humidifierhvac
I'm trying to understand why a whole house humidifier is placed on the cold air return where water is injected into the air flow and then it has to pass through a five inch filter before entering combustion area and hot air piping.
Would the filter not stop the condensation from going past it?
My own home has this and I'm lucky to ever get a humidity reading above 37% when it sounds like it's working constantly, I understood 40 % + is recommended. I just assumed the filter comes into play?
This problem can be multi-faceted. Someone could guess all day long as to what the problem(s) is / are and not even come close. Air conditioning isn't something to guess at. It's like having a rattle on a car and taking the approach of replacing one part at a time to find the rattle. It would be cheaper to just buy a new car. ( I give that as an example you can easily understand. You probably won't like it but the truth is always hard to swallow when it involves money.)
This is why air conditioning is a billion dollar plus industry. It's unlikely you will solve this kind of problem on your own as a "do it yourself" solution.
Sure you can do the things suggested like window coverings but if the problem is a "system performance" problem it's unlikely to make much difference.
With all of this said... if the problem isn't found and corrected it is quite possible to spend all kinds of money wastefully. The air conditioning business isn't known for being "easy". Certainly some repairs can be but issues such as these can be quite difficult.
It's quite possible it's just too hot. If out door temps are up over 110 degrees and you're hitting 76 inside... well if you think the AC is not working go outside for 15 minutes or so and walk back in. That dial on the wall is to turn the unit on and attempt to hit the desired temperature that you set. But there is no guarantee that it will. Air conditioning (depending on climate, location and design of the system) is mostly designed to lower the temperature 20 degrees from that of outside. (again this depends upon design of the system.)
Air conditioning loses noticeable capacity at 105 degree outdoor temp. again depending on climate and design of the system. Air conditioning isn't a cookie cutter appliance. One size does not fit all.
If out door temps hit 110 or more, be happy with what you get and reduce indoor loads. Plasma TV's, specialize computer equipment, excessive incandescent lighting, halogen lighting, excessive people loads (more than two per room), etc. will only add to your discomfort.
I am a licensed HVAC contractor with over 20 years experience in Residential HVAC systems. Serving the Katy & Cypress Texas area (suburb of Houston)
Had to move controller (with sensor on back) farther away to where only in house air was moving through duct. In my house this was at the ceiling as the return plenum area was mixed with outside air and inside..
Sort of like a "T" shape. Top Right side of T duct brought air in from outside, left side brought air in from return vents, and the middle (body of T/ Plenum) is where the air mixes together.. And of course outside air will have higher humidity, so it was messing with the readings.
Hope this helps someone else one day.
Best Answer
The biggest reason is probably "because that's where it fits."
It's true that warmer air can carry more grains of water than colder air can. That's a good physics-based reason for locating the humidifier on the supply air duct.
But lots of homes have an air conditioning evaporator sitting atop the furnace. Furnaces don't often get installed in a premium room; instead they end up stuffed in a closet somewhere that's lucky to have an 8 foot ceiling. Then the supply ducts have to remain below the floor joists, and the ducts are about a foot deep, and next thing you know there are only 7 feet of vertical height to fit the furnace and A/C into. There often isn't vertical space to accommodate a humidifier. Oh, and there are one or two ducts for the exhaust flue and maybe intake air too that come down in front of the furnace. And so on..
A return air duct, on the other hand, is often a large blank canvas. There is lots of unobstructed surface where the humidifier can be mounted. It might become routine to some installers to place a humidifier there "because that's how we always do it" even if there were room on the supply duct on a particular job.
A humidifier should be able to get the job done regardless of which duct it's installed on. If yours isn't, maybe you could ask a question about that.