Monday, September 2, 2019

Continuing to Improve My Energy Footprint

Over the years I have been systematically making small and large changes to my home to reduce my energy consumption. It is constant road to improvement as products change. I started with the easiest steps; lowering the thermostat in the winter and raising the temperature in summer, purchasing energy star appliances and in 2008 choosing an LCD TV over a plasma (an LED TV is even more energy efficient, but was not available at the time). The next simple step was to install solar films on the windows and patio door and drapes and curtains on all the windows. We then changed all the incandescent light bulbs for florescent bulbs.

Since that time most of our light fixtures have been converted to LED and we purchased 2 new LED TV’s. (Though we still have the old LCD TV we bought more than a decade ago, it’s on the list of thing to be replaced. Last year all of our kitchen appliances were once more replaced and updated. I moved from propane gas stove to an induction cook top and electric ovens and once more bought energy star refrigerators. Reportedly, the induction cooktop are more energy efficient because they use a magnetic field to heat the pot. In addition, the induction cooktop is really easy to cleanup. However, the induction cooktop only lasts about 8 year. These were small steps, but I’ve learned over the years that small steps do add up.

Using the Building Envelop Research of the Oak Ridge National Laboratory for guidance we updated our insulation and ducting. The Oak Ridge National Laboratory performs their Building Envelop Research for the US Department of Energy, DOE. Following their recommendations the attic, crawl spaces, eves, ductwork, underside of a large portion of the main level floor were insulated with cellulose. The pipes, wall end caps, knee walls, sump pumps and all identified areas were sealed, the garage ceiling was insulated and an insulated garage door installed, back when I widened the opening. Improving the insulation was both the most cost effective project I have done, and also the most satisfying with the improved comfort in the master bedroom and bath.

According to the DOE heating and cooling account for 56% of the energy use in a typical U.S. home, making it the largest energy expense for most homes. So that is where I looked for my next project. A wide variety of technologies are available for heating and cooling your home, and they achieve a wide range of efficiencies in converting their energy sources into useful heat or cool air for your home. Heat pump systems provide both heating and cooling and offer the benefit of delivering more useful energy than they consume. Unfortunately, their effectiveness at heating on the coldest days is limited and they have inefficient backup electric heat. For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners.

Higher energy efficiencies are achieved with geothermal (ground-source or water-source) heat pumps, which transfer heat between your house and the ground or a nearby water source. Although they cost more to install, geothermal heat pumps have low operating costs because they take advantage of relatively constant ground or water temperatures. However, the installation is expensive because of the need to bury coils horizontally or vertically to deliver constant temperature fluid or install a groundwater pump and injection well to supply constant temperature water to the system. Ground-source or water-source heat pumps can be used in more extreme climatic conditions than air-source heat pumps, and are more effective at cooling and heating at the extremes. Geothermal it turned out, was not a cost effective retrofit for this house.

One of the selection criteria for my home was the large southern roof span, perfect for solar panels. After saving up money, my next project I was able to snag some of the limited funds of the 2009-2020 Virginia Renewable Energy Rebate Program before all the money was gone and combining this incentive with the federal tax credit of 30% and I lucked into getting grandfathered into the Washington DC solar renewable energy credits, SREC’s, market so the rebates have paid for the system and all its repairs in a bit under 9 years. The solar panels themselves save us approximately $1,300 per year on our electric bill. That is about twice the savings we achieved by insulating the house; however, the cost (before rebates and incentives) was more than ten times the cost of the insulation project. The solar panels have had a series of problems and roof leaks and overall have been as much an annoyance as boon. It is my plan that when the SRECs expire, I will remove the PV solar array from the roof, replace the roof and look into installing ground mounted solar panels. At this time it looks as if the SRECS could pay me almost $20,000 during the remainder of their life. This will go a long way to paying for a new easier to maintain ground mounted system. Live and learn.

I’m still considering an electric vehicle, but since I drive less than 6,000 miles a year (including vacations), I want to get the full life out of my existing vehicle before I consider buying a new one. After studying the carbon footprint calculators I have realized that traveling by jet may be some of the biggest contributors to our carbon footprint. Since retiring, we have vastly reduced our traveling. These days we fly less than one round trip a year-weddings, funerals and visits seem to be the only things that take us from home these days. 

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