Heating, ventilation and air conditioning (HVAC) are used to heat or cool the air in the home, while replacing the stale air with new supplies from the outside. One of the main factors to consider when choosing an HVAC system is the size of the system. HVAC size refers to the performance capability of the system, rather than the size of the equipment or air handling units. The size of an air conditioning system is valued in British thermal units (BTU), which measure the volume of air the system can produce.

Most residential HVAC systems are sized incorrectly, which can cause a number of inconveniences for owners. A smaller system size will not heat or cool a sufficient amount of air to keep the home comfortable, while an oversized system often causes the house to be too hot or too cold. Systems that are too small and will not be able to control humidity and humidity inside a house, and will not be able to provide effective ventilation. More than size systems are often noisy and expensive to operate. They also cost more to the front, because of the large heating and cooling units, which must be purchased. If you need HVAC repair or installation service, M.B. Kiser will be the best option.

Traditional HVAC size calls for 12. 000 BTU per 500 square feet (46 square meters) of living space. Some contractors use tons of air per hour instead of BTU, with a ton equivalent to 12. 000 BTU. This rule of thumb is widely used by HVAC contractors, however, it often results in homeowners receiving a system that does not have the right size. More and more contractors are turning to more efficient methods of calculating loads for more efficient HVAC systems.

The Air Conditioning Contractors of America (ACCA) produces a publication known as Manual J, which is aimed at helping contractors with the size of HVAC. J Manual provides the most commonly used set of standards for HVAC pattern-making based on the specific needs of a homeowner, rather than simple square footage calculations. This manual takes into account all the factors that can affect the size of HVAC, ranging from sun exposure to the average temperature range in an area.

HVAC size in ACCA Manual J starts with the determination of needs based on the volume of air in square feet. Volume is added or subtracted from the original calculation based on insulation, air leak, and weather. Houses located in very hot areas naturally require a higher cooling load than those in more moderate regions. Structures that are perfectly insulated and have few air leaks require smaller systems than buildings that are poorly insulated. Contractors also consider the construction of orientation, shading, loads of appliances, and many other individual factors when determining the size of HVAC.

Author's Bio: 

Hasan Root, a dream lover.