Build/Design and Engineering of Ultra Efficient Homes and Buildings on the Passive House principals. Owners Allen Drewes and Marko Spiegel experiences combine to achieve beautiful homes without the use of furnaces. Heating/cooling is supplied through energy and cost efficient HVAC equipment as it is constantly evolving. Our homes are also healthy homes by exchanging the air with the outside air to the efficiency of over 90%. Keeping indoor air pollutants, CO levels and orders to extreme minimums.