If your central air-conditioning system is about to gasp its last breath of cool air, now’s a great time to replace it. With federal energy tax credits, manufacturer rebates and other incentives in place – plus the fact that an energy- saving new air conditioner will lower your monthly cooling bills for many years to come – you potentially could save thousands of dollars during the next several years.
When you upgrade your existing central air-conditioning unit, you have two good choices: a conventional split system – with the compressor outside and the evaporator inside – or an add-on, air-source heat pump that can cool your home in the summer and help with the heating load in the winter. If you’re swapping your entire heating and cooling system for a new one – or building a new home – you haveother possibilities; in addition to a conventional split system, look at an air-source heat pump or a geothermal heat pump.
A bad installation can cost you money. According to ENERGY STAR®, more than half the new heating and air-conditioning systems put in U.S. homes do not perform to their rated e ciency because of improper installation. A poor installation can reduce performance by as much as 30 percent, which can a ect your
electric bills and lead to a variety of comfort problems, including insufficient dehumidification, dust from leaking ductwork and poor air distribution.
When you’re talking with contractors, ask these questions:
- Do you offer ENERGY STAR quali ed equipment?
- Will you measure my home and calculate the correct size for my equipment using the Air Conditioning Contractors of America Manual J?
- Will you install a properly matched indoor coil and outdoor unit?
- Will you test to determine the maximum system size that can be installed with my existing ductwork?
- Will you consider if zoning, with separate temperature controls for different areas, would be appropriate for my home?
- Will you test to confirm that duct leakage does not exceed recommended levels?
- Will you check for damage to existing ductwork and duct insulation and make repairs if necessary?
- If insulating ducts, will you seal all duct seams first?
- Will you install new refrigerant lines, rather than reusing existing lines?
- Will you confirm proper levels of refrigerant and air flow across the coil?
- Do you offer third-party verification that my system was properly installed and set up?
- After installation, will you leave all manuals with me and provide documentation of installation procedures, including Manual J calculations, AHRI certificate and records of any measurements or testing?
- Will you install and help me to set up an ENERGY STAR qualified programmable thermostat, if I don’t already have one?
- Will you show me how to replace the air filter(s) in my new system?
- Will you provide me with information on any local rebate programs for which I might be eligible?
Bigger isn’t necessarily better. According to the U.S. Department of Energy, national surveys have indicated that more than half of all heating and cooling contractors don’t properly size heating and cooling systems. For air-conditioning systems, oversizing is a real problem; not only do oversized units consume more energy, they also remove less moisture from your home and have a shorter service life. The size of central air conditioners is measured
in Btu/hour – British thermal units per hour. A reputable contractor will need to do a lot of investigating and calculating on a worksheet or computer to come up with the correct rating for your cooling system, considering things such as the size, style, orientation and shading of your home; insulation levels; window types, locations and sizes; air in- ltration; location and condition of ducts; lighting and appliances in use; weather; your family’s lifestyle; and your comfort preferences.
e written bid you receive should be based on the Air Conditioning Contractors of America Manual J and detail the sizing calculations in writing. Don’t accept an estimate that is based only on the size of the existing unit, the square footage of your house or any other rule of thumb.