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Upgrading HVAC - Advice Please

Posted by Master_of_Time (My Page) on
Thu, May 5, 11 at 16:00

Hi,

I am a new member and came across this forum researching information to help me decide on what to do about our (inadequate) heating and cooling system.

There are some excellent posts and contributors and I hope to persuade you to give me your advice too.

We live in the D.C. Metro area in a 1920s single family home. Little to no wall insulation, new double-glazed windows, R19 attic insulation. Two original levels and a self-finished basement - 1200 square feet in the original levels.

Since moving here we have always struggled to get the house warm enough in winter or cold enough in summer. Current equipment:

Outside is a Trane XB1000 (TTB024C100A2)
In attic is a Trane XL 80 (TUD060R936H4) and control unit on the cooling blower(?) is a White Rodgers model 50A51-495.

Room temperatures are uneven and I think we have a balance problem with the airflow. I have closed the volume dampers (?) in the attic to lines for the small rooms that get too much heat or cold. We have two intakes, ceiling mounted, one on each of the original floors (14 x 14 served by 10" duct to the atic).

First floor has electric heated floors that keep toes warm but do not heat the rooms well enough in winter. The finished basement has electric baseboard heating and no air conditioning (rarely gets too hot and we have used a portable system on really hot days).

I have approached 3 highly rated contractors from Angie's List to hear their assessments: two have visited so far and I have one quote.

No Manual J calculations.

The contractor that has quoted recommended increasing the intake airflow by expanding the second floor intake and extending the first floor intake to low down on one wall. While inspecting the attic installation he adjusted the fan setup (it has color-coded pins) and showed how increasing air flow in would cause more air to flow from the registers. Their quote is also for replacing the system with Carrier equipment and doing the additional work:

-- Carrier 24ABB330 air conditioner (2 �-tons R410 @ 13 S.E.E.R.) with a Carrier CNPHP3617 3-ton horizontal coil
-- Carrier 58CVA070-12 2-stage gas furnace (Hi: 66,000 / Lo: 44,000 B.T.U.H. @ 80% A.F.U.E.)
-- Modify intakes as per above, plus refigerant lines, pad etc.

Total just less than $8000 (plus tax presumably).

For $500 I could upgrade further to a Carrier 24ACC630A air conditioner ( 2 �-tons R410 @ 16 S.E.E.R.) that would qualify for tax credit.

This seems a lot given that none of the duct work (except that related to the air intake) is going to be touched.

A final complication: we want to extend our house as the children grow and I was hoping to not have to upgrade the HVAC again. It may be that I will need a second complete system but that seems untidy and probably will be inefficient (an extension will not be self-contained).

Thank you for bearing with me so far. My questions:

-- Is it possible to calculate air flow in to determine better if that is a potential factor?
-- Is this Carrier system a good fit (notwithstanding no Manual J calculation)?
-- Any comments on the price?
-- Any ideas for upgradeable systems?

I am ignorant too about heat pumps and whether they are advisable and viable in my situation. Thoughts?

Thanks in advance.

MOT


Follow-Up Postings:

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RE: Upgrading HVAC - Advice Please

Find the right guy and you won't have to come on here asking so many questions.

If you had myself out to your house, your pose wouldn't be necessary. Keep looking.

When you start calling others ask them about the "ACCA quality installation checklist". If they haven't heard of it then move on.


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RE: Upgrading HVAC - Advice Please, correction

*post


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RE: Upgrading HVAC - Advice Please

If I were in your shoes, I would be looking for an unbiased energy rater and a local program to help pay their fee. They can identify the low-hanging fruit for energy savings and help you find the best solution to your HVAC problems.

For future expansion, consider heat pump mini-splits. Maybe even for now.


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RE: Upgrading HVAC - Advice Please

Here are some answers:

-- Is it possible to calculate air flow in to determine better if that is a potential factor?
A good contractor will measure your ducts and calculate the air flow it can support.

