Sunny Windows, Shady Trees and Other Non-Electrical Supports to HVAC

The various factors that influence the heating and cooling cost of a home can be difficult to understand--especially when the same term gets used in a number of different ways. Heating and cooling loads fall into this confusing category. If you would like to learn more about the different ways the word "load" gets used in the HVAC world, read on. This article will discuss two different types of HVAC load.

A Basic Explanation Of Load

At its most simple, load is a term used to designate the amount of heating and/or cooling required by a particular building under particular circumstances. Load is often confused with another HVAC term: capacity. Capacity refers to the maximum amount of heating or cooling provided by a particular piece of HVAC equipment. In other words, whereas load indicates a building's HVAC needs, capacity indicates the capabilities of a given HVAC system.

Design Load

Design load is the most general way to specify the cooling load of a home. It consists of numerous fixed variables, such as the size of the house, the R-value of the insulation used, and the home's orientation. These factors are then combined with so-called design conditions to determine the home's design load--in other words, the necessary HVAC capacity, as measured in tons.

Design conditions are fixed specifications for the heating and cooling needs in a particular area of the country at a particular time of year. They can be found compiled in such protocols as the Air Conditioning Contractors Of America's Manual J. The design conditions specify both an average outdoor design temperature, as well as a recommended indoor design temperature.

Extreme Load

While design load can be helpful in giving an overall picture of the HVAC needs of a particular home, it doesn't offer a completely realistic picture. That's because a home is rarely subject to conditions that conform precisely to those used to calculate design load. In particular, design load fails to account for the occurrence of extreme weather patterns.

Extreme load is a calculation that helps to make up for this glaring blind spot in design load. The idea here is that the historical temperature conditions are used to generate a picture of the sort of HVAC load that might be required during periods of extreme weather. This calculation of load should then be consulted in conjunction with the design load, in order to determine the ideal system for a particular home.

These are important ideas to keep in mind as you reach out to a company like Triad Heating & Cooling Inc for a new system.