Replacing an air conditioning unit can be a daunting experience for some people. But for those who know what to do, this task can be a chance to upgrade the existing unit and install more modern equipment that will prove worthwhile in both comfort and cost.

When your air conditioning unit goes out, here are some options to consider:

• Replace the condenser, or compressor, unit.
• Buy a new model – a high-efficiency model or a minimum-efficiency model.
• Install a complete new system. It may cost more now, but in the next few years the inside evaporator section will probably also fail. Spending a little more money now may save you money in the future.
• If your system’s ductwork is worn with age, it is a good idea to put in all new ductwork.

Weigh the pros and cons of all of these options before making a final decision. What you decide will impact your utility bills for the next 12-16 years.

How to select the right dealer

When trying to determine which dealer you should buy from, one method you can use to be sure your are selecting the right dealer is to make a call to the Better Business Bureau or local licensing agency. A referral can make you confident that you are selecting the right dealer.

It is important not to make a rushed decision. Get a least two prices from equally qualified HVAC dealers. Be sure to get the price on the exact same installation. This is a common error people make when comparison shopping.

Finally, make sure the dealer you select is licensed to do the job(s) you select him/her to do.

Questions that you may want to ask before buying a HVAC unit include:

• Are any rebates being offered (DNR rebates)?
• What is the warranty for the compressor (years)?
• What is the warranty on all parts (years)?
• What is the warranty on installation (years)?
• Is a service contract available?
• Is any special financing available?
• Is this the time to consider upgrading my insulation? Can I coordinate?
• If I insulate now, can this affect the size unit I might install?
• Can the discharge ductwork and return air ductwork be repaired, reinsulated and sealed instead of replaced? What if it just needs sealing?
• Does increasing insulation on the ducts reduce my operating costs?
• Can this be applied to the size of the air conditioning system I install? I have heard that if I decrease the temperature of my attic, my house will be cooler and lower my air conditioning operating costs. Is that so? What do you suggest I do?
• Should I also consider increasing the efficiency of a gas furnace? (This applies only if you have a natural gas furnace. Remember, natural gas rates also are increasing.)
• Will setting back the thermostats help lower costs?

Seasonal Energy Efficiency Ratio (SEER)

The SEER rating should be considered when selecting an air conditioning unit. The higher the SEER rating, the more energy-efficient the equipment is. A higher SEER rating can result in lower energy costs. This U.S. Department of Energy Web site, http://www1.eere.energy.gov/consumer/calculators/homes.html, can show you how to calculate potential energy cost savings of a more efficient unit. The Air-Conditioning and Refrigeration Institute (ARI.org) posts a certified ratings directory, which lists SEER ratings of various air-conditioning equipment.

Because this is a replacement unit for your current residence, you have some information, such as previous utility bills, you would not have if you were moving in to a new residence. By studying prior bills, you will be able to estimate air conditioning energy usage/cost from past bills and how a different SEER rating would factor in. This information also may give you insight as to sizing your equipment.

You can also use prior utility bills for levelized billing. Levelized billing is a service some utility companies offer that provides utility customers with a set monthly billing each month. Contact your local utility company and find out how if levelized billing is offered.

You may want to ask you dealer to show you the payback economics of a 13 SEER vs. 16 SEER or 18 SEER A/C unit.

Other things to consider

If you have resistance-electric heating, consider a high-efficiency heat pump when changing the HVAC unit. This may be the best choice for well-insulated homes. Use only the manufacturer's heat-pump-trained installers.

Also, make sure your unit is one that will be useful today, as well as in the future. Electric and gas utility rates are not decreasing. With this in mind, consider the best that economics will allow for HVAC equipment. Remember, this equipment is attributed to the use of over 50% of your utility bill. Analyze your situation and select equipment that will best meet your needs.

Be prepared when making decisions about replacing your HVAC unit, because what you do probably will impact you for the next 10 years or longer.