More blog posts about heating and air conditioning:

  1. The coils on my heat pump are covered with ice on cold mornings. What’s wrong with it?

  2. What is an HVAC system?

  3. What does “AUX HEAT” and “EM HEAT” mean on my thermostat?

  4. What size air conditioner is right for my mobile home?

  5. What does the “AFUE” rating of a furnace mean?

  6. My air conditioner won’t turn on. What’s wrong?

  7. Why is there mold around the air conditioning ducts?

  8. How much life is left in that air conditioner?

  9. What does the MERV rating number on an air conditioner filter mean?

  10. How much will it cost to replace my old air conditioning system?

  11. Is it alright to close the air conditioning vents in unused rooms?

  12. What is the difference between a heat pump and a cooling air conditioner?

  13. What is the difference between the SEER and EER rating of an air conditioner?

  14. What is the right MERV number for my air conditioning filter?

  15. What is an air conditioning heat recovery system?

  16. What is the average lifespan of an air conditioner?

  17. When should I switch the thermostat to “EMERGENCY HEAT” for my heat pump air conditioner?

  18. Why does the air conditioner condensate drain line need a trap in it?

  19. What is the purpose of the vent grille over the bedroom door?

  20. Should I have a return air vent in the master bedroom?

  21. Will closing doors reduce my heating and cooling costs?

  22. How much will I save on my utility bill if I get a new higher SEER air conditioner?

  23. Why is there a wall switch next to the furnace or indoor unit of the air conditioner in the garage?

  24. Why does an air conditioner condenser need to be level?

  25. Why is it bad to have a clothes dryer vent near an air conditioning condenser (outdoor unit)?

  26. When is an auxiliary drain pan required under an air conditioner indoor unit (air handler)?

  27. Why does it take so long to cool a house when the air conditioner has been off for a while?

  28. What are the right words to use when talking about a heating and air conditioning system?

  29. What is a ductless mini-split air conditioner?

  30. What is a FanRecycler and AirCycler?

  31. Why is my bathroom vent fan not exhausting enough air?

  32. Why has the thermostat screen gone blank?

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Welcome to our blog!
We want you to be an informed homebuyer, and each blog post is a question that we have answered for our friends and customers over the years. Hope they help you make a good choice for your next home.

Is it cost-effective to replace an older, low-efficiency air conditioner
system with a new high-SEER system?

   Generally, from an accountant’s total-cost standpoint and allowing for the time-value of the delayed expenditure for a new system, it’s less expensive to nurse your existing a/c unit until it dies. But one other factor may tip the scales toward earlier replacement: already-inefficient air conditioning systems get even less efficient as they get older, especially after about 20-years. The compressor draws more amps as it ages, and the temperature split (difference between the ambient room air and the cold air coming out the ducts) tends to decrease too. Your a/c service tech can give you a rough evaluation of the system’s current efficiency as a guide when you’re trying to decide whether to repair or replace.

   Although the SEER rating is not marked on older units, the average SEER for a system manufactured from 1970 to 1996 was between 9 and 10, trending up gradually towards 12 between 1997 and 2006. If your current SEER is 9 or below, then a new system will be at least 40% more efficient. So replacing an HVAC system that is 20-years old or more will make a significant dent in your monthly electric bill.

   When it is time for replacement, systems with SEER ratings up to 20 and beyond are available. Each notch of efficiency means more initial outlay and, for the very high SEER systems, more maintenance because of the more complex components. For most situations, the minimum or near-minimum SEER is the most cost-effective choice; but the length of the cooling season and cost of electricity in the region can change the equation. At the southern tip of Florida in Key West, for example, where the cooling season is longer and the cost of electricity is higher than normal, a high-SEER system makes both environmental and budget sense.


While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
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