Where to start

As you prepare to install a ducted system in your home, there are several things to weigh up. The three that matter most to the final decision are:

• your budget;
• your home's layout;
• your long-term heating and cooling needs.

Keep all three in view as you compare systems and quotes. A system that fits one of them and not the others will disappoint you. If you are still deciding between ducted and split systems, read Do I need a split system or ducted air conditioner? first.

Find the right capacity

Capacity is how much heating and cooling a system can deliver, measured in kilowatts (kW). Ducted systems for homes generally range from about 10 kW to 27 kW and can be set up to distribute air to several rooms. The right figure for your home depends on things like:

• the combined size of the rooms you want to condition;
• how much of the house is shaded, which helps keep temperatures down;
• the peak temperatures your area reaches in the warmest part of the year.

This is not something to guess. The ACDA Standards require an accredited member to work out the capacity your home needs using an approved calculation method, not a rule of thumb, and to show that calculated capacity on your written quote alongside the actual capacity of the equipment offered. If a quote does not show it, ask for it.A system that is too small will run flat out and struggle, which is hard on the equipment. A calculated capacity avoids that. For more on sizing, see How big a system do I need?

Ask about noise levels

Most ducted systems heat as well as cool, so yours will be running through winter and summer. That makes noise worth asking about early. As you discuss options with a dealer, ask how quiet each model is and look for systems designed to keep noise down. It is easier to choose a quiet system now than to live with a loud one for years.

Look for MEPS compliance

Australia has Minimum Energy Performance Standards (MEPS) for air conditioners. When you shop for a ducted system, make sure the one you are offered meets them, and compare the energy efficiency of the models you are considering. The more efficient the system, the less it costs to run, and a ducted system runs for a lot of hours over its life. Energy star ratings explains how to compare models.

Insist on professional installation

Ducted systems can be installed in a wide variety of home designs and layouts. That versatility comes with a catch: an incorrect installation can do more harm than good. To get the comfort and efficiency you are paying for, the system needs to be installed by an experienced, licensed professional.As you shop, ask for details about how the system will be installed and who will do the work. An accredited member's written quote must set out the number and location of outlets, the zones and the controls, and it must list what is included and excluded, such as the power supply, drainage, covers for exposed piping and wiring, and clean-up. Those details tell you a lot about how carefully the job has been thought through. See What a good installation looks like.

Find out the maintenance requirements

Every ducted system should be serviced at least once a year by a professional technician to keep it running efficiently. An accredited member's quote must state the recommended servicing frequency, so you know what you are committing to before you sign.Your system should also let you do some upkeep yourself. Before you buy, find out what regular maintenance is involved. For example, choose a system that lets you clean or change the filters yourself rather than needing a technician every few months. How to take care of your ducted air conditioner covers the routine.A good ducted system can keep your home comfortable for many years. Take the time to work through these questions before you make the final decision.

Before you sign for a ducted system

• Budget, home layout and long-term heating and cooling needs all considered
• Quote shows the calculated capacity in kW and the equipment's actual capacity
• Noise levels asked about for each model
• System meets MEPS and its efficiency compared against other models
• Quote names the installer, outlets, zones, controls, inclusions and exclusions
• Recommended servicing frequency stated on the quote
• Filters can be cleaned or changed without a technician

An accredited member must calculate the capacity your home needs and put it on a written quote, along with the outlets, zones, inclusions and servicing frequency. That is the shape of a quote you can judge properly.