Comments on: The Perfect Weather for a Dehumidifier

By: DAVID HILES

DAVID HILES — Mon, 21 Mar 2022 10:21:51 +0000

The hvac 2.0 program suggests using residential dehumidification with electric reheat. Heat pumps with already in-place heat strips can potentially provide this. I assume this is needed only in regions with high relative humidity in cooler weather. Is this something that is needed in particular areas of the country? How can I tell if my region needs it or not? Interested because I have an old system due for replacement.

By: Jim

Jim — Sun, 01 Mar 2020 00:46:41 +0000

In reply to Curt Kinder. Do you do this while the
Do you do this while the heater or the A/C is running? My assumption would be A/C only. Please clarify? Thank you, Jim

By: Scott

Scott — Sun, 23 Feb 2020 19:40:22 +0000

In reply to Curt Kinder. I know for a fact AC can't
I know for a fact AC can’t always control humidity. Our well insulated 2.4ACH50 home will have indoor temps in the 60s through spring and fall thanks to Ohio’s 50s - 70s outdoor temps. Our furnace/AC doesn’t run for weeks during these shoulder seasons but the exterior humidity comes in (in part) through our HRV. An independent humidifier would make my system perfect. At the moment I use a portable dehumidifier because I have it on hand and it gets the job done. I am hoping the next few years brings a dehumidifying HRV for when I replace my HRV.

By: Jim

Jim — Sun, 26 Jan 2020 11:06:39 +0000

Hello,
Hello,

I have a Sante Fe Compact 70 dehumidifier in the crawlspace of my rental home. The instruction manual has a Caution! message which states
“The dehumidifier will run continuously until the RH is reduced to the humidity control dial setting. It is not recommended to set the humidity control to “dry” in rooms under 65-degrees; doing so will result in long periods of ineffective dehumidifier run time.”
Would you recommend that I purchase a dehumidifier that will turn it self off if the crawlspace temperature falls below 65-degrees?

Thank you,

By: Josh

Josh — Thu, 23 Jan 2020 19:34:25 +0000

That squashed connection on
That squashed connection on the bottom hurts to look at after reading your excellent series on ductwork design.

By: abailes

abailes — Wed, 22 Jan 2020 20:58:24 +0000

In reply to Michael. Michael, two people who can

Michael, two people who can help you are David Treleven and Nikki Krueger. I sent you their contact info via email.

By: Michael

Michael — Wed, 22 Jan 2020 20:46:16 +0000

Do you have a ultra-aire rep
Do you have a ultra-aire rep/contact person that you could share with me? I would like to know all the possible sequences of operation that can be performed with this unit. Thanks in advanced.

By: Marvin McConoughey

Marvin McConoughey — Sun, 19 Jan 2020 18:39:03 +0000

In reply to abailes. Your comment on multi-stage
Your comment on multi-stage or variable capacity equipment makes sense. But the building user may have a different perspective. In my house, for example, the geothermal heat pump is inside the house. Despite sound insulation in the heat pump cabinet, and around the compressor, the sound level is objectionable, especially at night when competing sounds are absent or diminished. Since my two stage compressor operates at the same RPM at both stages, the sound level is much the same at either level. But the running time is longer on the lower capacity stage than if the system had only one stage, high. My new system is economical, but I would trade some of the efficiency for a shorter run time and fewer hours per year of compressor noise.

By: Thomas Dugan

Thomas Dugan — Sat, 18 Jan 2020 23:15:43 +0000

Great topic and one I am
Great topic and one I am quite familiar with here is coastal NC. Without debate, the only acceptable solution is a dedicated dehumidifier like the Ultra-aire or Aprilaire (my preference as the Ultra-aire can add an annoying low frequency hum to the building). I put them in every house I build. One can design all the HVAC systems you want and still not completely solve the humidity issue on a year round basis. We have four shoulder months here where very little if any HVAC is running. Still need humidity control. Even in winter, a very tight house can need de-humidification as we do things that create moisture in the air. Even government studies have shown the dedicated option as best. Lastly, I have installed HVAC heatpumps with dehumidify cycles and they are still not enough. Systems properly sized for low sensible loads in energy efficient homes, also drop the latent capability. The ones I have tried are limited to a 3 degree drop in sensible settings before they stop dehumidifying. The house can still be damp. I install mine in the conditioned attic space with separate ducting from the HVAC system. Makeup air is then drawn into the attic space to be mixed there before being introduced in the living space via an intake duct on the dehumidifier intake. I use an Air King QuFresh air exchanger with temperature and humidity limiting controls to bring in make-up air to the attic space. I never want my houses to go negative if possible. When bath fans or the clothes dryer is running, makeup air is naturally drawn in by the same system. We keep my personal home set at 45% RH year-round and it never deviates more than a couple of percentage points.

By: Jim

Jim — Sat, 18 Jan 2020 16:30:47 +0000

I am just an ignorant
I am just an ignorant homeowner struggling to wrap my head around this crawlspace humidity science. It seems if not for these warmer and wetter than usual fall, winter, and spring seasons an average homeowner just trying to maintain 14% wood moisture here in Greensboro, North Carolina could conceivably install the temperature controlled louvered crawlspace vents however he would cover them up during the warmer and wetter summer months. The wood moisture may increase a little during the summer season however it would decrease to acceptable levels during the other seasons. Now that the fall, winter, and spring seasons are in fact warmer and wetter I think sealing all of the vents and installing an Atmox system would be a whole lot more economical than a dehumidifier. I would like to believe a system like the Atmox could dry a crawlspace rather quickly after a 4 day rain spell in the 70s like you mentioned in your post.. At least here in my region. I own a rental and my tenant cannot afford to pay the electricity bill for a dehumidifier.
I am probably missing some key facts about crawlspace humidity science but this is where I am right now in my knowledge journey on this topic.

Cheers…