Got a bi-level house near St. Louis, MO. The house has cinder block walls on lower level. Humidity level this spring on the lower level has been consistently running 80-90% with very musty smell. This is the first season I've actually monitored the humidity levels. I know I need to address this problem ASAP. Maybe it's just me but I don't feel very energetic when I spend much time breathing the air in my home in the spring and summer time. I try to spend most of my time on the upper level, but even then I sometimes smell the mustiness. I have a lot of sinus problems too. Anyway, I'm considering installing either an Ultra-Aire APD 100V or an Aprilaire Model 1700 to address my problem. In comparing these two are there any advantages or disadvantages of one over the other? I know they hookup differently to the duct system. Am I on the right track considering these units? Any input will be much appreciated.
Which whole house dehumidifier?
stl hvac
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Got a bi-level house near St. Louis, MO. The house has cinder block walls on lower level. Humidity level this spring on the lower level has been consistently running 80-90% with very musty smell. This is the first season I've actually monitored the humidity levels. I know I need to address this problem ASAP. Maybe it's just me but I don't feel very energetic when I spend much time breathing the air in my home in the spring and summer time. I try to spend most of my time on the upper level, but even then I sometimes smell the mustiness. I have a lot of sinus problems too. Anyway, I'm considering installing either an Ultra-Aire APD 100V or an Aprilaire Model 1700 to address my problem. In comparing these two are there any advantages or disadvantages of one over the other? I know they hookup differently to the duct system. Am I on the right track considering these units? Any input will be much appreciated.
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Both are quality units and much better than typical residential dehumidifiers. The Ultra-Aire is been around for seven years and Aprilaire is new. UA is available in 100 pint and 150 pint/day capacity. Aprilaire 90 pints/day. The UA removes +5 pints per KW. Aprilaire removes 3.3 pints/kw. Making the Ultra-Aire 40-50% higher efficiency. The UA adds less heat to the house than anyother dehumidifier. The UA has high quality air filtering MERV 8 & a MERV 13 option. Its suggested to use 100 pints of dehumidification per 2,500 sq.ft.. This will provide <50%RH independent of the a/c load. Water leaks and excessive air leaks in the home/ducts are also critical issues to consider when controlling indoor relative humidity.stl hvac said:
we use ultraaire and it has proven very reliableat http://www.thermastor.com
I think you will find the Ultra-Aire to be most satisfactory. Recently bought one of the other Thermastor models, the Santa Fe RX and it has been effective in my case.
Of course my case isn't the same as yours. I used to live in St. Louis and know that your summer *feels* a lot like that in Houston TX, just not as long in duration. Hot and humid while it lasts.
I have a 3400 sqft one story house and wanted to lower the RH from 55-65% to 45-55%. It did that handily. But your being in 80-90% RH is uncharted territory for me. I have always read you need to get below 70% unless you want to grow mold.
Best of luck. -- Perpetual Student
Of course my case isn't the same as yours. I used to live in St. Louis and know that your summer *feels* a lot like that in Houston TX, just not as long in duration. Hot and humid while it lasts.
I have a 3400 sqft one story house and wanted to lower the RH from 55-65% to 45-55%. It did that handily. But your being in 80-90% RH is uncharted territory for me. I have always read you need to get below 70% unless you want to grow mold.
Best of luck. -- Perpetual Student
The 80-90% humidity level is on the lower level-50% of which is below ground with cinder block walls. The upper level seems to be more manageable in that the AC does a better job of humidity removal up there, when it is running. Upper level walls are 3/4" redwood.
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Cooler temps = higher %RH
Usually the absolute water content of air is similar main floor or basement. Lowering the temperature 1^F raises the relative humidity 2.5% RH. Meters are unable to accurately measure extremely high or low %RH. 80^F, 50%RH = 70^F, 70%RH = 60^F, 100%RH (under the carpet on concrete) are all the same water content. This demonstrates how 50% outdoor humidities contain enough moisture to grow mold on indoor cool surfaces without water leaks inside.stl hvac said:
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Mr. stl hvac, if you're still out there,
what equiptment did you finally decide on, and what were the results?
