day temps?

[dmelicious]

hey all, i just had my heil dx 1400 5 ton unit installed here in ny where it was a very humid 90 degree day. the house went down to 70 with no problem. it was about 78 before the unit was run, and i say in about 2 hrs is was at 70. i think 70 will be my night, and at home temp. now while we are away at work during the day what is the best temp to set the thermostat at? is 76 too high? again i will go for 70 from 5 pm till about 8 am, and it will stay at 70 for most of the weekend as we are home, but i am unsure what the optimum temp to set for when the house is not occupied by the family. thanks for the help. by the way the unit is great, very good looking, and very quiet, more so than i thought.

[BigJon3475]

I wouldn't bump it up more than a few degrees. The higher the temps go the more moisture the air can hold. I wouldn't go to crazy raising the temps cause when you come home and turn it down to your desired temp it runs the whole time till it gets there. removing moisture will make it take longer. Otherwise it runs for 15 or so minutes at a time and keeps the moisture low so it doesn't run forever trying to satisfy the thermostat.

[dmelicious]

I wouldn't bump it up more than a few degrees. The higher the temps go the more moisture the air can hold. I wouldn't go to crazy raising the temps cause when you come home and turn it down to your desired temp it runs the whole time till it gets there. removing moisture will make it take longer. Otherwise it runs for 15 or so minutes at a time and keeps the moisture low so it doesn't run forever trying to satisfy the thermostat.
so is 76 too much to raise it? what can i get away with and keep humidity down?

[BigJon3475]

Where are you located? Do you normally have really high humidity levels?

It's not really a easy answer. Some systems remove humidity so well that 76 is cold to some. Others do just well enough to make 70ºF with 50% RH feel comfortable. Is your system a variable speed system multi speed or one speed?

[dmelicious]

Where are you located? Do you normally have really high humidity levels?

It's not really a easy answer. Some systems remove humidity so well that 76 is cold to some. Others do just well enough to make 70ºF with 50% RH feel comfortable. Is your system a variable speed system multi speed or one speed?
i have a variable speed (2 speeds i think)first company 5 ton hydro unit, and a 5 ton 14 seer heil dx series condenser. i live in upstae ny, an hr from ny city. we have our share of humid days, like today, but overall it is pretty moderate i would say.

[BigJon3475]

Well I'm fighting with answering you because I can't explain it easily I don't want to guide you in the wrong direction.

Someone else can chime in and make it easier I think than I could I can really only explain from the psychrometric chart which you would have to have a basic idea of to know.

[cem-bsee]

play

what suits U, might not me --

Is it time to use a/c yet?
my office got to 84F Th

[beenthere]

If it dropped the temp in teh house 8 degrees in an hour when it was 90 outside.
You might want to get some hydrotherms. And check your RH%.

If its oversized, you'll be setting your stat lower yet when its 78 outide.

[BigJon3475]

I would think if you have a variable speed system humidity shouldn't be an issue if it's hooked up and working as it should. When it's hot out your system may run all day on low speed and only kick into high when needed. With very low humidity 45% or below 75ºF Feels cold to many people I have talk with. I would verify that your system is actually two speed and everything is running as it should maybe get a little cheaper hygrometer to keep an eye on humidity levels. What thermostat do you have?

[beenthere]

He doesn't know what he has.
He said its variable(2 speed) he thinks.

[Shophound]

5 tons? How large is your house?

Eight degree pulldown in two hours...that sounds like a lot of capacity...maybe too much? At your 70 degree setting, how is the humidity in your home?

[dmelicious]

5 tons? How large is your house?

Eight degree pulldown in two hours...that sounds like a lot of capacity...maybe too much? At your 70 degree setting, how is the humidity in your home?the humidity feels low to me. 70 feels cold. nicce and cold to me, too cold for the wife. the house is 2500 sq ft with 9 ft ceilings. it is oversized a bit because i am going to finish the basement a little later. at 70 degrees it feels cold and dry in the house. i is humid today, and about 82. the system seems to be working nice. i have no issue with leaving it set at 70, but i was just wondering if i would save a decent ammount of $ if i brought it to 76 for the day temp when we are not here. the pulldown was about 2.5 hrs, but the unit was also started up at 330 when the temp was also climbing down.

[dmelicious]

He doesn't know what he has.
He said its variable(2 speed) he thinks.
i do know it is variable just not sure how many speeds.

[dmelicious]

I would think if you have a variable speed system humidity shouldn't be an issue if it's hooked up and working as it should. When it's hot out your system may run all day on low speed and only kick into high when needed. With very low humidity 45% or below 75ºF Feels cold to many people I have talk with. I would verify that your system is actually two speed and everything is running as it should maybe get a little cheaper hygrometer to keep an eye on humidity levels. What thermostat do you have?
i have a white rodgers if80-261

[BigJon3475]

the humidity feels low to me. 70 feels cold. nicce and cold to me, too cold for the wife. the house is 2500 sq ft with 9 ft ceilings. it is oversized a bit because i am going to finish the basement a little later. at 70 degrees it feels cold and dry in the house. i is humid today, and about 82. the system seems to be working nice. i have no issue with leaving it set at 70, but i was just wondering if i would save a decent ammount of $ if i brought it to 76 for the day temp when we are not here. the pulldown was about 2.5 hrs, but the unit was also started up at 330 when the temp was also climbing down.


