IAQ questions for nyc apartment

[demetre1]

I am renovating a 2nd floor 2100sf 1-story apartment in NYC. It is an older 6-story masonry structure with 9 windows in the unit (6 new tilt and turn aluminum units/ 3 double hung wood units). It is heated via radiators from a building wide steam boiler. We are installing a ceiling hung 5 ton Trane variable speed air handler and high efficiency 2-stage condenser for cooling only. System will run in the hotter June-Aug months primarily. Radiators run primarily Nov-March. And April-May, Sept-Oct typically no cooling or heat is needed. Dryer will exhaust and exhaust fans will be provided for two baths and kitchen.

I have just started to consider indoor air quality though. I have read up on this forum a little and wanted to inquire about indoor air quality measures best suited for this particular project and location.

It has been suggested in this forum that a simple Merv 11 filter with a ventilating dehumidifier could be a simple and effective setup. Wondering if a dehumidifier is necessary though in this climate as the only months with high humidity seem to be the months when the A/C unit would be running and dehumidifying the air. I have never tracked indoor humidity though so maybe just because one is typically comfortable in the fall and spring months without any dehumidifying action does not mean the air is under 50% RH where it should be. Any input would be appreciated.

Other whole house ventilation setups seem to be ERV, HRV or a simple system like the Aprilaire 8126.

Few specific questions -

Worried about noise from a dehumidifier since the only space to install the unit is above a dropped ceiling in the unit (drop ceiling is 2 layers gyp board). How quiet would this unit be in relation to the noise from a variable speed air handler? We hung the air handler with vibration isolators to avoid noise transfer to the apartment unit above. Seems like you need to do the same for the dehumidifiers.

If I get the dehumidifier I see that the ones from Ultra-Aire come with a Merv 11 filter. If I do not get the dehumidifier does a Merv 11 filter simply replace the 22x20x1” Trane air handler filter or do I need a separate filter box?

Would the system significantly benefit from a Lennox HC16 or IQAir Perfect 16 air cleaner? Or for that matter a UV purifier? Or is this a little overkill if I have proper whole house fresh air ventilation and a Merv 11 filter?

In a 40sf laundry room we are installing a gas dryer in a built in cabinet enclosure . Will provide 60sqin openings top and bottom of cabinet door per manufacturer but was not planning on installing a supply register to that room. I am just wondering if the user closes the door to the laundry room while the unit is running if there would be enough make up (and combustion) air to that room via a ½" undercut to the door. Or would a supply register used in conjunction with a whole house ventilation system be a much better idea?

We are also building a shower stall that will not have any pivoting openings in the frameless glass enclosure aside from the frameless glass door. I was thinking of installing an exhaust fan grille to the shower stall in addition to the bathroom so that moisture could be exhausted from the shower stall after use via an inline Fantech unit. Would construct that exhaust duct run in aluminum to avoid future corrosion issues. Wondering if anyone had any input on this setup. Wondering if they think this design could properly dry out the shower (via 30 minute or more fan timer) or would a pivoting opening (ie transom above the glass door) be necessary to dry the shower out after use.

Last – wondering about adding an evaporative or steam humidifier to the system for the winter months when the radiant heat seems to dry the indoor air out. I have heard that evaporative humidifiers do not seem to work near as well as steam humidifiers. On the other hand though wondering if a ventilating whole house system eliminates any need for a humidifier by supplying the apartment with fresh outdoor air with a higher humidity?

Thanks for any help.

[teddy bear]

I am renovating a 2nd floor 2100sf 1-story apartment in NYC. It is an older 6-story masonry structure with 9 windows in the unit (6 new tilt and turn aluminum units/ 3 double hung wood units). It is heated via radiators from a building wide steam boiler. We are installing a ceiling hung 5 ton Trane variable speed air handler and high efficiency 2-stage condenser for cooling only. System will run in the hotter June-Aug months primarily. Radiators run primarily Nov-March. And April-May, Sept-Oct typically no cooling or heat is needed. Dryer will exhaust and exhaust fans will be provided for two baths and kitchen.

I have just started to consider indoor air quality though. I have read up on this forum a little and wanted to inquire about indoor air quality measures best suited for this particular project and location.

