House AC question in Orlando

[fk89]

This is my 1st July here in Orlando and have a question about my AC unit. It's a Traine Multi Stage Heat Pump. Never had cental air befor only window units living in NY.

1st let me say I had the unit serviced a month ago and all came back ok so this is just for my sanity.

Is this normal for a FL House with central air (I'm guessing so but what to be sure):

House is 1700 sq ft cathedral ceilings, 8 ft on the low end 12 ft or so in the middle. House is 60 ft long and 40 ft wide. Sun beats on the roof all afternoon (Not the morning), no shade at all, attic is like 140 degrees (Guessing not actual)! Ductwork runs trough attic.

55% humidity or so at all time in the house. 78 degrees at the return, 62 degrees at the ceiling vents (I'm guessing there is some heating from tracking through the attic as I understand normal is closer to -20 degrees)).

So here is my question, I'll use Friday as an example.

92 degrees outside, with about 55% humidity, no clouds at all sun beating on my roof, heat index of 104. House stayed at the set temperature of 76 all morning until about 2PM when the temperature began to rise to about 78 and never came down again until about 8PM. My unit ran the whole time never shutting off till about 8pm. Is this normal or could there be a problem? I'm guessing it's normal due the Sun and excessive heat but just want to be sure.

TIA, Felix

[SQLit]

Multi stage, that makes the unit less than 5 years old. Good thing Attic is not 140 more like 180 F Normal for duct work to run through the attic. Costs to much to put in soffits now days.

62 degress sounds a bit high to me. Your sparce on the specifics so I will GUESS. My 3 ton in Arizona pushes at least 55 air after it has been running for a few minutes. (new york 12 seer package unit)

Who serviced the unit?

Shade screens are your friend. Best money I ever spend on every home. Especially on the West facing windows. Can do wonders even with double glazed windows.

You do not mention the insulation in the attic. If it is less than R-40 (my opinion) put more in now. I had a home built in 1999 with R-30 last year. I spent $425.00 and had R-19 blown in the house and R-30 in over the garage, one of those west facing garage doors. Highest electric bill from previous owner, $250.00 per the utility. My highest bill, $150.00 I also insulated the garage door.

My dads home did exactly what you describe. I found a 30 foot duct run un- insulated in the garage. $40.00 of R-11 batts and some furring strips the problem stopped.

It might be time to check the ductwork for leaks.

Like I said guesses all.

[tbasc]

I suggest you look at the Building Science Corporation web site. It discusses building approaches for various climates. I think you will find that they do not like vented attics in your climate. Home Energy site is useful.

Echoing other comments: Duct leaks and duct insulation will help a lot. Running ducts through conditioned space looses least energy, but retrofit will be expensive. Shading of roof, wall, and particularly windows is very useful. TB

[JimL]

I vote normal with some recommendations.

But if you have a 2 stage compressor, I would guess that they have undersized your unit. I would want my 2nd stage to bring the temp down to thermostat on a 115 degree day.

Assuming that's the case then you first look elsewhere for solutions. Make sure that attic is heavily vented. Add more sophit vents and make sure your roof has lots of ridge vents. You can have power vents and a ridge vent if necessary.

Double pane glass everywhere. Heavy curtains.

Attic Ducts: Measure the vent temp at the distant locations. You can add extra insulation on the flex duct if you are gaining heat from the ductwork.

Shade trees.

etc.

[fk89]

1-My system is not mutli-stage on cooling only on heat

2-The house was built in 99 not sure on the insulation up there but I do know it's in sheets not blown. Whole length of roof faces west. Were are talking 60 ft in length and 30 or so feet of height, no way for me to shade.

3-I cannot even imagine how someone will get in my attic to check the ductwork. Like I said I have vaulted ceilings and I just cannot imagine how they are going to get all the way to the other side of the house, I don't see any place to walk up in there. Then again there probably is a crawl space I just don't know what to look for. And how will they get insulation all the way in there?

4-Side of the house (Windows) are shaded most of the time. The one issue that gives a lot of heat is the cube-textured windows (If you know what I mean) in the Kitchen. What do I do with them?

5-Del-Air serviced my unit. Again I'm new to central air & Central FL so I have no idea how good the inspection was. He was there about 1.5 hours.

6-Lots of roof venting! On the west side of the house there are 4 vents each about 4-5 feet in length and about 2 ft wide. Again this is guessing from site.

Any thoughts after this?

Felix

[fk89]

One more thing...AC is set to 76 during the day at all times and 75 at night. The bill this month will be about $190.00 last month was $170.00. Outside temps from month to month are about the same but much, much more sun so far this month, lots of rain last month. My main concern is not the $$, it's to make sure the unit is running correctly and to keep the house at the set point as much as possible. Right now the way it is there is no way I can get it down to below 76 on a Hot 90+, humid, bright sunny day until the sun goes down. They all is well.

