HVAC Ductless Mini-Split Systems

Question 1

What is the primary advantage of a ductless mini-split system over a central ducted system?

Accepted Answer

Elimination of duct losses (typically 20-30% of energy in ducted systems) and ability to serve spaces without existing ductwork

Answer

Ductless mini-splits eliminate duct losses (typically 20-30% of system energy in leaky or poorly insulated ductwork), enabling direct zone-level conditioning. They are ideal for additions, converted spaces, and buildings where installing ductwork is impractical or too costly.

Question 2

What does 'inverter-driven' compressor technology in mini-splits provide?

Accepted Answer

Variable-speed compressor operation that modulates cooling/heating capacity to exactly match the load, improving efficiency and comfort

Answer

Inverter-driven compressors vary their speed (and therefore capacity) to precisely match the zone's load. Unlike on/off cycling, the compressor ramps down at part load, reducing energy consumption, eliminating temperature swings, and improving efficiency — especially at part load (which is most of operating hours).

Question 3

What is the typical line set for a ductless mini-split system?

Accepted Answer

Refrigerant lines (liquid and suction), electrical power/signal wiring, and a condensate drain line

Answer

A mini-split line set consists of: refrigerant lines (small liquid line + larger insulated suction/gas line), communication/control wiring (typically 4-wire or signal wire between indoor and outdoor units), and a condensate drain line from the indoor unit.

Question 4

What is the maximum typical line set length for a standard residential ductless mini-split?

Accepted Answer

50-75 feet (15-23 m)

Answer

Most standard residential mini-splits support line set lengths of 50-75 feet (15-23 m) without additional refrigerant charge. Maximum lengths vary by manufacturer (often 98-164 feet). Longer runs require additional refrigerant charge (per manufacturer specification) and may reduce capacity.

Question 5

What is a 'multi-zone' mini-split system?

Accepted Answer

One outdoor unit connected to multiple indoor units (2-8 zones) via individual refrigerant branch piping

Answer

A multi-zone (multi-split) system connects one outdoor unit to multiple indoor units (typically 2-8 units), each serving an independent zone with individual temperature control. Refrigerant branches from the outdoor unit to each indoor unit via a header or individual line sets.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC Ductless Mini-Split Systems