What size air conditioner do we need for our home?

Author Rod Marchant-Smith | Peninsula Air Conditioning

Collaroy resident, Greg asks

“We live in a 2 story house with 5 bedrooms, and we’re looking at having air conditioning installed. What size air conditioner do we need and what would be the best sort?”

We use a specific formula to calculate the size of air conditioner you need to install, using the figure of 130 watts per square meter.  But choosing the correct size air conditioner for your home is not something that can be done over the phone.  You will need to set up an inspection of the property with a technician.  Not only will they measure up the space, they will be able to assess other factors that affect the size of the air conditioner you need to ensure you get the best efficiency.

Factors that affect the size of the air conditioner you need

Firstly, there are the structural factors to take into account.  Our technician will look at  the orientation of the house and rooms as this affects how much sunlight, and therefore heat, they are exposed to.  They will also factor in the roof height, and how much glass there is.  They will then explore lifestyle factors such as how many people live in the house and which rooms have additional heat sources such as computer equipment.  Nothing heats a place up like human beings!

What do you want to achieve?

Have you considered what your climate control needs are?  This will affect the type of air conditioning system we recommend for you, and therefore the specific size relevant to it.  For example, do you want to cool the whole house, or only a specific room?  There are various options.  They include a ducted system, where you can put an outlet into each room, or a collection of splits or multi splits where you have an indoor unit in each room that you want to commission.

There are pros and cons to both.  With the split and multi-split air conditioners, the advantage is that it gives you individual control in rooms in terms of temperature.  Aesthetically you achieve a better look with a ducted system, and it is a more affordable solution if you want to cool multiple rooms.  If you wanted eight split or multi-split outlets in a total of six rooms it would be an expensive exercise.

Another reason a ducted system is a popular choice is that you can look into investing in a system with a lower capacity.  Many of our customers choose to have a zoned system in their homes.  They have a day zone and a night zone and they are able to flick a switch at night and the air conditioner is redirected towards the bedrooms and prevented from going into the living areas.  The advantage is that the size and the capacity of the air conditioner you need under those circumstances is only half what you would need if you wanted to cool or heat the whole house all at the same time.  There’s a cost saving involved in that.

Naturally there are customers that prefer the versatility of having a system that has the capacity to cool the whole home at any given time, if they want to.  Mostly however they will choose to use the zones judiciously. This may mean only producing cool air in a certain room, or reducing the fan speed.

We certainly recommend this option.  The cutting-edge Daikin systems we install have technology that recognises when you have closed a zone, and automatically reduces the speed of the indoor fan accordingly.  With the drop in air produced, it makes it quicker for the outdoor unit to cool the air.  In the long run, this saves you money through a reduction in the power needed to cool the air.

We are sometimes asked by customers if they need a smaller air conditioner because they have a ‘passive house’.  This refers to a building that has design elements such as film on the windows that keeps the sun out.  These may be effective in Europe, but the Australian sun is harsh, and our houses do not benefit from these sort of ‘passive’ design interventions.

Install an aircon that’s right for your house!

Having an aircon that is too big, or too small, for your home or property is going to waste time, energy (and therefore money) and could even lead to your system wearing down prematurely.

Get in touch with use to book an inspection.  We will measure your property and our technicians will note all factors that will affect the system capacity you need.  We can then recommend the correct size air conditioning system and quote you on the perfect fit for your property.

Free, No Obligation Consultation.

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