One way consumers can protect themselves is to have the house designer include in the services contracted for a complete set of A/C and heating specifications including detailed duct design. These are included on all commercial designs. These specifications include a heat loss/heat gain calculation (the preferred method is to use J-1 form) and detailed duct designs and specifications.

Another way consumers can protect themselves is to get an economic analysis of the options that are available in the types and various Seasonal Energy Efficiency Ratio (SEER) -rated air conditioning and efficiency heating equipment systems on the market.

Too often, many steps in the building and rebuilding process are overlooked because of cost, lack of knowledge, the presumed need for short cuts, taking what’s available and/or an over-burdened city inspection group.

The following are questions you should ask to ensure you have a quality A/C and heating system installed in your home:

• What is the exact of the square footage of the house?
• Is there going to be one system or multiple systems?
• What is the insulation R-Value that you are going install in the attic, walls and/or floors? Remember an R-Value is R-Value, no matter what type of insulation it is.
• Are you going to energy-seal the house (caulking the openings and bottom plates)?
• What is the orientation of the house on the property?
• What are the types and number of windows and exterior doors?
• What is the maximum number of people who normally occupy the house?
• At what temperature do you normally feel comfortable?
• What is the type and amount of attic ventilation?
• Is there any exterior shading, such as trees, buildings or porches?

With answers to the above questions, a heat loss/heat gain calculation can be made. This calculation should be done by each A/C dealer who is bidding on the work. A copy should be presented to you with the bid (a J-1 Form is preferred). The dealer will use this information to determine the size of the unit(s) needed for your house.

Now that the unit size has been calculated, the next step is to determine the ductwork layout and specifications. This is the responsibility of the dealer. The ductwork of an A/C and heating system is important. Proper ductwork can make a system efficient, long-lasting and highly operating. Poor ductwork can make a system inefficient, short-lived and poorly operating. To ensure the proper ductwork has been installed, demand the dealer give detail specifications and a ductwork layout with the bid. It would be best to have all bids put on a similar layout and specifications. This is the only way to get comparable bids.

The following are minimum requirements for a quality A/C ductwork system bid:

• All ductwork joints should be sealed with mastic taping. This includes round sheet metal duct joints, duct board joints, sheet metal plenum discharge and return air joints and flex duct connections.
• Do not use flex duct for more than 10-foot runs.
• Avoid flex duct if possible.
• If flex duct is used, insist the contractors follow manufacturer's installation instructions.
• Install a minimum of R-6 (2-inch) duct wrap on round pipe and require R-6 (2-inch) insulation on flex ducts.
• Ceiling registers and return grills should be similar in quality. High-quality registers can vary the bids by hundreds of dollars.
• If duct board is used, 1 ½-inch high density is suggested, 1 ½-inch duct liner on sheet metal ducts also an option.
• Attic system units should have a coated safety pan under the coil or blower unit extending a minimum two inches all around. These units also should have a primary drain to the sewage system and safety drain to the box inside or outside a house that is visible. A float switch should be installed in the pan to prevent overflow. A float switch is a safety switch that turns the unit off if the condensate water builds up in the bottom pan. This avoids overflow onto the ceiling, causing costly damage.
• The unit should be raised in the pan at least three inches and mounted on sound-absorbing pads. A unit should never be mounted on wooden blocks or bricks. It also should be leveled.
• A sound-absorbing sleeve should be installed if the unit is installed with a ceiling-return air grill.
• Ceiling-return air grills normally are noisy. Over sizing helps, and a return-air chase works best. Rule of thumb -- to reduce noise on ceiling grills, use 1 square foot per ton plus 15 percent oversizing .
• If an indoor unit is installed in an indoor closet, the return air must be sealed from the attic. A major source of air leakage problems increases operating costs.
• Ductwork located in the conditioned space is the best choice. Doing this takes careful design but can be done if planned in most houses. Data show that 20% of the energy is lost from ducts located in an attic.

