Mitsubishi Heat Pumps: Wall Units, Ceiling Cassettes, Ducted Air Handlers & More

Mitsubishi Heat Pumps: Wall Units, Ceiling Cassettes, Ducted Air Handlers & More

When most people hear "Mitsubishi mini split," they picture one thing: the white wall-mounted unit. And while wall units are the most recognizable, they're just one of five different indoor unit styles Mitsubishi makes.

At Galaxy Heating & Air Conditioning, we've installed every one of them across Alameda County and the greater Bay Area — wall units, ceiling cassettes, ducted air handlers, slim ducted units, and floor-mounted units. Even better, they can all be combined on a single system. Here's a tour of your options.

The Five Mitsubishi Indoor Unit Styles

1. Wall-Mounted Units (MSZ Series) — The Classic

The familiar unit that mounts high on the wall. It's the most affordable, easiest to install, and offers some of the highest efficiency ratings in the lineup. Residential wall units carry the MSZ designation (like MSZ-GX or MSZ-FS) and come in capacities from 6,000 to 24,000 BTU per unit.

Best for: Bedrooms, home offices, additions, garages-turned-gyms — any single room that needs its own comfort control.

2. Ceiling Cassettes (SLZ / MLZ Series) — The Hidden Gem

A ceiling cassette recesses up into the ceiling between the joists. All you see is a slim, flat grille — no box on the wall. The SLZ four-way cassette throws air in four directions for very even coverage; the MLZ one-way cassette is designed to slot between standard 16-inch-on-center joists, which makes it a favorite for retrofits in older Bay Area homes.

Best for: Living rooms, kitchens, and primary bedrooms where homeowners want the comfort without seeing equipment on the wall.

3. Ducted Air Handlers (SVZ / PVA Series) — Invisible Central Comfort

This is the one that surprises people. Mitsubishi's SVZ and PVA multi-position air handlers connect to conventional ductwork — the same registers and vents a furnace uses. They install vertically or horizontally in an attic, garage, or closet, right where your old furnace sat, and the system is completely invisible in your living space.

If you love the idea of a heat pump but don't want to see any indoor units, this is your answer. It looks and feels exactly like central heating and air.

Best for: Whole-home comfort in houses that already have ductwork, or homeowners who prefer a completely invisible system.

4. Slim Ducted Units (SEZ / PEAD Series) — Small Spaces, Hidden Equipment

The SEZ and PEAD horizontal-ducted units are compact and low-profile — they hide above a hallway ceiling or closet and serve two or three nearby rooms through short duct runs. One hidden unit can handle a cluster of bedrooms.

Best for: Serving several bedrooms without putting a wall unit in each one.

5. Floor-Mounted Units (MFZ Series) — For Tricky Rooms

The MFZ floor-mounted unit sits low on the wall, similar to a traditional radiator. It's the solution for rooms where a high wall unit won't work: sloped ceilings, walls full of windows, attic conversions, and older homes with unusual layouts.

Best for: Attic bedrooms, sunrooms, and older Bay Area homes with limited wall space.

Decoding the Model Numbers (A Peek Into How We Design Systems)

When we design a Mitsubishi system, the outdoor unit model number tells the whole story. Here's how to read them:

MXZ Multi-Zone Condensers — The Mix-and-Match Workhorses

The MXZ series is what makes multi-zone systems possible. The model number encodes both the capacity and the number of indoor units it supports:

• MXZ-2D20 — supports up to 2 indoor units, rated at 20,000 BTU
• MXZ-3D24 — supports up to 3 indoor units, rated at 24,000 BTU (2 tons)
• MXZ-4D30NL — supports up to 4 indoor units, rated at 30,000 BTU (2.5 tons)
• MXZ-5D36 — supports up to 5 indoor units, rated at 36,000 BTU (3 tons)
• MXZ-5D42 — supports up to 5 indoor units, rated at 42,000 BTU (3.5 tons)

The first digit after "MXZ" is the port count, and the number after the letter is the nominal BTU rating in thousands. Each indoor unit connects to its own port on the condenser — wall units, cassettes, slim ducted units, and air handlers can all share the same outdoor unit. The 5D42 is the largest port-style MXZ; anything bigger moves to the SM branch-box series below.

