Daylighting
Within the constraints of the Palo Alto City Planning regulations, the lot size, and surrounding trees and structures, we have attempted to bring daylight into the house to maximize livability and to reduce the need for electric lighting. The large dormer over the loft illuminates the central space. The open stairwell is lit from above by operable skylights. The master bathroom is also lit by a skylight. Most rooms have light from at least two sides to balance the color and quantity of daylight.
Electric lighting
The majority of the lighting is either Light Emitting Diode (LED) or fluorescent. LED recessed ceiling lights are model LR4 by CREE. The CREE LEDs are more expensive than standard recessed fluorescent lights, but the payback on energy savings is rapid. LED recessed lights are more cost effective than PV panels at reducing household energy drawn from the grid.
LED and fluorescent lamp color-temperatures were specified to feel warm and match our expectations of “home.”
Filtered fresh air ventilation
During cold weather, when having the windows open is too uncomfortable, the house gets fresh air on-demand from a MERV-filtered ventilation system located in the attic. The heat-recovery ventilator (HRV) pulls a continuous exhaust of humid, stale air from the bathrooms and kitchen, and strips heat out before expelling it to the outdoors. In a waffle-grid heat exchanger, filtered outside air is pulled opposite the stale air and absorbs its heat before being distributed to bedrooms and living rooms. The air streams never mingle. The airflow is low (80-150 CFM), so small ductwork is used (4-6” round, rigid metal). Most of the ductwork is in a chase between floors. Despite the fan energy, the HRV creates a net energy savings for the house, and superior indoor air quality. Venmar EKO 1.5, www.venmar.ca
