Whole house dehumidifier placement
Syria
| Posted in Energy Efficiency and Durability on
This house is in climate zone 4A and is four years old, full basement and one floor above. It has spray foam insulation and is very tight. HVAC is (are?) Samsung mini splits and an ERV which also handles the bathroom ventilation. Humidity levels seem consistently high, 55-60 and moisture forms on the windows in the winter. Seems like a dehumidifier is called for. Or am I missing something??
And, consequently, what floor level would be preferable for the installation?
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Replies
IMHO, I only run a dehumidifier when it's humid inside and out.
If the OA dewpoint is less than about 13degC I would just open a window a crack to ventilate, or up your HRV/ERV flowrate/dutycycle. Not sure if there a point where the waste heat from the dehumidifier makes it worth while running versus ventilation.
I run a portable dehumidifier so the noise is a big factor in placement. I run it in my basement since it tends to be cool (raising the %rh). If my basement is below 60%rh then the whole house tends to be a bit lower (in the mid 50's or lower %rh).
Getting your indoor humidity bellow 55% in the summer is unrealistic in most climates.
If you were seeing over 50% in the winter then you would need is HRV to being in some dry air.
Some moisture condensing on the glass when it gets into the single digits is also normal.
Understand dehumidifiers lower the relative humidity mostly by making the air warmer.
If possible, eliminate the moisture at it source. If that it was from concrete walls with poor drainage and damp proofing and the basement smells musty only then would a dehumidifier be my last resort.
Walt
Thanks for these replies.
Any additional thoughts on whether a unit would be more effective in the basement or 1st floor?
Placement would depend on your goal.
If the goal is that the basement smells musty then put it in the basement.
If the goal that you are cold and clammy then put it upstairs. With the understanding that you are likely treating the symptom and ignoring the disease. Generally, this symptom in the summertime indicates the equipment is oversized for the load.
Walta