More Blogs on Similar Subjects:

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

  1. What is an HVAC system?

  2. What is the minimum SEER rating for a new air conditioner?

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

  4. How do I find the right size air conditioner for my house?

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

  6. How do I remove cigarette odor in a house?

  7. What is the difference between the “ON” and “AUTO” settings on my thermostat?

The fireplace doesn’t have a chimney. Is that alright?

  1. How can I improve the energy efficiency of my not-so-new Gainesville home?

  2. What is the SEER of my old air conditioner?

  3. What does the “R-Value” of home insulation mean?

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

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

  6. What do those numbers on the manufacturer’s stickers on new windows mean?

  7. What is wrong with an air conditioner when the air flow out of the vents is low?

  8. What is a geothermal heat pump?

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

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

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

  12. What is an air conditioning heat recovery system?

  13. What is the best air conditioner for a mobile home?

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

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

  16. Should I remove an old whole house fan or keep it?

  17. What is a jump duct?

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

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

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

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

  22. What are the most common problems with wall/window air conditioners?

  23. Which one is better for a home heating system: electric or natural gas?

  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 does the ban on R-22 air conditioning refrigerant take effect?

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

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

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

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

  31. What is a FanRecycler and AirCycler?

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

  33. Why has the thermostat screen gone blank?

How to Look

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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.

   One air conditioning contractor we know recommends using no more than a MERV 4 (minimal residential filtration) filter. As he puts it, “if you can’t see through it, don’t buy it!” We think that number might a little low, especially for homeowners with allergies and asthma problems. Plus, a system can be designed to accommodate higher MERV filters.

   But we do agree with the philosophy of installing a filter with lowest MERV number that accomplishes the level of air filtration you require. More is not necessarily better.

   And  the filter combo in the picture above is clearly “over the top” as far as we are concerned: a MERV 12 box filter in tandem with a pleated filter that’s unmarked, but probably a MERV 7. The homeowner was not present at our inspection to explain his logic for this combination, but the problem it created was immediately obvious. There was a noticeable lack of air flow at the registers. And, while the MERV 7 filter increased the load on the a/c blower and reduced the air flow through system, it did not do the one thing for which it was likely intended: better filtration.

   We also occasionally see homes where double filtration has been created by installing a filter at the base of the a/c air handler and also behind the return air register. Like the previous example, it creates reduction in air flow without any additional filtration benefit, and we recommend removal of one of the filters.

   We suggest that you talk with your a/c technician next time you have a service call, and ask for a recommendation for the MERV rating right for your particular HVAC system.

   It’s also a good idea to examine the outside edges of your filter while it is secured in the air handler to make sure that it fits snugly all around, with no gaps. Give the filter a light tug in the direction of the air flow, to simulate the suction action of the blower when operating. If the filter easily pulls away from the the mounting frame, that means unfiltered air is going around the edges, and you should ask your a/c technician to reinforce or replace the securing mechanism for the filter.

   Then again, sometimes just installing a filter with a stiffer frame will solve the problem. One-inch thick filters with a high MERV rating and a lightweight cardboard frame tend to buckle slightly as soon as a little dirt/dust accumulation increases their resistance to air flow. 

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.
©2015 - McGarry and Madsen Inspection.

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