Question from Sheri
Has anyone with MCS had to replace their central HVAC system? My doctor insists this is what I need to do.
Did you have any trouble in any way after installing the unit?
Also, has anyone made any modifications to their HVAC to minimize VOCs and other pollutants created by it?
And, does anyone with MCS have any experience with The Lennex Pure Air System installed in duct work to minimize chemical outgassing from a new central heat air unit?
Thank you.
Debra’s Answer
Readers? What is your experience purchasing and installing HVAC systems?
I don’t have any experience with the Lennex Pure Air System, but I took a look at the specs and it doesn’t seem to me to be useful for the purpose you stated. It is simply a UV-lamp, which is not the best method for removing toxic gasses. It says it removes only 50%. Carbon filtration would remove more.
You should have your HVAC system “performance” tested. In all probability there is leakage in the air distribution system of the system (the ducts) as well as the air handler (where the blower fan is), where the evaporator coil is (usually a separate box attached to the air handler), the supply and return plenums (where the ducts take off from the system) and the filter compartment. If there is leakage in any of these areas, let alone all of them you are getting nasty air introduced into the airstream that is then being delivered into your house.
Sheri, I see that you are in California. We have some excellent Home Performance Contractors throughout the state who can performance test your HVAC system. Home Performance mostly deals with energy efficiency but one of the side effects of a Home Performance Upgrade is better indoor air quality because the house and HVAC systems are sealed up so that your indoor air is not being contaminated by attic, crawlspace or air from inside the walls.
You will probably want a special filtration system designed into the HVAC system. I know one HVAC contractor who designs for the IQAir systems and has had really great results for his clients. He is in So. Cal. – His company is So Cal Air Dynamics. You can contact CBPCA (California Building Performance Contractors Association) – 1-888-352-2722. They should be able to help you find a trained Home Performance Contractor in your area.
Remember the problem is not only the materials the HVAC system is made of and what the ducts are sealed with but that the system needs to be designed for your home with the chosen air filtration system included in their design considerations (a Manual J, D & S – if a contractor is not talking to you about doing these calculations do not use them) and the installation must be performance tested to meet criteria well beyond California’s energy code – 20 CFM25 of duct leakage, approx 1000 sq ft of floor area per ton of capacity, refrigerant charge using superheat and subcool method with airflow at around 480 to 500 CFM per ton.
With the question “replace their central HVAC system?”, I can only half answer. We replaced baseboard heat with an HVAC system, air cleaners, etc. It does move the air and the filters collect a lot, but I agree with Debra, it’s not enough. A good air purifier is in order.