Robotman, if you are setting your thermostat higher during the day when nobody is home, I would consider eliminating that. You need consistent humidity control inside your house to minimize allergen bloom. Setback strategies work against that goal. I would also consider TB's advice regarding ventilating dehumidifiers for a long term solution.
Update... Had a guy come in and check the stuff i did yesterday. He said that was a good move. When i brought up different tape and stuff he said he used another brand and stuff. So i insisted. He said he would use that if i bought it. I think i am going to get one more quote. I bought hygrometer and humidiy levels are between 49 and 51 percent.
They seem to rise to higher levels during the hotter times of the day....like right now they are at 55% in the kitchen compared to 50% an hour ago.
Try giving Beco Services in Fort Worth a call. The owner knows his stuff about HVAC.
My uncle who does hvac was down visiting for a couple of weeks about 3 weeks ago....so I paid him and helped him to do the vents....so those are done. Since then I have noticed a remarkable difference as far as my comfort. However, the humidity is still on average around 55%. Generally it's lower at night 51% or 53% and can stay as low as 55% during the day depending on what temp I set the thermostat and the rh outside. Today the rh outside is 65%...so in order to keep the rh around 55%, I have to set the thermostat lower. I went ahead and switched the fan speed back to medium after I did the vents. It didn't seem to affect the humidity levels in the house. When rh was running low (35%) here for a few weeks, the internal rh stayed around 55% with the thermostat set on 71 or 72. When the rh gets higher outside, it seems to become more uncomfortable for me and my wife.
I called Beco services today. I talked to Bruce. He seemed nice and competent. I'm sure he is totally worth what he is asking. He said that in this area I shouldn't need a whole house dehumidifer. So that leads me to believe that my unit could be too big. After some research, it is estimated that around 50% or more of homes out there have some type of AC issue whether it be too big...leaking systems. Bruce said he couldn't be sure about anything until he comes out and looks around.
I have to ask a question at this point....I am in a 4 year old house and i am looking at the possibility of changing my unit. I thought by buying a newer home, I would avoid having to pay a lot of money on issues like this. With all due respect to all the professionals on this board....What are the training schools for AC doing? It's no wonder so many people are skeptical of AC people if many guys can't even get a brand new install right. I just spent $$$$ on this thing in January. Now I'm looking at possibly changing my unit. I've looked up in the attic and I don't see any bad practices as far as flex ducting going on.
I'm just totally at a loss about what to do....new unit....whole house dehumidifier....$$$$ here....$$$$...there....on a 4 year old house.
Unfortunately most contractors do not and will not spend the money on training an individual to be technically proficient at what they do. Now sales training on how to up sell you a system in respect to dollars, that is a different story. The problem is that if you can not determine what a home needs to become comfortable and energy efficient, then how can you determine what equipment choices are right for the home.
Originally Posted by robotman2009
Post some pics of your flex in the attic if you get a chance.
You should have Bruce come out for a look-around. He is more than able to advise you competently and with precision. Since I am not in contracting and I respect those who are (even though I'm in the trade) I recommend him to friends who ask me for HVAC advice and help, and I have not been disappointed yet with those who followed through. They still use Beco to this day.
Some homes in North Texas may need whole house dehumidiers, but not many. I can see very tight homes perhaps using one as an option, but with the average North Texas construction, even at four years old, I'd say no. I do not have one; there are only a few short days or at max a week or two each year where I might have to run the a/c a little colder than I'd like to get indoor humidity under control. The rest of the time it's fine.
Ok...I think I have decided to put in an extra return. I have a quote of $.
I really would like to see what people think. I have decided to go with this because of the layout of my house. There is a section of my house that is way off from the rest of it. So theoretically...I may have enough return (3 ton unit 20x25 x1 going to what looks like 18" flex duct). on the master bedroom side of the vaulted ceiling great room. However I may not have enough return spread evenly out through the house. On the other side of the house, there is a bathroom which my wife loves to shower in without venting fan on, a small hallway and two fairly good sized bedrooms. So one side of my house seems to be doing good but the other sides seems much hotter. I'm still concerned about the high co2 levels. But maybe this will help with that too.
Just doing some math... My math guru brother did some computations for me. According to what i have heard here my 3 ton unit should have around 400-500 square inches of return. Well i have a 25x20x1 air intake.... Wait for it...that goes down to what looks like 18 inches or a little more... If its 18 inches thats 254 square inches of return. I think this thinking reaffirms the decision to add another return.
This is turning into a helter skelter with lots of conficting advice. Many are confused.
First you need to understand the measure of moisture in outside air verses inside air. %RH will not work. You must use dew point or grains per lb. of air. Research on the web and give us feed back.
Second. A properly setup a/c with a heavy cooling load will get you to a low indoor %RH/Dew point/grains per lb.. At 75^F 50%RH, you have a 55^F dew point or 66 grains of moisture per lb. of air. The cooling coil must be less than 50^F degrees. Usually this means low speed on the fan.
During low/no cooling loads in any green grass climate, the inside moisture level will be higher than the outside moisture level when the home is occupied. Because the a/c is not removing any moisture and the occupants are adding moitsure. If the outside dew point is +55^F, the a/c is not runnin alot, and you want <50%RH, will need some dehumidification. If any a/c guy can explain how the dew point of the air in the home will be less than the outside dew point without dehumidification, please explain that to me.
Third If all of your inside doors are open, there is no big advantage for individual room returns. If you close a door on a room, a room return will better balance the pressures on that room.
Fourth All homes need a fresh air change in 4-5 hours to purge indoor pollutants and renew oxygen. On person in an 1,800 sqft. home would be about 600 ppm of CO2. In windy weather, most homes get enough fresh air. In calm weather most homes do not get enough fresh air.
A fan introducing 70-80 cfm of fresh air to your home will make a big difference during calm weather. The fresh air should be filtered, blended, and circulated throughout the home. This is a must when occupied.
A whole house ventilating dehumidifier will do all of this even with an over-sized a/c. A properly sized a/c without dehumidifier will not do this. An Ultra-Aire 70H can handle upto 2,500 sqft of home if the a/c is setup correctly and the home fairly air tight.
Thanks for the advice. I haven't ruled the whole home dehumidifier. However, either way, I will have to add an additional return. Not just that since I am getting some conflicting advice, I'm kinda at a loss at what is the best path. So I thought I would try the cheaper cant go wrong with more return air option first. It does seem like that part of the house is much worse on my sinuses. So it can't hurt.
Things have been going better. I went up in the attic with the ac guy the other day. He was giving me his price for putting in a return, amd a new plenum box with a 4 inch filter slot. He said its hot up here. For an ac guy to say that made me think about better ventilation. So I put in a turbine.....WOW! What a difference? Before the turbine, I had these mushroom looking things which didn't seem to be getting rid of any heat. Afterwards, my humdii started droppimg to the low 50s pretty much all the time with thermostat set on 71 or so....much better than getting 53% with the thermostat on 67. ...that was awesome. So I wasn't going to have the ac guy put in a return. But I thought why not? It could only make things better. So he came in today. Humidity seems higher thanit had been but that might have something to do with the fact we had the ac off for 3hours from 8:30 to 11:30. One question....and btw....I welcome any comments.....is it customary to turn on the ac system before the mastic has had a chance to dry. Also, is it ok for the new return to be laying on the ceiling joists?