Winona, Minnesota in the beautiful Mississippi River Valley, where it is so green that it makes your eyes hurt! (in the summer)
Leslie & Jo Hittner
In 2002, we began construction on a new home. At that time, we made a decision to use energy as wisely as possible. We set a goal of reducing our "carbon footprint." Below are the four initiatives that we have implemented since that time.
In 2002, we began construction on a new home. At that time, we made a decision to use energy as wisely as possible. We set a goal of reducing our "carbon footprint." Below are the four initiatives that we have implemented since that time.
Green Heat and AC - Geothermal
Geothermal heat pumps use the earth as a bidirectional heat radiator. The sub-surface temperature of the earth remains essentially unchanged throughout the year. Thus a bi-directinal heat pump can draw heat from the earth in the winter or store heat in the earth during the summer.
The two heat pumps shown in this picture provide our domestic hot water year 'round and provide both winter heating and summer cooling. A back-up gas furnace can provide heat in the event that our controlled electric heat pump power source is switched off by XCEL. The back-up requirement is imposed by XCEL in order to qualify for the cheaper power rate delivered by controlled power sources. It has been estimated that geothermal heat pumps are about 4 times as efficient in their use of energy as gas furnaces and conventional air conditioning systems. |
Green Power - Solar Photo-Voltaic
This photo-voltaic grid-tied array generates 6200 watts of electricity on a clear day. On a typical day in Minnesota, that represents 35 Kilowatt-hours of power during the summer months. Since the array only went on line in July 2012, we do not yet have data on winter operation.
Grid-tie systems do not store electricity. Every watt of power generated by this array is either used in the house or sold to XCEL. If used in the house, we save on our electric bill. If sold to XCEL, we are paid for it at a wholesale rate. Clearly, it is best if we can use the power ourselves and avoid paying a retail rate for our power. On most days, the array generates more power than we use. Since we use more power at night, when the array is not producing, we continue to purchase power from XCEL - and sell power to XCEL. We are now beginning to collect the data needed to analyze our net savings. You can see our system statistics here. |
Green Transportation - Toyota Prius Hybrid
The Prius, our first hybrid vehicle, was purchased in 2005. This car replaced an older Toyota Camry that averaged 32 mpg. The prius averages 44 mpg in summer and 38 mpg in winter (The engine runs more in order to keep the cabin - and itself - warm in the winter.)
If we did not live on the hill above Winona, our mileage would be even better. The best single tank mileage we have achieved is 49 mpg. |
Green Transportation - Ford Escape Hybrid
We purchased the Ford Escape hybrid in 2010. The hybrid system is the same as that used in the Toyota vehicles. The Ford replaced a Chrysler minivan that averaged 22 mpg. The Escape averages 35 mpg in the summer and 30 mpg in the winter.
Unlike the Prius, the Ford has an option to disengage the anti-skid traction system, which comes in handy when going up steep and slippery hills at low speeds in the winter. The best single tank mileage we have achieved is 40 mpg. |
CFL or LED?
Our ongoing efforts involve converting our lighting from incadescent to either CFL or LED. While CFL light is often "warmer" than the cold white light of LEDs, they come on more slowly and especially in rooms where we turn on the light, accomplish a brief task, and turn the light off again - CFLs seem not to be up to the task. LED lighting continues to improve. One issue - at least through local sources - is that retailers seem to think every light should be "dimmable." This increases cost and decreases efficiency - a price we are unwilling to pay for LED lamps that will be located in "non-dimming" applications. The same is true of CFLs, althouth they appear to be more widely available in "non-dimmable" forms.
A question we have asked: Should we toss out all of our perfectly good incadescent lamps simply to replace them with energy-efficient alternatives? So far, we have been doing this a little bit at a time - and waiting for the appropriate alternatives to show up in the stores.
A question we have asked: Should we toss out all of our perfectly good incadescent lamps simply to replace them with energy-efficient alternatives? So far, we have been doing this a little bit at a time - and waiting for the appropriate alternatives to show up in the stores.