Heating, Ventilation, and Air Conditioning
The goal for a HVAC system is to provide proper air flow, heating and cooling as well as humidity control to each room. This sets out key criteria that describes a quality system, and key design and installation parameters and considerations that should be met to achieve this goal. The following contains detailed information on design, fabrication, installation and performance testing.
Criteria for a Quality HVAC System
An HVAC system should:
- Be properly sized to provide correct air flow, and meet room-by-room calculated heating and cooling loads:
- 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;
- Have a sealed supply ductwork that will provide proper air flow to the fan, and avoid air entering the HVAC system from polluted zones (attic particulates, undesirable fumes, etc.);
- Have balanced air flows between supply and return systems to maintain neutral pressure in the home;
- Minimize duct air temperature gain or loss between the air handler and room registers, and between return registers and the air handler;
- Be properly charged with refrigerant; and
- Have proper burner operation and proper draft.
A building’s central air conditioning system must be periodically inspected and maintained in order to function properly. While an annual inspection performed by a trained professional is recommended, homeowners can do much of the work themselves by following the tips offered in this guide.
Exterior Condenser Unit and Components Maintenance
The exterior condenser unit is the large box located on the side of the building that is designed to push heat from the inside of the building to the outdoors. Inside the box of coils of pipe that are surrounded by thousands of thin metal fins that allow the coils more surface area to exchange heat. Follow these tips when cleaning the exterior condenser unit and its inner components AFTER TURNING THE UNIT OFF AT THE BREAKER BY THE COMPRESSOR!
- Remove any leaves, spider webs and other debris from the units’ exterior. Trim foliage back several feet from the unit to ensure proper air flow;
- Remove the cover grill to clean any debris from the unit’s interior. A garden hose is satisfactory;
- Straighten any bent fins with a tool called a fin comb;
- Add lubrication to the motor (if required). Check manual for instructions; and
- Clean the evaporator coil and condenser coil at least once a year. Dirty coils affect efficiency of the unit.
Condensate Drain Line
Condensate drain lines collect condensed water and drain it away from the unit. They are located on the side of the inside fan unit. Sometimes, there are two drain lines – a primary and a secondary in case the primary becomes blocked. Homeowners can inspect the drain line by using the following tops, which take little time and no special tools.
- Inspect the drain line for obstructions, such as algae or debris. If the line becomes blocked, water can back up into the drain pan (usually found in the attic) and overflow, potentially causing water damage;
- Make sure the lines are secure and fit properly;
- Continual drippings from the soffit drain pipe, usually over a window, should be investigated for obstruction in the drain.
Air filters remove pollen dust and other particles that would otherwise circulate indoors. Most filters are typically rectangular in shape and about 20 inches by 16 inches and about 1 inch thick. They slide into the main ductwork near the inside fan unit. The filter should be cleaned or washed periodically, depending on the type of filter. A dirty filter will not only degrade indoor air quality, but it will also strain the motor to work harder to move air through it, increasing energy costs and reducing energy efficiency. The filter should be replaced monthly during heavy useage periods. You may need to change the filter more often if the air conditioner is in constant use, if building occupants have respiratory problems, if you have pets with fur, or if dusty conditions are present.
Current Construction Standards
There are improvements in technology and material that are constantly being upgraded for construction of newly built homes. The standards call for thermal pane windows, higher efficiency air handling units and much higher efficiency compressor units than were standard only a few years ago. Other techniques include better attic venting, radiant barriers and higher efficiency water heaters.
In addition homeowners should practice the following strategies in order to keep their central air conditioning systems running properly:
- HVAC systems should be checked annually for proper, safe operation by a licensed HVAC company. Have the system inspected before the start of the cooling season;
- Reduce stress on the air conditioning system by enhancing your home’s energy efficiency. Switch from incandescent lights to compact fluorescent lamps which produce less heat.