IAQ Ventilation, UV lights and UV-PCO Air Purifiers - what do you have in YOUR house?

[garya505]

I'm looking to improve my indoor air quality and thinking about what I'd like to have. I'll ask my HVAC guy what we can install in my system, but I'd like to educate myself a little first about what technologies are available. My HVAC guy is sort of a techie like me and he likes it when I do my homework before I talk to him. I've done a little reading on IAQ so have some rough ideas, but I'd like your input.

I already have a good filter, Aprilaire 2210. Now I'm interested in stuff like ventilation, UV lights, and UV-PCO air purifiers. I have a VisionPRO IAQ which I believe can control ventilation. Since the house is fairly well-sealed and we have no ventilation the air gets rather stuffy at times. We get a little bad AC smell occasionally so would like to improve that too. This is a split system, upflow configuration.

So, what do you like, and what really works?

Sometimes actions speak louder than words. What do you have in YOUR house?

[classical]

Unless you have a very tight house that is below it's MVR (minimal ventilation rate) you do not need you do not need outside air. Have you had a blower door test performed on your home. For the most part UV lights do not work and are of little to no benefit for residential applications. PCO devices are great but again unless you have severe allergy and or odor issues. PCO units are very costly to install and more to maintain.

I use a Goodman extended media filter similar to the Aprilaire you have and that is what I put in 95% of the homes I do.

If you are getting odors from your system and you have an extended media filter I would ask was this installed at the same time as your evaporator coil or latter.

Most odors are due to an improper drain line no trap or from a dirty evap coil. Coils come from the factory with machine oil on the fins and this is a food source for mold. If the coil is not properly cleaned before installation even with a good filter you can still have mold growth and DSS.

[motoguy128]

5" Media filter. Currently MERV 8 but I'll probably replace it with a 11 or 13. I have a continously exhaust fan in the garage thats part of my basement, to keep it slightly negative. I have good exhaust fans on all bathrooms. I need to add a range hood exhaust duct some day. I have old windows with storms, so I'm not too concerned about fresh air intake, but the house is moderately tight I believe (never had it tested). It's not sutffy like msot modern homes and doens't have any carpet and little modern materials that would give off a lot of VOC's. I'm still considring adding a passive vent on my downstairs furnace only anyway.

[garya505]

Unless you have a very tight house that is below it's MVR (minimal ventilation rate) you do not need you do not need outside air. Have you had a blower door test performed on your home. For the most part UV lights do not work and are of little to no benefit for residential applications. PCO devices are great but again unless you have severe allergy and or odor issues. PCO units are very costly to install and more to maintain.

I use a Goodman extended media filter similar to the Aprilaire you have and that is what I put in 95% of the homes I do.

If you are getting odors from your system and you have an extended media filter I would ask was this installed at the same time as your evaporator coil or latter.

Most odors are due to an improper drain line no trap or from a dirty evap coil. Coils come from the factory with machine oil on the fins and this is a food source for mold. If the coil is not properly cleaned before installation even with a good filter you can still have mold growth and DSS.

The house is only 8 years old so is probably fairly tight.

The AC was added after the filter was in use for about a year. The AC has only been in use for 2 months. The installers DID NOT clean the coil when it was installed, and it hasn't been cleaned yet.

[teddy bear]

Unless you have a very tight house that is below it's MVR (minimal ventilation rate) you do not need you do not need outside air. Have you had a blower door test performed on your home. For the most part UV lights do not work and are of little to no benefit for residential applications. PCO devices are great but again unless you have severe allergy and or odor issues. PCO units are very costly to install and more to maintain.

Most odors are due to an improper drain line no trap or from a dirty evap coil. Coils come from the factory with machine oil on the fins and this is a food source for mold. If the coil is not properly cleaned before installation even with a good filter you can still have mold growth and DSS.

Here is a misunderstood subject. A blower door test attempts create the air pressure of average winter conditions. This is a 7 mph wind and your average winter temperature. The air leakage is measured at higher pressure and calculated to average winter. If the real leaks are randomly distributed throughout the home, estimated is fairely accurate. Great except what is the real air change on a calm summer day? Without the pressures wind and stack, even leaky home do not have adequeate fresh air change. \
So forget about the natural air rate during calm moderate weather and provide a minimum fresh air change like an air change in 4-5 hours to purge indoor pollutants and renew oxygen.
If you want to confirm the fresh air change of any space, monitor the CO2 levels in the space when occupied. If you know the number of occupants and the CO2 levels, you are able to calculate the real fresh air change. A 2,500 sqft. home with 2 occupants would be about 600-700 ppm of CO2. Of course a CO2 controller set for 600 ppm CO2 is a great way to provide fresh air when the home is occupied and the is not getting enough fresh air. This also avoid ventilation when the natural is adequate or the home is unoccupied.
ASHRAE is recommending the above.
Fresh air ventilation, a merv 11, and maintaining <50%RH throughout the home are basics for indoor air quality.
The HVAC trade has resisted this for many years because normal a/c is unable to maintain the <50%RH without supplemental dehumidification. In recent years the whole house ventilating dehumidifier has been developed to provide fresh air and dehumidification to be added to the high seer a/cs. Many brands are available like the Ultra-Aire, Honeywell, Santa Fe etc.
Regards TB
PS The above comments are important to regions with outdoor dew points above 55^F. Typically these are green grass climates. In arrid climate, dehumidification may not be needed. Basements in most climates need dehumidification to avoid +50%RH for extended times.

