What filter type would you recommend?

[metfan]

Hi all,

Have a one story 1300sf townhome and I am looking into upgrading the filter media. Right now I am using a 1 inch merv 8 filter that I change every month ( Im afraid of going any higher and damaging the system). In the past year and a half I took out the cartpet, put in laminate flooring and had the furnace and ductwork cleaned but the wife is still having allergy/asthma issues. I . Now I am looking into a better filter system on a rather tight budget. I have no pets and the furnace is in the finished basement. With all the choices out there what do you recommend I look for?

Thanks.

[wahoo]

Have the filter replaced with a 5" thick "air bear" type large pleated filter. You can usually get 11 MERV or higher with these filters and good filtration. Forget the 1" pleated filters unless you want problems. You will probably have to get the 5" filter professionally installed as it usually requires ductwork/RA drop changes!

[skippedover]

The term "Allergy/Asthma issues" is a very broad term. There are various methods of resolving indoor air quality issues but each has a price attached and a tight budget may not be so tight if you factor in cost of medicines, doctor visits or lost work/productivity issues. Here is a list of the recommendations I would make if your home was under our company's care.

1. Sealing of duct work, particularly return ducts is of the utmost importance for medical purposes, as opposed to efficiency purposes. But make no mistake, supply leaks to unconditioned spaces require infiltration of make-up air and so should also be addressed.

2. Any "panned bay" returns should ideally be abandoned and replaced with sealed sheet metal ducts or other air tight ducts.

3. All ceiling supply and return boxes should be sealed to the sheet rock.

4. Installation of a customer serviceable, electronic air cleaner is the best line of defense against airborne particles of all types. A good electronic air cleaner will remove 97.7% of particles down to about .3 microns in size but it is imperative, to maintain that level of efficiency, that the unit be kept in top, clean, condition. Something like the Dynamic or MicroPowerguard units are easily customer serviceable but do need to be professionally installed to prevent high static pressure issues. They are a 1-inch unit but I would not recommend installing them in the existing filter rack. When properly installed, the static increases are marginal. If just dropped in as a replacement, static pressures increase, beyond acceptable limits, IMO. Conventional EAC's do a great job initially but require chemical/professional cleaning regularly to keep them in peak condition.

5. I'd also recommend installation of at least one UltraViolet light to help control colonization of the living organisms that also reside in the indoor air. Ideally, you'd install more than one UVL but with budget constraints, you can always add more later. My suggestion would be to get a UVL that has a 2-year bulb and at least 120-Watts of output when measured at 6-inches from the bulb. The Quantum series of UVL's meet such performance standards but others may as well.

As a final thought, if you've not had a blower door test done on the home to determine how much air leakage is present, that would be a good place to begin. Pay less attention to leaking windows and doors, as they infiltrate fresh outdoor air. Places that leak into wall cavities, basement or crawl spaces and other locations from which you would not want air you breathe to come, would be the places to seal and stop the leakage.

As far as air filters are concerned, they're rates in MERV numbers. This is a relatively simple way of stating the density of the filter material. The more dense it is, the smaller particles it will trap. Likewise, the more dense it is, the less air can pass through the media, so static pressure goes up. This is why the better high MERV filters solve the high static problem by increasing the total surface area of the material through deep pleats of 4 or 5 inches, which effectively provides more area for air to pass. But none of the MERV filters can collect particles as small as those collected by a good quality electronic air cleaner. Hence the recommendation above.

[George2]

The term "Allergy/Asthma issues" is a very broad term. There are various methods of resolving indoor air quality issues but each has a price attached and a tight budget may not be so tight if you factor in cost of medicines, doctor visits or lost work/productivity issues. Here is a list of the recommendations I would make if your home was under our company's care.


1. Sealing of duct work, particularly return ducts is of the utmost importance for medical purposes, as opposed to efficiency purposes. But make no mistake, supply leaks to unconditioned spaces require infiltration of make-up air and so should also be addressed.

2. Any "panned bay" returns should ideally be abandoned and replaced with sealed sheet metal ducts or other air tight ducts.

3. All ceiling supply and return boxes should be sealed to the sheet rock.

4. Installation of a customer serviceable, electronic air cleaner is the best line of defense against airborne particles of all types. A good electronic air cleaner will remove 97.7% of particles down to about .3 microns in size but it is imperative, to maintain that level of efficiency, that the unit be kept in top, clean, condition. Something like the Dynamic or MicroPowerguard units are easily customer serviceable but do need to be professionally installed to prevent high static pressure issues. They are a 1-inch unit but I would not recommend installing them in the existing filter rack. When properly installed, the static increases are marginal. If just dropped in as a replacement, static pressures increase, beyond acceptable limits, IMO. Conventional EAC's do a great job initially but require chemical/professional cleaning regularly to keep them in peak condition.

5. I'd also recommend installation of at least one UltraViolet light to help control colonization of the living organisms that also reside in the indoor air. Ideally, you'd install more than one UVL but with budget constraints, you can always add more later. My suggestion would be to get a UVL that has a 2-year bulb and at least 120-Watts of output when measured at 6-inches from the bulb. The Quantum series of UVL's meet such performance standards but others may as well.

As a final thought, if you've not had a blower door test done on the home to determine how much air leakage is present, that would be a good place to begin. Pay less attention to leaking windows and doors, as they infiltrate fresh outdoor air. Places that leak into wall cavities, basement or crawl spaces and other locations from which you would not want air you breathe to come, would be the places to seal and stop the leakage.

As far as air filters are concerned, they're rates in MERV numbers. This is a relatively simple way of stating the density of the filter material. The more dense it is, the smaller particles it will trap. Likewise, the more dense it is, the less air can pass through the media, so static pressure goes up. This is why the better high MERV filters solve the high static problem by increasing the total surface area of the material through deep pleats of 4 or 5 inches, which effectively provides more area for air to pass. But none of the MERV filters can collect particles as small as those collected by a good quality electronic air cleaner. Hence the recommendation above.

Skip..............if we sealed the (return) ductwork where I live, we would have alot of frozen coils or cracked heat exchangers.

The leaks are the only reason the systems work at all. P.S. In our area, almost all of the return duct is in the conditioned space.

[metfan]

Thanks all. I agree the "asthma/allergy" reference was a bit broad. More specifically, I am looking to get the air as clean as possible with a system I can manage with reasonable ease and cost. My return is basically a wall cavity with 3 return grills of different sizes. If I remember correctly when it was cleaned I did not see any sheetmetal lining the inside. The main duct is in a bulkhead, 2 layers of firecode drywall, as is the rest of perimeter of the house. i'm a bit concerned of the EAC, seems there's a love/hate opinion of them because of reliability. Can anyone expand on the models mentioned above or have good results with another?

[jtrammel]

I don't like EACs, they work great if maintained properly but very few homeowners maintain them well, just my opinion. I would put a 5" filter and filter box at the air handler/furnace. Also if your return is using a wall cavity there is no telling where you a pulling air from, likely from attic and/or crawlspace/basement. You should look into having a blower door test performed on your home, there are likely a number of things that can be done to reduce dust and allergens inside your home

[dan sw fl]

U should use real HEPA filter(s) that specifically addresses your needs.

Starting with:
http://www.hunterair.com/product/hep...purifier/30378
( I have an older model of this one).

Buy 1 or more ...
http://www.hunterair.com/hunter-air-purifiers/hepatech

You may find similar products at Lowe's or Home Depot or Target. But, I would only buy Hunter Fan.

The basic function of Air Handling Unit filters are to protect the coils and fan, not you.