable temperatures in every room, you’ll need to install a mini-split head in every single room.  This is why they’re traditionally installed in small homes, apartments, etc.  They also work well for clients who are really only concerned with conditioning a single area (i.e. the master bedroom).

Ducted mini-splits overcome this issue by mounting the equipment in the attic space above the room (see photo below).  This removes the aesthetic problem – all you see if a simple register grill in the ceiling.  They also overcome the limitation of conditioning individual rooms.  Because they’re ducted, you can readily condition several rooms with a single unit.  The additional cost of adding ducting to a room is much less than adding a traditional mini-split to each room.

Ducted mini-split ceiling register

Upper floor too hot?

Perhaps the greatest benefit of a ducted mini-split is the ability to individually control the temperature of the house on each floor.  A typical two story home will experience a 5-8 degree temperature difference during the summer months.  If your bedroom is upstairs and you want to keep it below 72 at night, the downstairs will be quite cold.  Likely in the mid-60’s.  Not only is this uncomfortable, it’s very inefficient.  A ducted mini-split mounted in the attic can keep the upstairs at the desired temperature without impacting the rest of the home.

What types of homes are not good candidates for a ducted mini-splits?

Limited attic access

While much smaller than a traditional air handler, they still require a fair bit of a space.  If the attic is tight or has limited access, a ducted mini-split may not be possible.

Single story home with existing forced air system

If your home already has a ducted system and it’s a single story, you won’t experience a gain by moving to a ducted mini-split.  Your best option is to install a heat pump/AC air handler in place of your existing furnace.