What if we handled the water treatment for our pools like we handle the indoor air quality for our homes/buildings?

What if we handled the water treatment for our pools like we handle the indoor air quality for our homes/buildings?

This may sound like a ridiculous analogy, but it really isn’t. Both the pool water and the air in our buildings are fluids that we immerse ourselves in.  Improper treatment of either can negatively affect our health.  Both fluids have suspended solids or particles that must be filtered out, and both have chemical / mineral / pathogen contaminants that must be dealt with. However, the treatment approaches to these two fluids are vastly different.  The purpose here is to highlight a scientific, results oriented, sustainable approach versus an unscientific approach that produces considerable waste with lackluster results.  We will discuss some of the reasons why these approaches are different at the end of this analogy.  But first, let us pretend that we are required to treat our pool water like our indoor air to achieve what is believed to be a healthy and effective approach.

First off, we have to address the chemical, mineral and pathogen contaminants. These contaminants enter the pool from the original water source, they build up in the water from the pool occupants and materials introduced into the pool, and they enter from other sources in the surrounding environment.

  • In the air quality realm, these contaminants would be akin to gaseous emissions, VOCs, and bioaerosols.  For the vast majority of buildings, we address these types of contaminants by diluting the indoor air with outdoor air, and we fully replace all the air in our buildings approximately .35 times to 1 time an hour. 

To treat these contaminants in the water of the pool as we would our indoor air, we are going to replace the entire volume of water in the pool at least .35 to 1 time every hour at minimum.  The water in the pool will be dumped down the drain to prevent the concentration of chemical / mineral / pathogen contaminants.  The magnitude of the wastefulness of this approach is blatantly obvious to everyone when considering this methodology and what we know of modern pool treatment capabilities.  But most of us do not see the equivalent wastefulness when this approach is applied to the air in our buildings.

  • The response to this is often “this isn’t the same thing.  Exhausting indoor air outside isn’t wasting it like it would be for water.”  On the contrary, the air in your home or your building is “bought”.  You pay for the air in the form of considerable energy costs to heat it, cool it, humidify it or dehumidify it.  You pay for filters to clean it and you pay for a system to distribute it around your home or building.  The waste we produce by dumping the air outside is the energy that was put into the air to condition it.  For additional context, HVAC operational costs represent approximately 50% of the baseload costs of a facility. Buildings consume 30%-35% of all energy consumed in our country.  And for even MORE concerning context, this amount of energy produced system performance that led to sick building syndrome and rising health issues over the past 40-50 years.  A pandemic was also fueled by the ineffectiveness of our most common ventilation design methodology. In response to this, the most prevalent ideology for adapting our HVAC systems to address the health and wellness shortcomings we are dealing with is to INCREASE the outdoor air introduction into our buildings. At a time where energy demand reduction, decarbonization, and sustainability are critical objectives, there are those that are pushing a perceived solution that will significantly increase the energy consumption of our HVAC systems – already our largest energy consumer.

Back to the pool analogy.  What EXACTLY are we going to dilute our chemical, mineral, and pathogen contaminated pool water with?  Mimicking the requirements of ventilation for indoor air which calls for outdoor air being introduced at a specific rate; the pool will require “outdoor water”.  We will need to assume that all “outdoor water” is fresh and clean and adequate for our pools, just like we do with outdoor air for ventilation.  This is obviously challenging to the mind as it relates to water, as “Jane Doe” may have access to a mountain stream at her house to fill her pool but “Jim Smith” may only have a swamp at his disposal.  However, as long as there is no roof over the top of the stream or the swamp, and no walls surrounding them, they both classify as “outdoor water” and are approved for use for purposes of improved pool water quality.

  • This seems ridiculous on its face, but it is not far from accuracy as it applies to ventilation in our buildings. Since the mid to late 1800’s, outdoor air ventilation has been the primary means to achieve what was believed to be healthier indoor spaces.  It did not matter that certain buildings were located in more polluted areas than others. There was no other alternative to this form of “air cleaning” for many, many decades.  Although alternatives to the “way we have always done it” exist today, and the science has clearly begun to show the ineffectiveness of “the way we have always done it”, we continue doing things “the way we have always done it” for the vast majority of building HVAC designs.

How about all that particulate that is coming from Jim’s swamp water (a.k.a. Jim’s outdoor water)?  This is going to require a significant upgrade to the pool sand filter and pump.  You’ll need many more turnovers to keep that pool sparkling, and you’ll need to do quite a bit more backwashing of the sand filter that is accumulating substantially more loading (which will pour even more water down the drain).  This means larger capital expenses for higher capacity equipment to filter the pool, and substantially more operating costs in the way of energy to power that pump.

  • This is also the case with outdoor air ventilation.  With more outdoor air being brought in, you risk the introduction of more suspended solids and allergens.  We also know the health risks of fine particulate and that our most common HVAC filters are not effective at filtering this smaller particulate efficiently.  Since the pandemic, there has been a push to increase HVAC filtration efficiency to at least MERV-13.  Although MERV-13 is still limited in its efficiency against fine particulate, it does result in an increase in HVAC fan power. The increased filter efficiency of the MERV-13 introduces more resistance to airflow than the lesser efficient filters.  Therefore, the fan must work harder to provide the same airflow through the system.  More outdoor air means more energy consumed, faster filter loading, more frequent filter replacements, and added labor for maintenance.

