If you have read anything I have ever written, you know by now that I preach about the “domino effect” that’s created when we make one upgrade to a home without accounting for how it affects other systems. Case in point: I recently visited a client in the Lexington area who said they had a case of “sick house syndrome,” meaning their house was making them sick. They would travel away for a few days and feel better, but immediately upon return, symptoms would reappear. There was also an off-putting odor in their home that they could not eliminate or identify that was making everyday living unpleasant.
Identifying the Problem
Upon my initial survey of my customer’s home, I found that a crawlspace “expert” had come in to seal and insulate the crawl space. When I asked what prompted the homeowner to do this, they explained some animals had been found living in the crawl and had made it their den, which brought along wonderful things like feces and dead animal carcasses. They had a company come in and blanket the walls and floors with plastic sheeting, effectively sealing the crawl from outside. What no one realized, however, was they did not do a proper job cleaning out the crawlspace before the sheeting was installed. The result? The contracting company enveloped the crawl into the home’s living space. The home’s indoor air quality was now compromised since all those nasty airborne particulates started seeping into the home through floor penetrations and leaking ducts.
Now let’s add insult to injury!
At around the same time, the family felt their recirculating range hood was not doing enough to exhaust cooking odors so they upgraded to a 600 CFM turbocharged exhaust hood fan (the industry standard for spot ventilation in the kitchen is only 100 CFM). Kentucky code states that any exhaust fan over 399 CFM needs to also bring in fresh air so that the fan does not pull air from unintended places (like a nasty crawlspace). I completely agree with getting rid of the recirculating range hood. Joe Listebrik, a godfather in my industry, famously points out that a recirculating range hood is as good as a recirculating toilet: if you’re not sucking it out, you’re not doing any good. But you have to feed an exhaust system with fresh air, or it will find air from anywhere it can, most likely somewhere you do not want it to come from. In this case, air filtered through the nasty crawl spaces was being circulated through the home.
At this point, the domino was in full effect. Though the family was trying to do several things to make their air better, the “fixes” actually ended up trapping dirty air in their home’s living space.
What’s the Fix?
I often say “build it tight and vent it right.” In this home’s case, the upgrades missed the mark by building it tight and venting it...oh so wrong. Synergy came in to fix what had happened. Here’s our standard process for properly tightening a building envelope while ventilating it correctly:
Step 1: Controlled Ventilation
First, we need to introduce controlled ventilation, ideally with a Energy Recovery Ventilator (ERV) that brings in fresh air while exhausting stale air while in the process keeping warm air warm and cold air cold. Side note: I plan to write a whole article on how these work soon, so subscribe to the blog and I’ll give you more details on how beneficial ERVs can be! An ERV can be set to positively pressurize the house so that other exhaust fans have extra air to breath. In this case, the ERV pushes air from the living space down into the crawlspace instead of the other way around.
Step 2: Assess & Fix Indoor Air Quality
Next, I want to clean and deodorize what air is in the house. The first thing I take note of is the duct systems and how dirty they are. In this case, they were exceptionally clogged, so our team cleaned and deodorized the ducts. After that, we add a high-end UV light with carbon odor filtration to kill any viruses or microbes in the ducts’ air stream while eliminating odors at the same time. I say high-end UV light because many of the brands on the market are pretty weak. The nicer ones are much better for not much more cost. We also seal the ducts to prevent them from drawing air from the contaminated crawlspace.
Step 3: Balance Ventilation
The final step is to balance the ventilation, which should keep this home from having any more indoor air quality issues and the family will be much healthier.
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