Beating the Heat: Helping Your Air Conditioner
The new house you just bought is not so cool and the air conditioner seems to run all the time. You begin to worry that maybe something is wrong with the air conditioner. You tolerate it for a while until your spouse broaches the subject a few hours later. Both of you discuss the matter and come to the conclusion that something is wrong with the air conditioner.
You pick up the phone and call the HVAC service company that has serviced your heating and air conditioning equipment for years. The next morning the HVAC air conditioner technician arrives. You discuss the matter with the air conditioning technician and then he goes about his job of searching for a problem. Forty-five minutes later the HVAC air conditioning technician reports that everything is fine with air conditioning equipment. Everything is in tip-top shape with the air conditioner. Air conditioner refrigerant charge, clean coils at the air handler and the condensing unit, all air conditioner components have normal amp draws, ect, ect, ect........ As the truck pulls away you begin to wonder how to resolve this matter about keeping your new house cool.
The Core Problem with Keeping the House Cool
Heat is naturally attracted to a cooler area through the process of convection. The walls, windows, doors, ceiling, and even the underside of your home is constantly absorbing heat from the outside. If the heat is being absorbed faster than air conditioner can remove it, the temperature in your home will rise.
A common misconception among many people is that an air conditioner cools your home. While this is true in human physical terms it is not true in technical terms. You turn your air conditioner on to remove heat and humidity. That process makes us feel more comfortable. The evaporator coil, which operates below the dew point, condenses most of the humidity that passes through it. That also increases the comfort level in human physical terms (by removing humidity your body will feel cooler). The next thing your evaporator coil does is absorb heat from the air that passes through it. This air comes from your home through the return duct (usually where the air conditioner filter is located is the beginning of the return duct) and is distributed back into the home or dwelling through the supply vents. The air coming out of the supply vents should be cooler than the air going into the return. The air is then sucked back towards the return duct where the process of removing heat is repeated by the air conditioning system.
If more heat is entering the home than the air conditioning system is designed to remove then there will be a temperature rise and things can become uncomfortable.
The Solution To Your Cooling Problem
Assuming that your air conditioner system is sized properly and the HVAC technician did a thorough job of checking all your HVAC components in the air conditioning system, the solution to your problem is one of reducing heat gain into your home. A thorough check of your AC system includes checking the ductwork for leaks. Leaky ductwork reduces efficiency of the system drastically. Many times after a n air conditioning system is replaced the old ductwork is not replaced. This old ductwork leaks and does not properly deliver the air as designed. If the ductwork is in the attic then the attic is being conditioned from the leaks. If the ductwork is in the crawl space then the crawl space is being conditioned. It is like having a water hose that leaks really bad. The water is leaking at all the holes and not being delivered at the nozzle. It has reduced capacity at the nozzle the same as your ductwork has reduced capacity at the supply diffusers.
Another part of the AC system to look at are the coils. If the HVAC condenser coil or evaporator coil are dirty then the proper heat exchange rate is negated by a certain percentage based on how much dirt or debris is blocking the coils. If one were to get a piece of cardboard or plastic stuck on their car's radiator the car engine would surely overheat simply because the heat exchange from the radiator to the atmosphere is diminished. The same thing happens with the condenser coil or the evaporator coil. This can also cause bad problems with the compressor in your HVAC system.
The mechanical part of the AC is important but the entire system, including the insulation of the home or building itself, must work together as one machine to ensure proper capacity of cooling is achieved. We assume all these things were checked on the last HVAC maintenance check and the HVAC system is operating as designed.
If the AC system has been fully and thoroughly checked then the next step is to look at the house. There are simple and advanced HVAC solutions to this air conditioning problem.
The solutions for maintaining a cooler home even on the hottest days include but are not limited to the following:
- Sealing tiny cracks around doors and windows. To check for these tiny cracks, which cause drafts, light some incense and walk around to all the doors and windows. When you see the smoke from the incense flowing horizontally instead of vertically then you've discovered a crack that needs to be sealed. You will notice that many of the air conditioning supply vents in your office and home (assuming the system was designed correctly) are located near the doors and windows. The reason for this is because the greatest heat gain from the summer heat will be around the doors and windows. The cool air conditioned air is supplied in these locations to cancel out the heat load that is common around doors and windows. It is important to seal as many of the cracks as possible around the doors and windows because those areas have the highest heat gain. If you have single pane windows you may want to purchase heavy drapes or plan on buying newer more energy efficient windows. A combination of heavy drapes and blinds can add insulation value to the windows and reduce the heat gain which will help your air conditioner.
- While you still have the incense out check around all the wall and light sockets in your home or office that are located on outer walls. These areas, while being small, are usually less insulated because of the J-box which holds the receptacle or switch. The J-box has less insulation surrounding it and is a source of heat gain in the summer and heat loss in the winter. Foam-in-a-can can be used to seal out drafts and heat gain around and behind these J-boxes.
- When it is time to repair or replace the roof, remember the color of the shingles make a big difference in the amount of heat that is absorbed into the roof from the hot sun. Dark colors absorb the most heat while lighter colors reflect more heat. Remember, you want to absorb more heat in the winter and reflect it in the summer. Depending on your geographical location you may want to choose a color that is neutral between light and dark.
- Attics which are heavily insulated can reach temperatures exceeding 150 degrees Fahrenheit. Installing an attic fan with an automatic thermostat can reduce those high attic temperatures dramatically which reduces the amount of heat gain from the ceiling into the home.
- Avoid cooking as much as possible in the home. Using an oven or stove in the summer causes your air conditioning system to work overtime to keep up with the added heat load demand from the oven or stove. Fire up the barbeque grill anytime the mercury outdoors rises above 90 degrees. The dishwasher also produces heat inside the home so when you are finished with dinner load the dishwasher and wait until bedtime to turn it on. Do the same for the washer and dryer since both of these appliances also produce heat.
- Shade trees help keep the heat away. A home with shade trees will use less energy for air conditioning than a home without shade trees. Plant some fast growing shade trees around your home so that in the future (2 to 5 years) your home and your energy costs will benefit from the shade provided by these trees.
- When anyone in the home showers make sure they use the bathroom ventilation fan. The steam from an average shower will add humidity and heat to the home which must be removed by the air conditioning system. It may even be appropriate to crack open a window but don't forget to close it when finished with showering.
- Turn off appliances and lights when they are not being used such as computers and televisions. These things produce heat, including lights, which must ultimately be removed by your air conditioner.
- Wrap the water heater with an insulating blanket. This will serve two purposes. It will help maintain the heated water in the winter so the water heater won't cycle as often and will minimize the amount of heat that comes into the home or business from the water heater.
- If you use hot water heat from a boiler that has a domestic coil (domestic coil on a boiler produces hot water for showers, washing dishes, ect., ect., ect....) make sure you turn off the isolation valves (assuming proper installation and that isolation valves are present) for the heating system supply and return. Heat migrates through convection and the boiler runs year round to produce hot water for showers and domestic use. If you don't turn off the valves the heat will migrate through the hot water loop that supplies the radiators or baseboards. This adds unnecessary heat to the home or business. If you have a boiler with a domestic coil and it is not equipped with isolation valves call your local HVAC or Plumbing contractor to have them installed.
Some of these strategies can be applied immediately while others are long term like a new roof or planting the trees. These methods can make a big difference in keeping your home cool or suffering through the heat of summer. These methods also, once successfully employed, can save you money in power usage from the air conditioning system. Employ some of these methods and you can make a big difference in your comfort level.
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Air Conditioning 
