Air Conditioning 101
According to Energy Star, a division of the EPA, heating and cooling costs the average American about $1,000 a year, which is nearly half a home’s total energy bill. These days central air conditioning is becoming more of a standard in American homes versus a luxury. Since more and more homeowners are becoming dependent upon these systems, in addition to the large costs they represent to homeowners, it’s important for consumers to understand how they work, what different options are available with various systems, what standards or regulations these systems adhere to and lastly, how far these systems have come in what they can do to provide added comfort in our homes.Many people still do not know how their systems work. They are under the misconception that an air conditioner actually cools the air. This is not the case. What really happens is that warm air from your house is removed and cycled back in as cooler air. The definition of air conditioning is “system by which air is treated at a central location and distributed to and from rooms by one or more fans and a series of ducts.”
When choosing an air conditioner type there are basically three options, air conditioner systems, heat pumps and geothermal.
Air conditioner systems work by manufacturing cool air through the evaporation of Freon or some other refrigerant. This system basically has two sets of coils, one inside (for cold air) and one outside (for warm air). During this cycle, heat is transferred through the coils from inside the house to the outside, as the refrigerant absorbs the heat and releases it to the outside. The refrigerant changes from liquid to gas during this cycle and as it does so, it absorbs heat. When it changes back from gas to a liquid state it releases this heat. The remaining liquid in the indoor coil absorbs heat from the inside air, which turns into a low-temperature gas cooling the indoor air. Cool air is circulated through a system of supply and return ducts. These supply ducts and registers carry cooled air through the home. When the cooled air becomes warmer as it circulates through the home, it flows back to the central air conditioner through return ducts and registers.
Heat pumps actually operate as both heating and cooling systems. Heat pumps basically move heat from one place to another. In the cooling mode, a heat pump takes the heat from inside the home and pumps it to the outdoors. A heat pump is an air conditioner that contains a valve that lets it switch between "air conditioner" and "heater." When the valve is switched one way, the heat pump acts like an air conditioner, and when it is switched the other way it reverses the flow of Freon and acts like a heater. Imagine that you took an air conditioner and flipped it around so that the hot coils were on the inside and the cold coils were on the outside. Then you would have a heater. It turns out that this heater works extremely well. Rather than burning a fuel, what it is doing is "moving heat."
Geo-thermal units also known as ground source heat pumps (GSHP) were recently named by the Environmental Protection Agency as “the most energy-efficient and environmentally sensitive of all space conditioning systems”. The basic principle behind these systems is that they use the relatively constant temperature of the Earth as a heat or cool air source instead of generating thesame with electricity. The most common type of geo-thermal unit is a closed-loop system, which is placed below the ground or a pond. In cooling mode, heat is extracted from your home and either moved back into the earth loop or used to preheat the water in your hot water tank. Geo-thermal units typically cost more than the air conditioning units or heat pumps but can save you 30-50% on your heating and cooling bills, which will help you recoup your investment in 3-5 years.
When considering these various air conditioning and/or heating options it helps to understand how the industry rates them for efficiency.
SEER (Seasonal Energy Efficiency Ratio) is a measure of seasonal or annual efficiency of a central air conditioner or air conditioning heat pump. It takes into account the variations in temperature that can occur within a season and is the average number of BTU (British thermal units) of cooling delivered for every watt-hour of electricity used by the heat pump over a cooling season. The higher the SEER, the more efficient the unit; the more efficient the unit, the lower the operating cost.
The U.S. Government's minimum SEER was recently changed from a rating of 10 to a rating of 13 SEER on January 2006. The Energy Star minimum is set at 14 SEER. This may mean higher-up front costs to consumers but also means lower operating costs. A central air conditioning unit rated at a 13 SEER will use 30 percent less electricity than a 10 SEER system. With the rise in energy costs across the country, consumers may see a payback much quicker with less electricity being used.
AFUE (Annual Fuel Utilization Efficiency) is the standard measurement of efficiency for gas and oil-fired furnaces. This number (a percentage) tells you how much of your fuel is used to heat your home and how much is wasted. The higher the AFUE rating, the greater the efficiency. For example, if a furnace has an AFUE rating of 80%, the furnace converts 80% of the fuel that you supply to heat and the other 20% is lost out of the chimney. The most efficient furnaces in the industry have an AFUE rating of up to 96.7%. The minimum set by the Department of Energy is 78% AFUE and for Energy Star, 90%.
Currently consumers have a unique opportunity available to them if they need to replace their old inefficient heating and cooling systems. With the passing of the recent American Economic Recovery Act (ARRA) consumers can claim up to 30% ($1,500 limit) for the installation of higher efficiency furnaces, boilers, air source heat pumps, central air conditioners, and hot water heaters in the tax years of 2009-2010. Whereas the previous tax credits set a limit of $300 for central air conditioners now homeowners may use the entire $1,500 tax credit limit on a single qualifying improvement.
The ARRA has also removed the $2,000 max cap tax credit limit on geo-thermal systems. Homeowners who install geo-thermal heat pump systems may be able to claim up to 30% of the installed costs in tax credits in the year the system are placed into service. In addition, the geo-thermal tax credit has a longer term, from January 1, 2009 until December 31, 2016.
It’s amazing how far we’ve come from the basic window units we used to have. Central air conditioning will supply consistent even temperatures in your home and can even improve the air quality. Central air conditioning units can have air filtration systems, humidifiers and dehumidifiers added to them. Another great feature is a programmable thermostat. These can make your life easier and save you money. You can turn down the airflow when you are not at home and have it programmed to turn back up when you will be returning. This will increase your comfort when you are home and save you money when you’re not. A very revolutionary technology that exists is the communicating technology now available on heating and cooling systems. You can set your home temperature when you are away from home and even run diagnostics to make sure everything is running properly. If you travel a lot or spend your winters away from home, this can provide a wonderful peace of mind.
One last important issue in the heating and cooling industry is to always go with a reputable firm. This industry is highly regulated and when making changes in your heating and cooling system certain guidelines need to be followed and permits must be pulled. It is very important that you go with a professional heating and cooling company that has a good, long-standing reputation in your area. The cost of mistakes can be very high.
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