Research by Passivent, the UK’s leading natural ventilation specialist, is revealing that under changes to the SAP calculation method, installation of even its basic Passive Stack Ventilation system, in conjunction with a gas saver, waste water heat recovery and photovoltaic equipment, can achieve capital cost savings of up to £780/ dwelling, and achieve an improved DER, against the widely-accepted route of MVHR (mechanical ventilation with heat recovery).
“The findings come from analysis of, and SAP calculations done for, ‘real life’ semi-detached homes, which reinforces the validity of our claims,” observes Dennis Bates, Passivent Domestic Product Manager. “Even with an airtightness factor of 3, our combined solution gives a better DER- of 20.33 against 21.41- and costs at least £200 less than MVHR. On even a small development, that adds up to a significant reduction in bottom-line costs, whether private or social housing, even before you’ve factored in the ‘lifetime’ costs of maintenance, replacement parts etc. It truly is giving ‘more for less’ and delivering best value practice.”
Under Passivent’s analysis, on a four-bedroomed semi-detached with three wet rooms and an airtightness of 3, PSV + gas saver+ waste water heat recovery required just 0.82kWh of PV to achieve Code Level 3 and costs less than £4000 for all of the technologies; with an airtightness of 5, the systems still cost only £4145 against almost £5000 for MVHR to reach the same Code level. With the 5 airtightness value, the same solution still costs just over £6500 to attain Level 4, against an MVHR cost of over £7000.
Passivent’s PSV is the only domestic ventilation strategy that uses NO electricity to function, instantly contributing towards low carbon emissions. It harnesses natural air movement principles, like a chimney, to ensure the home is adequately ventilated 24/7, 365 days a year. Passivent PSV uses planned air paths to exhaust warm, ‘used’ internal air out through the roof terminal, creating a natural draught-free ‘suction’ effect to stimulate replacement with fresh air through strategically positioned inlets. It is therefore ‘fit and forget’, requiring no operator, service or maintenance input.
Passivent supplies background ventilation solutions including tricklevents and through-wall ventilators, standard and ‘intelligent’ mechanical ventilation, passive stack natural ventilation and the new and innovative iHybrid, which combines natural ventilation with heat recovery to yield a 55% reduction in fan energy use and a 39% saving in lifetime costs over standard mechanical heat recovery, with its systems supported by its nationwide Mastercare scheme of approved installers. Its ability to design, supply and install all domestic ventilation solutions means it can provide authoritative, unbiased advice to the building industry to ensure new schemes comply with the new Approved Document, and all other regulatory requirements.