-- Is this Carrier system a good fit (notwithstanding no Manual J calculation)?
The Carrier Infinity furnace is very good. I recommend moving up to the Comfort AC rather than the base model. You need to find a contractor who will do a Manual J calculation. I think 2 1/2 tons is oversized, but no one can tell without the proper calculation.

-- Any comments on the price?
The price seems on the high side, but it is not fair to critize it without seeing the installation.

-- Any ideas for upgradeable systems?
Do you have an idea how you will expand your house? You may be able to install a system which could cover the current and future needs. If you are planning a major expansion, then you will need to put in a second system. Discuss your expansion plans with the contractor for possible ideas.

A heat pump is a viable option. Your electricity and gas rates will determine how much savings you could achieve with the heat pump versus the furnace.


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RE: Upgrading HVAC - Advice Please

An expandable option that I used was a 2 stage zoned Infinity heat pump. It was sized to my final house size. Oversized initally, at least it could run in low stage and not act oversized. This solution is not ideal but may be a possibility for you.

So no one has mentioned it, R19 in the attic is pretty bad for DC and easy enough to fix. If you have blown insulation, it is usually recommended to remove, air seal, then replace with more. I guess even if you don't have blown insulation, you could the same thing.


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RE: Upgrading HVAC - Advice Please

Thanks for your responses.

All three contractors have visited and I have two quotes. The first in the original post. The second recommends Amana 16 Seer 2 ton, 2 stage compressor with an oversized 3 ton coil for cooling and Amana 80,000 BTU/80%, 2 stage, variable speed furnace. Nothing about changing return ducts.

The third firm suggested zoning the system split first floor and upstairs with separate thermostats to control a pnuematic damper in the attic. Do this first and then see if the cooling and heating systems needed to be upgraded. He was their ducting expert and he thought it would be better if the returns were larger, but he thought too that the zoning would solve the problem for the majority of the time. I have yet to get their quote so this detail may change.

I am not sure that I have found the right contractor yet. The lack of Manual J calculation bothers me. I am concerned too that there has been no attempt to better quantify the flow issue. I have asked pointed questions about this and been given answers along the lines of " xx years experience" or "not needed for replacement of existing systems". These are, in theory, the top rated HVAC firms in the DC Metro area on Angie's List.

So how do I find a firm that, as seaton puts it, would make it unnecessary for me to post so many questions?

Returning to the point of my post. I think it would be unwise in my situation to size for the future and so am concentrating on getting the house right as it is. I will not be worrying about the basement either.

I found a link to a blog that talks ducts: Fred Weldin (that can be googled) - I learnt some things from his site last night.

Does anyone have experience or opinions about the Amana furnaces and cooling systems? I was told that they have lifetime warranties on key parts that distinguishes them from all the others.

Second, does putting in a coil that is 3 tons make sense for a 2 ton condensing system?

I need to fix my attic insulation and appreciate the nudge from david cary!

Any other thoughts or advice welcome.

MoT


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RE: Upgrading HVAC - Advice Please

I know nothing about HVAC systems other than I am looking for one.....but all the 5 contractors that have quoted me, say to stay away from Amana, so I'm passing that along. I have had Lennox quoted(very high) Carrier, Bryant(a division of carrier), Goodman(what I have now),and another Carrier dealer. I like the Carrier name since they seem to have the best units out there right now. The one who quoted Bryant says they just have different tags on the same equipment, that it is exactly the same machine. Who knows?


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RE: Upgrading HVAC - Advice Please

I've been working with MOT to troubleshoot his duct system.

It turns out the 2001 work leaks like a sieve, has a high resistance fitting arrangement at the supply plenum, is underinsulated (overcompressed R4.2 wrap and R4.2 flex), the flex branches are 'snaked', and two 10" flexes for the two ton return are borderline at best.

He's currently looking for a sheet metal contractor to make it right.

Here is a link that might be useful: Weldin Engineering Co.


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RE: Upgrading HVAC - Advice Please

While he's in his attic, he needs to go from R19 to R40.


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