A high-wall heat pump heats one room from a box on the wall. A ducted heat pump heats several rooms, or the whole house, from one unit hidden in the ceiling or under the floor. Both use an outdoor unit, and both heat and cool. The difference is in how the warm air reaches you, what you see inside, and what your house needs to make it work.
The quick version:
- High-wall suits one main living area, or a few rooms done one at a time. It’s the most common type in New Zealand homes.
- Ducted suits a whole house you want warm, a new build or a big renovation, and a ceiling or underfloor space with room for the unit and ducts.
How does a ducted heat pump work compared with a high-wall?
A high-wall unit is mounted near the top of a wall. It pulls in room air through a filter, warms or cools it, and blows it back out across the room. Pipes and a cable run through the wall to the outdoor unit, which is usually on the nearest outside wall.
A ducted system has one larger indoor unit in the roof space or under the floor. Insulated flexible ducts run from it to a grille in each room. A return air grille draws air back to the unit and filters out household dust on the way. You control it from a wall controller rather than a remote.
Which one feels warmer?
A high-wall heats the room it’s in very well. Rooms further away, like bedrooms down a cold hallway, get very little. Shut the lounge door on a frosty Taupō night and the rest of the house stays cold.
Ducted heating spreads warmth more evenly because every room has its own outlet. A ducted system also tends to read the indoor temperature more accurately, so it doesn’t work harder than it needs to. In a long villa or a two-storey house, that evenness is the main reason people choose it.
For cooling, a high-wall has an edge in the room it serves: cold air falls, so air from high on the wall drops through the room. Ducted outlets in the ceiling work the same way, just spread over more rooms.
→ Related: Ducted heat pump systems
What does a ducted heat pump look like inside the house?
This is where ducted wins. All you see inside are flush grilles in the ceiling and a controller on the wall. There’s no box above the couch. The indoor unit sits out of sight in the roof space, which keeps it quiet in the room.
A high-wall is a visible appliance. Modern units are slimmer and come in more colours, but it’s still there. It also needs a spot clear of direct sun, light fittings and other appliances, because they upset its temperature sensor and the airflow. In some rooms that leaves only one or two workable walls.
Can my house take a ducted heat pump?
Before you fall for the idea of ducted heating, check your house can take it.
- Ceiling or underfloor space. The indoor unit and ducts need room, plus access for servicing later. Some indoor units are thin, low-profile models built for tight roof spaces, and some split into two sections so they fit through a ceiling hatch.
- Good duct insulation. Poorly sealed or poorly insulated ducts lose heat before the air reaches the room. That’s why ducted systems are a little less efficient than a high-wall heating the same space. Ask what R-value the ducts are and how the joins are sealed.
- A home that holds heat. Warming the whole house only pays off if the house keeps the heat in. Insulation in the ceiling and walls helps any heat pump work more efficiently.
- Timing. Ducted goes in most easily while the ceiling is open, during a build or a big renovation. It can be retrofitted into an existing home, but the work is bigger and the installer needs to get through the roof space.
A high-wall needs much less: a wall that can take the bracket, a path for the pipes to the outdoor unit, and a power supply.
→ Related: How to choose a heat pump and installer
Can you zone a ducted heat pump?
Yes. Motorised dampers in the ducts open and close to send air only where you want it. A common setup has two zones: a day zone for the living areas and a night zone for the bedrooms. You run the lounge in the evening, then switch to the bedrooms at bedtime. Zoning lets a smaller unit do the job, because it isn’t heating every room at once. It usually needs a zone controller, so ask whether that’s included in the quote.
With high-walls, each unit is its own zone already. You turn on the one you want. If you want several rooms done with wall units, look at a multi-room system, where one outdoor unit runs several indoor units.
→ Related: Multi-room heat pump systems
Which suits my home better, ducted or high-wall?
A high-wall is usually the better fit when:
- you mainly want the lounge or an open-plan living area warm
- the ceiling space is tight, or there isn’t one
- you’re adding heating to a finished house without a renovation
- you want to start with one room and add more later
Ducted is usually the better fit when:
- you’re building or doing a major renovation with the ceiling open
- you want every bedroom warm, not just the living area
- you don’t want units on the walls
- the house is well insulated, so the heat stays where you put it
On the energy label, compare like with like. The label is compulsory for single-phase non-ducted units, so a ducted model may not carry one. Ask the installer for its heating capacity and efficiency figures in writing. Where a ducted unit does show noise on the label, you’ll only see an outdoor figure. Start with what size heat pump you need for the kW numbers.
What should I ask an installer before choosing?
- Is there enough room in my ceiling for the unit, ducts and servicing access?
- Where will the return air grille go?
- How many zones, and is the zone controller in the price?
- What R-value are the ducts?
- Where will the outdoor unit sit, and how loud is it?
A good installer will get up into the roof space before quoting a ducted system. If they quote without looking, keep looking.
Who fits ducted and high-wall heat pumps near me?
Find installers who fit ducted systems or high-wall units, or pick your town to see who works near you.