MXZ-SM Series — Branch Box Systems for Larger Homes

For bigger projects, Mitsubishi's SM series takes over — and at 48,000 BTU (4 tons) and above, it's the only multi-zone option. SM systems work differently: instead of individual ports on the condenser, the SM connects to a branch box — a distribution hub that splits refrigerant to the indoor units. The lineup:

• MXZ-SM36 — 36,000 BTU (3 tons), available in standard and Hyper-Heat versions
• MXZ-SM42 — 42,000 BTU (3.5 tons), Hyper-Heat only
• MXZ-SM48 — 48,000 BTU (4 tons), standard and Hyper-Heat
• MXZ-SM60 — 60,000 BTU (5 tons), standard and Hyper-Heat

The branch-box approach has real advantages on larger homes:

• Fewer refrigerant lines running back to the condenser — the branch box sits centrally (often in the attic or crawlspace) with short runs out to each room
• Cleaner installations on three-story homes where home-run lines to every unit would be impractical
• Support for larger total capacity and bigger mixed systems

Both the standard MXZ and the SM branch-box systems support mixing ducted and ductless indoor units on the same condenser — that's the technology behind the hybrid installations we do.

SUZ / SVZ — Dedicated One-to-One Ducted Systems

If a home needs a strictly ducted system — one outdoor unit paired with one air handler, like a traditional furnace-and-AC setup — that's the SUZ (outdoor) matched with the SVZ (indoor air handler). No ports, no branch boxes: one condenser, one air handler, whole-home comfort through ductwork. This is our go-to when we're replacing a gas furnace in a home with good existing ducts and the owner wants the simplest possible heat pump conversion.

The Wiring Advantage Most People Don't Know About

Here's a detail that saves our customers real money: on Mitsubishi systems up to 3 tons, the indoor air handler is powered directly from the outdoor condenser. It doesn't need its own dedicated 220V circuit.

Why does that matter? In many Bay Area homes — especially older ones with crowded electrical panels — adding a new 220V circuit to the attic or a closet means electrician time, panel work, and sometimes a panel upgrade. With Mitsubishi, we run power to the outdoor unit only, and the communication/power cable to the indoor unit comes off the condenser. Fewer circuits, less panel space used, simpler permits, lower cost.

Cold-Weather Performance: H2i Hyper-Heating

Mitsubishi's H2i (Hyper-Heating INVERTER) models maintain full heating capacity down to 5°F and keep operating well below zero. That's far colder than the Bay Area ever sees — which means an H2i system here is never working anywhere near its limit. For homes in colder microclimates like Orinda, Moraga, or the Oakland hills, it's extra insurance that the heat keeps coming on the coldest mornings.

The Best Part: You Can Combine Them All

Here's what makes Mitsubishi special — all five unit styles work together on the same outdoor unit. Each room gets the style that fits it best, and every zone has independent temperature control.

We've completed many projects on two- and three-story homes where one floor is ducted and another is ductless:

• Two-story homes: A ducted air handler in the attic serves the upstairs bedrooms through ductwork, while ductless wall or floor units handle the downstairs living areas — each zone controlled independently.
• Three-story homes: A slim ducted unit serves the middle-floor bedrooms, a ceiling cassette covers the main living level, and a floor-mounted unit warms the ground-floor office. One outdoor unit runs it all.
• Homes with partial ductwork: Keep the ducts where they exist, go ductless where they don't. No need to tear open walls to extend ductwork.

This flexibility is why these systems work so well in Bay Area homes — our housing stock ranges from 1920s bungalows with no ducts at all to modern two-stories with ductwork only upstairs.

Why People Love These Systems

• Quiet operation — indoor units run at whisper-quiet levels, and the outdoor units are far quieter than conventional AC condensers
• Room-by-room control — stop arguing over the thermostat; every zone sets its own temperature
• Heating and cooling in one — a single system replaces both your furnace and air conditioner
• Efficiency — inverter-driven compressors adjust output continuously instead of blasting on and off
• No more hot and cold rooms — zoning solves the classic "upstairs is boiling, downstairs is freezing" problem

Our Experience Installing Mitsubishi

We're an experienced Mitsubishi installer and have completed projects across Alameda County — Oakland, Berkeley, Fremont, Hayward, San Leandro, Dublin, Pleasanton, Livermore — as well as Contra Costa, San Francisco, and the Peninsula. We've installed every unit style in the lineup and design mixed ducted/ductless systems regularly.

Every installation starts with a proper load calculation and a walk-through of your home so we can recommend the right unit style for each room — not just the default wall unit.

Thinking About a Mitsubishi System?

If you'd like to see what a Mitsubishi system could look like in your home — fully ducted, fully ductless, or a combination — we're happy to walk you through the options.

Call us at (925) 578-3379 or schedule a free consultation. We'll design a system around your home, not the other way around.