Oversizing: The #1 Mistake in Air Conditioning Design

In HVAC, bigger is not necessarily better.  It is the most common mistake we see in air conditioning design.  Compared to a correctly sized system, an over-sized system cools poorly, costs more to operate, is noisy, and has a shorter lifespan.

Design occurs in the field

HVAC systems are not designed in the factory.  They are designed by HVAC contractors.  Each system is unique to the home it will be servicing.  We account for your home's design, layout, the type of construction, its orientation tot he sun, shade, our local weather, and (most importantly) your lifestyle.  How you plan on using your air conditioner has a big impact on the design.

After we collect the necessary information, we will perform a load calculation (a highly specialized set of engineering calculations).  Sometimes, we make the calculations on the spot.  Other times, we return to the office to use special design software.  When we perform the calculations in the field, it is not unusual for us to double check them in the office.

You will be unhappy with a HVAC system, no matter how reliable and well-made, if other components of the design are wrong (i.e. poor field fabrications, sloppy installation, etc).

The impact on comfort

When an air conditioner is over-sized, it powers on, runs for a few minutes, lowers the air temperature at the thermostat to the setting, and stops.  A few minutes later, the air temperature rises, and the system powers back on.  This is called short-cycling and is indicative of an over-sized system.

The impact on accoustics

The HVAC system and duct system should be designed together.  If the system is sized larger than the duct system, the volume of air pushed through the ducts raises air velocity, creating what feels like a windstorm in your home.  Noisy grilles, registers, and diffusers indicate over-sized equipment or under-sized ducting.

The impact on efficiency

Short-cycling is not efficient.  It takes a lot more energy to start a motor than to keep one operating.  With your air conditioner, you start three motors: the compressor, the condenser fan motor, and the indoor fan motor.  In addition, you are operating larger, more expensive motors than you need.

Think of a properly sized HVAC system as a fuel-efficient car rolling down the highway.  The over-sized system, by contract, is like a 1960's muscle car in stop-and-go traffic.

The impact on equipment longevity

Short-cycling causes your equipment to wear out sooner.  Just like an old car with lots of highway miles has a longer life than one used for city driving, a correctly sizes air conditioning unit will outlast an over-sized unit.

A continually running air conditioner does not guarantee that it is sized correctly.  Over-sizing covers up other problems.  For example, if your system is over-sized and has a refrigerant leak, it may not be readily apparent until the compressor fails.

If your air conditioner starts and stops regularly on very hot days, it's probably over-sized.  Call Elite and have us perform a load calculation for your home.  Call us today!  918.610.7300

Green Building in Oklahoma

Elite Service Co. is the Tulsa area leading expert on Green Building and energy efficient home construction.

We are an Energy Star Home Building rater, LEED for homes verifier, and a NAHB Green Building verifier.

Elite can perform Load Calculations & duct designs, duct leakage testing, blower door testing, Thermal Imaging, and Air Balancing on your home. We have the tools and instruments to be able to design the entire enviromental comfort system for your home to insure the highest quiality of living

We will work with your builder to insure your home meets all regulations.

NAHB™ Green Building Verifier

The National Home Builders Association certification provides independent, third-party verification that your home meets the highest green building and performance standards.  The NHBA Green Building Standards have been approved by ANSI (American National Standards Institute). All certified projects receive a NAHB GREEN certificate. This certificate  is the nationally recognized symbol demonstrating that your home is environmentally responsible, energy efficient and a healthier place to live.

There are both environmental and financial benefits to earning NAHB Green certification.

GREEN-certified Homes:

· Provides lower operating costs & increase value.

· Help reduce waste sent to landfills.

· Conserve energy and water.

· Healthier, safer living environment for occupants.

· Reduce harmful greenhouse gas emissions.

· Qualify for tax rebates, zoning allowances and other incentives across the State.