Inquiring STL minds want to know! :^)
Electrajim
what equiptment did you finally decide on, and what were the results?
Inquiring STL minds want to know! :^)
Electrajim
I've decided on a different path-kinda. I learned my system is using a 3 1/2 ton coil with a 3 ton 12 SEER condenser-not a good combination for humidity removal. This is a better pairing for high SEER numbers though, which at this point doesn't matter to me. I'm working on installing a downsized Aspen A coil according to design suggestions by Airman 1. I'll end up with a 3 ton condenser, 2 ton A coil, a 3 ton Sporlan balanced port externally equalized adjustable expansion valve, and 1200 CFM of air flow. This aggressive sizing method supposedly will produce much better humidity removal than standard sizing methods. I've been waiting for the TXV to come in. I have it now. By time it came in I was so busy doing HVAC for others I didn't have time to do the change-out. I'm planning on doing it this weekend. I'll be reporting back soon on the results. I expect to still need some additional lower level dehumidification, but how much is subject to guess work at this point. I also contacted Thermastor and Aprilaire. I feel like I have a good understanding of the choices these companies provide. If needed I prefer to get a unit from Thermastor.
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Way to go!
Sounds like you are on the ball. I hope your installer (if it's not you) will be happy to work with your custom choices!
My measured indoor humidity falls between 46 to 51%, with our new Trane 4 ton system, and was wondering what it took to drop the humidity just a few more points. Your methodology sounds best.
Lemme know how it works.
Good luck!
Electrajim
Sounds like you are on the ball. I hope your installer (if it's not you) will be happy to work with your custom choices!
My measured indoor humidity falls between 46 to 51%, with our new Trane 4 ton system, and was wondering what it took to drop the humidity just a few more points. Your methodology sounds best.
Lemme know how it works.
Good luck!
Electrajim
st hvac..do you know lennox rates a 3 ton condenser ARI with a 1.5 ton coil...let me know how it works all the temps and pressures for those who said i was WRONG WRONG WRONG... then you will learn how little this industry knows imo about promoting comfort!!IMO
I installed the downsized coil and balanced port TXV yesterday evening. WOW! It really works!!! Prior to the change out I couldn't get the second level humidity below 62%-even on 90-95 degree days when the AC should have run more. The lower level was hanging between 70-75% RH. Earlier in the spring the lower level RH was running 80-90%. With the 3 ton 12 SEER condenser and 3 1/2 ton coil the system was always short cycling. Now the system runs longer and removes more humidity, yet still seems to have the capacity to cool under a heavy load. The humidity level on second floor has dropped to 50% @ 72 degrees indoors(I like it cooler in the morning). Downstairs is 57% RH @ 72 degrees. The upstairs seems so dry now that I may need a summer humidifier ...not.
With 85 degree outside temp and 91% RH I have 14 degrees superheat at the condenser. My subcooling at the TXV is only
7 degrees though. Airman 1, is this within a workable range?
This weekend the St. Louis weather is supposed to be the hottest and most humid of the season. This should really put the system to the test.
I still think I might benefit from a dehumidifier on the lower level for Spring and Fall periods when outdoor temps are lower yet humdity is high. For now, though, I'm cool, dry, and very happy. Thanks Airman 1, for sharing your theories and techniques.
...not.With 85 degree outside temp and 91% RH I have 14 degrees superheat at the condenser. My subcooling at the TXV is only
7 degrees though. Airman 1, is this within a workable range?
This weekend the St. Louis weather is supposed to be the hottest and most humid of the season. This should really put the system to the test.
I still think I might benefit from a dehumidifier on the lower level for Spring and Fall periods when outdoor temps are lower yet humdity is high. For now, though, I'm cool, dry, and very happy. Thanks Airman 1, for sharing your theories and techniques.
