Monetizing the Return on Mechanical Ventilation
Insulating a house saves energy and that saves money. However, using mechanical ventilation causes conditioned air to be removed from the house only to be replaced by air that requires energy to condition - to warm it or cool it. Utility programs are reluctant to pay for adding mechanical ventilation to the house because it can’t be justified in terms of energy savings. DALYs (Disability Adjusted Life Years) provide a means to monetize the savings in health and productivity. One of the difficulties is that DALYs are population aligned and not individual aligned - although populations are made up of people.
Tight, energy efficient homes must have well designed and well installed mechanical ventilation systems for the health of the occupants as well as the health of the building. So what’s a DALY? DALYs represent the total number of years lost to illness, disability, or premature death within a given population. There is a growing population of people who live in air-tight houses. We’re sealing everything up from windows and doors to light fixtures and heating systems. And not only are we making houses tighter, we’re spending more time in them - closing in on 100% of the time.
If you click on this button and enter your zip code, it will provide you with the number of years of life expectancy at your location.
Life ExpectancyThere are a lot of elements that impact our life expectancy. All the diseases that we face growing up like mumps or measles or COVID-19. There is mold and soot from roads and furnaces. There may be rodents and maybe the range hood or the bathroom fans don’t get used.
And then there is cigarette smoke. Tobacco smoke contains more than 7,000 chemicals.Thirdhand smoke is residual nicotine and other chemicals left on indoor surfaces by tobacco smoke. People are exposed to these chemicals by touching contaminated surfaces or breathing in the outgassing. This residue is thought to react with common indoor pollutants to create a toxic mix including cancer causing compounds, posing a potential health hazard to nonsmokers - especially children.
EXPOSOME
The exposome, conceptually and practically, provides a holistic view of human health and disease. It includes exposure from our diets, our lifestyles, and our behaviors. The human exposome is the environmental equivalent of the human genome . It is a representation of the complex exposures we are subject to through our lives. The exposome encompasses much of what we refer to as nurture - in the old battle of nature vs nurture.
What we are particularly concerned about here are the pollutants that are floating around in the air that can be ameliorated with good ventilation. The ultra-fine particles - PM2.5 in size - have the greatest impact on DALYs. Much of the acrolein and ultra-fine particles come from cooking and those can be removed from the house with a range hood with an effective capture efficiency. Common sense clearly shows that air quality has a significant impact on human life. In fact, it has been estimated that the most common diseases cause the loss of 2,129,090 years of Europeans’ life.
But we don’t want to cut off the connection in bacterial diversity between the inside and the outside of the house. There needs to be a balance. Microbes are all around us. Many species are beneficial to us and help our immune systems to function and control and compete with pathogens and pests. We can’t thrive in a purely sterile environment. We need the air exchange that ventilation provides.
PRODUCTIVITY
Productivity is the key source of economic growth and competitiveness. A country’s ability to improve its standard of living depends almost entirely on its ability to raise its output per worker. In the United States it’s about $34.02 per hour.
HEALTH CARE COSTS
US employers paid nearly $880 billion in health care benefits for employees and dependents. However, illness-related lost productivity costs them another $530 billion per year. That amounts to 60 cents for every dollar employers spend on health care benefits. In the U.S. almost 1.4 billion productive days are lost annually because of absent employees.
ADDING IT UP
Clearly indoor air quality has a direct impact on the health of the occupants. Changing the air - diluting the pollutants - will improve health.
Make some assumption:
Outdoor air is generally 75% better than indoor air;
Choose an effective air change rate of 0.35 ACH;
Multiply those two numbers together: 0.75 x 0.35 = 26.25%
Lost productivity in the U.S. per year is about $1,608 per person
Attributing 26.25% of loss of productivity to poor ventilation: 26.25 x $1,608 = $422/person/year.
This is not perfect math, but the assumptions are reasonable. A well designed, well installed, well maintained residential mechanical ventilation system will pay for itself in less than a year, particularly if there are two people living in the house. And it will keep on paying back year after year after year.
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