An over-sized HVAC system could cost you...

In air conditioning, bigger is not better.  It’s just the most common mistake we see in air conditioning design.  Compared to a correctly sized air conditioner, an oversized air conditioner cools poorly, costs more to operate, is noisy, and has a shorter lifespan.

Design Occurs In The Field

Air conditioning systems are not designed in the factory.  They are designed by us and other contractors like us.  Each system we design is unique.  We account for your home’s design and layout, the type of construction, it’s orientation to the sun, shade, our local weather, and most important, your lifestyle.  How you plan on using your air conditioner has a big impact on the design. 

  

After we collect the necessary information, we crunch through a series 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’s not unusual for us to double check them in the office.

We use many factory designed and built components in the systems we design.  We also fabricate parts of your system in the shop or on-site.

You will be unhappy with an air conditioning system, no matter how reliable and well made you consider the air conditioner and other components if the design is wrong, the field fabrication is poor, and the installation is sloppy.

The Impact on Comfort

When an air conditioner is oversized, 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 it powers back on.  To you, it feels like the air conditioner is intermittently blasting frigid air.  This is likely an air conditioner that is short cycling. 

               

An important role of air conditioning is dehumidification.  When an air conditioner short cycles, it pulls moisture from the air stream and leaves it on the indoor coil, where it evaporates back into the air stream.  An air conditioner’s ability to remove moisture from the air stream is lowest at the start of the cycle.  Inadequate moisture removal results in a cold, clammy feeling.

               

When the air conditioner runs for longer cycles, it does a better job pulling moisture from the air stream and disposing it down the condensate line.  Cold, clammy air indicates oversizing.

The Impact on Acoustics

The air conditioner 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 a windstorm.  Noisy grilles, registers, and diffusers indicate oversizing or too small ducts.

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 outside fan motor, and the indoor fan motor.   In addition, you are operating larger, more expensive motors than you need. 

               

Think of a properly sized air conditioner as a fuel efficient car rolling down the highway.  The oversized air conditioner, by contrast, is like a 1960’s muscle car in stop-and-go traffic.  The miles per gallon is pathetic.  Oversizing costs money.

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 more life left than one used for city driving, a correctly sized air conditioner will out last an oversized one.

Identifying Oversized Systems

If your air conditioner starts and stops (i.e., cycles) regularly on very hot days, it’s probably oversized.  Have us perform a set of engineering calculations if you’re unsure. 

               

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

               

If you think your system is oversized, don’t make guesses.  Call us at Elite to run the engineering calculations on your home.  918.610.7300.

What will energy prices do?

After 2008’s run up in energy prices, oil and gas crashed along with Wall Street’s financial collapse.  Economists will debate the cause for years.  Was it the market, or manipulation?  More significantly, what will energy prices do next?

Robert Bryce, Managing Editor of the Energy Tribune, believed that the oil price run up reflected supply and demand.  He’s now changed, writing:

Today, with prices plunging to near $40 instead of the $145 level seen in mid-July, it’s abundantly obvious that speculators were a key driver, probably the main driver, of the surge in oil prices.

Could it have been as simple as speculation?  According to the US Senate Permanent Subcommittee on Investigations’ 2006 report, “The Role of Market Speculation in Rising Oil and Gas Prices,” oil prices above $40 to $50 per barrel were caused by speculation and hedge funds, not supply and demand.  This report was issued before the 2008 price run up.

A growing body of evidence suggests that speculation played a significant role in the skyrocketing price of energy during 2008.  When the speculative bubble burst, energy prices crashed.

Could energy be subject to another speculative price run up?  Much of the speculation is suspected to have occurred in “dark markets,” not overseen by the Commodity Futures Trading Commission.  With the opening of commodities exchanges in India and Dubai, it will be harder than ever to stop worldwide speculation and market manipulation. 

A speculative frenzy could reoccur, but will it?  The answer, unfortunately, is, who knows?

For now, energy prices are likely to stay low until the global economy recovers when they begin rising.  Higher prices do not mean we are running out of oil, but that we’re running out of cheap oil, that’s easy to extract.   

The Green River Formation in parts of Colorado, Wyoming, and Utah, holds 800 billion barrels of recoverable oil by itself.  That’s triple the proven reserves of Saudi Arabia.  Additional oil is available off shore, in the Bakken Formation spanning parts of Montana, North Dakota, and Saskatchewan, in Alberta’s Athabasca Oil Sands, in ANWR, in the Arctic, and on unexplored federal lands in the U.S.

In short, North America has abundant oil, though much of it is unconventional and expensive to extract in an environmentally responsible manner.  So while we will not run out of energy for a long time, we will pay more.

Electricity differs from oil and natural gas.  In the U.S., coal generates 49% of electrical power, followed by natural gas (20%) and nuclear power (19%).  Excluding hydroelectricity, renewable energy accounts for just 2% of electrical power generation, and most of the 2% is biomass.

Coal is abundant and cheap.  Yet, environmental concerns impede the use of coal in favor of renewable energy for the future .  While no one opposes renewable energy, it’s simply not economically competitive with fossil fuel generation or nuclear power.  Reliability issues with solar and wind, for example, necessitate expensive standby capacity.  Utilities will simply pass the increased costs along in the form of higher prices. 

Heating and air conditioning accounts for the majority of home energy use.  Yet, dramatic improvements in heating and cooling technology, as well as improved installation practices can result in dramatic reductions in home utility bills through upgrades of older heating and air conditioning systems.  Since the financial return is based on physics, not the financial markets, it’s the safest investment you can make today.  It can generate an attractive return today and a hedge against higher prices in the future.  Plus, it’s a guaranteed investment.

Call us Elite for a free estimate today!  918.610.7300

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