Purest possible residential HVAC setup for new home for child

[biglew]

My daughter has very bad allergies and a very weak immune system

We are building a new house and we are entirely focused on creating as clean an environment as possible for her (no carpets, no rugs, etc).

Clearly a whole house HEPA filter seems to be the way to go - what we would like your opinon on is are other add-ons like charcol filters, UV lamps (Non ozone), gas phase filters, etc that will improve upon a whole house HEPA.

If i could create a clean room at home i would, but that costs hundreds of thousands - we are comfortable spending up to $30k - $50k on the HVAC equipment for a our 4,000 sq foot house (not including duct work etc) to make it the best environment for her as possible

Thank you in advance - all advice is much appreciated

[Joehvac25]

Trane make a clean effects air filter setup, it's pretty expensive, I would get the biggest one they make and use a transition between it and funrnace. There maybe something better than this so wait awhile and someone else will chime in.


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[George2]

The Trane unit is not very well constructed (you get what you pay for). They were catching on fire. Maybe they have that problem solved.

The Carrier/Bryant Infinity/Evolution Air Purifier is better constructed AND does more (cleaner air).

[viceman]

have you contacted a qualified engineer or iaq specialist?

[Joehvac25]

The Trane unit is not very well constructed (you get what you pay for). They were catching on fire. Maybe they have that problem solved.

The Carrier/Bryant Infinity/Evolution Air Purifier is better constructed AND does more (cleaner air).

The trane units are pretty expensive, why did they burn up?


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[mark beiser]

The options are many, but you need to make sure the house is built to minimize the contaminants to begin with.

If you are careful about selecting low/no VOC building/finish materials, and furnishings, have good tight construction, and proper fresh air ventilation, you won't "need" as many IAQ gizmos.

[mark beiser]

The trane units are pretty expensive, why did they burn up?

Most of the small number of cases were upflow air handlers that dripped water on the collection cells.
The problem was solved 5 years ago, and the potentially bad collection cells replaced under a voluntary recall.

I'm not a fan of the Clean Effects/AccuClean because the vast majority of homeowners don't maintain them, or any type of EAC, as they should.
I'm also not a fan of the Carrier air cleaner because of the high cost of changing the filter.

I'm more a fan of good high efficiency media air cleaners and source control of IAQ gremlins.
If more is needed to deal with some specific problem, it can be added to a system.

[classical]

Mark is correct simple is better and basic fundamentals is most important. Start with proper sizing (paramount) very tight sealed ductwork, good extended media (HEPA) filter MERV 12 or better and most important start with a clean coil. Coils come with a coating of machine oil from the manufacturing process and this promotes mold growth. I clean all coils with a good green cleaner, treat it with an algaecide and spray it down with a Teflon coating.

Proper sizing is critical for humidity control, maintain the home with a dew point between 50 & 55 degrees and a relative humidity level below 50% will combat mold growth & growth of dust mites which is a source of allergies in many young people.

For the most part UV lights are of little benefit however in your case they could have some benefit, additionally a good whole house supplemental dehumidifier with outdoor fresh air capabilities would be helpful; the Thermastor products are excellent you might also look at Lifebreath.

As far as whole house high end filtration systems like the Carrier and Trane units I would look at the Lennox Pureaire the best of all (IMHO) but as stated they are expensive to maintain. I am not enamored with any of the equipment manufactures certainly not Lennox or Trane but the Pureaire is an excellent product.

[amd]

Forget about high end filters and uv lights.

Electronic air cleaners produce ozone and bypass filters don't move enough air to be effective.

Filtering the pollution out of the air after the fact is an exercise in futility; the propose of the filter is the keep the equipment clean.

----------------------------
One of the best things you can do is install a central vac that's vented outside.

A new, tight house should have a HRV or ERV to vent out excess moisture (showering/cooking) and noxious fumes (new building materials)

Avoid particle board where possible since the glue has formaldehyde in it.

[biglew]

Guys,

Awesome stuff - thank you

We have hired an enviromental engineer to help us with the home material selection (low output, aged materials, low acidity materials, floating floor for less adhesive materials, etc)

Great stuff - THANK YOU

[Salesleader]

You already recieved some good advice. There is another product out there that can be installed allong with a high quality media filter that produces great results. You may want to look into:
https://www.activtek.net/CatalogProd...ategoryId=3905

[jtrammel]

The best way to go about it is with a tight building envelope that brings in fresh filtered air from outside the best way to ensure this is being performed properly is by having a supervisor on the job that is up to the task of ensuring that the practices are being followed through on (someone familiar with LEED green buildings and homes). Then the duct system needs to be as close to 100% sealed as possible, this will keep dust etc from ever being distributed by the hvac system. Electronic air cleaners work well but must be properly maintained consistently to ensure they are working properly. I like the 5" media filters(Honeywell,aprilaire, etc) better than eac's.

[SolarMike]

Start with hydronic floor heat, then keep the vinyls and formaldehydes out of the materials. Watch out for wood resins in some trim wood (pine is bad, hemlock is good). Use real linoleum for flooring or cement with some wool carpets (if she is not sensitive to it). A really tight house with a good HRV with HEPA filters so the house is not breathing in the outdoor air through the walls. My mom had multiple environmental sensitivities and I had to design and build a house for her.

