Wise Energy Choices
By Bill Bullock
Most of us don’t give a lot of thought to what fuels power the energy using devices in our homes. It may not seem like it, but we actually have some energy fuel choices. Some options, such as lighting your house with natural gas, heating your home with electric resistance heat, or cooling your home with natural gas absorption cooling, have gone by the way side because of inefficiency and cost. There are some options, however, where the wise choice is not so clear cut. In these cases, to determine the best choice, it is important to understand what energy source is optimal for the desired outcome.
Except for a small percentage derived from solar, wind, or hydro power, the first step in generating electricity is generating heat. The Tennessee Valley Authority (TVA) generates most of its heat by burning coal or developing a nuclear reaction. Steam is then created to drive a turbine that turns a generator. Generated electricity travels through the grid, across wires, to get to you.
If you use an electric water heater in your home, this heat was originally created at a generating plant, converted to mechanical energy, then into electrical energy, transmitted over power lines, and then transformed to a lower voltage. In each stage there are losses, so that the amount of heat you get from a kilowatt-hour is a fraction of what is originally burned at the power plant. If you have a natural gas water heater, you are generating heat and heating the water in one step. At current pricing it is more than twice as expensive in Memphis to operate a traditional electric water heater than a traditional gas water heater.
Therefore, if you are creating heat it makes more sense to burn a fuel (natural gas) at home than to use electricity generated far away to do the same thing. That is why most homes are heated by burning natural gas.
An air conditioner moves heat. In the summertime we want to move heat from indoors to outdoors. Through the process of a hot, high-pressure refrigerant, we can actually move heat from a 70 degree house to the outside on a 90 degree day.
The same process in reverse can take heat from 40 degree outside air and move it to a 70 degree house. The device that does this is merely an air conditioner with a reversing valve or a heat pump. Heat pumps have been around for decades but did not gain a lot of traction in cold climates or where natural gas is readily available. Heat pumps put out colder air than a traditional gas furnace, and they do not deliver enough heat to a house when temperatures are colder than freezing. Heat pumps need an auxiliary heat source, and that source has traditionally been a very expensive electric resistance heat. This design did not lend itself well for energy conservation strategies involving thermostat set-backs.
In recent years heat pumps have become more efficient. Now you can get a hybrid variety that uses electricity to move heat when temperatures allow, and when auxiliary heat is needed, an efficient natural gas furnace kicks in. While capital costs are higher, operating costs are lower. You can also achieve a reasonable payback in many circumstances, especially if you already need to replace an air conditioner.
If you have an electric water heater and you have natural gas available to your home, strongly consider switching to natural gas. You will need to hire a plumber to do piping and venting, but in virtually all cases where chimney work is not needed, there is a very reasonable return on investment. If you have an air conditioning system, you have the backbone for a heat pump installation. You’ve already got a ducted system and a gas furnace/blower unit. When it is time to replace your unit, go with high efficiency and strongly consider a heat pump. In whatever decision you are making, do your homework on what is available. Talk with neighbors to find reputable contractors and get several quotes for similar work. There is no better time to make these decisions, because they are harder to make after the water heater or air conditioner has stopped working.
Bill Bullock has been working in the energy field for over 25 years and is a long-time resident of Midtown. If you have questions regarding this information or energy use in general, contact him at firstname.lastname@example.org.