Heat pump/duct work replacement


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Old 04-11-07, 08:15 PM
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Question Heat pump/duct work replacement

First question:
I recently got a quote to have the main trunk line of the duct work in the attic replaced from one 18" flexible line to two 12" flexible lines. One for the main section of the house supply and one for the back section of the house supply.

Another 12" duct line will be installed to add an additional return line from the back section of the house. Currently the return is in the floor with a duct in the front and back section of the main section of the house and one in each bedroom (back section). The current return is believed not to be an adequate return for the a/c system. Also not efficient because it is in the floor.

This work is being done to help with a big problem with uneven cooling/heating in the main section of the home vs the bedroom area (back section) of the home.

I was quoted approx $2300 for the above work.

In addition, I received a quote for a new Lennox 3 ton Heat pump, and 3 ton air handler. (13.5 SEER). This includes a UV light. The amt for this was quoted at $5300. The equipment has a 10 yr warrantly on labor/parts.

Do these prices sound reasonable?

Second question:
My current system is a 3 ton, Airco Air heat pump that is 10 years old (9 SEER). The system is working but makes loud clanking sounds when it starts up and shuts down.

Is the payback in savings of replacing this system worth the cost? Is it too early (in age/yrs) to replace this system?

This is a pretty big expense ($7600) and am looking for some advice on this.

Thanks.
 
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Old 04-11-07, 08:32 PM
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Most systems make it to 15 years. But 10 years and so low of seer Id say go for a new one. But go for a seer of 15 or more that way you will also get a better HSPF on the heat pump. The way power cost now it will just go higher. Also with the 15 seer you can get a tax credit back from the IRS.
Dont think you need the UV light . Can go a better filter Like a Air Bear. Id also see if you cant get the main supply duct up in the attic made out of ductboard and the silver flex pipe used for registers runs off it. You will get a much better air flow. If you will stay in the home for 10 years here Go for a V/S blower coil on the system .
 
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Old 04-12-07, 05:22 PM
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Thanks

Thanks for your thoughts. I agree and feel in the long run this will save me some money on my electric bill that goes up over $225/month in the summer.

I currently use the Aprilaire filter system with the 4" accordian type filters which will be put on the new air handler.

The plan right now is to replace the one main 18" flexible trunk with 2 12" flexible trunk lines with one going to each of the 2 parts of the house. An additional 12" flex return is being installed as well to pull some hot air from the ceilings in the bedroom/hallway area. Do you think changing from flex to duct board would shoot the parts cost way up on me? Everything I read and everyone I ask says the flex is just as good as the ductboard but have a hard time believing that.

Thanks again.
 
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Old 04-12-07, 07:16 PM
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Question Replacing ductwork

I recently asked this question on the a/c forum and see this forum is geared more for ductwork so I'll ask part of my question here.

I have a ranch style home in FL. The 2 bedrooms (farthest side of house from air handler) have poor air flow. Cold in winter/warm in summer.

I recently got a proposal to have the current main supply trunk line (flexible 18") replaced with two 12" flexible lines. One going to the center of the house splitting off to supply vents in liv rm/din rm/kitchen and the second line going to the 2 bedrooms/2 baths.

The existing return is in the floor with 4 vents (one in each bdrm and 2 in liv rm). I was told by several people that the return in the floor is unusual for Florida and undersized. So, the second part of the proposal was to run another 12" flex line adding a second return to the system from the hallway (new vent in ceiling) with a new return vent in each bedroom.

The house is 1600 sq ft, with a 3 ton heat pump. The length of the current main flex trunk line is approx 30-35 feet long.

Now for the questions:
1. Should this help my airflow problem? I had the single 18" trunk installed in the house to replace a single 12" (??) main trunk line when I first bought the house (never was completely satisfied with the outcome and am attempting to finally get it done correctly)
2. Is flexible the way to go or is duct board better?
3. What about sheet metal ductwork?
4. Does $2300 for the above 2 part proposal seem reasonable?
 
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Old 04-12-07, 08:54 PM
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All the flex ducts have a bigger drag on the cfm . Migh pay to rig a damper in the 12 " pipes so you can put more air in the one you need the most. Did you look at a V/S blower? Duct cost ia different all over. The filter is good.
 
 

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