When selecting the type of system for your house, it is important to consider the tightness of the structure.

In the New Orleans and South Louisiana areas, the summers are long, with temperatures in the high 90s, and the winters usually are mild.

If a house is insulated to energy-efficient standards – meaning at least R-30 ceiling, R-19 walls and R-19 floor if raised -- basic insulated windows, insulated doors, weather-sealed openings and base plates and a properly ventilated attic are sufficient.

Owners of new houses have various choices, which include:

• A standard natural gas furnace and a high-efficiency A/C unit
• Electric-resistance heating and a high-efficiency A/C unit
• A ground source heat pump
• An air source heat pump

Any of these would be a good choice because heating is not a major factor in South Louisiana. But what if we were to rate the systems on efficiency and initial cost?

The ground source heat pump would be highest in efficiency and highest in initial cost

The second would be the air source heat pump -- high efficiency and high cost

The third would be a natural gas furnace and high-efficiency A/C. this is reasonable on heating efficiency and low in cost to install and high on A/C efficiency.

The fourth would be the resistance heating and high-efficiency A/C. This is lowest in cost to install and high on A/C efficiency and highest on cost to operate for heating.

The factor that all must understand is that in a well-insulated house in South Louisiana, the need for heating is small. Therefore, the efficiency of the heating system is not as important as the efficiency of the cooling system. Other factors and features also may come in to play in our selection process. These include:

• A Ground Source Heat Pump
• Can also heat your water cheap.
• Has the highest SEER and EER (Energy Efficient Ratio) rating. These units are rated only by EER because they are not effected by the seasonal conditions, so take out SEER.
• Requires an A/C dealer with special training, duct design training and special equipment.
• Milder and more comfortable heating.
• Air Source Heat Pump
• Requires an A/C dealer with heat pump training and ductwork design skills.
• Milder and more comfortable heating.
• Standard Natural Gas Furnace and A/C
• No special skills required; just current training for highly efficient A/C unit.
• Usually heating unit is grossly oversized and causes air dryness.
• Resistance Heating and A/C
• No special skills required; just current training for highly efficient A/C units.
• Heating can be better matched to heat loss than a natural gas furnace; therefore providing more comfortable heating than the gas units.

All four choices provide high energy efficiency. The minimum efficiency SEER for ducted A/C units is SEER 13.

The range runs from 13 to above 19 SEER. Most higher-efficiency air source air conditioners and heat pump units require two speeds or a variable-speed compressor. The higher-efficiency ground source heat pump units also have special compressors.

Deciding on the right energy efficiency level takes some thought and economic analysis.

The first factor you must take in to consideration is how long do you plan to stay in your house? High-efficiency A/C units over SEER 16 units usually carry a 10-year warranty on the compressor and all parts.

The second factor you must consider is, can the saving you achieve in operating costs justify the increased cost of the unit in reasonable time?

Existing houses are much more difficult to make as tight as you might make a new house. The main point to consider is that the type equipment used is different. Often the more inefficient the house, the more you can justify a high-efficiency HVAC system.

Existing house owners have numerous new points to consider in equipment selection. These are:

• Will I need to increase my electric service for this new equipment?
• Will I have to change out my ductwork?
• Will I have space for this new equipment?
• Is a central air conditioning and heating unit the best choice?

The best choice in most existing house applications is a high-efficiency (90 plus) natural gas furnace with a high-efficiency air conditioning unit of 14 SEER or greater. The reason a 90-plus-efficiency natural gas furnace is preferred over a standard-efficiency furnace is that heating loss will be greater, thus justifying the more efficient models. These models are more expensive but should be cost-effective with rising natural gas rates.

Everything discussed above for new houses also can apply to existing houses in ensuring a quality system is installed. Consumers who do some planning will be able to protect themselves from fraud and give their A/C dealer guidelines that are iron-clad. This should get them an A/C and heating system that gives many, many years of service and efficiency.

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