Heating/Cooling-Air Filters

August 13, 2011

 Indoor Air quality is between 2 to 5 times more polluted than the outdoor air (US Environmental Protection Agency, September 1999)

I am invoking the 90/10 rule on this subject. Good basic air filtration will reduce dust and keep your HVAC equipment in good working order. For the other 10%, specialized filtering may be required to obtain hospital grade filtration, reduce allergies or conditions that have caused your house to be considered sick. If you have concerns of that level you may try some expensive HEPA type filters or consult an air quality specialist.

aifilter

MERV 1-4

To help us understand filter performance,  the standards body ASHRA created the 52.2 standard for rating replacement air filters. MERV or Minimum Efficiency Rating Value defines filtration performance with a 1-16 scale with 16 being the most efficient. However, “efficient” in this context is about  the amount of  particulate collected through the filter at the cost of reduced air flow. Using  a filter with the highest rating will require more service as it may 1) clog more quickly, 2) require more regular replacements, 3) be more expensive, and 4) add undue wear to HVAC components, 5) cause your system to over work, in-turn use more electricity.  So, if you do not have specialized filtering needs, finding a happy medium between efficiency and air flow is the prime objective.

 MERV Rating 1-4: Typically a very thin membrane made of fiberglass strands. This filter will picks up the big stuff and will reduce particulate to your system but will not provide any real air quality value.  The efficiency rating is <20%.  A MERV 1-4 filter can be purchased for a around $1 each.

Pleated MERV8

MERV 5-8

MERV Rating 5-8:  Typically a pleated cloth type membrane is more efficient and should meet most normal needs. With an efficiency rating of >20 but <50% these pleated panel type filter will provide adequate filtration as well as keep your equipment in good shape. They are about $3 each.

MERV Rating 9-14: Used in commercial or industrial applications based on their ability to remove certain smells and oders are becoming more popular for the home market. Assuming you can find the size you are looking for it will cost you $8 or more. When you get past a MERV11 they can be more difficult to find and expensive.  See the ASHRA MERV table for specific filtering requirements.

TIP: When you jump from a MERV7 to a 11, the price triples. The biggest difference is the amount of efficiency.  Based on the NAHB (National Association of Home Builders) Green Building Program they recommend a MERV 9 or better.  ASHRA 62.2P  also recognizes proper air filter efficiency at 60% or 3 microns ( MERV 9).

When you visit your home center they will probably limit your selection to 3 or 4.

  1. The cheap fiberglass stran filter, MERV 1-4
  2. A large selection of MERV 5-7. They may even be packaged in quantity priced at about $3 each or a little less in quantity.
  3. A MERV 9-11. Fewer sizes but still a reasonable selection. About $7.95 each. If you are struggling with allergies, something greater than a 10 may help.
  4. Maybe a HEPA (MERV14-15) or another high-end disposable filter at $15 to $100. These may be recommended to you for specific algeric conditions.
electrostatic-air-filter

Lifetime Electrostatic

Reusable or Life-time filters: Unfortunately there is not a standardized rating method for these type filters and I have failed to find enough independent data to support their use. Depending on who you listen to, an electrostatic filter could be similar to a MERV 4 on the low end and a MERV12 on the high. An electrostatic filter can cost between $60 to $300. If you are using a MERV 9 or better you may consider a reusable electrostatic type filter. You will have to be the judge as to it meeting your needs. HomeownerBOB has no recommendation here but I have read more positive comments about the BOAIR brand. If it works for you, it will  pay for itself in less than 2 years and you won’t be throwing filters in the trash.  The biggest advantages of  electrostatic filter are 1) they can be washed out and reused, 2) their efficiency rating is in the 90% range and 3) the airflow is excellent and does not deteriorate at the same rate as a pleated filter. Once you wash it, it is completely restored. Many times electrostatic filters come with a lifetime warranty.

Hybrid pleated/electrostatic charged filters:  MERV does not rate this type filter either. The manufacturers market this filter by having the attributes of both pleated and electrostatic filters, but at $17, its still a disposable filter.

