Air purification - most modern air conditioning systems have anti fungus filters, catching allergy-causing mites and pollen, dust particles and odours so air is clean & fresh.
Security - You can cool your house or office while you are out and keep the place secure because you don’t have to have windows/doors open. Flying insects can be more easily kept out.
Humidity reduction - Most air conditioning units have a dry mode that reduces humidity - great for sticky British summers or homes offices in damp areas.
Energy saving - Heating is achieved through a high-efficiency heating pump which can consume 80% less energy than other forms of electric heating.
Safety - Removing old gas central heating systems & replacing with air conditioning is much better for health & safety. There is a reduced risk of gas leaks & water leaks from air conditioning units.
Cost - Removes the overhead of getting boiler serviced. Air conditioning maintenance is usually cheaper than boiler servicing.
Convenience - Direct heat exactly when you need it. Use timers to heat or cool your office before your staff arrive. Air conditioning is much more responsive than central heating systems, quicker to warm up or cool down.
Flexibility - Not everyone in a building wants to be the same temperature. Use of individual units or zones is more flexible than central heating.