Info from Teddy Bear who lives humidity like i live ac...."I understand how a smallish coil gets colder and removes +30% latent heat instead of 20% latent from a standard sizing @75 degree F, 50% RH. This equals too 4 lbs. of water per ton per hour of run time from the smaller coil compared to 2.5lbs./ton/hr from a larger coil. This is +60% in moisture removal in a basement." This is exactly why it works in a house. I was FLOORED when he typed this...please keep me informed on how it worls for you stl hvac,
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A little trick from an old timer
Twenty-five years ago, back in the time when I knew everything, I was teaching a refrigeration school. On hot day in the middle of week long school, we lost our old seven ton a/c compressor. That night, we installed a new 4 ton condensing unit because the seven was oversized and the 4 ton was the biggest on hand. The old coil had a fx valve and was in good shape. We concluded it was ok and it would be very efficient. Temp control was excellent with much less short cycling but by two pm the relative humidity was +75%RH. With 30 uncomfortable trainees in the class, we were down to 68^F, 78%RH and clammy. We were stumped. In a panic, called an old pro teck. He showed up 10:00 am, I explained events, he checked everything, says "I got an idea" and disappeared. I am trapped in class but in 10 minutes its clear that he worked magic, humidity rapidly falling. He sticks his head into class asks "how's that". The class is cheering and applauding. I ask, "Ok, what did you do"? "Its a trade secret", was his answer. After inviting him in, offering him a donut/coffe, and giving him the opportunity to be a featured 10 minute presenter, he agreed to share his secret. In a few moments, he explained the effect of a large coil on a small condensing unit, raising the coil temperature 10-15 degress. He moved the bulb of the expansion valve to the middle of the coil. This lowered the coil temperature to 30^F below entering air temperature. It raised the superheat to 20^F. It was great lesson and the teck left with much pride and a box of donuts. Within a couple hours the %RH was <50% and we raised the temp to 75^F. In a few minutes, he down-sized the effective area by reducing the area that had evaporating refrigerant and increasing the superheating area. We used that a/c that for +10 years, until vacating the building. Sorry so long its important concept.
Twenty-five years ago, back in the time when I knew everything, I was teaching a refrigeration school. On hot day in the middle of week long school, we lost our old seven ton a/c compressor. That night, we installed a new 4 ton condensing unit because the seven was oversized and the 4 ton was the biggest on hand. The old coil had a fx valve and was in good shape. We concluded it was ok and it would be very efficient. Temp control was excellent with much less short cycling but by two pm the relative humidity was +75%RH. With 30 uncomfortable trainees in the class, we were down to 68^F, 78%RH and clammy. We were stumped. In a panic, called an old pro teck. He showed up 10:00 am, I explained events, he checked everything, says "I got an idea" and disappeared. I am trapped in class but in 10 minutes its clear that he worked magic, humidity rapidly falling. He sticks his head into class asks "how's that". The class is cheering and applauding. I ask, "Ok, what did you do"? "Its a trade secret", was his answer. After inviting him in, offering him a donut/coffe, and giving him the opportunity to be a featured 10 minute presenter, he agreed to share his secret. In a few moments, he explained the effect of a large coil on a small condensing unit, raising the coil temperature 10-15 degress. He moved the bulb of the expansion valve to the middle of the coil. This lowered the coil temperature to 30^F below entering air temperature. It raised the superheat to 20^F. It was great lesson and the teck left with much pride and a box of donuts. Within a couple hours the %RH was <50% and we raised the temp to 75^F. In a few minutes, he down-sized the effective area by reducing the area that had evaporating refrigerant and increasing the superheating area. We used that a/c that for +10 years, until vacating the building. Sorry so long its important concept.
decrease your humidity levels in concrete/c-blocks walls if possible
http://www.radonloc.com/
We've done a lot of research on this - HVAC options are part of it - & I don't know what kind of access you have to your c-blocks - but unsealed cement/ c-block walls act like sponges to the water/moisture they come in contact with - absorbs up and ultimately creeps up to the wood/drywall on the next level up of your home.
It makes total sense to me that your humidity levels are that high in the lower level. Dehumidifier will address some, but with such high levels increase your utility bills too.
You may want to read up on this product we've learned about - there are others - you can investigate & choose your own comfort level about any of them (Deco waterproofing is another - but we like Radon Loc the best) - the best option is the combo of both a dehumidifier and sealing your concrete.