Demonstrates an owner’s commitment to environmental stewardship and social responsibility

ENERGY STAR™ Home Rater

Home energy raters provide energy-efficiency strategies and tests for existing and new residential and commercial construction.  As a home energy rater we play an integral part in the ENERGY STAR process.  We offer two major types of services:

1. Assistance in reviewing current construction practices and recommended improvements that will result in ENERGY STAR compliance.

2. Conducting Home Energy Rating System (HERS) ratings.

LEED™ for Homes Verifier

LEED (Leadership in Energy and Environmental Design) certification provides independent, third-party verification that a building project meets the highest green building and performance measures develop by the USGBC (United States Green Building Council).  All certified projects receive a LEED certificate, which is a nationally recognized symbol demonstrating that a building is environmentally responsible energy-wise and a healthy place to live and work.

There are both environmental and financial benefits to earning LEED certification.

LEED-certified buildings:

· Creates less waste.

· Uses less energy, water, and natural resources.

· Safer, healthier, more comfortable, and more durable

· Reduces exposure to mold, mildew, and other indoor toxins.

· Reduces harmful greenhouse gas emissions.

· Lowers operating costs and increases asset value.

· Qualify for tax rebates, zoning allowances and other incentives in hundreds of cities.

Demonstrates an owner’s commitment to environmental stewardship and social responsibility

Call Elite today for more information on Green Building in Oklahoma!  918.610.7300

Beat The Heat

Beat the heat by preparing your air conditioner for warm weather.

            Warm temperatures are around the corner – and it’s important to make sure your home is ready.  Being prepared can save you money.

            “Proper care of cooling equipment can keep your unit running efficiently, which saves money and helps avoid costly repairs,” said Joel Kinsch, President of Elite Service Company Heating and Air Conditioning.  “Cooling and heating equipment use more energy than any other appliance.  This inevitable shows up every month on the energy bill, but it’s important to remember that energy costs can be controlled.”

            Consumers’ play a vital role in making sure their cooling equipment for warm weather is to schedule an annual maintenance check up to make sure your unit is running efficiently.  “One of the most effective steps consumers can take to help ensure they’ll get the efficiency they paid for is to contact an experienced, reputable air-conditioning contractor to check their system’s refrigerant charge and operating safety controls,” said Kinsch.

            Although a qualified service technician should handle major maintenance, owners can also help keep the equipment running smoothly.  Operating a dirty unit can cause unnecessary loss of efficiency and can damage the unit.  You can take the following simple steps to ensure your system is running properly:

• Trim brush and shrubbery near outdoor units to prevent airflow obstruction

• Remove grass clippings, leaves, and other debris from the outdoor coil

• Replace indoor unit’s filter monthly

• Reduce clutter in your attic to maintain proper ventilation and reduce the system’s cooling load

“A few minor steps are a small price to pay for high efficiency, which means lower energy bills and improved total comfort,” Kinsch said.

            If you’re in the market for a new cooling unit, consider purchasing a high efficiency model.  They can help reduce your energy costs as well as conserve our natural resources.

            When selecting an air conditioner or heat pump, pay close attention to the SEER (Seasonal Energy Efficiency Ratio).  This is a system for rating the efficiency of cooling equipment.  The high the SEER, the less your unit will cost to operate.  The minimum SEER rating is 10.  Some units can have a SEER rating higher than 19.

            Zoning can drastically lower your heating costs.  With zoning, you no longer have to pay to heat or cool areas of your home that are rarely used.  You won’t have to heat or cool the whole house just to make one room comfortable.  Zoning divides your home into separate comfort areas, which are heated or cooled based on your needs.  Zoning is efficient, easy to install, and flexible enough for any home.

            Programmable or setback thermostats can make a big difference in energy consumption.  These thermostats deliver maximum comfort, efficiency, and energy savings.  Setback thermostats are used to achieve the temperatures you want throughout your home.  For example, if you’re going to be away, you can set the whole house at an energy-saving temperature to avoid heating an empty house.  If you have setback thermostats, you can program them to have your living areas comfortable when you arrive home.