It has been suggested in this forum that a simple Merv 11 filter with a ventilating dehumidifier could be a simple and effective setup. Wondering if a dehumidifier is necessary though in this climate as the only months with high humidity seem to be the months when the A/C unit would be running and dehumidifying the air. I have never tracked indoor humidity though so maybe just because one is typically comfortable in the fall and spring months without any dehumidifying action does not mean the air is under 50% RH where it should be. Any input would be appreciated.

Other whole house ventilation setups seem to be ERV, HRV or a simple system like the Aprilaire 8126.

Few specific questions -

Worried about noise from a dehumidifier since the only space to install the unit is above a dropped ceiling in the unit (drop ceiling is 2 layers gyp board). How quiet would this unit be in relation to the noise from a variable speed air handler? We hung the air handler with vibration isolators to avoid noise transfer to the apartment unit above. Seems like you need to do the same for the dehumidifiers.

If I get the dehumidifier I see that the ones from Ultra-Aire come with a Merv 11 filter. If I do not get the dehumidifier does a Merv 11 filter simply replace the 22x20x1” Trane air handler filter or do I need a separate filter box?

Thanks for any help.

2nd story 2,000 sqft with 5 ton a/c is a big a/c. Make sure it is not grossly over-sized. With your cooling season and if you have supplemental dehumidification, go single speed properly sized a/c. An extra .5 ton is suggested for reasonable cool-down when using t-stat set-up when unoccupied. You do not have a hot attic to cause high cooling loads like a house. You are cooled above and below.
If you want a 75^F, 50%RH, 55^F dew point home with adequate fresh air, be prepare to provide dehumidification when the outdoor dew point is +60^F. During hot weather, a properly sized, setup a/c will remove 3-8 gallons of moisture per day to maintain 50%RH. During rainy, wet, cool weather the dehumidifier is needed.
I would suggest 80-100 cfm of fresh make-up air with a Ultra-Aire 90H whole house ventilating dehumidifier mainly for spring/summer/fall fresh air when occupied and windows closed. During winter, the stackeffect and wind will probably get the air change in 5 hours that you need to purge indoor pollutants and renew oxygen. If you only have a couple occupants, you need humidification. You can hook a evaporative simple humidifier into the dehumidifier loop for winter humidification if needed to maintain 35%RH. This works good.
Use a 4" merv 11 on your a/c also to keep the equipment clean. With good air change and merv 11, hold on additional filtering/treatment unless there is proven need.
Certianly noise should be a concern. Suggest that the air handler/dehumidifier be located over space like the utility/kitchen area not bedrooms/office/tv watching area. If not possible, be prepared to isolate the equipment with sound deadening encolsures like 3/4" plywood.

Other whole house ventilation setups seem to be ERV, HRV or a simple system like the Aprilaire 8126.

Few specific questions -

Worried about noise from a dehumidifier since the only space to install the unit is above a dropped ceiling in the unit (drop ceiling is 2 layers gyp board). How quiet would this unit be in relation to the noise from a variable speed air handler? We hung the air handler with vibration isolators to avoid noise transfer to the apartment unit above. Seems like you need to do the same for the dehumidifiers.

If I get the dehumidifier I see that the ones from Ultra-Aire come with a Merv 11 filter. If I do not get the dehumidifier does a Merv 11 filter simply replace the 22x20x1” Trane air handler filter or do I need a separate filter box?

Would the system significantly benefit from a Lennox HC16 or IQAir Perfect 16 air cleaner? Or for that matter a UV purifier? Or is this a little overkill if I have proper whole house fresh air ventilation and a Merv 11 filter?

In a 40sf laundry room we are installing a gas dryer in a built in cabinet enclosure . Will provide 60sqin openings top and bottom of cabinet door per manufacturer but was not planning on installing a supply register to that room. I am just wondering if the user closes the door to the laundry room while the unit is running if there would be enough make up (and combustion) air to that room via a ½" undercut to the door. Or would a supply register used in conjunction with a whole house ventilation system be a much better idea?

