This is a question that often arises when considering air conditioning for the first time. And it’s not always easy to answer.

Purchase too few units and some rooms will remain hot despite extended run times. Purchase more than you need, and you’ve invested a lot of money in equipment and installation that you actually don’t need.

Below we will explain how air conditioning systems operate and what truly dictates the number of units a particular home requires.

It is not a one-size-fits-all

Factors that affect a home’s cooling needs vary significantly. The amount and location of cooling needed depends on factors such as:

• Room orientation
• Ceiling height
• Glazing area
• Insulation quality
• The number of occupants
• Typical heat-generating activity in each space.

This is why it’s important to get a proper professional evaluation before an air conditioning installation.

Understanding split systems vs multi-split systems

The most common type of domestic air conditioning system in UK homes is the split system. This is a configuration where an outdoor compressor unit links to one or more indoor units that deliver cooled air into individual rooms. Single split systems are the most appropriate choice for a home with a small space that requires cooling.

Multi-split systems connect a single outdoor unit to multiple indoor units. It is often anywhere from two to five.Each is independently controlled and serves a separate room or zone. For multiple rooms, this option is typically more affordable and less disruptive to install than several separate single split systems.

Rooms that usually require separate units

Not all rooms in a house need an air conditioner. The rooms that benefit most are those that:

• Produce the most heat
• Get the most direct sun
• Are used most frequently in the hottest part of the day.

Living rooms, open-plan kitchen, and dining areas are almost always priority zones given their:

• Size
• South-facing glazing in many UK homes
• The activity that takes place in them through the evening.

Cooling plans are increasingly incorporating bedrooms. Night temperatures rise on warm days in the south, making sleep more challenging.

Another regular priority is home offices used during the day. Heat has a significant impact on concentration and productivity.

When just one unit is sufficient

A single well-specified unit is actually adequate for many UK homes where air conditioning is mostly required for one main living area or a single bedroom that becomes extremely hot on summer nights.

Instead of trying to cool the entire property at once, it makes sense to invest in a properly sized unit for the most difficult room. If the need arises in later seasons, other units can be added.

The bottom line

The ideal number of air conditioners for your house covers the areas that need cooling without going overboard on capacity. The most dependable method to arrive at a specification that produces the correct outcome at the right cost is to have a professional assessment.

An expert takes into account the unique features of your home, such as its:

• Layout
• Orientation
• Insulation
• How each room is utilized.

Making sure that the assessment is done correctly from the beginning reduces costs and the annoyance of a system that falls short of your expectations.