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Heating, ventilation and air conditioning is a component of the home that can be overlooked as many homebuyers assume that the system being installed will meet their needs. There are many choices to be made. It is important to have some basic knowledge of how HVAC systems and their ductwork come together to provide efficient heating and cooling so that you can make informed decisions in the building of your home.
Most homes today use forced air systems for heating and cooling. Depending on the temperature required, the fans in either the furnace or the air conditioner blow air through the ducts. Ducts are metal chases that are placed in a network to cover the entire house. Because of the duct layout, the more centrally located the HVAC system is the more efficient it will be. Long stretches of ductwork have a more difficult time sustaining desired air temperatures and are more susceptible to leaks. In addition, longer and/or larger ductwork networks are going to be more costly because of the added time and materials needed for installation. Grills or registers, which are typically located on the floor, are connected to the ductwork and allow the forced air into the various areas of the house. Registers can be opened or closed to monitor airflow. The thermostat controls the temperature of the air being sent through the system. Larger or centrally located rooms will have a register return. This allows the release of stale air so that it can be replaced with new fresh air coming from the HVAC system.
Ventilation is becoming a more important component in the overall heating and cooling of new homes. The register return has historically been the primary exhaust to rid the house of stale air. Older homes were not built to be as energy efficient, so a majority of stale and moist air would pass outdoors along window and door seals or up through attics. With today's energy efficient construction techniques air does not transfer to the outdoors as easily, which can lead to a build up in stale or moist air. With this problem becoming more evident, most builders try to provide a balanced ventilation system, meaning an equal amount of air will be exhausted to match the new air coming in from the furnace or air conditioner. Proper ventilation has led to many newer options for HVAC systems. Products such as humidifiers, dehumidifiers, heat exchangers, air cleaners, and other types of filters can be installed within your system to give the home better air quality.
HVAC systems are most commonly gas or electric. This can depend on what utilities are readily available and what local building codes allow. The gas or electric is used to power heating coils, blowers and filters.
The selection process for the HVAC system is determined by factors ranging from the size of the home to seasonal weather and climate conditions. A larger HVAC system and ductwork network is required in larger homes. Homes over 3,000 square feet will often have a second HVAC system installed. This second system will be set up to handle specific areas of the house and has its own duct system, return air registers, thermostat and controls.
The design of your new house, the type of wall framing, insulation, windows, and your homes orientation to the sun can all influence the size and type of HVAC system you will need. The size or capacity of the HVAC system is expressed in tonnage. The HVAC unit's ability to heat and cool, or output, is calculated in terms of BTUs (British Thermal Units).
The builder often handles decisions regarding the size and type of HVAC system installed. It is important that you be sure they are installing a system that will keep your home healthy and comfortable year round. A system that is sized improperly can either provide too much or too little capacity or BTUs for the space it handles. This will waste energy and reduce the effective life of the system. For example, an undersized HVAC system must work harder to heat or cool the house, which in turn uses excess gas or electricity as well as strains all of the working components.
It is important to have an understanding of what HVAC options are available. Decisions may arise during construction that are important in ensuring your home will be efficiently heated and cooled in all seasons.
