Regular Guest
What do you guys think? For the central Indiana climate, does an ERV or a ventilating dehumidifier make more sense?
In May we had new HVAC systems installed. One system upstairs and a separate system downstairs (ground level). Humidity level downstairs (per the tstat) has been running in the 50s. During some of the very humid summer days, we saw it creep into the low 60s. Upstairs is usually 8-10% less, so usually in the 40s.
The house is over a closed crawlspace that has a dehum in it set for 45%. It's just a relatively cheap portable model, so not sure how accurate that is.
We finally got the blower door test done and it came back around 3 air changes per hour, so we're talking about adding mechanical ventilation to the downstairs system. My installer said he's done both ERV and ventilating dehum, but far more of the latter.
Professional Member*
.() () () () HDD 5249
... ... ... ... CDD 1106 () () () ()
________ .:. ERV
___ Indianapolis __ ASHRAE Climatic Conditions
____ Your climate is obviously Predominantly Heating
A/C Set-up: 360 CFM/ Ton
Ventilation Set-up: you may wish to investigate Demand Controlled Ventilation
https://svach.lbl.gov/demand-controlled-ventilation/
Last edited by dan sw fl; 09-24-2021 at 08:51 AM.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Sponsor & Professional Member*
An ERV requires a dehumidifier to maintain 50%RH because the ERV only removes about 40% of the moisture. The ERV does reduce the dehumidifier load by 40% as long as the exhaust air is <50%RH. The return on investment in most homes makes using a whole house dehumidifier with the make-up fresh air ventilation more practical.
Check out the Santa Fe ultra with Merv 13 fresh air filtering for most home applications.
The pressurization of make up fresh air on a home slows infiltration of soil gases and unfiltered outside air.
Keep us posted,
Regards Teddy Bear
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
Regular Guest
Very interesting, I'll discuss this with my installer, thank you.Originally Posted by dan sw fl
Makes total sense and jives with some of the things my installer was telling me. I'm pretty sure he mentioned they use Sante Fe so easy enough there.
Is it fair to assume that a Sante Fe style system can run as ventilation only (no dehum) in the drier winter months?
Sponsor & Professional Member*
The dehumidifier and ventilation are independent functions with separated controls.
Keep us posted.
Regards Teddy Bear
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
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