Felix

[fk89]

As for adding more insulation:

What type of businees provide this service?

Felix

[fk89]

Richard

Funny you mention about the drain line, I never paid attention to it before but on Friday I was mowing the lawn and it was really running (Actual puddle nest to the unit). The only reason I knew that was OK is I looked at a couple of my neighbors units and they were gushin too.

Yes all week last week for the most part was hot, sunny and humid 55+ easily each day. Right now for example it's:

90 °F / 32 °C Mostly Sunny Heat Index: 99 °F / 37 °C Humidity: 60%

Thanks for all the great tips / advise here, it's much appreciated.

[fk89]

Richard Funny you mention about the drain line, I never paid attention to it before but on Friday I was mowing the lawn and it was really running (Actual puddle nest to the unit). The only reason I knew that was OK is I looked at a couple of my neighbors units and they were gushing too. Yes all week last week for the most part was hot, sunny and humid 55+% easily each day thanks to Dennis offshore and some High pressure system from Bermuda Right now for example it's:

90 °F / 32 °C Mostly Sunny Heat Index: 99 °F / 37 °C Humidity: 60% We really need some cloud cover here in the afternoons to help cool house down a bit! Without that there is a HUGE difference IMO>

Thanks for all the great tips / advise here, it's much appreciated.

[fk89]

WOW! I always leave my ceiling fans on, ALWAYS! Is it better to leave them off altogether? I just thought it was but then again my wife tells me I never think correctly, so are you saying she is right? If you are I'll never tell her that!

If leaving them of is the best, when and how do you ideally use a ceiling fan??

Felix

[Richard J Kinch]

Sounds normal. You had about the worst outdoor conditions you typically see, PLUS, Friday was a real windy day with Hurricane Dennis offshore from you, right? Unlike a normal hot day, you therefore had lots of humid air blowing around and infiltrating your house. In those conditions, your unit can't keep up with the latent heat demands of all that moisture constantly infiltrating, in addition to the usual heat load. Did you check the condensate drip? I expect it was running like a faucet then.

Evaluate it again on a calm, hot, sunny day.

The most economical system is just large enough to keep up, or just start falling behind, on the worst day. Bigger or smaller is less economical and less effective.

[SQLit]

Ceiling fans cool people not spaces. They work by evaporation on your skin. Feel the breeze and your cooler. I turn mine off when I am not in the room.

[gfretwell]

If you do find someone who wants to blow in more insulation DO NOT go for the cellulose! In Florida, everything you learned about vapor barriers in New York is wrong. The warm moist air is in the attic. Cellulose simply soaks up that moisture and rots. There are some blown plastics and glass products that work. I would agree that reducing the heat load is the cheapest long term way to fix this. There are films that reflect the heat off your windows and there is always the idea of awnings, trees or whatever to shade you.

BTW turn off the ceiling fan in the great room. Leave that hot air up in the vaulted ceiling, don't blow it down in your face.

[gfretwell]

The ceiling fan is for when you want to bring that heat back down in the winter.

[Jim Yanik]

[e-mail] wrote in news: [e-mail]:

I wonder if he has double insulated windows,or the typical Florida single pane windows that let a lot of heat into his home?

An attic ventilation system (fan) would help greatly,too.

[fk89]

Thanks again for all the great advice! When I left for work this morning I did in fact shut all the ceiling fans OFF. I'm curious to see how the temps are when I get home with them off. I guess if makes sense to keep them off and have the heat trapped in my high ceilings! As for my windows: Single pane. I found that kind of odd when I moved here. I'm hoping to have them replaced over the winter by a good friend (Who will be using my house as a hotel for 10 days in November with his family) who does windows up in NY. I'll just have to pay for the windows, a few days off to help and lots off beers on hand. He did offer to do it and plans to come in August to do the measurements.

Also I'm going to call today to see about adding insulation to my attic and inquire about an attic fan.

BTW - Yesterday High 92, 50% humidity on Avg, "not much sun" in the afternoon: Temp set to 76 house stayed between 76-77 between

2-6pm...Not complaining!

Thanks again all, Felix

[gfretwell]

I imagine when we really get serious about energy savings we will have a passive heat exchanger that piulls that heat out of your vaulted ceiling without needing to bring in hot "make up" air like you would if you simply vented it outside. I am looking at passive cooling schemes for my S Fla home. It is already fairly good since it is the "pre AC" design with awning windows and awnings on all the windows. It does shorten my AC season a month or more compared to the newer homes. My next project phase will include a cupola on the roof for passive ventilation of the attic.