A-104 · Comfort
72° and still sticky.
This is the most common complaint we are called about and the one most often answered with a bigger unit, which makes it worse. A house that reaches temperature but stays damp is telling you that the system is not running long enough to do the second half of its job.
Air conditioning is a dehumidifier that happens to cool
Warm indoor air crosses a cold evaporator coil, water condenses on the fins, runs into the pan and leaves down the drain. That is the whole mechanism. It only works while the coil is cold and air is moving across it.
An oversized system drops the room temperature quickly, satisfies the thermostat and stops. The coil never gets properly cold and never stays cold long enough. You get your degrees and none of your water. Every short cycle also re-evaporates the water still sitting on the coil and sends it straight back into the house.
Rule of thumb we use If your system satisfies on a 95° afternoon in under twelve minutes, it is too big for the house.
The order we try things
Cheapest and most likely first. We have talked more people out of a dehumidifier than into one.
- 1 · Lower the airflow per ton
- Commissioning the blower from 400 down to about 350 CFM per ton makes the coil colder and pulls noticeably more water. Free, if the equipment allows it.
- 2 · Seal the duct
- Humid attic air pulled in through a leaky return is a moisture load you are paying to fight. Sealing removes the source rather than treating it.
- 3 · Fix the outdoor air
- An unbalanced bath or range fan, or a return in a vented attic, can put more water in the house than the family does.
- 4 · Right-size at replacement
- When the equipment is due anyway, sizing it correctly and choosing variable capacity solves this permanently.
- 5 · Whole-home dehumidifier
- Ducted, drained, and controlled independently of the thermostat. Genuinely the right answer for some houses. It is the last thing we reach for, not the first.
Measured, one house
Prairieville, 2,400 sq ft, no equipment changed
Same condenser, same coil, same house. Blower speed commissioned down and 27% duct leakage brought to 7%.
Questions we get asked
What indoor humidity should I be aiming for?
Between 45 and 55 per cent relative humidity at your normal setpoint. Above 60 per cent the house feels clammy at any temperature and you start seeing it on window frames and in closets.
Is a whole-home dehumidifier the answer?
Sometimes, but it is the third thing we try, not the first. Most damp houses in this parish are oversized or over-blown, and both are cheaper to correct than to compensate for.
Why does my house feel worse when the system runs more?
If the ducts leak into a hot attic, longer run time pulls more humid attic air into the return. Running more makes it worse, which is the opposite of what you would expect.
Put a number on it first.
We will measure your indoor humidity, cycle length and duct leakage before anybody suggests buying anything.