Upgrading HVAC - Advice Please

12 years ago

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

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Comments (9)

seatonheating
12 years ago
last modified: 9 years ago
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.
seatonheating
12 years ago
last modified: 9 years ago
*post
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I'm disappointed that what had at first seemed a very balanced comment was followed by what seems to be misinformation and misdirection. People buy ground source heat pump equipment because they want to and can afford it. Or decide they need to in their locations. They're hugely more expensive than alternatives, which is why they're still not very common. "When’s the payback on a Tesla? People still choose to buy them for reasons other than the ‘bottom line’." Not a comparable. A false analogy. "I would not choose natural gas or propane for reasons relating to the environment, safety, IAQ & paying for yet another utility hookup for an energy source that might not even be used for months on end during the year." What effect having a gas furnace has on indoor air quality. Another hookup? Most people prefer gas cooking appliances and besides, the OP is talking about an existing home, he either has gas service or he doesn't. "Rather than spending perhaps tens of thousands of dollars on a Solar Array, I would sooner invest that same money, hopefully less, in a ground loop for a Geothermal system." Sure you would, that's the business you're in. The ground source heat pump market is not growing as expected by those in the industry, which suggests that your opinion isn't widely held or easily sellable. In many parts of the country, solar panels can have a quick payback. Not so ground source heat pumps. "I often hear about Solar Panels when geothermal is mentioned, as an alternative way to save money by creating energy." In a place like Texas, where electricity is cheap (other than during cold weather crises as they just experienced) there's likely no payback from a solar panel installation. People do it as a personal statement, call it for environmental or other personal reasons. Like buying the Tesla, not a financial decision. An HVAC system blows warm air when it's cold, cool air when it's hot. It's one of those things people don't care about - either it works or it doesn't work. Spending extra money for an exotic system doesn't equate to extra payback when the home is sold. Neither owners, nor visitors, nor people passing by, nor anyone else, concern themselves with what's doing the work. It's equipment that doesn't produce an experience for someone in the house if it's working. In the US, there are vast areas where electricity is cheap. It will remain so for some time. People don't spend money today to potentially save money 10 years out when market conditions may or may be different. I suspect you could build a house with mahogany or teak framing. Or you could paint the framing bright colors. Why bother, you can spend less money and effort and get something else that will do the same job. "We almost never use setbacks at our home - even when going on vacation for weeks on end with no one home, our geothermal just runs." You're combining two different things to produce confusion. Thermostats that have a setback feature ALL are set up to provide lower overnight temperatures to have more comfortable sleeping conditions and then a recovery in the morning before wakeup time. As sleep specialists recommend. That in demand comfort features isn't possible with ground source heat pumps because the warm up period from a setback is too slow to be convenient to use, absent triggering a secondary heating source (like a furnace) to help. THAT'S why you don't "believe" in setbacks with a heat pump - they don't work. Turning down a thermostat during heating season when the home will be unoccupied is not a "setback" as that word is most commonly used. It's done to save money, why heat a vacant house? No setback thermostat is needed, even a dumb 50 year old analog thermostat can be turned down.
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ionized_gw
12 years ago
last modified: 9 years ago
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.
mike_home
12 years ago
last modified: 9 years ago
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.
david_cary
12 years ago
last modified: 9 years ago
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.
Master_of_Time
Original Author
12 years ago
last modified: 9 years ago
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
starhikers
12 years ago
last modified: 9 years ago
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?
ferd42
12 years ago
last modified: 9 years ago
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.
weedmeister
12 years ago
last modified: 9 years ago
While he's in his attic, he needs to go from R19 to R40.

Upgrading HVAC - Advice Please

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