STAY COOL WITH THESE IDEAS DURING THE Rio Grande Valley SUMMER
IT’S ANOTHER HOT SUMMER!
Summer is in full swing here in RGV. Most of us rely on air conditioning to beat the heat and it’s important to stay comfortable indoors. Unfortunately, many cooling systems are inefficient. Find ways to stay cool with these ideas for your AC and your home in general.
STAYING COOL: HOW AIR CONDITIONERS AFFECT HOME COMFORT
TEMPERATURE AND HUMIDITY CONTROL
The purpose of an air conditioner is twofold. It should decrease air temperature while controlling humidity. Cooling was actually just a bonus to the its primary purpose: humidity control.
How we feel heat is affected by the amount of moisture in the air. As we sweat, we cool ourselves by evaporation. However, as humidity rises, sweat doesn’t evaporate as quickly, so we can’t shed unwanted body heat. An efficient cooling unit that works properly is key to keeping your home comfortable as outdoor temperatures climb.
CENTRAL AIR CONDITIONING: HOW DOES IT WORK?
• An air conditioner consists of four main components:
• An evaporator
• A compressor
• A condenser
• An expansion device
Air conditioners depend on refrigerant. As warm indoor air is blown across the evaporator coils, refrigerant flows through them absorbing heat from the air, and turns from a cold liquid to a warm gas. The refrigerant then enters the compressor, is pressurized and pushed to a higher temperature until it flows into the condenser, where heat is then radiated away.
As air moves across the evaporator coil of an air conditioner and absorbs heat, it also removes water vapor. Finally, the cooled refrigerant goes to the expansion device and the cycle begins again.
BREAKING DOWN AIR CONDITIONER EFFICIENCY
WHAT IS SEER?
Seasonal Energy Efficiency Ratio (SEER) is the efficiency rating for an air conditioner in a cooling climate. The higher the SEER rating, the more efficient the unit. The minimum federal efficiency requirement in California is 14 SEER, but even higher ratings are available.
You can maximize the performance of your air conditioner by:
• Choosing the highest SEER (minimum of 14).
• Ensuring the unit is properly sized for your home.
• Keeping refrigerant charge balanced.
• Establishing short refrigerant lines.
• Installing the outdoor unit or condenser in a shady area.
BIGGER DOESN’T MEAN BETTER: YOUR AC CAN BE TOO BIG
Contractors who don't do detailed modeling and just estimate air conditioner sizing regularly recommend systems larger than necessary, which reduces their efficacy. Central air conditioners and heat pumps have to be appropriately sized. An oversized unit uses an excessive amount of energy and short cycles, which can result in high humidity. Alternatively, undersized units won’t meet your cooling needs on extremely hot days.
In addition to being properly sized, cooling systems need to have the appropriate amount of refrigerant. Many systems are overcharged with too much refrigerant, or undercharged with too little refrigerant. Incorrect refrigerant level will cause your air conditioner to cool inefficiently.
ALTERNATIVE AC SOLUTIONS
Apart from central air conditioners, California Energy Services offers other cooling solutions including:
A heat pump moves heat instead of generating it. Throughout the cooling season, heat pumps move heat from your house to the outdoors. Then during the heating season they move heat from the outside into your home.
DUCTLESS MINI SPLITS
Ductless mini splits do not require ductwork, unlike central air conditioning units. Ductless mini splits have an outdoor condenser, in addition to one or more compact wall- or ceiling-mounted blower units (“mini-splits”). Each of these mini-splits have their own set of controls to provide cooling exactly where it is needed.
These systems work to cool in the summer and heat in the winter, both of which are important in the Sacramento area. To get the most efficient unit for your heating needs, you should consider the Coefficient of Performance (COP), which is the rated efficiency of the energy usage of the unit in heating mode, and the Heating Season Performance Factor (HSPF), or the overall heating efficiency of the unit over the course of a heating season. The most efficient heat pumps have high COP and HSPF ratings.
HOW TO MANAGE HEAT SOURCES IN YOUR HOME
Four major factors affect your home’s cooling load:
1. Solar heat gain
2. Air leakage
3. Temperature difference between your home and the outdoors
4. Internal heat gains
The majority of solar heat gain is built up through your attic and windows, both of which account for about 16% and 45%, respectively.
PREVENTATIVE IDEAS AGAINST SOLAR GAINS
Homes across the RGV, TX area heat up when the sun comes out. If your home isn’t appropriately equipped to deal with high temperatures, it won’t be effective at resisting the sun’s thermal energy and will experience “solar gains”. Fortunately, you can make changes which will prevent solar gains from having too much of an impact.
