Hello.
I recently purchased a 4-story townhome, 1st level garage, 2nd level kitchen/living/dining/bath area humidity level based on thermostat 47-50%
3rd level two master bed/bath, guest bed/bath, and laundry room, humidity level 54-60%. The master bath is between 58-60% pretty consistently
4th level loft bedroom/bath and HVAC closet. humidity 58-63. Right now its 64% humidity outside so its pretty bad to be so close to the humidity level outside
Some more information:
Above the 4 stories is the attic with a metal roof. The 4th story also has two rooftop decks that sit on top of the bedrooms in the extremities of the 3rd floor. In other words, the 3rd master bed/bath has a roof deck on top. The 3rd-floor guest bed has the other roof deck on top. The roof decks have Trex decking and are not covered. The sun beats down on these pretty good at various times in the day.
The master bed/bath ceiling/guest bedroom ceiling is about 4-5 degrees warmer than the center of the 3rd floor not exposed to the rooftop decks. So 80-81F for the ceilings vs 76F on the center floor on the 3rd floor.
The fourth floor is ceiling ranges from 75-80F as there are flex ducts feeding the AC registers in the ceiling on the fourth floor. The crazy thing is the bath in the 4th-floor ceiling is 80-82 and the bath exhaust fan is 97F.
This is a 3-zone system with one HVAC 3-ton unit zoned controlled with Honeywell controls. There is a mixing box in the attic to feed the 4th-floor ceiling registers. There is a flex duct that travels through a chase to feed the 2nd floor with a mixing box likely in the bath ceiling on the 2nd floor. The 3rd-floor zone feeds a mixing box in the attic that splits down two separate chases to feed the 3rd floor with two mixing boxes on the third floor.
I don't know for sure where the mixing boxes are on the 3rd floor but I know there are two feeds to the 3rd floor.
There is one main return on the fourth floor, no returns on the 2nd floor, and 4 returns on the 3rd floor. The thing is the 3rd floor looks to only have one return operating with any kind of draw in the master bed inside corner all others draw nothing. I put a small tissue up against it to test it and only 1 out of the 4 pulled the tissue up to the register.
Lastly, I purchased a 40-pint Homelabs dehumidifier that lowered the humidity level while heating the master bedroom to 84F at 45-50' humidity level. But it ran all day and I dumped 40 points in 24 hours like it was rated to perform. When I moved it to the center of the 3rd floor it could barely keep it at 57% and it ran all the time, the compressor didn't stop. There is also a musty smell in the master bath coming from one of the supply registers.
I had one HVAC company that recommended that I air seal the attic, add insulation, and install an air scrubber. clean all the supply ducts and sanitized the system and install a UV light in my air handler to deal with microbial growth and deal with the musty odor in the master bath register as well as the Air handler. I have a Lennox system that is 7 years old and it seems like a lot of the neighbors are getting theirs replaced this year.
The ducts in the attic could use more strapping to reduce the arcing and keep them away from each other as some of them are resting on each other. The attic register boots showed signs of rust and mildew growth on the exterior surface of the duct as well as the fire sprinkler pipes. So there has been a moisture problem before possibly with ducts that were leaking as the HVAC contract pointed out some leaky ducts that were connected to the controlled tampers. I had the exterior duct surface cleaned and haven't seen any mildew return so its possible this was an incident that happened a while back and was corrected after the mildew had already formed
So the question is what kind of service should I request to figure out what the problem is before getting anything repaired.
Any recommendations or DIY tests that I can do would be a great start. I know I can seal the attic and add batt insulation or have a contractor seal/blow in more insulation. Btw there is supposedly 8" of bath insulation up in the attic now. Will adding insulation cause more moisture issues in the attic, should the flex duct and registers be covered or surrounded by blown-in insulation. I'm just concerned that more insulation may cause moisture issues in the attic. In so far as the 3rd floor bedrooms, the rooftop decks may be contributing heat transfer into those bedrooms especially the master bath which could be the culprit of the high humidity that exists now.
Anyhow I appreciate any comments so that I can figure out how to proceed.