For what it's worth & if you can't do it where you are, but don't stay where you are - perhaps you can do this is your next abode.
Good luck!
L (of M&L)
http://www.radonloc.com/
We've done a lot of research on this - HVAC options are part of it - & I don't know what kind of access you have to your c-blocks - but unsealed cement/ c-block walls act like sponges to the water/moisture they come in contact with - absorbs up and ultimately creeps up to the wood/drywall on the next level up of your home.
It makes total sense to me that your humidity levels are that high in the lower level. Dehumidifier will address some, but with such high levels increase your utility bills too.
You may want to read up on this product we've learned about - there are others - you can investigate & choose your own comfort level about any of them (Deco waterproofing is another - but we like Radon Loc the best) - the best option is the combo of both a dehumidifier and sealing your concrete.
For what it's worth & if you can't do it where you are, but don't stay where you are - perhaps you can do this is your next abode.
Good luck!
L (of M&L)
Re: A little trick from an old timer
How does this effect the air that passes through the evaporator downstream from the bulb?
Are you saying the tech moved the bulb to the middle of the coil because the new condenser was about 1/2 the coil size? With a coil larger than the condenser would trial and error determine the best bulb location?teddy bear said:
How does this effect the air that passes through the evaporator downstream from the bulb?
yes that is what he is saying ...the load was probably enough to get the run time needed..i will try it on an oversized coil as a last resort...it wasnt perfectt but the price was right..we see a lot of not so perfect systems installed so poorly that they work well because they are oversized with crappy ductwork
Got some run time on my 'new system.' Lower level is 72 degrees with 52% RH. Upper level runs 74-75 degrees with
44% RH. When I last took these readings the outdoor ambient was 94 degrees with 82% RH. Superheat at compressor was
14 degrees with 9-10 degrees of subcooling. The lower level
feels a bit more comfortable than the upper level. The upper level feels rather dry. I've turned on ceiling fans to move the air around more. I'm thinking I need to allow some time to adjust to the substantially lower upper level humidity level. Isn't the ideal human comfort level range for humidity somewhere between 40-60%? One thing's for sure, I'm safely out of the mold growing range I had been in.
44% RH. When I last took these readings the outdoor ambient was 94 degrees with 82% RH. Superheat at compressor was
14 degrees with 9-10 degrees of subcooling. The lower level
feels a bit more comfortable than the upper level. The upper level feels rather dry. I've turned on ceiling fans to move the air around more. I'm thinking I need to allow some time to adjust to the substantially lower upper level humidity level. Isn't the ideal human comfort level range for humidity somewhere between 40-60%? One thing's for sure, I'm safely out of the mold growing range I had been in.
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Re: Re: A little trick from an old timer
If the a coil is circuited that some air passes through the coil unconditioned, mixing is ideal before reaching the first supply drop. If the first drop is an overcooled area, no problem. The mixed air will have a higher latent heat removal ratio then a normal coil. This is similar to a commercial "by-pass air" concept. It also raises duct/grill temperatures to reduce condensation. It also allows more air flow for better air distribution throughout the home while operating a very cold coil.
Keep in mind, small/partial coil lowers the SEER and there is no humidity control when there is no cooling load. You may also have slight over drying/low SEER and capacity during max loads. I like high SEER simple a/c systems with a whole house dehumidifier best.
As you move the bulb toward the inlet of the coil, the evap. temp changes. He had a coil temperature in mind for 75^F air.fastfred said:
If the a coil is circuited that some air passes through the coil unconditioned, mixing is ideal before reaching the first supply drop. If the first drop is an overcooled area, no problem. The mixed air will have a higher latent heat removal ratio then a normal coil. This is similar to a commercial "by-pass air" concept. It also raises duct/grill temperatures to reduce condensation. It also allows more air flow for better air distribution throughout the home while operating a very cold coil.
Keep in mind, small/partial coil lowers the SEER and there is no humidity control when there is no cooling load. You may also have slight over drying/low SEER and capacity during max loads. I like high SEER simple a/c systems with a whole house dehumidifier best.
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