This summarizes the building's energy production and consumption for calendar year 2011.
Solar electricity produced: 6033 kW h (16.5 kW h per day)
Electricity consumed: 6150 kW h (16.8 kW h per day)
Non-heating: 5350 kW h, heating: 800 kW h
Net electricity deficit: 117 kW h (-2%)
Owners Report: Our first 12-month report started April 1 2010 when we first activated the PV system and went through April 1 2011, but this report covers calendar year 2011 so there are a few months of overlap. For calendar year 2011 we fell just short of our goal to produce more electricity than we consumed, with a net deficit of 117 kW h for the year. Compared to our first 12 months of operation, average daily production dropped by 0.3 kW h but consumption increased 1.8 kW h. Some of that is due to having an additional family member living here since mid-year, and some is due to adding an upright freezer that uses about 1 kW / day.
Below is a graph showing the inside (red) and outside (blue) temperatures that we recorded throughout the year. Overall the house was very comfortable, with just a few days in the upper 70s during some hot summer weather when allergies made us reluctant to open up the house at night since our ventilation system filters out pollen from the incoming air.
The graph below shows the heat storage tank temperatures over the year. The big gap is when we drained the tank due to a leak, and we were able to get the tank warmed up again in the fall but not to the degree we would have liked.
Here is a list of some of the features of our home that qualify for LEED credits. This is not an exhaustive list, just some of the more interesting features:
- Universal Design - every room in the home is usable by persons with limited mobility
- Limit conventional turf - we will have no conventional turf at all, just gardens surrounding the house
- Reduce irrigation demand - all our permanent plantings will have far less water demand than typical landscaping in this region
- Water reuse - our rainwater harvesting system collects water from more than 50% of our roof, to be used for watering the gardens and flushing toilets
- Indoor water use - all our toilets, lavatories and showers have very high efficiency fixtures that use much less water than conventional fixtures
- Optimize energy performance - our home is designed to generate more energy than it consumes, using a combination of superinsulation, energy efficient appliances, active and passive solar heat collection, and solar electric generation
- Construction waste reduction - our construction will generate about 1/10th as much waste per square foot as a typical home construction
- Combustion venting - our wood stoves are EPA certified for low emissions, and have an outside combustion air supply to avoid drawing warm air from the house
- Outdoor air ventilation - we use a heat recovery ventilator (HRV) to provide continuous ventilation, and to recover about 70% of the heat from the outgoing stale air
- Local exhaust - our bathrooms are equipped with humidity sensors, which will increase the airflow through the HRV whenever excess humidity is present
- Air filtering - the ventilation air intake is equipped with a high efficiency air filter (rated MERV 13) to reduce particulates in the incoming fresh air
- Indoor contaminant control - we have a shoe removal and storage space near the front door, and a central vacuum system that exhausts to the outside
In addition, here are some of the environmentally preferable products in our home that earn LEED credits:
- Floor - polished concrete generates far less emissions and traps far less dirt than carpet
- Walls & ceilings - our drywall was made less than 200 miles away from 96% recycled material
- Paints - All walls and ceilings use zero-VOC paint
- Countertops - we're making our own countertops using recycled glass
- Insulation - our cellulose wall insulation is about 85% recycled paper
Source: Alliance for Environmental Sustainability & Jay & Liz McClellan Homepage