I recently purchased a 4-story townhome, 1st level garage, 2nd level kitchen/living/dining/bath area humidity level based on thermostat 47-50%
3rd level two master bed/bath, guest bed/bath, and laundry room, humidity level 54-60%. The master bath is between 58-60% pretty consistently
4th level loft bedroom/bath and HVAC closet. humidity 58-63. Right now its 64% humidity outside so its pretty bad to be so close to the humidity level outside
Some more information:
Above the 4 stories is the attic with a metal roof. The 4th story also has two rooftop decks that sit on top of the bedrooms in the extremities of the 3rd floor. In other words, the 3rd master bed/bath has a roof deck on top. The 3rd-floor guest bed has the other roof deck on top. The roof decks have Trex decking and are not covered. The sun beats down on these pretty good at various times in the day.
The master bed/bath ceiling/guest bedroom ceiling is about 4-5 degrees warmer than the center of the 3rd floor not exposed to the rooftop decks. So 80-81F for the ceilings vs 76F on the center floor on the 3rd floor.
The fourth floor is ceiling ranges from 75-80F as there are flex ducts feeding the AC registers in the ceiling on the fourth floor. The crazy thing is the bath in the 4th-floor ceiling is 80-82 and the bath exhaust fan is 97F.
This is a 3-zone system with one HVAC 3-ton unit zoned controlled with Honeywell controls. There is a mixing box in the attic to feed the 4th-floor ceiling registers. There is a flex duct that travels through a chase to feed the 2nd floor with a mixing box likely in the bath ceiling on the 2nd floor. The 3rd-floor zone feeds a mixing box in the attic that splits down two separate chases to feed the 3rd floor with two mixing boxes on the third floor.
I don't know for sure where the mixing boxes are on the 3rd floor but I know there are two feeds to the 3rd floor.
There is one main return on the fourth floor, no returns on the 2nd floor, and 4 returns on the 3rd floor. The thing is the 3rd floor looks to only have one return operating with any kind of draw in the master bed inside corner all others draw nothing. I put a small tissue up against it to test it and only 1 out of the 4 pulled the tissue up to the register.
Lastly, I purchased a 40-pint Homelabs dehumidifier that lowered the humidity level while heating the master bedroom to 84F at 45-50' humidity level. But it ran all day and I dumped 40 points in 24 hours like it was rated to perform. When I moved it to the center of the 3rd floor it could barely keep it at 57% and it ran all the time, the compressor didn't stop. There is also a musty smell in the master bath coming from one of the supply registers.
I had one HVAC company that recommended that I air seal the attic, add insulation, and install an air scrubber. clean all the supply ducts and sanitized the system and install a UV light in my air handler to deal with microbial growth and deal with the musty odor in the master bath register as well as the Air handler. I have a Lennox system that is 7 years old and it seems like a lot of the neighbors are getting theirs replaced this year.
The ducts in the attic could use more strapping to reduce the arcing and keep them away from each other as some of them are resting on each other. The attic register boots showed signs of rust and mildew growth on the exterior surface of the duct as well as the fire sprinkler pipes. So there has been a moisture problem before possibly with ducts that were leaking as the HVAC contract pointed out some leaky ducts that were connected to the controlled tampers. I had the exterior duct surface cleaned and haven't seen any mildew return so its possible this was an incident that happened a while back and was corrected after the mildew had already formed
So the question is what kind of service should I request to figure out what the problem is before getting anything repaired.
Any recommendations or DIY tests that I can do would be a great start. I know I can seal the attic and add batt insulation or have a contractor seal/blow in more insulation. Btw there is supposedly 8" of bath insulation up in the attic now. Will adding insulation cause more moisture issues in the attic, should the flex duct and registers be covered or surrounded by blown-in insulation. I'm just concerned that more insulation may cause moisture issues in the attic. In so far as the 3rd floor bedrooms, the rooftop decks may be contributing heat transfer into those bedrooms especially the master bath which could be the culprit of the high humidity that exists now.
Anyhow I appreciate any comments so that I can figure out how to proceed.
source https://hvac-talk.com/vbb/threads/2240964-Humidity-Levels-in-a-four-story-townhome-by-the-beach-in-Tamba-Bay-Region?goto=newpost
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