WHEELER ON HVACR: 0% Greenhouse Gases - Is It Possible?
Everywhere you go you’ll find people who are worried about and talking about the need to reduce energy consumption, and thus global warming, but they’re all waiting for someone else to do something about it, or for some invention to come along, or for some government regulation to be passed to get the job done; that may or may not happen. Rather, reducing energy consumption must be done on a personal level, and believe it or not, many of the tools and means to accomplish this goal are already at hand.
The American Institute of Architects (AIA), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), Architecture 2030, the Illuminating Engineering Society of North America (IESNA), and the U.S. Green Building Council are now in the process of developing a handbook of guidelines, which is initially targeted for the design of retail stores and light commercial buildings (but can be adapted to homes), that if implemented, could reduce energy consumption by these buildings an average of 30%. And it is their goal to keep on revising the guidelines as new technology becomes available, with the eventual target goal of 0% greenhouse gases by the year 2030.
Understand that reducing energy use doesn’t necessarily come easily or inexpensively. Rather, it requires a whole new way of thinking and building designing. Yet, many of the means are currently at hand and are not at all expensive to implement.
Of course, reducing the use of energy in residential and commercial buildings isn’t always as simple as purchasing some new product, for the guidelines mentioned above cover every step of construction from the design and orientation of the structure, to the pouring of the foundation, and up to the building’s eventual use and maintenance. Yet, new products can be found and purchased and simple operational procedures implemented that can presently go a long way toward reaching the 30% goal!
LightingOne of the simplest and least expensive changes that brings immediate results is to lower the wattage of the lighting inside the building (change the light bulbs). The lighting levels in most residences and commercial buildings are currently much higher than we actually require in order to see well. Changing from incandescent lighting to high-efficiency fluorescent bulbs can achieve a lighting energy reduction of as much as 80%!
The guideline goal is to reduce the output of all lighting to just the required levels for the occupied space. Also, just turning off the lights when they aren’t needed and employing sunlight wherever possible is inexpensive, easy to do and necessary.
Replacing manual switches with motion sensors to turn on lights only when people are present is a good idea for rooms where turning the lights off is often neglected (such as public restrooms and conference areas).
It’s interesting that tests show reduced lighting wattage to be one of the best energy savers in all of the different design zones across North America, because reducing lighting wattage also reduces the need for air conditioning. For instance, every 12 100-watt bulbs (in a retail store, for example) require an extra third of a ton of air conditioning to remove the heat they create.
Air ConditioningAlso, in areas where air conditioning plays a significant role in energy consumption, just making sure that the units are properly sized so as to not exceed the expected loads is a very important goal (most are oversized), and adding extra duct insulation and stopping duct leakage is vitally important, because most air conditioners don’t actually reach their rated efficiencies due to duct air leaks into unconditioned areas, such as attics.
Depending on the local climate, even total replacement of the air-conditioning system can be done economically, because the current higher efficiency systems can often recoup their replacement costs in energy savings in less than five years. For, whereas the minimum efficiency of such systems was 6-SEER (6 Btus of cooling per watt of electricity) just 10 years ago, the minimum efficiency for new residential air conditioners is now set at 13-SEER, resulting in more than a 53% energy savings when the old systems are replaced with new ones. Also, some air conditioners are now available that provide an efficiency of 23-SEER (thanks to new compressor technology), which can cut the energy consumption below that of old existing systems by as much as 74%!
HeatingThe minimum efficiency for most gas and oil furnaces was raised from 60% to 78% by the federal government back in the mid-1980s, and many of the old furnaces have already been replaced. However, systems with efficiencies into the 90% range are now available, and eliminating duct leaks on forced-air systems and slightly reducing temperature settings can provide significant energy savings in colder climates. Also, in some cases, changing the entire system from a fossil fuel to a high-efficiency electric heat pump (and especially a ground-source water heat pump) may achieve even greater energy reductions.
Water HeatingYet, simply replacing an old or leaking water heater for one of several available types of higher efficiency models can also significantly reduce energy consumption.
The efficiency of gas and oil water heaters, like gas and oil furnaces, has been raised from the 60% range to as high as the 90% range over the past 20 years, but there is even more to this story. This is because almost all of the old water heaters lost a larger portion of their energy because they weren’t properly insulated and through the uninsulated connecting hot water pipes. So, adding insulation to hot water pipes (where possible) throughout a building, and employing new highly insulated water heaters can achieve much greater energy savings than the listed ratings would imply.
Unfortunately, not much (other than adding insulation) can be done to raise the efficiency of electric water heaters, because the output of electric resistance is constant (3.414 Btus per watt) and can’t be changed. Yet, new water heater designs that seem to have originated in Japan have added higher efficiency options here. Rather than heating water in a tank, which loses energy as it sits there, a new concept is to heat the water as it is being consumed in small, tankless, wall-mounted heaters. These are also available for use with gas as the heating fuel. In addition, one manufacturer from Montreal, Canada, has come up with a tankless electric water heater that uses highly efficient microwaves to do the heating.
Other Energy-Saving IdeasOf course, simply adding more insulation to a house or commercial building will reduce energy consumption, as will changing the color of the exterior walls and roofing (lighter colors in warm climates, darker colors in cool climates).
Since windows lose (or gain) more heat than walls, reducing the window and exterior door area of a building will save energy. And replacing existing windows with those that have evacuated (had the air removed between) multiple panes and with those that have automatic shades is also a good way to reduce energy consumption. Adding overhangs (such as awnings) to provide shade when the sun is at its highest (summer) position in the sky, and to allow its warmth to enter when it’s at its low winter position, will carry the savings a step further.
Of course, it’s impossible to cover all the energy-saving options (such as energy-recovery devices, set-back thermostats, timers, zoning, etc.), but here are some of the simple and obvious ways to personally reduce global warming, by reducing energy consumption in our homes and in our work places. They will be covered in the guideline when it becomes available sometime next year. But after all is said, the final success of such a project comes down to the human element - to how we personally use and conserve energy, and to how we maintain the energy-saving methods and systems that we purchase, install and employ.
For more information on the coming energy guide, contact Don Colliver at firstname.lastname@example.org.