Armed Polite Society
Main Forums => The Roundtable => Topic started by: AZRedhawk44 on June 09, 2010, 04:55:32 PM
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My house has 2 smallish AC units. One controls the kitchen, living room and 1st bedroom. The other controls the 2nd bedroom, master bedroom, both baths and the hallway.
The 2nd unit is giving me just a hint of grief right now. The attic air handler fan is squeaking on it, and I get just a faint whiff of ozone or some sort of burnt electronics if it runs too long or too intensely.
I have a home owner's warranty and the AC folks are coming out to look at the problem, and until then my front unit is doing fine in keeping the house tolerable, augmented by brief runs of the troubled unit.
But:
I'm thinking of augmenting the entire system with the addition of one or two of these Fujitsu ductless units.
http://www.fujitsugeneral.com/wallmounted9-12RL.htm
Or... perhaps even retiring the system in the back half of the house entirely and re-running a single duct line from the front AC system to cover the hallway and 1 bathroom (which overlap with air from the master bedroom and bedroom #2).
My master bedroom is perhaps 325 square feet, plus walk in closet and master bath, so about 500 square feet total.
The 2nd bedroom (serves as my office) is 11x15, about 165 square feet.
Two reasons I'm thinking of getting rid of the second unit:
1. It's LOUD.
2. Ducted systems are supposedly less efficient from both a comfort angle and a financial one. I spend 8-10 hours a day in bedroom 2 (my office) and another 8-10 hours a day in the master bedroom, and neither feel as well conditioned as my living room area. All the numbers I see so far are marketing ones and I'm taking them with a grain of salt, but I'm hearing that ducted systems are 25-40% inefficient if the attic is particularly hot and the ducts go through the attic. That describes my second air handler perfectly. The living room air handler is in a closet-like enclosure that services the living room and bedroom #1 without being exposed to the hot attic, and the distance to the kitchen is quite short so less thermal loss there.
Anyone have one of these? They appear to be much nicer than one of the cheapo window units and actually an improvement in efficiency and comfort. Supposed to be able to run at variable speeds, so can operate quietly rather than being either full-blow PITA loud or off like my current system.
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Mitsubishi Mr Slim. Very nice units. Get the heat pump and you'll save on heating as well.
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Also thinking about increasing the insulation in my attic.
Is it economical to rent a spray-foam insulation sprayer and do it myself? I'm thinking of coating the entire roof of the attic so that the trapped radiant heat from the shingles doesn't make it into the house as easily.
I also have a couple spots in the attic where the attic covers a patio, and there is no insulation over that area but it shares attic air space with the rest of the house.
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you should not spray directly against the bottom of roof sheathing!
http://www.roofhelp.com/ventilation_main.htm
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What CSDaddy said.
Also, we noticed a major difference in heating and cooling by making sure the attic was vented well (pulled the current insulation out of the eaves and slid in baffles all the way around so the soffits vent) then adding R25 blanket over the ceiling joists and existing insulation (R19) perpendicular to the joists. R44=sweet! Easy to do, too.
Installed a squirrel cage at either hip end vent (L-shaped rambler) with a thermostat to really pull the air through during the summer. The blanket material is great, no itching afterward. No ducts in the attic, though.....just toys. =)
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Thanks for the heads-up on the spray foam on the roof under-deck. Plans canceled.
My current insulation is pathetic. I can see the ceiling joists. I'd guess the whole system probably averages R15-R20 or so. Recommended insulation for AZ is R48.
I'll be adding insulation to the master bedroom and my office in the next month to see if it helps. Maybe start re-working the soffets, too. Remove a few and drill large diameter air flow holes in them, then cover the hole with mesh so critters can't get in.
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I was right about the attic air handler though. AC guy just left. A mount broke on the motor. Motor was grinding against the housing, increasing resistance to the motor stators, which is probably the ozone/burnt electronics smell I detected. The squeaking was metal on metal.
So, I'm down to 1 AC system until they get the parts in stock to replace the motor and mount.
Fortunately, the weekend is supposed to cool off a few degrees from the last few days. The 1 unit should be able to keep everything tolerable.
Wish I had a ductless unit in my bedroom now, though.