Many professional will encourage you to change filters on a monthly basis and depending on where you live, that may be the right thing to do. HomeownerBOB recommends that you replace your filter some where between 2 to 4 times a year. You will need to be  the judge on the conditions that may warrant more or less frequent changes.

Reasons to change/clean your filter more frequently may include:

  • Continued use of heating or air conditioning throughout the year
  • Living on or near a busy street, highway, airports or rail road track
  • Living in a dry/arid part of the country
  • Living in an area with a low percentage of annual rain and or high winds (Texas, New Mexico, California, etc)
  • Living on rural property with a lot of exposed dirt
  • Living on an unpaved road

As I said in the beginning of this article, these filter recommendations are based on the larger body of population that does not have health related conditions. There are many more filters, filtering systems,  filtering strategy (cascading) and air exchange studies that can be used to solve air quality issues.

Recomendation:

It should be pretty obvious, unless you have special needs, or live in a very dusty enviornment, the MERV 5-7 should work fine.

Key Inspection Points and Action Items:

  1. Change, or clean your HVAC filter at least 2 to 4 times per year.
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Seasonal Reminder – Summer Household To Do List

July 5, 2009

100_0497Summer is Here!!!  Its been close to 100 degrees most of the week, and it could be that hot till Labor Day. This seasonal reminder is more about making sure everything continues to work well through the stress and strain of the summer months more than anything. If you live near me, getting these things done before 10 AM in the morning is the best time of the day, otherwise you may wait till after 6 PM or so.  If you need details on what to look for or what to do, click on the link (if there is one) and it will take you to the post that was written on the subject and provide more detail.

  1. Heating/Cooling-Air Filters: If you live in a dusty area and/or have been using your air conditioner a lot, inspect you filter and change it if it has noticeable build up from your spring change out. 
  2. HVAC Outdoor Unit: We did this in the spring and it’s good to do it again as vegetation has been growing through the spring months. Get your garden trimmers out and trim away any vines or growth away from the  outside condenser. You should have 18″ to 2 100_0233feet of clearance around the unit. Airborne particles generated by the blooming of trees and bushes can easily show up around the air conditioning condenser. Take your water hose and wash down the outside coils. Check the condensation drain that comes from the air handler in the house. Ensure that it is clear of obstacles or debris by pouring water through it.
  3. Water Leaks: Check all water fixtures and toilets for leaks. Inspect fixture drains for water puddles or loose joints in the traps.
  4. Lawn Sprinklers: If you read my weekly posts, you may notice I have been writing a lot on lawn sprinklers. This subject has been getting the most hits and questions so I have responded by writing more articles on the subject. Even though we performed this maintenance during the spring, yard work and vegetation growth can cause some additional sprinkler maintenance. Exercise the system. Look for excessive water traveling down the driveway or sidewalks. Inspect the sprinkler heads, look for blow-by, odd spray patterns, missing heads, pooling water and brown spots.  Replace or repair the heads. Chasing Lawn Sprinkler Leaks is the first of the series and covers the inspection, leak detection and repairs in more detail.
  5. 100_0503Exterior Inspection:  Walk round the house, look for bird and wasp nests, as well as locations that rodents might be using to get in the house. Use caulk to re-seal  any breaches in structure that may be an entry point for rodents or bugs.  They are all looking for cool locations and possible water.
  6. Interior Inspection: Flush kitchen and bathroom sinks with scalding hot water for approximately 3-5 minutes to clear out any build up.
  7. Appliances: Use a hand held vacuum cleaner to clear the dust bunnies from the vent at the bottom the unit. Pull you refrigerator out from the wall and do the same. If it’s within your skill set, turn off the unit, pull the back cover off,  and vacuum out the condenser coils and all the dirt around the fan.
  8. Surface Water Drainage: Culverts, waterways and landscape drainage systems should be cleared of debris and overgrowth that has occurred.100_0206
  9. Electrical Service: Inspect the Entrance, Mast and Weather-head. With tree limbs heavy with leaves, seed pods, fruits and nuts, you may have some limbs that are drooping on your electrical service lines. 
  10. Electrical Service-Smoke Detectors: Clean your smoke detectors of cob webs and change the battery.
  11. Test your security system: Work with monitoring service to validate all the door, window, glass break, and motion sensors operate properly. 

