Sniffing Out the Cause of House Odors
We react to bad odors on a very basic, fundamental level. A smelly house is unpleasant and almost always unhealthy. When you can’t find and correct the reason for the odor it can affect your health, quality of life. It can devastate your pocket book if you try to sell your home.

Bad odors are almost always Mother Nature’s very firm and insistent warning sign to “stay away”. If you are living in a home that smells bad, the message she is sending is to fix the cause or get away. If you are looking at a home to purchase, the message is “YUK, don’t buy this house!” 

There are solutions to the indoor air odor problem other than moving into a tent or leaving the windows open all year around 

House odor identification is a complicated issue because it is usually the result of several causes working together. It can involve heating, plumbing, animal control, pesticide application, hot water tanks, cleaning products, furnishings, appliances, mold and a host of other causes that even professional tradespersons may not recognize. Usually a homeowner has exhausted a list of contractors before calling a house odor environmental specialist.

Homebuyers, Sellers, Realtors and Odors

An odor creates a subliminal, unsanitary feeling about a home.  If you are selling a house with odors, promptly identifying and eliminating odors may save a sale or get you thousands of dollars more for your home. People will not usually take the risk of buying a smelly home hoping to find a solution after closing.

Buyers also react to the “plug in” and other fragrance dispensers that seller mistakenly think will trick buyers into not noticing the odor in the home. These fragrances often have formaldehyde or other synthetic chemicals as the vehicle or active ingredients that can be an irritant. One seller had the bright idea of putting potpourri in the blower area of a furnace. Despite the valiant effort, the buyer still saw the fuzzy mold all over the house and moved on to purchase another home.

Homeowners, Illness and Odors

Imagine that you bought new windows, a new furnace, new carpet or a kitchen for your home. Then you notice a slight odor, maybe you notice it getting a little stronger with the passing of months. Maybe you get used to the odor, but it is getting stronger each month. You had a leak you never noticed, or a neighbor started pouring a chemical down the drain in a home up the street .You may have a child or spouse often getting sick. What on earth can you do? 

Odors can be occasional. Many causes of odors are only activated by moisture or high temperatures. Some are only transferred or moved into the home when a heating system is operational or the wind blows changing the homes air flow.

There are Many Causes of Odors in the Home

We have found two cases of pesticide poisoning, many cases of animals dying inside the home, gas leaks, malfunctioning heating systems and blocked chimneys to name a few of the many discovered odor causes.

  • Mold
  • Gas leaks
  • Pesticide
  • Improper Heating Equipment
  • Hidden Leaks
  • Open Sewer Vents
  • Spilled Chemicals
  • Odorous Building Materials
  • Blocked Chimneys
  • Legionella in Hot Water Tanks
  • Pet Odor
  • Critter Infiltration
  • Crawl Spaces
  • Interior Sump Pumps
  • Breakdown of Materials
  • Cleaning Chemicals

If you can’t identify the cause or distribution process, it is important to have a professional “assessment” or inspection to determine them. If that odor creating process isn’t resolved, cleaning or “remediating” the problem is no better than cleaning out a gym locker out and then putting dirty, smelly gym cloths back into that locker.

There are several steps to the house odor elimination process:

  • Identify the cause
  • Identify the method of odor distribution
  • Remediate or remove the cause of the problem
  • Correct the cause for the odor and the distribution method

 What Can I Do Right Now for Odors and Contaminants?

There are some steps you can take if you can’t figure out what is happening or afford professional help to identify or solve the odor problem.

Fresh air movement will always help. Open windows is a basic step. Installing an exhaust fan is a step better. If you have a forced air furnace, turning the fan setting on the thermostat for the furnace blower to “on” instead of “auto” will move air through your home. Install as good of a quality filter for your furnace as it will accommodate.

HEPA Filters can help for some odors. This will not work for most chemical odor causes, but is successful for particulates.  Some of these particulates are mold, cigarette smoke, dust, pollen and allergens. Use a HEPA filter in the room where the person that needs help is spending the most time. This is usually the bedroom.  

One very important warning is to not purchase a filter that also produces ozone. These are still being sold but can cause serious health issues.

Remove items that can hold odors. Remove odorous papers, stuffed animals, stored cloths and similar items. These items can hold allergens and odors like a sponge. Odors can be absorbed by furnishings, flooring, contents and building materials. You may need to change or remediate contents and building components to resolve the odors.  

There are coatings and chemicals that can neutralize odors, but beware of chemicals that have residual odors.

Getting Help

There are environmental professionals that specialize in odor identification.  These specialists are generally building science people familiar with both chemical and particulate air contaminates. They should have an understanding of building design, construction and trade practices. HVAC systems are often a major part of the odor problem. The common available certifications are those such as CIAQT (Certified Indoor Air Quality Technicians). These can be found at   Other associations such as IAQA have a professional search feature at 

One last piece of advice is to hire a professional who is not going to sell you the service of correcting the problems that are found. That’s a serious conflict of interest.