When should you replace an HRV or ERV to protect indoor air quality?

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I have chronic illness from the air quality of my home, can you help determine if I need to replace the HVAC system?

Niki Harrison Sept. 6, 2019Last updated: Aug. 4, 2020

Our home was built in '45, most things updated in 60's/70's but with my health issues need to continue improving air quality- some return air/vents were completely blocked off by some not very intelligent homeowners - so air isn't moving properly in home.

The electric isn't grounded (tech North America's electrical grounding isn't grounded properly anyway (need to lower EMFs), gain access to attic, remediate, add air exchanger (with filter and dehumidifier if that's possible?). Anyway, a bio-home inspector would be ideal but all funds need to go towards the actual updates. HVAC right now is not efficient, full of dirt (despite having cleaned) and new furnace/AC with extra filtration and UV  light. Without knocking down the house, is there a way to replace old metal dirty hvac (suspect mold caught in joints etc.)? Local HCAV didn't offer a good suggestion - just air exchanger and that's not enough... need to remove source of issues.

Also welcome the best insulation (in Ontario) for cubbies 16", 2-3" thick. Has to be super clean, no off gassing, mold resistent. 

Also, suggestions for best air exchanger set up for someone with chemical and mold sensitivies. 

And any tips on setting up proper air pressure for air flow in home, don't want the attic air coming into home which I suspect is happening.

Thanks! 

Responses (4)

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Niki Harrison Sept. 13, 2019, 12:18 p.m.

Thanks, yes we had another HVAC specialist in this morning. It was more of what I expected with suggestions. While he also suggested an ERV (not HRV) to use all year around given our humidity zone in Ontario... it's exactly what I wanted to hear from a professional - I shouldn't know more than the contractor coming in based on a 5 min online search ;) We've had the vents cleaned 3 times by 3 different companies (not cheap ones and researched their equipment/cleaning process) and it was still dirty smelling after 2 weeks.

I think it has more to do with age, the previous old furnace (currently have 3 stage filter with UV) and inability to get decades of gunk out that may have caught on metal joints etc. It looks like we'll replace what is accessible at some point, change the direction the furnace to reduce the number and length of HVAC needed, flip the set up so that return is on the inside and heat/cooling on the outside. So I think we are on a better track. Electrical, still need to find someone who understand EMF issues, likely background in EU set ups, they have an appropriate grounding system with bedroom switch off at night. The rest aside from attic remediation is sorted so we are getting there....thanks for your input ;)

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Caroline Scott Dec. 31, 2020, 1:35 a.m.

Hi! You may want to check for a professional air duct cleaning service provider if you're looking to get your ducts cleaned before you try cleaning it yourself. This way you'll know the difference and have a basis on how it's supposed to look once it's cleaned. Having a professional come over and do that work for you could also help you test for leaks while they're at it, you might want to try that out first before calling a separate technician to take a look at it for you.

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Caroline Scott Dec. 31, 2020, 1:41 a.m.

Hey Niki, have you tried calling in a different HVAC contractor/service provider? Because it's really weird that your ducts were "cleaned" but still full of dirt afterwards. You may want to check for some references on how air ducts should look like before and after being cleaned by a professional. Personally, I would prefer to have the whole HVAC system including the duct work replaced if possible given the age and how long it's been since it was last updated. Although, it would definitely be costly so you may want to consult with several HVAC contractors if they could offer other solutions for you other than a complete replacement to improve your indoor air quality.