The benefits of small duct heating cooling and ventilation

by Francesca

Used extensively in the US, small duct, heating, ventilation and cooling is now more widely available than ever before thanks to a partnership between the leading US manufacturer, Unico Systems, and UK distributor and training provider Bell Plumbing Supplies. Here Richard Soper CBE, from Unico Systems, reveals all about how the technology is set to transform the way we heat and, importantly, cool our homes.

Air conditioning and ventilation has always been seen as a nice to have in the UK, thanks to our temperate climate, but with a series of record summers and increasingly unpredictable weather patterns it is now an essential requirement in new build homes. Both air conditioning and climate control are more widespread than ever before in our public spaces, businesses and cars and people are now seeking that same level of comfort in their homes.

The problem to date is that the air conditioning systems available in the UK have traditionally been developed for commercial applications with little or no regard for homes. Often those refurbing or developing properties have had to rely on large unsightly outlets that are entirely unrelated to heating systems. The US is used to much larger variances in temperature, meaning that domestic ventilation and air conditioning is often installed as standard. One of the main solutions to this is small duct heating, ventilation and air conditioning. Small duct systems provide both heating and cooling through small, discreet outlets, similar to recessed spotlights. Primarily developed for the domestic market the system is ultra-quiet operating at a decibel level equivalent to a soft whisper.

How it works

To enable air conditioning as well as heating the best option is to connect the system to a reversible heat pump, which will absorb geothermal energy or warm and cool air from the outside which is passed through the specially designed heating and cooling coil. The system will then redistribute throughout the home to create the required temperature. The unique design of small duct systems means that they remove up to 30 per cent more humidity than conventional air conditioning and heating systems saving energy, creating a more comfortable environment and contributing to the prevention of damp and mould. 97 per cent of the system energy is delivered to the conditioned living space.

While traditional systems distribute air unevenly, creating drafts and uneven temperatures throughout different parts of the room. Small duct heating and cooling uses aspiration, which creates a gentle suction around itself that draws the room air into its stream of cooled or heated air. This delivers even, draft free cooling and heating, from room to room, floor to floor, and floor to ceiling. The temperature differential is no greater than 1°C.

Near silent operation

Because small duct systems have been developed for domestic and light commercial properties sound attenuation has been considered from the start. The supply tubing is designed to be as quiet and efficient as possible, with a nylon inner core and insulation that absorbs sound. The air handlers isolate noise and vibration, with closed cell, sound-deadening insulation. As a result, the system is near silent operating at under 30 decibels.


As you would expect with a small duct system, there isn’t the requirement for large recesses and cavities. The system’s modular air handlers can be easily installed in lofts, utility rooms and cellars. It is important however to carefully consider the location of the central duct and the sound attenuated flexible supply tubes that run through and around the construction of new or existing buildings.


As opposed to a standalone air conditioner, small duct systems are fully integrated with heating, as a result there is just one controller required to cover both heating and cooling, with full compatibility with the appropriate smart controls. For self-builders and renovators this provides a unique opportunity to give occupiers the same level of climate control and comfort that they’ve come to expect in cars, hotels and gyms, no matter the season. Non-invasive installation methods also mean that it’s as applicable to the refurbishment market as well as self-build and new-build projects.

Cooling is now a must have in UK homes, but systems have to be designed for the specific requirements of domestic properties, ensuring low intensive installation and the highest standards of sound attenuation. Fortunately, the more mature US market can point the way and small duct heating, cooling and ventilation offers a solution to meet all requirements, whether new-builds or refurbishment.

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