Some comfort decisions are easy. Ducted versus ductless isn’t one of them. I coordinate emergency installations for a Mitsubishi Electric heating dealer in Melbourne, and when a client calls at 6 a.m. with no heat, my first question isn’t “which unit do you own?” It’s “when was the filter last touched,” because a compressor will keep running long after a blocked or backwards filter makes the heat pump useless.
This article compares the two main routes for Mitsubishi Electric heating in Melbourne: ducted central systems versus ductless mini-split or multi-split units. This isn’t a brochure comparison. I’m comparing the things that decide real comfort: zone coverage, filter placement, circulation, and moisture control.
Ducted vs. ductless: the framework that matters
A ducted Mitsubishi Electric system sends heated or cooled air through ducts from one central air handler. Done well, it covers many rooms off one thermostat. A ductless system connects one outdoor unit to wall or floor units in individual spaces, with no ducts.
The questions I ask before recommending either one:
- Is there existing ductwork, and what condition is it in?
- How many rooms actually need heating and cooling?
- Where will the filter go, and who will change it?
In that order. It’s tempting to think the choice is only about upfront price and inverter label, but a system that doesn’t get good airflow is the quickest way to turn a high-efficiency heat pump into a high-power bill.
Coverage and zones: where the two differ most
A ducted system can heat the bedrooms, hallway, living area and bathroom from one unit, as long as the duct runs make sense. Its weakness is zoning. Without dampers, a ducted system often works in big zones: either the whole house or one giant area. Add zoning dampers and controls, and the quote goes up—transparency matters because that’s often an “extra.”
A ductless multi-split sets each indoor room head independently. That independent control can save real energy in a house where only two of four bedroom doors are used daily. For a 1930s Melbourne layout with walls that block airflow, one indoor head in the hallway may not reach the far bedrooms. That’s not a flaw in the heat pump; it’s a placement problem. Sometimes a circulator fan can help; sometimes you just need a second indoor unit.
Filter placement: the practical difference
Now we get to the part where I earn my call-out fee.
Ductless units have a washable mesh filter behind the front panel. Easy to reach. Ducted units use a standard 1-inch disposable filter at the return grille or at the air handler cabinet. If that central filter is missing, backwards, or too restrictive, then everything downstream gets dirty—including the indoor coil and the blower motor.
It’s tempting to think “higher MERV equals cleaner air.” Not always. MERV 16+ in a 1-inch internal filter can create pressure drop that reduces airflow. In most houses I’d rather see a MERV 8–11 filter matched to the equipment than a max-rated filter that makes the system choke. The AHRI 210/240 performance rating assumes a clean filter and rated airflow; it doesn’t reflect what happens when the filter is carrying two months of dog hair.
Which way to put air filter in furnace?
If you search “which way to put air filter in furnace,” you’ll see people say the arrow points toward the furnace. That’s true if the filter slot is at the furnace/air handler. The arrow indicates airflow direction, and air should pass through the filter first and then into the blower.
So here’s the rule: for a typical filter slot at the furnace, the arrow points toward the furnace—toward the blower. For a filter located in a ceiling return grille, the arrow points into the return duct, which leads back toward the furnace. Either way, the arrow follows the path of the air, not upward or outwards.
When the arrow points the wrong way, pleated filters can collapse against the frame, blocking the return. I once wasted two hours diagnosing a high limit shutdown before finding a MERV 13 filter installed backwards. Ten minutes after flipping the arrow, the supply temperature was back to normal. Not ideal, but workable.
The “Mitsubishi Electric inverter filter” question
For ductless units, people search for a “Mitsubishi Electric inverter filter” because they think they need to order a spare. Usually, the filter inside the indoor unit is a washable mesh—not a disposable cartridge. Open the front panel, slide the filter out, vacuum or rinse it in warm water, let it dry in the shade, and put it back. Change it if damaged, but don’t stockpile expensive disposables unless your ducted system needs them.
How often? In daily use, clean that Mitsubishi Electric inverter filter every 2–4 weeks. Inverter technology is brilliant at part-load efficiency, but it still needs airflow over the indoor coil. A matted filter makes the compressor work harder, lowers leaving air temperature, and forces more defrost cycles in Melbourne’s damp mornings.
Fans: the Vornado fan and the bathroom exhaust fan
A heat pump is only as balanced as the air around it. This is where Vornado fans and bathroom exhaust fans come in, and they do opposite jobs.
Vornado fan: circulation, not heat
A Vornado fan is a compact air circulator that pushes a column of air across a room. It doesn’t create heat. In a high-ceiling room, it can push warm air down from the ceiling and reduce hot and cold spots. In a ductless room installation, aiming a Vornado fan on low from the far corner helps mix the air before it returns to the indoor sensor. The surprise isn’t the fan itself; it’s how much more even the room feels when the air isn’t stuck near the ceiling.
A Vornado fan should supplement, not replace, a properly sized heat pump. If a room needs its own heating, install another indoor head rather than buying three fans and hoping.
Bathroom exhaust fan: humidity removal
Here’s an outsider issue: a bathroom exhaust fan exists to remove humid air. A heat pump in heating mode does not. In summer it may remove moisture, but in winter, the heat cycle mostly lets steam linger and condense on windows, walls and filters.
For bathroom ventilation, ASHRAE 62.2 points to a minimum intermittent exhaust rate of 50 CFM for a typical bathroom under 100 square feet. Run the fan during the shower and leave it running for 15–20 minutes after. Vent it outside—not into a roof cavity, where it adds moisture to insulation and can corrode metal roof components.
That little fan is another reminder that your indoor air setup is a system. Ducted or ductless, filter and fans work together.
So which should you choose?
If you already have well-designed ductwork and want whole-home, out-of-sight heating and cooling, a ducted Mitsubishi Electric heat pump is often the right call. If the house has no ducts and you want zone independence with minimal disruption, a ductless multi-split system deserves the job. Combination options exist too: ductless in an extension plus a ducted unit for the original part of the house.
Still torn? Talk to a local Mitsubishi Electric heating dealer in Melbourne who will include a filter rack check, a static pressure test, and all potential extras in the written quote. Be careful of easy-looking low prices with no filter line item. I’d rather see a quote that lists every fee up front—even if the total looks higher—because the cost of fixing hidden flaws after installation is way higher.
Ask what’s not included before you ask what’s included. The right system is the one someone will maintain with clean filters, unblocked ducts, and a dealer’s number saved on their phone.
