Ridge Top Home w/Solar and Wind
Site characteristics or focus during construction or remodel:
We purchased this property with 270-degree views. When we designed our home, we wanted to have a floor-plan that benefitted from our very sunny very exposed location.
In planning the positioning of the home, these were the factors we wished to work with:
- Make the home as energy efficient as possible
- Situate the home such that from the picture window where the lazyboy chairs are – we could see the Palisades at Squaw Valley, while at the same time aligning the position of the windows to block the main view of the sewer plant.
- Use active and passive solar whenever possible.
- Use the existing group of trees to the west of the house as a way to increase the shading of the home during the hottest months of the summertime.
The glacial moraine on which the house is located is one of the windiest parts of Truckee. During winter storms blow in from the southwest and literally pummel us with 85 mph winds.
During the wintertime, this location gets unobstructed sun from 7am until 5pm and in the summertime the solar panels get sun from 6am to 6pm.The house is situated such that after about 3pm in summertime, it is in the shade of the trees directly to the west of the us offering a welcome shading effect to both the front and back porches during the hottest part of the day.
We positioned the home to take advantage of the summertime down slope winds to cool the home in the summertime while conversely in the wintertime we often endure sustained gale force winds.
In the wintertime, the majority of our energy production is from our solar panels- while occasionally the wind supplements our output as storms blow in. Summer is the time of year when we experience the greatest energy output of both our solar panels and wind turbine during the late mornings and early to late afternoons.
Construction Type: The house is wood frame construction with stucco walls and log accents. Stucco was an attractive feature due to its complimentary look coupled with logs and fire resistance of the material that is a valid concern while living on property that is surrounded by thousands of acres of sagebrush.
Passive Solar System: The home was positioned to take advantage of the full day exposure to the winter sun. In the summertime, the sun is high enough and the edge of the roofline is such, that the sun’s rays barely enter the house. Yet, during the wintertime, when the sun is lower in the sky, it shines on the northern wall in the great room. Our main mistake when we built the home was to assume the gypcrete in the floor would be enough mass to store and retain our passive gains. However, eliminating our carpets in the great room could possibly help.
Solar Domestic Hot Water: For over 4 years we have been using a 2-panel solar hot water system that was designed to act as a pre-heating unit for our propane- fired domestic hot water tank. The solar system is a closed-loop set up — where the glycol-based water in the panels is circulated from hot water side of the panels to a heat exchanger and back to the panels.
Solar Hydronic Hydroponic Greenhouse: I thought it would be kind of neat to grow my own lettuces and tomatoes in the wintertime in order to have minutes-old fresh wintertime salads. I just so happened to have a couple of extra 4x10 foot solar panels to use for this project. First I built a 9x16 greenhouse, with an insulated foundation and hydronic pex lines embedded in the concrete floors.
The solar hot water system includes a similar system design as my solar domestic hot water. The panel to the heat exchanger is an identical design. The floor loop system is a little different than with the solar domestic hot water. During a sunny day in the late fall, winter and early spring, the thermostat in the greenhouse turns on and allows the solar heated water to circulate into the floor all day long. Since the greenhouse has the potential to lose heat rather quickly, I added some more mass to the heating system by building a water wall on the north side of the greenhouse- the water wall is basically a 2x6 stud wall which has a netted face which holds six 55 gallon bags of water on the wall. There is a hydronic pex line that loops behind the bags to add a little extra heating to them during the day.
The plumbing design of this system starts from the solar hot water tank. The solar heating circuit goes from the bottom of the tank, through the heat exchanger and back into the tank. The floor heating circuit, runs from the mid point of the tank, through an instantaneous hot water heater, and out to the floor and then back to the tank. During the sunny day, when the floor pump turns on, the cold water in the tank will pass through the instantaneous hot water heater and since the temp will be colder than acceptable, the burners of the instant hot water heater will turn on and flash heat the water, which then circulates into the floor. As the water circulating through mass will keep the greenhouse warm. During the evenings when the temp of the greenhouse falls below 60 degrees Fahrenheit, the thermostat in the greenhouse will turn on only the floor pump, which circulates the water through the instant hot water heater to the floor. At that point, the instant hot water heater flash heats the water and provides the hydronic night-time heating on demand.
Active Solar System: In an effort to make an environmental conscious statement, we chose to supplement the power we purchase from TDPUD with our own “Solinsky Utility District” power. We currently have 1800 watts of solar panels (1200w of which is on a tracker and 600w is on a fixed mount) and a 2500 watt wind turbine on the property. The power is directed through two 4000 watt Trace inverters and stored in a 24 volt battery bank with 1750 amp hours of storage. The system is set up to be manually switched to back up power during times of TDPUD power loss. We currently produce around 9 kilowatt hours per day, which is back-fed into the PUD’s power lines in accordance with California’s net metering law.
Main Heating System: The home has a 5-ton ground source heat system coupled with a hydronic in floor heating system. I can’t say enough about how happy we are with this system- the house is a welcome refuge during even the coldest days in the wintertime- there is not a single cold spot in the place.
Auxiliary Heating System: Since the ground source heating is electrically driven (and it draws a lot more power than my inverters can produce), we needed to have a back-up heating system in case of PUD power outage. We chose to use a propane gas fireplace (Extrordinare) – this fireplace is rated as a furnace and quickly takes the edge off during the spring and fall and will operate without power.
Conservation Features: Dual Pane Low- E windows, some energy efficient appliances (freezer in garage), compact fluorescent bulbs, a house design which allows a single light on in order to illuminate most of the whole house, cellulose insulation in the walls.
Subjective Evaluation/ design considerations: When we were first designing the house, I specifically stated to our designer I wanted to design a solar home. Her reply was “ I know how to design a solar home” — well, apparently to her, a solar home means a home having plenty of south facing glass. What she neglected to add to the design was any MASS! Mass is an extremely important feature to a solar design- mass provides a heating “carry-over” time- so when the sun leaves the mass, and the house cools down, the mass then re-radiates the heat into the home. Our home lacks that feature and thus during the cold winter nights, the ground source heat pump runs all night long.
When we insulated the home, we chose to pay a little extra to get cellulose insulation instead of fiberglass insulation. From what I could read about it, the cellulose insulation works better in our extreme climate than the fiberglass does. We had one minor problem when the insulation people showed up; they only filled the walls with Cellulose, but neglected to do the ceilings and instead used fiberglass on the ceilings. At the time, the contractor said that there was no way to make the cellulose stick to the ceiling (which upon later reflection, I found out that it was just that he preferred not to do so). The problem with this is lack of the cellulose barrier on the ceiling, is that since there is no sheetrock between the fiberglass and the wood deck ceiling, the hot air in the room easily flows out the joist bays to exit out the roof.
Also, in an attempt to “save money,” I went out and purchased the “cans” for the living room ceiling. Unfortunately, I was unaware “insulated cans” were available so I purchased the un-insulated cans and had them installed. I then had a “swiss cheese” ceiling which allowed even more heated air to exit to the roof. I later added insulated reflectors to the cans, which seemed to help dramatically the heat loss through the light cans.
Since we have a lot of south facing glass, in the nighttime -in the winter, we could feel some cold drafts from the windows. We went out and purchased “duette” type of window coverings, which dramatically helped keep the great room warm during the evenings.
Our wintertime monthly utility bill is around $50/month for both gas and electricity.