Get you a cheap hygrometer for reference. You would be surprised what <45% RH feels like at 70ºF as opposed to 60% RH @ 70ºF. I would also look into if your can set your system up for humidity control if possible that might be a way to look at saving some money. You could up your t-stat temps and still stay comfortable. With such a big system I seriously doubt it's removing humidity very well.

[OlManRivah]

but i am unsure what the optimum temp to set for when the house is not occupied by the family. thanks for the help.

I've been on the Net for quite a few years, but, I don't think me in Virgiinia is going to be able to advise a guy in NY (whom I don't know) what's going to make him happy. And the Famiy? :p

Try this.....Set the temp while you're away at 72...try it for a week. If everyone is happy, set it at 74. Keep doing this until you find the sweet spot. As soon as the wife is happy...you got it. Until she gets moody one day......lol!

[beenthere]

Post model number of the indoor unit.

[beenthere]

Are you confusing multispeed(2,3, or more speeds), with variable speed.

[dmelicious]

Are you confusing multispeed(2,3, or more speeds), with variable speed.i think so. it is a 2 speed first company 5 ton unit. here is the model #60MBXB-HW

[beenthere]

Thats just a 2 speed blower, not a variable speed blower.

Check your humidity.

[fxb80]

Many years ago, Honeywell studied the cost effectiveness of setback in the average home, and determined that the best savings occur when the cooling setback is 5 degrees and the heating setback is 10 degrees. Concerning wear and tear on the equipment, it should easily tolerate any cooling setback temperature setpoint that is less than ARI design conditions, namely 80 degrees entering air temperature at 50 percent relative humidity.

[dmelicious]

Thats just a 2 speed blower, not a variable speed blower.

Check your humidity.well my house is set at 70 degress now, and the a/c is is on but not coming on a whole lot because the out side temp is only about 80, but it is humid out. i got 2 hygrometers, one (dial) is at about 39%, and one (digital) is at 41%. so i think all is well, and even at that low % i like 70 just fine, but what can i run the system at during the day when house is unoccupied? looks like my unit is sized correct for my house being that the humidity is right where it needs to be.

[dmelicious]

Get you a cheap hygrometer for reference. You would be surprised what <45&#37; RH feels like at 70&#186;F as opposed to 60% RH @ 70&#186;F. I would also look into if your can set your system up for humidity control if possible that might be a way to look at saving some money. You could up your t-stat temps and still stay comfortable. With such a big system I seriously doubt it's removing humidity very well.at 70 degress the humidity is at 39%, and 41% depending on which hygrometer i look at. one digital, one dial. so i think it is doing it's job and removing the humidity well. i actually feel 70 deg at 40 % hum is perfect for me, but i like it cold i guess.

[Kevin O'Neill]

Ah....the old 500 sq ft per ton rule of thumb...probably oversized.

when you say you have 2 speed, are you refering to the outdoor unit or indoor unit?

[dmelicious]

Ah....the old 500 sq ft per ton rule of thumb...probably oversized.

when you say you have 2 speed, are you refering to the outdoor unit or indoor unit?both are 2 speed. it may be a litlle oversized because i am going to cool the basement with it when i finish it off. the rh in the house is at 41% so i am happy.

[BigJon3475]

I would say then the choice is yours. Do as above poster said and bump it up a degree a day until you get used to it. You may be able to bump it up several more degrees this way because your body's will get use to it and not have a sudden jump in temps.

[beenthere]

Post the model number of the OD unit.


If your humidity is down you should be ok.

[dmelicious]

Post the model number of the OD unit.


If your humidity is down you should be ok.
it is a heil dx 1400 14 seer 5 ton.

[tpa-fl]

If you have a good thermostat (like one of the Honeywell VisionPro series), it'll automatically figure out how high it can let the space get and still be able to make it to your temperature by the time you get home. How high is too high? Depends on how humid your climate is. If you have a thermostat which reacts to humidity (like the Honeywell IAQ), then 85F for a setback isn't a problem.

Down here in steamy FL, I usually use 85F as a setback temp, but keep humidity at 50% or less to prevent mold/mildew growth. If you have the means to dehumidify the space separate from cooling, then temperature is practically irrelevant.

Energy savings is directly connected to the runtime of the equipment, and heat loss/gain is mostly connected to outside temperature (plus heat gain from sun entering through windows). As long as the AC can recover by the time you get home, you're saving money with higher set-backs. Plus, AC equipment runs most efficiently on long cycles, such as what happens during the "recovery" portion of a setback.

