HVAC Testing and Installation

At AppleBlossom, we have partners who are specially trained in fine-tuning furnaces and balancing airflow.

HVAC Testing is part of our commitment to energy conservation and increasing the comfort of our clients while minimizing home and business climate-control costs.

Procedures for HVAC System Design, Proper Duct Design, and HVAC Installation

The goal for a Heating, Ventilation and Air Conditioning (HVAC) system is to provide proper air flow, heating, and cooling to each room. This page sets out key criteria that describe a quality system, and key design and installation considerations that should be met to achieve this goal. The pages following contain more detailed information on design, fabrication, installation, and performance testing.

Importance of Correct Sizing

Can save up to 1 1/2 times in equipment sizing.  This equals a significant reduction in energy usage.

Sizing Heating and Cooling Systems

Older space conditioning systems (more than 10 years old) are often unreliable and much less efficient that a modern system.  When it's time for a new replacement, choosing one of the correct size (heating and/or cooling output) is critical to getting the best efficiency, comfort, and lowest maintenance and operating costs over the life of the new system.  Some national surveys have determined that well over half of all HVAC contractors do not size heating and cooling systems correctly.

The most common sizing mistake is in over-sizing.  This not only makes the new system more expensive to install, but also forces it to operate inefficiently, break down more often, and cost more to operate.  Oversized heating equipment also often creates uncomfortable and large temperature swings in the house.  Over-sized air conditioners (and heat pumps) do not run long enough to dehumidify the air, which results in the "clammy" feeling and unhealthy mold growth in many air-conditioned houses.

Incorrect Sizing Methods

It is the installer/contractor's job to perform the correct sizing calculation for the building.  However, many installers only check the "nameplate" (the label on the unit that has the Btu per hour output among other things) of the existing system and sell you one just like it, or even worse, on that's larger.  This is not a correct sizing method and not in your best interests!  Other methods include simple "rules of thumb" based on the size of your home or using a chart that accounts for a variety of factors.  While these methods might provide a first estimate, they should not be used to size your system.

Manual J and Manual D: The Correct Way to Size an HVAC System

Correct system sizing requires considering many factors other than simply reading the nameplate of the existing unit.  Key factors for correctly sizing a heating and cooling system include the following:

• The local climate
• Size, shape, and orientation of the house
• Insulation levels
• Window area, location, and type
• Air infiltration rates
• The number and ages of occupants
• Occupant comfort preferences
• The types and efficiencies of lights and major home appliances (which give off heat).

Homeowners should insist that contractors use a correct sizing calculation before signing a contract.  This service is often offered at little or no cost to homeowners by gas and electric utilities, major heating equipment manufacturers, and conscientious heating and air conditioning contractors.  Manual J, "Residential Load Calculation," published by the Air Conditioning Contractors of America (ACCA), is the recommended method for use in the United States.  There are also many user-friendly computer software packages or worksheets that can simplify the calculation procedure.  You should make sure that the procedure used by the contractor follows Manual J.

If ducts are part of the installation, they should be sized using the ACCA's Manual D, "Residential Duct Design."  The ACCA also offers a comprehensive guide for choosing home heating and cooling systems, called Manual S, "Residential Equipment Selection."

At AppleBlossom we have over thirty years experience in the design and installation of heating, air conditioning, ventilation and filtration systems. If you are considering a new home or remodeling your existing home, let our Building Scientist give you the advice that you need to insure your health, comfort and energy efficiency in your new product.


Criteria for a Quality HVAC System

An HVAC system should:
1. Be properly sized to provide correct air flow, and meet room-by-room calculated heating and cooling loads.
2. Be installed so that the static air pressure drop across the handler is within manufacturer and design specifications to have the capacity to meet the calculated loads.
3. Have sealed supply ductwork that will provide proper air flow.
4. Be installed with a return system sized to provide correct return air flow.
5. Have sealed return ductwork that will provide proper air flow to the fan, and avoid air entering the HVAC system from polluted zones (e.g., fumes from autos and stored chemicals, and attic particulates).
6. Have balanced air flows between supply and return systems to maintain neutral pressure in the home.
7. Minimize duct air temperature gain or loss between the air handler and room registers, and between return registers and the air handler.
8. Be properly charged with refrigerant.
9. Have proper burner operation and proper draft.

Procedures to Design and Install an Air Distribution System

The following steps should be followed in the design and installation of the HVAC system to ensure efficiency and comfort:

1. Determine room-by-room loads and air-flows using ACCA Manual J calculation procedures (or substantially equivalent).
2. Layout duct system on floor plan, accounting for the direction of joists, roof hips, fire-walls, and other potential obstructions. Determine register locations and types, duct lengths, and connections required to produce layout given construction constraints.
3. Size duct system according to ACCA Manual D calculation procedures (or substantially equivalent).
4. Size HVAC equipment to sensible load using ACCA Manual S procedures (or substantially equivalent).
5. Install equipment and ducts according to design specifications, using installation requirements and procedures from the Uniform Mechanical Code, the Air Diffusion Council, SMACNA, California Residential Energy Efficiency Standards, and manufacturers' specifications (Title 24); Using these procedures and those in Appendix A, the duct system should be substantially air tight.
6. Charge the system appropriately, and verify charge with the evaporator superheat method or sub-cooling method (or substantially equivalent).
7. Check for proper furnace burner operation and fire-box drafting.
8. Test the system to ensure that it performs properly by determining (1) that the system is properly sized, (2) it does not leak substantially, and has either (3a) proper air handler fan flow, and proper plenum static pressures, or (3b) proper room and return air flows, and proper plenum static pressures.

I would highly rate John and AppleBlossom Insulators. John is the owner and the person that I dealt with from the first call to the completed project. Our job and attic was a very difficult job due to the tight quarters and age of the house, the heat, and the animal droppings. John was great. He returned my calls very promptly, and he was timely with meeting for a quote. Our job had some minor setbacks and complications; however, John was very timely in correcting those and was genuine in his concern for our satisfaction. He is a great example to the commitment to excellence of a small business owner. I am delighted with the finished product and the man that stands for the company.

~ Donna B., Charlotte, NCC