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I've worked on a bunch of those through the wall heat pumps like in motels. A museum nearby has about 40 of them.
I think these are Trane.
I gotta say they're very nice. Not very hard to work on and they heat and cool really well.
Not sure how much they cost, though.
If the one you've linked up top is as nice it should work fine.
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Adding 20 bags of cellulose-based insulation tomorrow via blower, my dad is helping from the ground as I crawl around in the attic.
I'll do this 20 bags now, wait a week or two, and do another 20 (the blower rental is free if you buy 20 bags @ $9/bag).
1 bag is supposed to be enough to add R13 to about 60 square feet, or R19 to about 36 square feet.
I plan on targeting specific areas: Master bedroom, office, back deck roof (that has NO insulation over it but is still exposed attic!), living room. Not gonna just "average" it over the whole thing, I'm going to hit the trouble spots.
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http://www.rd.com/images/tfhimport/2004/20040601_You_Can_Fix_-Y_page005img004.jpg
put these in the eves before you blow in. then you will maintain free passage of air when you do soffit vents. you would be surprised how much movement convection will give you
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http://www.rd.com/images/tfhimport/2004/20040601_You_Can_Fix_-Y_page005img004.jpg
put these in the eves before you blow in. then you will maintain free passage of air when you do soffit vents. you would be surprised how much movement convection will give you
Ain't gonna happen at this point. It's too hot up there today to do it, and I've got everything arranged for tomorrow including blower rental and help coming. I don't even know if Home Depot sells those. Didn't see anything like that near the insulation.
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they sell em cheap too and they friction fit in then the blown insulation holds em in place
what kinda soffits are on house now?
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they sell em cheap too and they friction fit in then the blown insulation holds em in place
what kinda soffits are on house now?
Umm... wood? How are soffits different from each other?
I'll look for 'em and if they aren't a PITA to install then I'll get a couple dozen.
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they are a real pita after the insulation is blown in.
on wood soffits i like this style lots of folks make em you don't have to worry about getting holes in a regular spacing like the round or rectangular ones
http://www.airvent.com/homeowner/products/intake-soffit.shtml
snap chalk lines cut out slot insert i use a smaller cordless circular saw since cutting upside down blows
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they are a real pita after the insulation is blown in.
on wood soffits i like this style lots of folks make em you don't have to worry about getting holes in a regular spacing like the round or rectangular ones
http://www.airvent.com/homeowner/products/intake-soffit.shtml
snap chalk lines cut out slot insert i use a smaller cordless circular saw since cutting upside down blows
I just installed those same soffit vents in my soffits last year; also installed their ridge vent (http://www.airvent.com/homeowner/products/ridgeVents-shingleVent.shtml). Cutting upside down the length of the house was indeed a royal pain. I need to manipulate a couple of the soffit vents to close some gaps in-between vents still. I have blown insulation in the attic, but it peters out at the soffits (roofs not terribly steep) so it doesn't plug up the intake vents.
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I just installed those same soffit vents in my soffits last year; also installed their ridge vent (http://www.airvent.com/homeowner/products/ridgeVents-shingleVent.shtml). Cutting upside down the length of the house was indeed a royal pain. I need to manipulate a couple of the soffit vents to close some gaps in-between vents still. I have blown insulation in the attic, but it peters out at the soffits (roofs not terribly steep) so it doesn't plug up the intake vents.
saw gets heavy don't it? i have a light weight 18 volt and i use a laser light to guide me. and saw dust goes fun places
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heh, I was watching "Homo on Homes" er I mean "Holmes on Homes" and his pretty tart girl was wearing a low cut shirt and creating huge amounts of sawdust. Need I say more? :lol:
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Those slim profile wall units work great. We have three in the tower rooms in the river house and just turning on the second floor unit keeps it and the first floor cool and dry. Mine are European in origin--German maybe?
TC
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http://www.rd.com/images/tfhimport/2004/20040601_You_Can_Fix_-Y_page005img004.jpg
put these in the eves before you blow in. then you will maintain free passage of air when you do soffit vents. you would be surprised how much movement convection will give you
Exactly what we used...come in a cardboard case. They're molded two per sheet and snap apart for install. They're in the insulation dept. at the Ho Depot. Could be a PITA if the blown in i already in the eaves, though.