[garya505]

In my case, indoor RH reduction is not a problem. It normally stays between 20% and 40%. Outdoor RH is normally low here, maybe 40% maximum unless it is raining. I might not want to pull in outside air when it rains.

[classical]

TB I agree with most of what you say however the OP was in NM so I doubted that humidity was a problem, although with a very tight house it could become problem.

I have been checking Co in homes for more than ten years and have never found high levels of background in a home in Houston even with gas stove tops.

Granted it may be different in colder climes.

I respect your position and like your product but I have no problem with getting my homes comfortable and healthy with a properly sized and installed system with an ECM motor.

I do install your units on SIP homes and ICF homes where the units are oversized even at 2-tons. I just find that in Houston with a proper system supplemental dehumidification is only necessary less than 10 to 20 days a year and the extra expense is just not warranted.

[garya505]

OK, I think I've decided that a 6 inch duct with a normally-closed damper connected between the return plenum and the outside of the house would probably work for my fresh air. Honeywell has kit for this (Y8150), and Aprilaire has one that includes a controller that would limit ventilation by outside air temperature.

Now, about those UV lights and PCO purifiers ... ?

[teddy bear]

TB I agree with most of what you say however the OP was in NM so I doubted that humidity was a problem, although with a very tight house it could become problem.

I have been checking Co in homes for more than ten years and have never found high levels of background in a home in Houston even with gas stove tops.

Granted it may be different in colder climes.

I respect your position and like your product but I have no problem with getting my homes comfortable and healthy with a properly sized and installed system with an ECM motor.

I do install your units on SIP homes and ICF homes where the units are oversized even at 2-tons. I just find that in Houston with a proper system supplemental dehumidification is only necessary less than 10 to 20 days a year and the extra expense is just not warranted.

We are talking about CO but the breathing generated CO2. It is a measure of the amount of fresh air entering the and mixing with CO2 from the occupants. You need an air change of fresh air every 4-5 hours. When the outdoor dew point is +55^F and cooling load is low, the indoor ^F dew point/%RH will be high. Plus occupants add moisture. Fresh air ventilation is a must in all well built homes. Building science.com did a 5 house study in Houston proving the point. Then again what do I know.
Thanks for the follow up.
Regards TB

[teddy bear]

OK, I think I've decided that a 6 inch duct with a normally-closed damper connected between the return plenum and the outside of the house would probably work for my fresh air. Honeywell has kit for this (Y8150), and Aprilaire has one that includes a controller that would limit ventilation by outside air temperature.

Now, about those UV lights and PCO purifiers ... ?

This is not fresh air ventilation, but go ahead. Keep us posted. The idea is get an air change in 4-5 hours which requires a trickle of 100 cfm when the house is occupied, not a closed damper or an open damper when the fan runs and the outside weather is suitable. Try fresh air when occupied continuous and off., Keep us posted. You have to start someplace.
Regards TB
REgards TB

[hvacmike85]

This is not fresh air ventilation, but go ahead. Keep us posted. The idea is get an air change in 4-5 hours which requires a trickle of 100 cfm when the house is occupied, not a closed damper or an open damper when the fan runs and the outside weather is suitable. Try fresh air when occupied continuous and off., Keep us posted. You have to start someplace.
Regards TB
REgards TB

Man you are a IAQ guru! I'm pretty good at service now so the Air stuff intrest's me and is really technical I think, just another step in this trade i guess

[energy star]

I'm looking to improve my indoor air quality and thinking about what I'd like to have. I'll ask my HVAC guy what we can install in my system, but I'd like to educate myself a little first about what technologies are available. My HVAC guy is sort of a techie like me and he likes it when I do my homework before I talk to him. I've done a little reading on IAQ so have some rough ideas, but I'd like your input.

I already have a good filter, Aprilaire 2210. Now I'm interested in stuff like ventilation, UV lights, and UV-PCO air purifiers. I have a VisionPRO IAQ which I believe can control ventilation. Since the house is fairly well-sealed and we have no ventilation the air gets rather stuffy at times. We get a little bad AC smell occasionally so would like to improve that too. This is a split system, upflow configuration.

So, what do you like, and what really works?

Sometimes actions speak louder than words. What do you have in YOUR house?

For the most part UV lights do not work and are of little to no benefit for residential applications.

Coils come from the factory with machine oil on the fins and this is a food source for mold. If the coil is not properly cleaned before installation even with a good filter you can still have mold growth and DSS.

Never washed a new coil, and why would you say UV lights are of little benefit in a residential application?

[hvacmike85]

Never washed a new coil, and why would you say UV lights are of little benefit in a residential application?

I have had coils from factory so oily water would drip off of it before it hit the pan, not always but I try to hit a new coil with some foam cleaner helps em drain, as far as the rest stated above not sure.