If you are needing some additional information on one of the topics that I have not written about, let me know and I will put it higher on the list of articles to write. Email to HomeownerBOB@gmail.com


Seasonal Reminder – Spring To Do List

March 7, 2009

springSPRING HAS SPRUNG!!  Okay not everywhere. Here in my part of the country the daffodils have been out for about 4weeks. Yep, it got here early, so if your local temperatures are above freezing and the trees are starting to bud, it’s time to move forward… its inevitable. It’s time to fix all those items that broke during the winter months, repair the items that have deteriorated over the last few months and perform a little preventative maintenance around the house. This seasonal reminder  provides a list of items you need to review before the summer months set in. If you need details on what to look for or what to do, click on the link (if there is one) and it will take you to the post that was written on the subject and provide more detail.

  1. Heating/Cooling-Air Filters: Assuming you have a forced air system, change the filter prior to the heavy air conditioning months.
  2. Roofing-Looking For Leaks:  Spring rains are approaching so inspect your roof for leaks, trim away any tree limbs and clean debris off the roof. Look for raised nails and any breaches in the roof surface.
  3. HVAC Outdoor Unit: Get your garden trimmers out and trim away any vines or growth away from the  outside condenser. You should have 18″ to 2 100_0233feet clearance around the unit. Also take your water hose and wash down the outside coils  that may have accumulated dirt. Check the condensation drain that comes from the air handler in the house. Ensure that it is clear of obstacles or debris by pouring water through it.100_02311
  4. Water Leaks: Check all water fixtures and toilets for leaks. Inspect fixture drains for water puddles or loose joints in the traps.
  5. Lawn Sprinklers: Exercise the system. Look for excessive water traveling down the driveway or sidewalks. Inspect the sprinkler heads, look for blow-by and odd spray patterns. Replace or repair the heads.
  6. Exterior Inspection:  Walk around the house, look for rotted wood, peeling paint and other exposed surfaces. Use caulk to re-seal cracks and touch up paint to reseal the surfaces. Replace rotten wood as necessary.
  7. Interior Inspection: Winter dry-out will have caused some surface cracks around doorways and windows. Also  re-caulk/grout any cracks that may have surfaced in the bathroom and kitchen, especially around the tub and shower. These two areas experience the most use and require the most maintenance.  Replace or clean water filters, faucet strainers and vent-a-hood filters in the kitchen. Flush kitchen and bathroom sinks with scalding hot water for approximately 3-5 minutes.
  8. Water Heaters: Tank type water heaters should have their pressure release valve tested (opened and closed). This will also validate the the drain pipe is clear and open.
  9. Gutters and Downspouts: Clean you gutters of leaves and debris. Flush them with water to ensure they flow freely.
  10. Surface Water Drainage: Culverts, waterways, landscape drainage systems should be cleared of debris and overgrowth that may have occurred.100_0206
  11. Windows and doors: Look at the edges where the windows and doors connect to the house. Ensure the caulk is in good shape and add caulk as necessary, indoors and outdoors.
  12. Electrical Service: Inspect the Entrance, Mast and Weather-head. Look for any damage that may have occurred over the winter. Look for tree limbs that may be contacting the entrance cable.
  13. Electrical Service-Smoke Detectors: Clean your smoke detectors of cob webs and change the battery.
  14. Test your security system: Work with monitoring service to validate all the door, window, glass break, and motion sensors operate properly. 

If you are needing some additional information on one of the topics that I have not written about, let me know and I will put it higher on the list of articles to write. Email to HomeownerBOB@gmail.com