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Insulation And HVAC Equipment For Better Air Quality

October 23rd, 2023 | 5 min read

By Kilian Agha

Like many others, you’re concerned about the quality of the air in your home. You do not want to breathe any dust, allergens, or pollen. Whether you’re facing poor indoor air quality or taking preventative measures, you want to know what you can do to improve your air quality.

The two essential building blocks that impact your air quality are your insulation and your HVAC system. South Central Services has a background in both. We’ve insulated hundreds of homes with spray foam insulation. Spray foam insulation, paired with the appropriate HVAC equipment, is a powerful tool for improving your indoor air quality.

By the end of this article, you will know:

  • Why spray foam offers better air quality
  • Why other insulations can’t compete with spray foam regarding air quality
  • What HVAC equipment best compliments spray foam
  • What HVAC equipment you can add to your system for better air quality

How Spray Foam Insulation Improves Air Quality

Spray foam insulation is not an air-purifying product, so how can it improve indoor air quality? When we think about air quality, we should consider two different factors: the quality of existing air inside and the quality of the air entering from outside.

Spray foam improves air quality by preventing air from leaking into the home. Both open cell spray foam and closed cell spray foam have an air-sealing ability, also known as the ability to create an air barrier. Through this air barrier, spray foam can handle one of the two factors that impact indoor air quality.

Without an air barrier, air can leak into your home at random. That leaking air can bring allergens, dust, pollution, and other VOCs with it. Homes that are not air-sealed essentially have many tiny open windows that allow air to flow uncontrolled. If the home is located in an area with outside air pollution concerns, that pollution will filter inside through air leakage.

While other products for air-sealing exist, spray foam conveniently provides insulating power and an air barrier. If you need insulation somewhere in your home and you want the best indoor air quality, spray foam insulation is the product you’re looking for.

Why Fiberglass And Cellulose Cannot Improve Air Quality Significantly

No other insulation product has a built-in air-seal. Fiberglass and cellulose insulation actually function by allowing air to pass through. As the air travels through the insulation, its heat dissipates. The traditional measurement of insulation effectiveness is R-value, which measures resistance to heat transfer. R-value only speaks to the temperature of the air passing through the insulation, not the quality.

A layer of loose fill cellulose insulation, which can be installed as a blown-in insulation in attics or as a dense pack insulation in wall cavities.

For insulations like fiberglass and cellulose, air barriers must be created with other products before installing insulation. Improving air quality with fiberglass or cellulose is possible, but only after investing in a separate air-sealing product. Whereas when insulating with spray foam, air-sealing and insulating happen simultaneously. The product is a 2-in-1.

What About Off-Gassing Fumes?

You may have heard about off-gassing fumes and spray foam insulation. You may even read some horror stories about families who invested in spray foam, and it failed them. These personal stories can be scary, especially when considering the same product.

Anyone who experiences a phenomenon called continuous off-gassing has failed spray foam insulation installed in their house. The installer, whether a DIY homeowner or a professional contractor, failed to recognize that the foam was off-ratio. Any time that foam is off-ratio, it must be removed and replaced. Off-ratio foam is not a safe or inert insulation product.

What do we mean when we say foam is off-ratio? Spray foam insulation is created through a complex chemical reaction between two liquid chemical components. These components react in a 1:1 ratio. When foam is installed on-ratio, it becomes a safe and inert finished product. The liquid chemical components entirely transform into foam.

When foam is installed off-ratio, some amount of liquid chemical is left over with nothing to react with. Since the chemical cannot react, it stays in its raw form forever, posing health risks and potentially off-gassing continuously.

All spray foam insulation off-gasses during manufacturing. This off-gassing is why professional contractors wear respirators and set up ventilation within a home. Off-gassing during manufacturing is why residents and pets must vacate while the foam is sprayed. Off-gassing is a normal, controlled byproduct of a successful chemical reaction. A fixed amount of off-gassing fumes are created that dissipate and never impact your indoor air quality again.

This diagram shows the breakdown of the chemical reaction and its products and byproducts.

Chemical Reaction to Create Spray Foam

HVAC Equipment For Better Air Quality

Spray foam insulation handles one factor of better indoor air quality: preventing outside air from leaking into the home. But how can you control the second factor of purifying the air you already have inside?

The standard HVAC system in a home is driven by comfort, not air quality. While these systems can have a minute impact on air quality, the standard ventilation system is not built for air quality improvements. If you are concerned about the air quality in your home, you will need to add supplemental equipment to your HVAC system.

Let’s examine some of the additional HVAC equipment you can invest in for better air quality.

1. UV Lights In Ductwork

When air passes through your ductwork, it circulates throughout your home. However, the ductwork itself does not purify the air it circulates. You can install UV lights into your ductwork to kill bacteria in the air as it passes through.

REME HALO is a reliable brand for in-duct air purifiers. These UV light systems are often the first step homeowners will take to improve indoor air quality. Installation is simple, and these systems can function for a variety of home sizes.

You can expect to invest about $500 into a UV light system like a REME HALO.

2. Whole House Humidifiers And Dehumidifiers

In our service area of southern Pennsylvania, houses can become dry in the winter and humid in the summer. We need a relative humidity level of 50% to 55% to be comfortable in our homes. To ensure the air quality inside meets these humidity requirements, whole house humidifiers and dehumidifiers can be installed.

This type of equipment is two different systems. A whole house humidifier is used in the wintertime to raise humidity levels inside, while a whole house dehumidifier is used in the summertime to lower humidity levels.

The equipment cost will vary depending on the brand you have installed and the contractor you work with to install the equipment.

The lowest you can expect to pay would be approximately $1,000. Some systems can cost as much as $3,000 to install.

3. Energy Recovery Ventilators And Heat Recovery Ventilators

When insulating with spray foam, we recommend investing in a heat recovery ventilator (HRV) or an energy recovery ventilator (ERV). These systems better support spray foam insulation than traditional equipment can alone.

HRVs and ERVs process temperature differences from the outside air and also purify the air in your home as outside and inside air are exchanged.

Generally, an HRV or ERV will cost between $1,000 and $4,000 to install. Whether you should invest in an HRV or an ERV will depend on where you live.

The Bottom Line About Air Quality And Spray Foam Insulation

Spray foam insulation is the only insulation product that can create an air barrier. Through this air barrier, spray foam prevents outdoor air from leaking into a home. The air outside can have allergens, dirt, and pollution. With spray foam, none of those pollutants can enter your home uninvited.

When insulating with spray foam, we recommend pairing your HVAC system with either an HRV or an ERV. These systems will make your home more efficient, lower your energy bills, and purify the air as it exchanges with the outside air. You can also consider other HVAC equipment like UV lights and whole house humidifiers.

Now that you understand how insulation, air-sealing, and HVAC work together for better indoor air quality, your next step is to:


Kilian Agha

Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends.