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chas045

General questions re: New heat pump or not.

chas045
11 years ago

I see that there are a lot of serious experts here and believe that you might be able to begin to point me and my thinking in the right direction to saving some money in the future. I heard that efficiencies have improved and replacement might actually create cost savings. However, after casual exploration, it sounds like it might take many, many years to see a gain.

Here are my specifics, to the extent that I understand them.
We live in central North Carolina near Raleigh and Durham. We are the 3rd home owner.
2300 sq ft two story house with uninsulated attic. 9 ft ceilings downstairs, open floor plan with an 18 foot entrance area. Upstairs is bedrooms with 8 foot ceilings.
Our house was built in 1999 and is what I would call semi-respectable builder grade. The house seems well insulated. We are in the country using propane with a 500 gal rented tank. The propane company said that newer houses in our subdivision have 250 gal tanks because the insulation appeared adequate.
I do not know how to determine our specific HVAC units, but they are probably basic builder grade. They are Goodman units. We have regular propane heat with electric air in the crawl space downstairs; and a heat pump in the unfortunately uninsulated attic for the second story. Ducting is via round flexable bulky insulated stuff. I suspect that the units were reasonable. We do have slight problems with the master bedroom which is on the longest run from the heat pump. It only gets one duct plus one in the master bath. I think we could easily add an additional duct because the attic is open (except for all our stored junk). Otherwise things heat and cool well.
I currently see that our electric rate is 10.4 cents/KWhr. I don’t know if it was a mistake, but our recent propane cost $2.00. It has been running around $2.80 although when we first got here in 2005 and perhaps 2006 it was under $2.00.

Unfortunately, we do have one problem. The heat pump appears to have a slow undetectable leak. I believe that we have had to add refrigerant twice, so it needs a boost every three years approximately. While I have never enjoyed the cost of a service call, I don’t recall thinking the ‘freon’ added that much to the bill. I suspect we are coming up on a third year! Vendors are saying that limits on R22 or whatever are causing the cost of refrigerant to increase dramatically. I noticed that some are selling tanks of the stuff on craigslist for more than Amazon so I guess something is going on. I would think that if prices were really that bad, that HVAC guys would be taking their equipment to junk yards or the curb and pumping out any white thing they saw sitting there. So what is actually going on here??

So, here are the actual questions: Is this slow leak a real concern considering the ‘possible’ lack of R22? Combining with efficiency, does it make good or obvious sense to get a new unit? Regarding heat, the heat pump gets less use because the downstairs unit’s rising heat takes over after the morning chill is off (we drop the units to 60 at night). I don’t suppose it is very efficient when it is below 30 anyway which it often is during winter. It gets a workout in the summer!!
Would DIY insulating the attic, which wouldn’t be that hard since it is essentially open, be particularly useful? Anything else I'm missing?

Comments (10)

  • mike_home
    11 years ago
    last modified: 9 years ago

    You should never recharge a heat pump or condenser without investigating the source of the leak. It is expensive and not good for the environment. The phase out of R22 is causing the price to rise. This is happening everywhere.

    The heat pump is about 14 years old. It probably doesn't make sense to spend money fixing it given it is a builder's grade Goodman unit. Leaks are some times difficult to find and contractors typically don't like to spend time looking for a leak in an old unit. I suggest you start shopping for a new heat pump.

    Are you sure the attic floor is not insulated? If you have plywood on the floor, then lift a board to see if there is insulation. You must have insulation between the attic and the ceiling of the house.

  • tigerdunes
    11 years ago
    last modified: 9 years ago

    Post mdl number of your furnace.

    I would install a basic 13 SEER heat pump with matching coil. Something of good quality, no Goodman.

    You will need a DF thermostat with outdoor sensor if you don't already have one.

    What size is your current condenser?

    Post back.

    IMO

  • stoveguyy
    11 years ago
    last modified: 9 years ago

    U have a propane gas forced air furnace for 1st floor? So it has an external a/c unit with condenser in plenum? So u have 2 a/c units? What is ur typical summer a/c elec bill?

  • chas045
    Original Author
    11 years ago
    last modified: 9 years ago

    cavell: Yes I have two ac units. Forced air furnace on first. Everything as you say. Summer usage is approx 2000KWhr/mo and 230 to $270/mo. Half that in winter.
    Tigerdunes: Tomorrow I will see if I can find condenser size. I don't know where to look. Perhaps GOOGLE will tell me. Same for furnace.
    mike: Yes of course I have insulation under the attic floor. I am talking about the roof. There is no insulation up there and the attic can get real hot in summer (i imagine 120 degrees F) and the heat pump ducts all run there. And yes, I know R22 is phasing out but I assumed that provision is being made to reclaim old stuff and millions of homeowners must have 14 and 30 year old units. I don't consider 15 yr old units to be old, do you really? If I bought a new unit, would it be old at 15 years?

  • audiomixer
    11 years ago
    last modified: 9 years ago

    All attics get hot the key is how much of that hot air gets downstairs. You could add blown in or batt insulation to get up to r60. As far as age, yes 15 years for new equipment would be considered old. Just ditch the old one and get a new one.

  • audiomixer
    11 years ago
    last modified: 9 years ago

    Duplicate

    This post was edited by audiomixer on Fri, Feb 22, 13 at 18:46

  • mike_home
    11 years ago
    last modified: 9 years ago

    You are correct in R22 is being reclaimed from old equipment. But due to decreasing supply the price continues to rise.

    I don't recommend insulating the roof deck. You are better off upgrading the insulation of the duct work (R8 would be a minimum) and sealing any leaks.

    I don't consider 15 year old units old either. It more the fact you have a leaky builder's grade Goodman heat pump.

  • chas045
    Original Author
    11 years ago
    last modified: 9 years ago

    "I don't consider 15 year old units old either. It more the fact you have a leaky builder's grade Goodman heat pump."

    Thanks Mike. That makes sense to me. Now, I am just guessing about this being a builder grade, but it is likely true. Can you or someone, let me know exactly what (or where) I am looking for to determine the size and effeciency of the unit?

    And one more question. I am quite sure I had two charges to this unit but I don't know for sure, it might have only been one. I had a tech out two years ago re something else and asked him to check the unit. At first he said it was a little low and suggested some leak stop stuff he had. It sounded to me like it might be something like car radiator stuff that has been known to gum up rather than fix small radiator leaks. After a few minutes, he checked again and he said the unit was fully charged and didn't need anything. I suspect that you all are going to tell me that the stop leak stuff is bogus. However, if it has possibilities, under the circumstances it might be worth risking.

  • chas045
    Original Author
    11 years ago
    last modified: 9 years ago

    I see that the unit is listed as goodman CPKE 24-1AB. I googled all around and can't find anything clear although one poster stated that his unit as listed above was a 10 seer 2 ton. However, someone else said something different. It also indicates original charge was 106 oz R22.

    I checked my records and I can only find one HVAC record in 2007 for a recharge of 1.5# of R22 ($28.00 for the 1.5#). I still suspect I needed a charge in 2010. Perhaps I just didn't file it.

    I looked at my flex ducting. There are no marks on the final runs but the bigger stuff says R5.8 dynamic and R4.2 static. They are very bulky. Are R8 ducts rigid or also flex but of better materials?

  • fsq4cw
    11 years ago
    last modified: 9 years ago

    Your electrical rate seems reasonable. I would recommend replacing your systems with Carrier Infinity Greenspeed heat pumps coupled either to Infinity gas furnaces (96% efficiency minimum) or Infinity fan coil units.

    Your present equipment is getting on in years and there have been a lot of advances in efficiency. I would not spend the money to repair it unless you plan on selling in the next year or 2. What size capacity is your electrical entrance?

    I too would not recommend insulating the roof deck but I would recommend evaluating the attic ventilation to determine if there is sufficient airflow from the soffits through the roof vents.

    SR

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