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Serving The Greater Fresno Area Since 1970

Serving The Greater Fresno Area Since 1970


Donald P. Dick Air Conditioning Blog

Load Calculations: The First Step in an HVAC Upgrade for Area Homes

If your Fresno area home is ready for an HVAC upgrade, hire a contractor who uses proper, industry-standard load calculations. An improperly sized furnace will cost you thousands more over the course of its lifetime in terms of elevated utility and repair bills. The wrong furnace can also cost you in terms of whole-home comfort and compromised indoor air quality.

Before energy efficiency was a major concern, many contractors used “rule of thumb” estimations to select HVAC equipment for their clients, or else they just repaced your A/C or furnace with another model of the same capacity. They considered things like the square footage and the number of rooms in a home but not much else. This ad hoc approach has led to oversized and undersized equipment, which is an energy and maintenance drain.

Here are some of the things your contractor should be doing to get accurate load calculations for your HVAC upgrade:

Manuals J and D. These manuals are published by the Air Conditioning Contractors of America (ACCA) and are available in software form, which makes the calculations easier than ever. Ask your contractor if he uses these manuals when assessing your needs. If the contractor isn’t familiar with them, or doesn’t use them, find one who does.

A thorough inspection. Your contractor will want to inspect your existing system, your ductwork, and the rest of your home to get the information he needs for the Manual J and D calculations. Manual D is used for ductwork planning and design. If yours is older and inefficient, a new design that’s compatible with your upgraded HVAC equipment will be a worthwhile investment to maximize energy efficiency. With Manual J, the contractor will conduct a heating or cooling load calculation on your home, the results of which allow him to determine the right sized equipment. Factors he will take into account include:

  • Size and layout of the home
  • The orientation of your lot and home
  • Window and door specifications
  • Air leakage
  • The type and quality of your insulation
  • Number and type of heat-generating appliances
  • Lighting fixtures
  • Occupancy

Manual S. Once the other calculations are complete, your contractor can use Manual S, which will make specific make and model recommendations based on the results.

Contact Donald P. Dick Air Conditioning to hire an HVAC contractor who uses accurate load calculations to replace HVAC equipment in your Fresno area home.

Our goal is to help educate our customers in the greater Fresno, California area about energy and home comfort issues (specific to HVAC systems).

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