Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/971754
32 | HOUSE WHISPERER —April 2018 Driving the Point Home Even if you place a monitor for days or weeks, as I did when I had an Air Advice IAQ monitor, you have to won- der what was going on after the monitor was retrieved. It couldn't track from season to season. I realized, just like I want a temperature gauge on my car every time I drive it, I also want an air quality gauge in my home every time I'm breathing there. It's something that should be normal. This led me to ask the question: is it better to have a lot of information about a little bit of time or a little information about a lot of time? This quandary reminded me of the Heisenberg Uncer- tainty Principle which states that you can either know the speed or the position of a particle, but never both. It leads to what is at first a very frustrating realization: you can't know everything all the time. Could I find a way to be ok with that, like Heisenberg did? That's when I got interested in the new crop of surpris- ingly affordable consumer grade IAQ monitors. My review of them was published in the December 2017 edition of this magazine. I was hoping to find my security camera. Everything Is a Proxy The truth of the matter is that we can't "know" anything, not when the subject is complex. All we can do is measure some things that give us insight into the larger picture, whether that's looking at the health of a body, home, or another complex subject. Admitting we can't really know anything, let alone everything, is actually quite freeing. It lets us try to understand what we can know. This is where proxies come in. According to Oxford, a proxy is "a figure that can be used to represent the val- ue of something in a calculation." Find the right proxies, and you can come as close to "knowing" a thing as possi- ble, and often with simpler measurements than you might have thought. FitBit wrist monitors are good examples of a health proxy, because they collect multiple data points. These data points are actually proxies. To have a deeper look at health, we need more advanced testing like MRIs, stress tests, blood tests, etc. But as we discussed, those are only valid for a moment in time. To have a long term look at health we need to find proxies. The main proxy of FitBit is steps taken, which is imper- fect because 1) it's only accurate +/- 9% and 2) it doesn't measure some activities like swimming or biking. Be- cause FitBit also measures heart rate, it can be combined with steps taken to understand fitness levels, sleep qual- ity, and general health. FitBit can even be used to predict strokes and pregnancy! All from measuring a few proxies. Having multiple proxies can lead to an alchemy of usefulness where the weaknesses of one proxy are over- come by the insights provided together with other proxies. FitBit for Homes What does a FitBit for homes look like in trying to catch our health thief? As much as we'd love to have a ton of sensors, that's not practical if we want to keep costs down. Air quality monitors often border on an impulse buy, and impulse purchases stop right around $199. So that's a really important target price as the device needs to sell broadly enough to be commercially sustainable. The new crop of monitors hover around this $199 cost. We've also found that multiple monitors per home teach us a great deal. This is another important reason to keep the cost down. We can see if a home is uncomfort- able if the temperature or humidity spikes up and down quickly, or if one part of the home is much hotter or colder than another. We can see how quickly pollutants travel from one part of the house to another. For example, when something gets burned in the kitchen, do other monitors take a while to react? And of course we can see if the basement is too damp while the first floor is fairly dry, or vice versa. I can't recommend multiple monitors enough, but again the cost needs to be a number consumers find "reasonable." Indoor Air Quality Proxies Here are the four proxies I think achieve a useful alchemy. They're like the telltale signs of the various tools of the health thief - his gloves, crowbar, glass cutter, etc. 1. Temperature: A good proxy for comfort. If tem- perature rises or falls quickly, it can be an indi- cator of either oversized HVAC, high amounts of air leakage, or both. Either is a strong indicator of potential health problems in the home because the home is out of control. 2. Humidity: While we prefer dew point for compar- ing indoor and outdoor moisture levels, we'll settle for relative humidity. Relative humidity also gives you a good idea of when mold growth or high VOC levels are likely. Above 60% mold gets likely, above