New ductwork and a furnace, or a ductless mini split?
If your home has uneven rooms, an old furnace or no ductwork at all, you may be weighing a new ducted central system against ductless mini splits. Here’s a plain comparison to help you decide, and why a real load calculation beats a guess.
The two options
Ducted central system
A furnace or a central heat pump sends heated or cooled air through ductwork to vents in each room. If the home doesn’t have usable ducts, new ductwork has to be designed and built into the house as part of the job.
Ductless mini splits
An outdoor unit connects to one or more indoor heads mounted in the rooms you want to heat and cool. There’s no ductwork, and each head is controlled on its own.
Side by side
Swipe to see the whole table.
| What matters | New ductwork + furnace or heat pump | Ductless mini splits |
|---|---|---|
| Installation disruption | New ductwork has to run through walls, ceilings, attics, crawl spaces or closets. Older homes often need walls or ceilings opened and patched. | No ductwork. Each indoor head connects to the outdoor unit through a small opening in an exterior wall, usually about 3 inches. |
| Comfort room by room | One thermostat for the house (or a few zones). Rooms far from the furnace or over a garage often run hotter or colder. | Each indoor head has its own setting, so you can fix the rooms that never feel right and leave unused rooms alone. |
| Efficiency | Depends on the equipment and on how well the ducts are sealed and insulated. | Mini splits can be up to about twice as efficient as typical ducted systems. |
| Duct losses | Heated or cooled air can leak out of seams and lose heat through ducts in attics and crawl spaces before it reaches the room. | No ducts, so no duct losses. The air is heated or cooled right in the room. |
| Install timing | Many central system installers are booked months out, and duct work adds days to the job. | We can usually schedule much sooner than installers who are booked months out. |
Less disruption at home
Adding ductwork to a finished home usually means tearing open walls or ceilings, giving up closet or attic space, and patching and painting afterward. A mini split install skips all of that. The line set runs through a small opening in an exterior wall to each indoor head.
Fix the rooms that never feel right
With one thermostat, the room it sits in sets the temperature for the whole house. Bedrooms over the garage, sunrooms and finished basements end up too hot or too cold. Mini splits give you room-by-room (zone) control, so each space gets the heating or cooling it actually needs.
Efficiency and duct losses
Mini splits can be up to about twice as efficient as typical ducted systems. Part of the reason is the ducts themselves: air that leaks from duct seams or runs through an unheated attic or crawl space loses energy before it ever reaches the room. With no ducts, a mini split doesn’t have those losses.
Shorter wait
Many installers of central systems are booked months out. We can usually schedule much sooner than that, and a ductless install doesn’t need the extra days that building ductwork takes. We’ll give you real timing when we book.
A load calculation, not a guess
The right size depends on your home, not on a rule of thumb.
- A quote given off the cuff, over the phone or from a quick look, is a guess at how much heating and cooling your home needs.
- A Manual J load calculation works it out room by room from your home’s size, insulation, windows and layout.
- An oversized system short-cycles and handles humidity poorly. An undersized one can’t keep up on the coldest and hottest days. Either way you pay for it for years.
- Getting the size right is what makes the efficiency and comfort above actually happen.
Get real answers for your home
Book a Comfort Consultation with Mini Splits USA®. It’s a paid in-home visit: we take a LiDAR 3D scan of your home, run a Manual J load calculation and give you flat-rate pricing. The consultation cost is credited toward your install. We serve homes in West Virginia.
Mini Splits USA® installs come with a 12-year labor warranty on qualifying residential installs. Business installs don’t qualify for the warranty.