Why mini-splits win in bonus rooms and sunrooms
Targeted comfort
A single-zone ductless system conditions the room you actually use. No stealing airflow from the rest of the house, no rebalancing headaches.
No new ductwork
A simple 3-inch wall penetration and a tidy line set get it done. Your drywall, trim, and weekend plans stay intact.
High efficiency
Modern inverter mini-splits sip energy, modulating to match the load. Many deliver high SEER2 and excellent low-ambient heating.
Quiet
Indoor units often hum in the low-20s dB on quiet modes. That’s library-level calm for a home office, craft room, or Netflix cave.
Zoned control
Close the door, set your preferred temperature, and stop dragging the rest of the house along with it.
Sizing cheat sheet for tricky rooms
Final sizing should come from a professional load calculation, but these rules of thumb will get you in the right ballpark:
| Room type | Typical size | Glass/insulation factor | Ballpark capacity (BTU/h) |
|---|---|---|---|
| Bonus room over garage | 200–450 sq ft | Moderate insulation | 9,000–15,000 |
| Attic/loft conversion | 200–400 sq ft | Often under-insulated | 12,000–18,000 |
| Sunroom, 3-season (many windows) | 150–300 sq ft | High solar gain | 12,000–18,000 |
| Sunroom, 4-season (good envelope) | 150–300 sq ft | Improved insulation | 9,000–15,000 |
Translation: lots of glass and marginal insulation push capacity up. West-facing glass pushes it up even more.
The right indoor unit for the job
- Wall-mounted: most common, fast install, great for offices, playrooms, and craft spaces.
- Ceiling cassette (1-way or 4-way): keeps walls clean and spreads air evenly in longer rooms or sunrooms.
- Floor-mounted: ideal for knee-wall spaces and alcoves when high wall space is limited.
Ethridge will recommend the style that fits your room geometry, line-set route, and aesthetics. Nobody wants a beautiful sunroom spoiled by the wrong grille in the wrong place.
Placement tips that actually matter
- Keep it out of the dead corner. Aim airflow across the room’s longest dimension.
- Be mindful of glass. Don’t blow straight at a wall of windows or you’ll feel “drafts” that aren’t really there.
- Give the outdoor unit breathing room. Solid pad, clear of leaves, not under a bedroom window.
- Plan the line-set path. Short, neat, protected. Painted covers look clean on exterior walls.
- Electrical counts. Most mini-splits need a dedicated circuit and a proper disconnect. We handle that.
Mini-split vs. extending ducts: a quick reality check
| Consideration | Mini-split | Extend existing ducts |
|---|---|---|
| Construction impact | Minimal | Often significant (ceilings, soffits) |
| Comfort control | Room-by-room | Tied to main system |
| Efficiency | High, inverter-driven | Depends on main system and long runs |
| Risk of condensation/airflow issues | Low | Higher in attics/garages |
| Time to install | Typically faster | Can stretch with surprises |
What to expect from an Ethridge install
- Room-specific load calculation for dead-on capacity
- Unit style and placement plan that respects your space and the line-set route
- Clean, code-compliant install with testing, start-up, and a homeowner walk-through
- Warranty and maintenance guidance so it runs like day one
We’ve installed ductless systems across Birmingham, Hoover, Homewood, and nearby communities for bonus rooms, studios, and glass-heavy sunrooms. You get the comfort you paid for without turning your house into a construction zone.
FAQ
- Can a mini-split actually heat my sunroom in winter?
- Yes, with the right sizing and a cold-climate rated heat feature. Insulation and air sealing still matter, but a properly specified system keeps sunrooms comfortable on cold nights.
- Is a single-zone better than tying into a multi-zone system?
- For one room, a single-zone usually delivers better efficiency and control. Multi-zone shines when you’re conditioning several spaces at once.
- How long does installation take?
- Most single-zone installs wrap up quickly since there’s no ductwork to build. We’ll confirm timing during your quote.
- Will it look out of place?
- We plan line-set covers and unit placement so it blends in. Ceiling cassettes and low-profile wall units keep things tidy.
- What about maintenance?
- Rinse or vacuum the indoor filters regularly and schedule annual service. That keeps efficiency high and helps prevent nuisance issues.
Ready to make that bonus room or sunroom actually usable?
Call Ethridge Heating & Air at (205) 428-6935 or request a visit online. We’ll size it right, install it cleanly, and you’ll finally enjoy the space you paid for.
Explore ductless service: Ductless Mini-Splits
Keep learning: Optimizing Your HVAC for Birmingham’s Humidity • How Often Should I Service My HVAC System? • Is Your Heat Pump “Blowing Cold Air”?
Related location page: Ductless Mini Splits in Homewood, AL
