Sarasota area homeowners expect a lot from their central air conditioners. What was the best equipment 10 years ago is easily overshadowed by modern, more efficient A/C and heat pump systems. When upgrading an air conditioner or heat pump, work with your qualified HVAC contractor to plan around four important factors.
Your Sarasota-area home’s aging outside A/C unit may need replacement much earlier than the indoor component, since it’s exposed to the elements. This leads to the temptation to replace only the outside condensing unit, leaving its still operating evaporator/air handler inside. This may be the right move, but talk to your trusted HVAC contractor first, because this short-term savings can lead to long-term regret. Indoor and outdoor units work the best when they’re matched with regard to their cooling efficiency ratings and refrigerant. Often, the indoor and outdoor components of an A/C or heat pump won’t work together at all if the compatibility issues are serious enough.
A wiser choice, though more expensive up front, when upgrading an air conditioner or heat pump is to replace the entire system. This removes doubt and will actually lengthen the life of both outdoor condenser and the indoor air-handling unit. Moreover, the issue of refrigerant compatibility may be the guiding force in reaching a decision on replacing one or both units.
Sizing the A/C or Heat Pump
The Air Conditioning Contractors of America (ACCA) publishes Manual J, the only reliable way for an HVAC technician to calculate the cooling load for your Sarasota area home. Going by the size of the old system (5-ton, 4-ton, or whatever it may be) when upgrading an A/C or heat pump is not valid due to improvements in energy efficiency and cooling power in the last decade.
Manual J factors in home size and layout, as well as room orientation, number of windows, landscaping that may shade the home, location of registers, and expected occupancy. These variables lead to a precise determination of your cooling needs, so you can select the right size system when upgrading an air conditioner. Selecting the correct size saves money at purchase, money during installation, and money for the life of your system.
Choosing to oversize the A/C or heat pump will cause some unpleasant effects:
- Your home will feel humid
- You will feel strong, cold blasts of air
- Your equipment may short-cycle (start and stop frequently)
- Your new equipment may fail frequently, necessitating expensive repairs
Undersizing a cooling system is bad, too, simply because your Florida home will not cool properly during hot weather and the machinery will run constantly. Either condition is a waste of energy and natural resources, and can be avoided by using ACCA’s Manual J to calculate cooling load, Manual S to select the right size equipment when upgrading an air conditioner, and Manual D to determine that your home’s ducts are able to handle the airflow from the new system.
Your contractor may be able to show you that Manual D indicates needed improvements or modifications to your home’s ductwork. This is not done as an unnecessary add-on to increase installation costs, but as a way to improve your system’s energy efficiency. Both main ducts and the smaller ducts leading to individual rooms need to be correctly sized to match your new system.
Today’s modern central air conditioners are significantly more efficient than old models. Part of this is due to the federal push for American energy independence and a drive to reduce greenhouse gases. The federal Energy Star program mandates that the models you look at when upgrading an air conditioner have, at minimum, a Seasonal Energy Efficiency Ratio (SEER) of 13. This is easily obtainable, but models exist up to SEER 24.5. The higher the SEER value, the more money you will save on lower energy bills. You will conserve natural resources and lower atmosphere-fouling emissions.
This efficiency extends to the new refrigerant, R-410A, which provides impressive cooling power while not chipping away at the ozone layer. Modern equipment built to handle this newer coolant (as opposed to the old, discredited R-22) will deliver ample cool air with greater energy efficiency than your old system.
The HVAC contractor who carefully calculates cooling load, sizing and ductwork must follow through with conscientious installation. This means attention to details:
- Rebuilding or redirecting ductwork as needed by Manual D
- Installing the interior unit to provide easy access for servicing
- Installing an access door to reach the evaporator coil
- Insulating any ductwork that must run through your home’s attic
- Recommending and installing programmable thermostats in at least two zones
- Locating the outdoor condenser unit to minimize noise and vibration for you and your neighbors
- Ensuring adequate airflow into the outdoor condensing unit
- Securing your outdoor unit against theft
- Double-checking the refrigerant charge and airflow rates to meet manufacturer’s specifications
For more information about upgrading an air conditioner or heat pump for your Sarasota area home, contact us at Aqua Plumbing & Air.
Written by John Miller
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