Most manufacturers nowadays produce two distinct types of air-conditioning unit - 'inverters' and 'non-inverters'. A non-inverter is a basic model which operates at a fixed speed and simply controls air temperature by switching alternately on / off. This type of unit, commonly sold in DIY superstores etc, is significantly cheaper to purchase but will consume up to 30% more electricity, because of the way it fluctuates. Alternatively, a more sophisticated 'inverter' unit has a variable-speed compressor which constantly adjusts and regulates to the desired temperature – a much more efficient method of operation. Although costing more to buy, inverters are more economical (and quieter) to run, offering better long-term value-for-money .
Penguin offer both inverters and non-inverters – it's your choice.
Whether inverters or non-inverters, Penguin only offer quality brands and products. We categorise these by price as 'Gold', 'Silver' and 'Bronze' – the difference being mostly in their quality of components, quietness of operation (perhaps significant in a bedroom) and energy efficiency (Gold units carry a category 'A++' energy-rating).