How to specify the right ventilation system for your project

By Kevin Hippey, general manager at Vortice Ltd

What are the key issues facing housebuilders and developers with regard to ventilation systems in modern houses?
With regulations, legislation and products all driving up energy efficiency in modern homes, buildings are becoming increasingly air tight – great for energy bills, but not necessarily so great for your health. The design and specification of a domestic ventilation system not only affects the performance of the product, but has a vital part to play in the health of occupants. Reaching optimum performance levels from today’s fans and heat recovery systems depends largely upon the design of the system, in particular the ductwork and its installation.

The 2013 regulation changes will soon come into play and part L is the one specifically relating to ventilation. In the meantime, the NHBC has put its best practice guide out for consultation to the FMA, the RVA and housebuilders and includes a whole section tackling the pet problems facing the industry – incorrect system design (ducting and valves) and insufficient quality of ducting specified. It may cost more to put the control valve far away from the door but you get far fewer dead areas and better cross ventilation in the room thereby helping any issues of damp and making the air in the room healthier.

The implication of not following this best practice, for example by using ducting that’s been inappropriately specified, is that the property might not receive its 10-year NHBC certificate. There have been many instances where, in an attempt to cut costs, builders have used bendable ducting (designed originally for the tumble dryer market) which degrades and splits in a short time – this will not be acceptable under the new best practice guide.

What lessons are there to be learnt?

  • Ensure that system restrictions, like bends in ductwork, are avoided. This will mean that the ventilation fan can work at its optimum level and achieve its energy efficiency
  • Choose the right ventilation product for the requirements of the building – generally selecting the product on the basis of how many ‘wet rooms’ there are will help to specify the fan or heat recovery system that’s up to the job.
  • Scrimping on the quality of the ducting will cost time and money.

Over the last few years, the key area of development has been heat recovery units. These take stale air from the wet rooms of a building, remove the heat and replace that heat into the fresh air that they bring back into the building from outside.

Heat recovery units come in different shapes and sizes and are usually selected based on the number of wet rooms they need to extract from – a wet room is a bathroom, WC or utility room.

These heat recovery systems now have pretty impressive performances, with thermal efficiencies already achieving the low 90 per cent range and with excellent specific fan power ratings, so the trend is in designing them to fit within smaller spaces. They can be designed to fit within a roof space, a kitchen cupboard space or, where space is at a premium, some of the newer units are designed specifically for ceiling voids in apartments.

The market’s not all about heat recovery systems of course, there are still many excellent continuous running fans out there which will provide good air movement and quality to a new home. Look out for energy efficient SAP Appendix Q eligible products for the best results.

Even the humble 4” bathroom fan will probably be included in the changes to the upcoming 2013 regulations. The bathroom, utility room and kitchen will require a fan consuming no more than 0.5w/l/s but still meeting the required air changes to comply with regulations, thus further reducing the energy consumption of the whole house when compared with existing intermittent extractor fans.

With ventilation systems for housebuilders and developers, what’s left to improve upon?
System design, specification and installation.

Many of the reputable ventilation system suppliers offer a design service at a cost which is refundable against a product order – this is well worth the investment and can ensure that problems are avoided and energy savings are made right from the word go.

More and more improvements are being seen when volume housebuilders select contractors who they ensure have BPEC accreditation for ventilation systems. The BPEC course is the only one out there planned to train installers and contractors to ensure that both the ducting and ventilation system are designed and set up to work to their optimum capacity.

As in all things, the time invested in specifying reaps benefits in the longer term, in terms of energy efficiency, fewer snagging issues and quality of life for the occupant of the property. For the ongoing reputation of a housebuilder or developer the benefits are immeasurable.