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Getting to know your HVAC System

Some information about your HVAC System that should make you into a more knowledgeable Homeowner.

I want to impart some information about your HVAC System that should make you into a more knowledgeable Homeowner and help you get the most out of your investment. You should consult a professional HVAC technician for more detailed information.

Sizing: As a rather classic rule of thumb, your air conditioning system should be sized based on a generally accepted ratio of one ton of air conditioning capacity for every 500 square feet of living area. If your home contains 2,500 square feet of living area for example, you should expect your AC system to be of approximately 4¼ to 5 tons of capacity (it’s normal to have a little less tonnage, oversized systems tend to create complicated and costly problems). Unfortunately your outside (condenser) unit will almost never have the pertinent information on the info plate (e.g. “X-ton unit”) this information must usually be deciphered within the MODEL or SERIAL numbers.

Example

Types of systems: A conventional air conditioning, forced air system will have gas heat and electrical air conditioning; on rare occasion, both systems will be electrically operated. A heat pump system should be basically viewed as an air conditioning system that runs in the forward mode to produce cool air, and in the reverse mode to produce warm air, sounds like voodoo, but that’s basically how they work. These systems can usually be easily identified by the fact that their thermostats have an “Emergency Heat” setting, and that the outside unit will be in operation for both cool air and warm air (year around). Heat Pump systems can be characterized as having generally lower operating costs, along with longer anticipated service lives; they also are known to require more time to bring temperatures up or down. The first measure of proper function for your air conditioning is what is called a cooling differential. This differential (ratio) is determined in an elementary way by taking a measurement of the temperature at the supply vent closest to the inside (evaporator) unit and subtracting that from the temperature at the return (filter side) unit (temp at the supply side subtracted from the temp at the warm air return side). An example: place hanging thermometers at the closest supply vent and also at your return (usually filter) vent; subtract the cool from the warm; you’re looking for a difference of between 14 to 18 degrees F. Any higher? There’s a problem- Any lower? There’s a problem. Smart Homeowners leave these hanging thermometers in place year around to be able to quickly check their function by themselves.

Your normal maintenance: As a Homeowner, HVAC maintenance doesn't require much: change your disposable filters (if so equipped) at least every 30 days; keep the condensate line clear by bi-annual application of (1) gallon of warm/hot water mixed with (1) cup of household bleach solution delivered down the PVC pipe access opening via a funnel. Alas, like flossing, most of us tend to absent-mindedly forget chores like these.

A better idea: sign up with a reputable local HVAC Contractor for twice-a-year servicing (usually about $85.00 to $125.00 per year); they will call you when the time is right, make sure the refrigerant is fully charged, clean all condensate lines, clean the burners on your furnace and most important reduce your chances of freezing or frying at the wrong time of year along with getting the maximum life from your system.

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