Author Topic: A/C Distribution Problem (Read 4022 times)

TarpleyG · « **on:** July 15, 2006, 04:15:10 AM »

I have a 1 1/2 story house. I know, either/or right.

Anyway, we have a "bonus" room above our garage and it stays about 2-7 degrees warmer than the temperature downstairs which we keep at 75. The room has a return and 2 vents in it but it has vaulted walls and ceiling making the surface area rather close to the roof. I can only assume that just the very nature of being upstairs and with black shingles on the roof makes it hot.

Anyone have any ideas on how to effeciently cool this space without freezing out downstairs?

I had contemplated getting a portable A/C unit and figuring out a way to vent it (a whole other problem). Window units are out of the question.

Greg

Ron · « **Reply #1 on:** July 15, 2006, 04:34:50 AM »

Look into duct free split systems. Carrier makes them as well as several other manufacturers.

This would require an evaporator fan unit to be hung on the wall someplace in the room. They are not really that intrusive and they are very quiet.

http://www.residential.carrier.com/products/ductfree/index.shtml

K Frame · « **Reply #2 on:** July 15, 2006, 06:43:51 AM »

First things first.

Does your current system have dampers on the distribution lines near the trunks? If not, your system is very likely out of balance. Properly balancing the system will deliver proper amounts of air to each area so that you don't have these nasty temperature excursions.

Adding the proper dampers might be easy, or it might be a fricking nightmare, depending on how your house is built.

How's the insulation and ventilation in the bonus room? If you don't have enough insulation to prevent heat migration, and ventilation to take trapped heat away, you'll never make any meaningful headway.

Next, how about ceiling fans? They may not drop the temperature in the room, but they'll help make the room feel cooler.

You say a window unit isn't a possibility. How about a window unit installed semi-permanently in a sleeve through the wall? More expensive, but a LOT less expensive than a ductless minisplit system.

As for the portables, the only logical way of venting them is through a window. But, it's not permanent, and the duct is easy to remove and store.

280plus · « **Reply #3 on:** July 15, 2006, 07:18:21 AM »

The bonus room over the garage is notorious for being too hot in the summer and too cold in the winter. It has more wall/floor/ceiling area exposed to outdoor temps than any room in the house and is almost invariably at the farthest point away from the blower that pushes the air around inside, meaning it will get the LEAST amount of air out of all the rooms in the house when in fact it usually needs the most. They are tough to get right, especially if the builder is trying to save a few bucks or the HVAC contractor underbid and cut corners to get the job. When I design a system for a house that includes a bonus room I make DARN SURE there's going to be enough air reaching it. Balancing may help and having a "pro" with a velocity meter do it is the best approach. There ARE portable rollaround A/Cs these days that only require an insert in the window to hook a ~ 4" hose up to for discharge air. I think that's what you and Mike are refering to? Nothing obtrusive hangs out the window. I have no experience with those except I know they require regular emptying of a bucket. They shut off when the bucket is full. You MIGHT try leaving your fan in "On" if it's not to nosiy and doesn't bother you, that may help to push more cool air to the bonus room when the A/C is satisfied for the rest of the house and is off. Next step is to get a "duckman" in there (DUCT man

) and see if there's anyway to increase the volume to the room by adding more or larger duct. Then there's the inline "booster" fan. This is a small 110 volt fan inserted directly into the branch to the bonus room. It will help push more air to the area and is usually thermostatically controlled so you don't over cool. If the room is warm and the t'stat is calling for it the fan will run whether the main A/C is on or not and will draw cool air from the rest of the house. I think that's all I have for you. If I have a sudden revelation I'll chime back in. Cheesy

Good luck!

280plus · « **Reply #4 on:** July 15, 2006, 07:25:01 AM »

Revelation (quick eh?) Have you checked your ductwork to make sure it is ALL intact and not crushed or pinched off in any way? If you have a branch that has come off for some reason a good portion of your energy could be escaping into the attic. If someone rooting around up in the attic stepped on the branch line and crushed it that would be a cause as well.

If there ARE dampers at the beginning of the branches make sure the bonus room one is full open.

How old is the house / system? Is it in the attic or basement?

