With the overriding need to replace fossil fuels as an energy source, heat pumps and other renewables have quickly made their mark on modernising our existing UK housing stock. Demand for effective HVAC solutions in the home is also being driven by new legislation that addresses overheating through the Building Regulations, Part O and because of the ban on gas boilers in new homes from 2025. The consequences of these developments, together with the incentives such as the Boiler Upgrade Scheme, are encouraging positive change in the quest to achieve net zero carbon output and to achieve the optimum indoor living environment.

Unico Lapford Project. Shows Ducted system.

Considerations in HVAC Selection

There are decisions to be made by homeowners and installers on selecting the most appropriate HVAC solution. With climate change and the trend towards warmer summers, how to cool a property is becoming as important as how to provide warmth. Heat pumps provide a source of renewable energy that can be used for complete indoor climate control and are available in many variations.

Assessing Heating and Cooling Delivery Systems

When it comes to the heating and cooling delivery systems, the alternatives have both advantages and drawbacks. Traditional radiators? Air conditioning units on the wall? Ducted systems? All in one solutions?  These choices must be weighed up and aside from energy efficiency and thermal comfort considerations, aesthetics and installation practicalities can be significant issues. These can include the need to make structural alterations to a property, maximising the use of available internal walls, dispensing with unsightly radiators or grilles and having sufficient space for ducting.

The Evolution of Ducted Systems

One viable approach would be to consider a central air distribution system that features small ducts to deliver heating and cooling into the living space. It can overcome many of the perceived obstacles when specifying and installing an HVAC system, whether in a new home or as part of a refurbishment project.

When it comes to ducted systems, traditional ducted AC systems in the home in the UK are uncommon and often impractical due to duct sizes and space requirements. Those who are looking for either permanent or temporary air conditioning consider split systems and portable solutions and these too have their drawbacks.

The reputation of ducted systems may have been tarnished by memories of original warm air heating systems. Their performance was often considered below par, not only in terms of efficient heat output, but also because of lack of air movement in room circulation, operational noise and maintenance issues. Of course, times have changed and there have been great steps forward in technology, so today’s warm air heating has much improved performance and controls.

The Unico System: A Modern Ducted Solution

It comes as a surprise to some customers that the Unico System Small Duct High Velocity (SDHV) system is a ducted solution. Its versatility as a central air delivery solution is highlighted by the fact that it is wholly compatible with heat pumps and offers air filtration, UV light air purification, ventilation and humidity control properties alongside heating and cooling. Its air delivery method uses a lower volume of air moving at high velocity resulting in significant advantages over other traditional forms of forced air ducted systems.

Small flexible ducting mixes and delivers conditioned air into living spaces. It has an internal diameter of only 51mm and the standard twist-fit connector simplifies the installation process. The compact design means that it can be conveniently twisted and fitted in the tightest of ceiling spaces, between joists and through wall cavities, before connecting to room outlets. The sound attenuating tubing is optimised for low noise and its outer jacket of two-ply reinforced Mylar provides a vapour seal to prevent leakage and moisture migration. It also enhances the energy performance by reducing radiant heat transfer and reducing thermal losses. 97% of the system’s energy is delivered into the conditioned living space.

With whisper quiet operation, discreet room outlets can be positioned seamlessly in walls, floors or ceilings. The air is delivered with decibel levels of < 30 and the aspiration principle of operation drives high velocity small jets of conditioned air driven into the living space, eliminating drafts, cold/ hot spots and keeping temperature differentials within +- 1ºC, floor-to-floor, floor to ceiling and room to room.  The design of the Unico System is a major advantage in refurbishment, self-build and new homes, affording a much better choice of room furniture layouts and maximum use of wall space.

Unico flexible ductwork is around 33% the size of conventional ducting and links via a central duct to a small footprint air handling unit that can be conveniently located in an attic or even a cupboard. Aside from size, however, there are other considerations when it comes to the specification of a ducted HVAC system.

Ductwork that is installed in unconditioned areas will reduce system efficiency and the ducts seen in attics with traditional AC systems are technically outside the building’s thermal boundary, often losing some 15% – 20% of the air going through them.

Efficiency and Performance

Putting values to duct efficiency, conventional ducts are generally 70 – 85% efficient and sometimes as low as 60% if significant leakage occurs from improper installation. On the other hand, Unico’s small ducts are easier to locate inside the conditioned (insulated) building envelope and therefore duct efficiency is not a significant issue. Indeed, efficiency is in the 85 – 95% efficiency bracket, based on correct installation practice.

Integration and Adaptability

The versatility and flexibility of the Unico ducted system, including its ability to counteract humidity issues and integrate with other forms of heating and ventilation, gives it even greater appeal. It can, for example, be easily installed and used just within the upper levels of a home, alongside traditional ground floor radiators or underfloor heating. In new homes that focus on high energy efficiency and building tightness with no adventitious air, the Unico System can help overcome hot sleepless summer nights as well as preventing overheating.

Professional Installation and Maintenance

Of course, careful design and layout of any SDHV system is essential and its specification must be based on calculations for heating and cooling demand within a home. Commissioning, installation and planned maintenance is also a task for experienced professionals including Unico’s Specialist Partners (USP) network.

For more information about The Unico System, please contact the team at [email protected].