[ArthurHagar]

Go with the Trane Clean Effects. Obviously her health is important to you so you will set aside the time to regularly clean the thing, unlike most people. When it is clean it is the most efficient in the industry, the only problem is people who actually keep theirs clean are the minority. Also go with a variable speed blower and 2 stage condenser. This will keep the air moving over that filter for long periods of time, so you get more filtered air.

In addition, Trane claims their electronic one doesn't produce ozone.

[Chris_Worthington]

Thread relocated to AOP

[motoguy128]

I would consider first a ventilating whole house dehumidifier. In a new home, indoor pollutants from new, modern materails may cause more issues than jsut dust and pollen. A dehumidifier and ventilation will dilute these and keep indoor humidiy in an ideal range which is improtant for someone with sensitive lungs and airway. In many ways a new construction home might be a lot workse than an 80+ year old home with original flooring and more natural materials in terms of indoor pollutants. It actually easier to mitigate things like lead paint and asbestos than the off-gassing for synthetic modern materials for those that are ultra sensitive.

For reducing dust, a good vacuum cleaner used 2-3 times a week with a HEPA filter with be 10X more effective than anything other than a commericial clean room air handler.

Keeping the home under slightly positive pressure will make a big difference.

A MERV 13 Media filter will pull out plenty of allergens as 1/4 the cost of an actual HEPA filter.

One more recommendation. Get ride of all carpeting if you have any. Tile or real hardwood is more sanitary, doesn't contribute to airborn dust and contains fewer chemicals overall.



A litlte off topic... but if I was building a custom home for someone that was ultra sensitive, I've actually specifiy a completely ICF home with tile floors and beleive it or not, plaster walls (antimicrobial and no dust during installation) with radiant heat, zoned chiller water cooling with hot water reheat and steam humidification, and a whole house ventilation system with continous exhaust in bathroom and the kitchen. The garage would be mostly detached and completely sealed. Plus a cool roof design with a conditoned attic with closed cell insualtion under the roof. Window area would be at least 25% using larger picture windows since they are tighter and you don't need an many operable windows in this design.

[Shophound]

A lot of good stuff has already been posted above. All I will add is that if you want to assure the cleanest air via filtration possible, you need to constantly circulate and filter this air. Standalone filtration units where your daughter spends a lot of time may be a way to assure filtration continues when the HVAC system is not running. These units are available with carbon filters (which will give you gas phase filtration). The challenge of putting high levels of filtration in HVAC equipment is doing so without causing an excessive pressure drop through the system. That is, if the filters are too restrictive, the HVAC will not funtion properly, and can be damaged over time as well.

I also can't stress highly enough how important quality source control is, as others above have mentioned. Don't put stinky stuff in your house. No formaldehydes, minimal VOC paints and other materials as much as possible. And you will need to be vigilant about this...it can sneak in many ways that on the surface appear innocuous. You don't want to build an ultra airtight house only to seal in a bunch of toxic, stinky stuff. Basic rule of thumb on construction material VOC content is that if it has a strong odor, it's probably toxic. In practical terms that means no wallpaper, no oil based primers or paints on the millwork, no formaldehydes in the insulation or in the cabinets and shelving material, etc. Also be choosy about floor coverings and window treatments. And furniture. The stinky stuff can sneak in multiple ways.

[SkyHeating]

Here are my thoughts on what I would do if I was in your situation.
First, I would highly seal the home or use spray foam insulation to KEEP OUT all possible issues
Second you will NEED an HRV or some sort of fresh air ventilation
Third Radiant floor system or Daikin Quaternity(the quaternity might be to much for your size house)
If you do not go radiant or ductless make sure your ducts are sealed as good as they can be, 6% or less is good 3% or less is possible and we routinely are able to seal our duct systems to a 3% duct loss on a brand new home. Any ductwork that you can keep inside the envelope is a good thing, open web joists or conditioned attic areas for the trunk lines.
The Trane clean effects is a great product, but you need to clean in monthly or more often for best performance. The Carrier unit is the same as the Honeywell truClean and the truclean may cost a bit less so you might want to look into that but as others have said they are expensive for replacement filters. A HEPA filtration system is also a great option if you want very very low ozone emissions but a HEPA system costs about 3X as much as tru clean filters in my experience.
Lastly, you might also want to look into some of the new plumbing pipe options. I recently had a customer use a type of plumbing that had no VOC emisions and it was fused together.
Look at no or zero VOC paint and finish's and have an air test performed once the house is operational via an Air Advice or similar unit to verify that everything is as clean as stated.

[tedkidd]

Keeping the home under slightly positive pressure will make a big difference.

constantly circulate and filter this air. .

highly seal the home or use spray foam insulation to KEEP OUT all possible issues
Second you will NEED an HRV or some sort of fresh air ventilation

make sure your ducts are sealed as good as they can be, 6% or less is good 3% or less is possible and we routinely are able to seal our duct systems to a 3% duct loss on a brand new home. Any ductwork that you can keep inside the envelope is a good thing, open web joists or conditioned attic areas for the trunk lines.

have an air test performed once the house is operational via an Air Advice or similar unit to verify that everything is as clean as stated.

Manage RH to stay between 40-50% rh. Avoid dust/static on one side and mold on the other.

[motoguy128]

I wonder if you could actually find a plasterer anymore. I would be cool to see a new home done in plaster. 0 dust when installing plaster. Again line based plaster is antimicrobial too. Its' installed wet and cures without any VOC's. Drywall is a absolute mess... and thats an understatement.