We are also building a shower stall that will not have any pivoting openings in the frameless glass enclosure aside from the frameless glass door. I was thinking of installing an exhaust fan grille to the shower stall in addition to the bathroom so that moisture could be exhausted from the shower stall after use via an inline Fantech unit. Would construct that exhaust duct run in aluminum to avoid future corrosion issues. Wondering if anyone had any input on this setup. Wondering if they think this design could properly dry out the shower (via 30 minute or more fan timer) or would a pivoting opening (ie transom above the glass door) be necessary to dry the shower out after use.

Last – wondering about adding an evaporative or steam humidifier to the system for the winter months when the radiant heat seems to dry the indoor air out. I have heard that evaporative humidifiers do not seem to work near as well as steam humidifiers. On the other hand though wondering if a ventilating whole house system eliminates any need for a humidifier by supplying the apartment with fresh outdoor air with a higher humidity?

Thanks for any help.

A adequate undercut on the laudry room door with take care of the gas dryer make-up air. Exhaust from the shower and above the stove are good ideas. This also points out the need of fresh make-up ventilation instead of sucking air from ajoining apartments.
Have you a/c contractor talk to Ultra-Aire about connections for fresh air circulation and humidifier connections.

Regards TB

[demetre1]

Thanks for your response.

I just bought one of those co2 meters and started to test in an adjacent apartment in the building. Outdoor co2 levels are around 380ppm and indoor co2 levels are around 650ppm with windows closed and one occupant. Weather is calm and warm.

Wouldn't that discrepancy of +/- 300ppm indicate that the apartment is receiving sufficient natural ventilation and air changes per hour without further mechanical ventilation?

Thanks for any input.

[demetre1]

Actually the longer I leave the detector on it seems to be showing indoor readings of about 550ppm.

[teddy bear]

Thanks for your response.

I just bought one of those co2 meters and started to test in an adjacent apartment in the building. Outdoor co2 levels are around 380ppm and indoor co2 levels are around 650ppm with windows closed and one occupant. Weather is calm and warm.

Wouldn't that discrepancy of +/- 300ppm indicate that the apartment is receiving sufficient natural ventilation and air changes per hour without further mechanical ventilation?

Thanks for any input.

Wow! Thanks for caring. The CO2 inside verses outside shows the amount of fresh air infiltrating verses the CO2 from the occupants. With 380 ppm outside and 650 ppm inside, indicates 70 cfm of fresh air per occupant. Consider that you must wait for the fresh air to mix thoroughly with the CO2 from the occupants. This takes several hours with some circulation of air. Also that is only for the outside condition at the time of observation. Mainly wind/temp outside and the operation of mechanical devices in the home influence the amount of outside air entering the home. As all of these varibles playout, you see the pattern of CO2 levels that with indicate the amount of air change the home is really getting verses the number of occupants. At the current levels, you are getting enough fresh air.
One occupant with 650 ppm CO2 as a average indicates 7o cfm of fresh air. 18,000 cubic feet of space with 70 cfm of fresh air gets an air change in 260mins or an air change in 4 hours. This is consider adequate to purge the indoor pollutants for and renew oxygen by most. That amount of air change will handle upto 10 occupants.
Here is a rough estimate of the cfm of fresh air occupant.
Starts with 450 ppm CO2 outside air.
CO2 ppm levels CFM Fresh air per occupant
600 70
700 40
800 30
900 23
1500 15
2000 7
The important point is that occupied space needs an air change in 4-5 hour to purging indoor pollutants and renew oxygen.
It is not about the CO2 levels be to high. Ten occupants in the same space would be +2,000 ppm and the space has adequate air change. Higher levels need more fresh air for the occupants to renew oxygen.

What brand of CO2 meter are you using?
You need long term monitoring to verify the amount of fresh air during the different seasons. Supplement the fresh air only when needed. Maintain <50%RH to avoid mold and dust mites. When the outdoor dew point is +60^F and the space is occupied, you need moisture removal, a/c or dehumidification. You may have to humidify during cold dry weather.
Keep us posted.
Regards TB

[demetre1]

Thanks so much for your response.

Insofar as the co2 meter I am using the AQ100 from co2 meter.com.