[madhat]

SEVENTY DEGREES!!! :eek: Are you made of money? in Maryland if you set your T-stat at 70 degrees the power company would personally send a Brinks truck to pick-up the payment. Our house is set at 76 24/7, once in a while I get giddy and set it to 75. Go away for the weekend it's up to 82. PS AC units do there best dehumid when they run long periods of time. So setting you t-stat up then back down will do very well on dehumid.

[dmelicious]

SEVENTY DEGREES!!! :eek: Are you made of money? in Maryland if you set your T-stat at 70 degrees the power company would personally send a Brinks truck to pick-up the payment. Our house is set at 76 24/7, once in a while I get giddy and set it to 75. Go away for the weekend it's up to 82. PS AC units do there best dehumid when they run long periods of time. So setting you t-stat up then back down will do very well on dehumid.
actually i built this house myself. i am a carpenter on the side. i put in the best windows, and used all high density insulation, and foam backed vinyl siding. the a/c kicks on way less than others i have seen and the house stays cool longer than alot of others i have been in. the humidity today was 44% with the a/c set at 72. at 72 the a/c was hardly on today. i set it to 70 at 6 pm when i got home and it is back down to 41 % rh. so much for my oversized system making my house too humid. i am super happy with this first company air handler, and heil dx 1400 unit.

[BigJon3475]

actually i built this house myself. i am a carpenter on the side. i put in the best windows, and used all high density insulation, and foam backed vinyl siding. the a/c kicks on way less than others i have seen and the house stays cool longer than alot of others i have been in. the humidity today was 44% with the a/c set at 72. at 72 the a/c was hardly on today. i set it to 70 at 6 pm when i got home and it is back down to 41 % rh. so much for my oversized system making my house too humid. i am super happy with this first company air handler, and heil dx 1400 unit.

Is a relative humidity hygrometer? Just curious. You have two stages the first stage is for humidity removal. That means it's doing it's job. I still can't believe you can take 40%RH @ 70ºF I'd be freezing even in sweat pants and sweat shirt. Much less I can't believe the wife can take it. Most women seem to be cold @ 75ºF with low humidity. hey but if your happy more power to you you choose well especially since your going to do the basement later sounds like your system is right for your conditions now. I hope the higher humidity from the basement doesn't effect it to much.

[dmelicious]

Is a relative humidity hygrometer? Just curious. You have two stages the first stage is for humidity removal. That means it's doing it's job. I still can't believe you can take 40%RH @ 70ºF I'd be freezing even in sweat pants and sweat shirt. Much less I can't believe the wife can take it. Most women seem to be cold @ 75ºF with low humidity. hey but if your happy more power to you you choose well especially since your going to do the basement later sounds like your system is right for your conditions now. I hope the higher humidity from the basement doesn't effect it to much.
my foundation was hammered out because it is rock and the rock holds little moisture. . i have a 40 pint dehumid down stairs and it keeps the basement rh at 50-55% so i think it will be ok. plus i am only gonna finish off a room of 300 or so sq ft. the wife is preggo so i think that is why she is not complaining to much. i had the house at 72, and she likes it better which is fine with me, but i like 70 to sleep. i think that is what i will do. 70 on the bedroom zones for bed, and 72 for the house living area zone. while we are at work i think everything will go to 74 or 75. that should be ok right?

[BigJon3475]

If thats what please you then that is what is right. Honestly if I were in your situation since you seem to have a system that works for you. I would be doing fine tuning meaning. I would do as you stated with finding temps for when we are around the house then when we were gone I would work on finding a temp that was high enough to keep the system from coming on all the time but low enough to where I didn't need to wait 4 hours to get comfy after I get home. It will be a back and forth thing from now on I believe.

[skippedover]

You say the system is over sized somewhat but that it pulled the house down several degrees on a 90-degree day, starting a 3:30 PM? If that's truly the case, you system is more than a LITTLE oversized. The peak load on the home is between 3PM and 6PM. That's because the home has been absorbing heat all day long, right through the apex of the sun at midday. By the time all that heat begins to penetrate to the interior of the home it's about 3PM and that pentration continues right into about 6PM. It's called the "fly-wheel affect" because of the delay in heat penetration. So as you can see, if you're pulling the home down several degrees between 3:30 PM and 6:00 PM, you're system is very much oversized. Did the installing company do a heat gain anaylisis using manual 'J'? If you don't know that answer, then did they measure the whole house, room-by-room, including all of the windows and doors and note the magnetic orientation of the home, N-S-E-W? If the answer to the last question is "NO" then there's no way they could have done a heat gain analysis. 75% of the companies out there don't do an analysis despite the fact that every manufacturer, the EPA, ACCA, SMACNA, RSES and all the other alphabet groups all say "You can't get a proper job without a Manual 'J' heat gain/loss analysis."