TarpleyG · « **Reply #5 on:** July 15, 2006, 07:47:17 AM »

House was built in '98. I'll have to check the ducts and see if anything is crushed. How much would a typical inspection and recommendation visit cost to evaluate something like this?

280plus · « **Reply #6 on:** July 15, 2006, 07:57:11 AM »

Hmmm, if you get the right folks a "consultation" might be free as they would hope to get some work out of it. What I would do is call the closest HVAC company to you and ask them what they would charge. I say that because you won't find yourself having to pay them a lot for travel back and forth. I always pick the closest service company first. Then, if i decide I don't like them or their price I call the next closest etc etc. The object is to not spend too much on travel.

Tell them you want an "estimate" of what it would take to improve the cooling in your bonus room.

Have you been changing your filter regularly? Is it REAL dirty when you do?
On an older house it's possible the evaporator coil has gotten too dirty over time to allow sufficient air to flow through it. (It's a lot like your car radiator) Probably not the case in your 8 YO house but if the house is in a dusty location it can happen more quickly than average. So if your filters get dirty fast you may have a dirty coil too. It doesn't hurt to have them check the A/C function either. Make sure there's enough freon and the condenser coil (outside) is clean too. Dirt is the biggest enemy of A/C. I Wouldn't expect an average service call to go much more than $200 and to me that sounds expensive. Shouldn't take more than 1.5 hours unless they find a problem.

K Frame · « **Reply #7 on:** July 15, 2006, 12:11:00 PM »

"I think that's what you and Mike are refering to? Nothing obtrusive hangs out the window. I have no experience with those except I know they require regular emptying of a bucket."

Yep, a portable AC unit.

Not all of them require emptying of buckets. Some discharge water vapor out the same hose that discharges the heat from the room.

280plus · « **Reply #8 on:** July 15, 2006, 01:45:47 PM »

Cool

I didn't know that.

K Frame · « **Reply #9 on:** July 15, 2006, 02:01:49 PM »

"Cool, I didn't know that."

Seems to be a fairly recent design innovation.

They're not as common, but they're available.

My only concern would be water possibly collecting in the hose and flooding the room in really humid weather like we have here in DC.

I personally would be inclined to go with the bucket one for that reason. Some of them can take hose discharges just like a dehumidifier, which means that it might be possible to route to a floor or even a shower drain in a bathroom.

I use the water that my dehumidifer takes out of the air in the basement for watering my roses when anti-watering restrictions are in place (which got me into a big fight with a cop a couple of years ago when he wanted to ticket me) or I simply dump it into the washing machine and use it for washing.

Same with the discharge from the main air conditioner.

280plus · « **Reply #10 on:** July 15, 2006, 02:16:18 PM »

Hmph, good idea. Must have been interesting trying to convince the cop how you got the water. I imagine he was in "Yea, sure buddy" mode.

K Frame · « **Reply #11 on:** July 15, 2006, 08:24:19 PM »

I offered to take him down stairs and show him exactly how the jug I was using to water my roses fit into my dehumidifier. I also offered to show him the hose running from my AC air handler to the 5 gallon bucket. I also offered to give him a sample of the water I was using for testing. I knew that it would show up absolute pure -- no chlorine and no dissolved solids (my area has decently hard water).

He retreated to his car and chatted with someone on his radio for a bit and then said he wasn't going to cite me THIS time...

I told him to come back tomorrow at the same time and I'd be watering my roses again, with the water that I extracted from MY air in MY basement.

I was unbelievably pissed.

He never came back.

Perd Hapley · « **Reply #12 on:** July 15, 2006, 08:29:57 PM »

Wait, Mike, was this before you seized control of the HOA Politburo?

Azrael256 · « **Reply #13 on:** July 15, 2006, 08:55:09 PM »

Tarpley, how big are the supply and return ducts into that room, and what is the size of your return into the unit? How big is the unit? How big is the house?

As you observed, the problem is most likely insulation, but sometimes you can monkey with airflow just a tad and get enough extra air into that one room to cool it off a few degrees without a dramatic effect on the rest of the house. Most houses don't have half the return they need anyway, so you could knock out several problems at once here.

