Heat-pump ventilation system exceeds Passivhaus requirements
Heat-recovery ventilation systems from Total Home Environment installed three years ago in three houses in Somerset have exceeded Passivhaus requirements. The Passivhaus requirement is that the annual primary-energy demand should not exceed 120 kWh/m2. Despite being all-electric, these houses have achieved 94.2 kWh.
These properties have high levels of insulation and no central heating, so heat-recovery ventilation was needed to minimise ventilation heat loss.
Total Home Environment supplied its Genevex Combi 185 system, an all-in-one unit combining heat-recovery ventilation and a heat pump for space heating and domestic hot water. They change the air every two hours via a 95% efficient counterflow heat exchanger. The integrated heat pump extracts heat from the exhaust air. The entire energy bill for one of the properties last year was under £500.
The Combi 185 gives priority to hot water, which is stored in a 185 l integrated cylinder. Maximum airflow is 350 m3/h, and a unit can provide ventilation, space heating and how water for up to three people in a 290 m2 home.
The homes were built by local builder Arthur Bland, who explains, ‘I went out on a limb when I decided not to install a traditional heating system and rely solely on the Genevex appliance to provide heat and hot water in each of the homes. However, the Combi 185 has exceeded my expectations. The system performs better than predicated, which has vindicated my choice, and I am completely satisfied with the results.’