This is a really exciting time for us at Michael Bonsby HVAC & Plumbing – we’re working with Southern Exposure Homes on the first passive house in Arlington! A Passive House is a house designed to be almost 100% energy efficient. They are very well insulated, almost completely airtight and primarily heated via passive solar gain and internal gains from people, electrical equipment, etc. This minimizes energy losses and helps cut heating costs by an astonishing 90% while maintaining extremely high indoor air quality (remember that most tight homes tend to have poor IAQ – the Passive House doesn’t!).
So where do we fit in? Naturally – we’re the heating and air conditioning consultants! We’ll be installing our favorite thing – a Mitsubishi heat pump – along with an Energy Recovery Ventilator (ERV). The ERV is the secret to the Passive House’s great indoor air quality. Since the house is completely airtight, it’s the ERV’s job to remove stale air and replace it with fresh air. As it does this, the outgoing air transfers its temperature to the incoming air, eliminating the need to completely reheat or recool the incoming air!
The Mitsubishi heat pump is there to act as a supplemental heating system. Southern Exposure Homes has it all figured out in terms of the home’s thermal envelope, but there are some days when it will get too hot or too cold to rely exclusively on passive gains. We’ll be installing a 1.5 ton reversible Mitsubishi MiniSplit, but according to our models the Passive House will require an active heating load that’s only about 10% of conventional homes!
We also devised a strategy to reduce the chances of temperature stratification when bedroom doors are closed. We’ll be installing transfer fans to blow air between different rooms and floors.
This is shaping up to be a really exciting project! We’ll be sure to keep you posted with more details as they come in! And remember – if you want to know more about the Passivhaus, or if you want to install a Mitsubishi heat pump in your own home, call Michael Bonsby HVAC & Plumbing today!