by • January 29, 2013 • HVAC & DehumidificationComments (3)3890

Dehumidifier Necessity for Texas Homes

  I attended a lecture from my favorite Building Science teacher Joe Lstiburek last December here in Austin and I’ve been meaning to do some blog posts from my notes.  If you’ve been following my blog you know I’m a big proponent of stand-alone dehumidifiers for houses in our Hot/Humid climate.   See these past blog posts here and here to get up to speed. 
  Joe spent quite a bit of time talking about Dehumidification and here’s my notes:
Air Conditioners are wonderful dehumidifiers but they only work when they RUN! 
-Put in a white roof, they don’t run as much
-Put insulation in the walls, they don’t run as much
-Put in CFL bulbs, they don’t run as much

When you bring in outside air, you bring in moisture, but the AC isn’t running as much.
You can’t simultaneously meet ASHRAE 62.2 and not have humidity control. 
You can’t conserve your way to cold/dry.
You can design to no-AC it’s called Uncomfortable.  (This is a reference to Passive Haus)

At the end of the day in hot/humid climates you need to expend energy to make houses cold/dry.
We over-ventilate our buildings in hot/humid climates.  You have to spend energy to make the air dry. 
Up till recently you had to make the air cold in order to make it dry.  AC! 
We can no longer make the AC do the humidification work. 
You need to use a dehum to control humidity separate from temp.
Use a stand alone Dehum to:
     -Be comfortable,
     -Not create an indoor air quality issue
     -Not rot the building…

Here’s an Ultra-Aire Dehum unit I use on the smaller houses I build. 

If you are building or remodeling a home in Texas I highly recommend you talk to your HVAC contractor & Builder about a stand alone Dehumidifier for your house.  You won’t believe how comfortable your house will feel compared to having your humidity controlled purely by your Air Conditioning system.
Matt Risinger
Risinger Homes is a custom builder and whole house remodeling contractor that specializes in Architect driven and fine craftsmanship work. We utilize an in-house carpentry staff and the latest building science research to build dramatically more efficient, healthy and durable homes.
Be sure to check out my video blog on YouTube

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  • Thanks for the information. I’ve been shopping around for a dehumidifier rental and reading reviews for the past few hours trying to figure out which would be the best for a medium sized basement. I have tons of electronics and lab equipment, as well as chemicals down there that I am worried the humidity may destroy.

  • Rob Moore

    I am building a home in Climate Zone 3A with SPF insulation throughout and my HVAC designer/contractor has recommended a variable speed system (Trane XV20i) and says that because of this he does not think I will need a stand alone dehumidifier – your thoughts?? On a separate issue, my builder has installed Dow Sill Seal between the base plate and slab. Would you still recommend using something like Tremco Dymonic for additional air sealing? Thanks in advance – I really enjoyed your tweet regarding Tim Keller/Idolatry – we attend a PCA church in Tuscaloosa, AL and our one of our former pastors is now in Austin at CrossPointe Church. P.S. Just made a donation to your PayPal account toward your coffee fund.

    • Rob, Thanks for your kind donation! Yes, still spec the Dehum! They tell you that the variable speed AC will do it, but it’s not true in practice. Yes too on the Tremco Dymonic at the sill to concrete slab connection. Sill seal is good but still leaky. Always glad to hear from other believers. Very much appreciate the donation. Matt