K Frame · « **Reply #14 on:** July 16, 2006, 04:47:35 AM »

What does my HOA have to do with county-mandated water restrictions?

roo_ster · « **Reply #15 on:** July 16, 2006, 12:26:30 PM »

Quote from: 280plus

On an older house it's possible the evaporator coil has gotten too dirty over time to allow sufficient air to flow through it. (It's a lot like your car radiator) Probably not the case in your 8 YO house but if the house is in a dusty location it can happen more quickly than average. So if your filters get dirty fast you may have a dirty coil too.

This is what occurred to us 2 years ago.

The coil was well & truly pulgged with hair, dust, etc. It was an amazing thing to see. Once we let it dry out, 80% of it peeled off in great, big sheets of hairy/dusty nastiness. Not something you'd like to see on top of your ice cream.

Our unit was ~10 years old at the time, a Janitrol. (Jani-junk to one fellow who serviced it.) The truth hurts. It is junk, compared to the sexy new Trane my buddy installed in his place.

Also, the return right under the filter was filled with--get this--over 80 lbs of busted up concrete & aggregate. WTF, Over? Who shoves more concrete & stone than I can fit into a 5 gal bucket in a return area? It is a pier & beam, for the love of Pete!

When we build a house, I am definitely getting my ASHRAE buddy in on the plans from the get-go.

280plus · « **Reply #16 on:** July 16, 2006, 02:33:25 PM »

Quote

Once we let it dry out, 80% of it peeled off in great, big sheets of hairy/dusty nastiness.

Just like a blanket, right? Yea, I've peeled a few off in my day. Tongue

280plus · « **Reply #17 on:** July 17, 2006, 05:17:48 AM »

Tarpley,,,I saw a portable spot cooler at Home Depot yesterday for $425. I didn't pay attention to how big it was I'm afraid.

TarpleyG · « **Reply #18 on:** July 17, 2006, 02:06:38 PM »

If I were to get one of these portable units, can I vent the exhaust into the attic? I have access on 3 walls to the attic space.

Greg

K Frame · « **Reply #19 on:** July 17, 2006, 03:05:24 PM »

"Can I vent it into the attic?"

I wouldn't see why not, it's just hot air. That is, as long as that portion of the attic is vented properly to the outside with eaves and ridge vents, louvers, etc.

If you go that route, though, I'd avoid getting one of the ones that vents water vapor from the hose. No sense in adding even more moisture that could damage the insulation or the framing.

TarpleyG · « **Reply #20 on:** July 17, 2006, 03:19:18 PM »

Yep, I agree about the wator vapor discharge. Just as well I suppose since they are even less expensive in that configuration.

Greg

TarpleyG · « **Reply #21 on:** July 19, 2006, 01:41:45 AM »

I tried an experiment yesterday.

I put a fan at the bottom of the stairway and blew air upstairs all day yesterday. The result, even though the high temperature was even higher, was some 5* cooler than the day before. Not sure what this means other than simply pumping more cool air cools it off, duh...

Anyway, just thought I'd share.

Greg

280plus · « **Reply #22 on:** July 19, 2006, 02:08:30 AM »

Yup, you got it. Get a bigger fan if you don't mind it in the way. I have to do the same thing here in my office on a hot day. Here it's an "out of place" thing so it bugs the wifey. Tongue

J.J. · « **Reply #23 on:** July 19, 2006, 08:20:12 PM »

Wow I was getting on to ask a similar problem.

Mine is a 2 story (A/C upstairs) downstairs is much warmer than upstairs. I have 2 vents downstairs and the one in the kitchen blows out all the air the one in the living room has hardly any coming out. I have had people out 2 times (new house still under warranty) All they have done is made the upstairs hotter and the downstairs not much cooler...

And took the A/C Filters because they were dirty. I need to chat with them about that (it was the week before payday I change them every payday) but with 3 cats and 2 dogs sometimes they dont last an entire month. They had no right to take my property (they took them probably because they want to make it so we cant have a warranty, look how dirty this was&etc.)

I am sick of having these people out to do nothing.

News:

Author Topic: A/C Distribution Problem (Read 4022 times)

Ron