Sometimes you need air conditioning or heat in a home without attic or basement space to run ducts. A ductless mini-split unit may be your best answer in those situations. What is a ductless mini-split, and is it the right solution for you?
HVAC without ducts
A ductless mini-split is a heating and air-conditioning (HVAC) system that blows into a room directly from the equipment. There are no ducts running through an attic, basement or closet, and no duct supply rooms. The blower-air handler is mounted on the wall about eight feet up in the room you want to heat and cool, and the condenser-compressor unit is outside the house.
When to use ductless mini-splits
Ductless mini-splits are a good solution when you’re adding a room or converting a garage or a basement to a living space, and structurally there is no place to run ducts. They’re also appropriate when you have an outbuilding, cabin, or guest cottage that’s too small to justify a complete HVAC system or in older buildings heated with radiators and space heaters with no interior wall, ceiling, or floor spaces for running ducts. A wall-mounted ductless unit connects to the outdoor compressor-condenser unit via a three-inch hole drilled through the structure’s outside wall.
Mini-splits vs. window units
Window air conditioning does a fine job of cooling and heating a small space. But it takes up a window, creating an opportunity for intruders to enter your home. And in a basement, you may not have an adequate window for a unit.
- Mini-splits are easy to install. There is no expensive and intrusive running of ducts from room to room.
- Mini-splits are more energy efficient than traditional HVAC, since duct systems often leak treated air into attic, basement or wall spaces.
- Mini-splits are great for zoned air treatment. You can cool or heat one room but omit the next if needed.
- They can be cost effective for additions, remodels and buildings that are separate from a main house.
- Mini-splits are affordable if you need to treat only one or two rooms but become expensive when used in multiple rooms.
- You may dislike the appearance of the wall-mounted unit.
- Mini-split filters are thinner than those in traditional systems and require cleaning every month.
- Ductless mini-splits don’t perform well in extreme temperatures. When outside temperatures are 20 or more degrees higher or lower than you want a room to be, a mini-split system will struggle to perform.