UPGRADES TO YOUR HOME’S EXTERIOR
Controlling heat buildup through attics, windows and walls with weatherization and home performance upgrades is a straightforward solution. You can protect your house against the summer heat and the winter cold by:
• Air sealing and insulating your attic, walls and ducts.
• Inspecting, repairing and replacing all window weatherstripping and caulking regularly.
• Reducing roof and attic heat buildup by using a reflective surface for the roofing material and adding a radiant barrier on the underside.
ENERGY EFFICIENT WINDOWS BY MILGARD
You can reduce your home’s solar gain by selecting energy efficient windows that have a low Solar Heat Gain Coefficient (SHGC). The SHGC is dependent upon the reflective coating that is applied to each window. In order to be useful, the type of coating must be chosen to suit the window’s general location and orientation. Milgard, a producer of elegant and energy efficient window solutions, has many options to suit your home’s needs.
Windows can also be “tuned” to optimize natural ventilation. By opening smaller windows on the lower floor, on the upwind side of the house, and larger windows, on the upper floor of the downwind side of the house, you create a pressure difference that pulls air through and effectively cools your home.
WINDOW TREATMENTS AND SHADING
Stop heat from getting into your home by shading the outside. It’s most effective to use plantings, permanent shade structures or removable devices such as awnings, louvers and shutters, on the south and west sides. However, if outside shading is not an option, you may use indoor shading treatments like shades, blinds, curtains and solar screens indoors. Exterior finishes in light colors also reduce solar heat gain throughout the year.
INTERIOR HOME UPGRADES
Anything inside your home that produces heat increases the burden on your cooling system. These internal heat gains can come from people, lighting, appliances, and electronics, in addition to mechanical ventilation and hot water tanks.
Some basic practices can reduce internal gains, including:
• Switching lights off and using daylighting to its full potential
• Removing incandescent light bulbs and switching to LEDs or CFLs
• Turning electronic appliances off
• Using heat-generating appliances early in the morning or late in the evening
• Cooking outdoors whenever possible
• Replacing aging appliances with energy efficient options
• Insulating your hot water tank and pipes
WHY IS DUCTWORK IMPORTANT?
Duct leaks increase the burden on your AC unit. The EPA (Environmental Protection Agency) estimates that 25% to 40% of the energy produced by heating and cooling systems in the typical home is lost through duct leakage.
If you have leaky ducts, they are probably also contributing to the overall air leakage of your home. This can have a negative impact on your indoor air quality (IAQ) and decrease your comfort by producing unpleasant drafts. To ensure well-being during any season, your ducts must be properly tested, sealed and then insulated to help guarantee you’re breathing quality air and staying comfortable.
YOUR HOME IS A SYSTEM
Your home consists of various components -- including the building, mechanicals, environment and occupants -- all of which influence each other. When attempting to find an efficiency or comfort solution for your home, you shouldn’t isolate any aspect. The home must be treated as a whole system.
Think about just how many factors go into keeping your home cool. Your insulation has an impact on the efficiency of your HVAC system, but it’s also dependent on air sealing and ductwork. And don’t forget about having to properly size your air conditioner and monitor refrigerant levels! It would be misguided to simply focus on one of these aspects. Begin thinking of your house as a system by taking everything into consideration.
MYTH BUSTERS: HOME COOLING MISCONCEPTIONSMYTH: A CEILING FAN COOLS THE ROOM.
Fact: Ceiling fans don’t cool rooms, they only cool you through the wind chill effect. They can help you save energy by allowing you to raise the thermostat by approximately 4 degrees with no change in comfort. Make sure that when you’re in the room, your fan runs counterclockwise so it directs air downward. But be sure to turn it off when you’re not in the room!
MYTH: ATTIC VENTILATORS DON’T WORK.
Fact: Just like properly-sized heating and cooling equipment is essential, the right amount of attic ventilation is key for home comfort and lower energy usage. Insufficient ventilation decreases energy efficiency in the summer and leads to moisture problems during the winter. However, too much ventilation can be just as bad, if not worse.
MYTH: WHOLE HOUSE FANS CAN REPLACE AIR CONDITIONERS.
Fact: A whole house fan is useful in low-humidity areas that have hot summer days and cool nights. By using the fan during the morning, late evening and night to draw cool outside air in through open windows, you can exhaust hot indoor air through the attic to the outdoors. Having a whole house fan run during the day’s cooler hours, and using a central air conditioner through the hottest parts of the day is effective for reducing electricity use.
MYTH: INSULATION DOESN’T MATTER IN THE SUMMER.
Fact: Many people believe that insulation is only important in the winter. However, it doesn’t care where the heat is. Insulation works to slow heat transfer from inside to outside, or from outside to inside.