Next, we have to ensure that the pool is comfortable for the swimmers, just like we want the air in our buildings to be comfortable.  Nobody is going to enjoy jumping into a 50F pool.  Outdoor water in most cases is going to be much colder than the ~ 80F we find comfortable for swimming. And with the volume and rate of new outdoor water being brought in to keep our pools up to code, the standard size pool heater you are used to seeing is NOT going to cut it any longer.  Maintaining an 80-degree water temperature in our pool while we replace all the water once an hour will be HIGHLY challenging, especially for Jane Doe who is filling her pool with a frigid mountain stream, or for those using 45F to 50F degree ground water.  To achieve the required comfort temperature, it will require significant, increased capital expense for a giant pool heater and pump and an upsized electrical feeder. Not to mention the increased daily costs of keeping the pool at 80F.  Needless to say, the carbon footprint of your pool is getting out of hand.

  • In building air quality management, we must heat or cool the air being brought indoors for people’s comfort and productivity. When outdoor air comes into the building and is outside of the ideal conditions, it requires the HVAC system to consume energy to cool, heat, dehumidify, and/or humidify. Therefore, cool or warm outdoor air that is brought into the building represents a load on the HVAC system. This amount of outdoor air being brought in affects HVAC equipment sizing and power requirements. So, in summary, Increasing outdoor air introduction for ventilation is NOT free.  Furthermore, existing buildings may not be able to increase outdoor air beyond the design conditions, because the HVAC system may not be large enough to take on the added loading.

Now that we have gone through this analogy, what is the point I am trying to make?  The point is we, as a society, have a much better understanding of water, water quality and water treatment methods.  However, the same knowledge and understanding is not prevalent for air quality. We have gone through our water quality revolution.  We understand what is good and bad in water.  Very often we can see or smell the anomalies, and we are comfortable with the tools and application process used to remedy them. We all have Brita filters, R.O. water systems, and buy bottled water for drinking.  Many of us won’t drink “outdoor water” even when treated and sent to our household taps.  And swimming pools have been around for a very long time. We know the importance of healthy water, and we know how to produce it.

As for air quality?  We have not had our air quality revolution. Not yet. In addition, you can’t always see the things in the air that are bad for you.  Many of us depend on primitive tools that are ineffective at comprehensive air treatment.  The theories and methodologies used for indoor air quality improvement today date back to the mid to late 1800’s with the discovery that allowing outdoor air into the home helps dilute smoke from fireplaces and bodily odors. Sure, we have played around with the amounts of air that should be introduced, but there has been little to no innovation or progress towards health and wellness outcomes insofar as indoor air quality since that time.  During the 70’s and 80’s when buildings were being built tighter and reduction of HVAC energy became paramount, we began seeing the health impacts of reduced indoor air quality.  Was there an indoor air quality revolution then?  There was not. It took a global pandemic and the discovery that viral pathogens could travel from person to person via airborne transmission to get the majority of us to open our eyes.  Only when the masses recognized the problem and demanded action did the wheels of the indoor air quality revolution begin to turn.

So here we are on the cusp of the indoor air quality revolution.  But facing us is more than a singular challenge.  Not only must we achieve improvement of health and wellness in our indoor spaces, but also the health and wellness of our environment, and of our power transmission system.  We have an energy crisis facing us, as we seek to lean more on renewable energy sources and reduce our dependence on fossil fuels.  Ending fossil fuel reliance is easy, as it can be done by mandate.  However, providing for our energy needs while we figure out how to design and construct the renewable energy grid of the future?  That’s not so easy.  Nevertheless, we are pushing forward with the initiative of electrifying our homes and buildings while bracing ourselves for EV adoption.  We are facing a substantial electrical grid demand increase at a time when we are drawing down the major fuel sources that feed it.  Something has got to give.  There needs to be some sort of energy subtraction.

This brings us full circle to our air versus water treatment analogy.  HVAC represents the largest consumer of energy on our grid, and much of what determines that consumption is the way in which we ventilate the buildings (aka make the air “clean”).  Ventilation has represented a large piece of the HVAC energy story even while achieving poor results.  Yet, one of the prevailing theories on how we can achieve improved indoor air quality is to increase that ventilation rate even further.  This would make the largest consumer of energy on our grid even LARGER at a time when we need reduction of demand, and reduction of emissions.  The math does not work.

Here is what most people don’t know.  They don’t know that there are innovative tools out there that can allow us to treat air similar to how we treat water.  We can clean the air instead of dumping it out.  We can remove the airborne particles more effectively and in such a way that is compatible with existing HVAC systems. We can scrub the air of VOC’s and odors with commercialized sorbent filtration technology that is similar to that which has been in use in submarines and space shuttles.  We can mitigate airborne and surface pathogens with organic sanitizing air treatment technology that has been in successful use for decades.  We can validate our air quality with user-friendly IAQ monitoring and trending products that have existed for many years.  Our design engineers can use existing, approved mechanical codes to design new or retrofit building ventilation to reduce outdoor air dilution and provide cleaning instead.  All of these tools pave the way for reducing the current costs of HVAC operation while simultaneously improving indoor air quality.  We can achieve those health and wellness outcomes for our people and our environment.  To do this, we must become familiar with the tools that exist to facilitate the execution of the indoor air quality revolution.  And then, we need to be willing to do it, and not continue doing things “the way we have always done it”.  Change isn’t easy.  Especially when we are so good and efficient at doing things the way we are currently doing them.  But the consumer, occupant, or client can move the revolution along by demanding better.  The science is there, and the tools are there.  We just need to take the first steps in the right direction.


Written By Mark Miersen
Hedrick Associates
Vice President of Business Development