Need Advice: Repair or replace system

Discussion in 'HVAC Heating & Cooling' started by hans_idle, Sep 9, 2008.

  1. hans_idle

    hans_idle New Member

    Messages:
    51
    Location:
    Princeton Junction, NJ
    Hello everyone. I have a very general question, and of course, there is no right or wrong answer to this. But I'm looking for advice or opinions on my situation.

    I have a 20 year old house that still has the original furnace and A/C. I'm expecting to have to replace them at any time given the original lifespan of 15-20 years for the units. I live in New Jersey, which means that I need both A/C and furnace to get through the year. I believe the equipment that I have is Trane.

    I just found that the A/C has some type of leak in it so that coolant is constantly leaking out. I found this out by having 3lbs of coolant added only to have it completely leak out within a day. So that's a pretty big leak.

    The local shop that I've used a number of times is estimating $150-$250 to do a full leak check to figure out where the leak is coming from. Now, I know that's expensive, but they do good work, and I'm hesitant to find a cheaper contractor.

    But, the big issue is do I bother spending the money on the leak check, or do I just consider replacing the A/C unit considering it's age and effeciency? Granted, a full new system is going to be much higher, like $7000 if I do the furnace and A/C at the same time. But, I could also find out that the leak is a minor part that is easily replaced and be good for another year or more. Also, it's getting to be cooler now, so the A/C will not be used as much.

    I guess what I'm looking for is are there any other factors that I'm overlooking? I hate to throw away $250 just to find out that the condenser or coils need replacing, which would push me in the direction of the replacement.

    I'm sitting on the fence either way because I'd love to get a new system that is more effecient but i hate to spend the money unless it is necessary.

    Any thoughts?

    Thanks!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,323
    Location:
    New England
    Personally, I'd replace the system. A new a/c could be twice as efficient as the old one. The furnace could be in the low-90% range, probably 20-40% more efficient. Not sure what your utility bills are, but they are unlikely to go anywhere but up.

    One thing I really like on my (also Trane) system, is the variable speed fan option. It allows you to extract much more moisture out during the summer and the start and stop are almost unnoticable because of the ramp up/down funtion. In the winter, you don't get that short blast of cold air when it first starts up until the air in the ducts gets hot. It also runs after the a/c or heat is on to extract the conditioned air you've paid for. Couple the dual-stage furnace with the variable speed fan and expect nice, even heat or cooling with good dehumidifcation. Since it does so well on dehumidification, you might find you are comfortable at a higher temp, saving even more money.

    Technically, the a/c people should not have added refrigerant without checking for leaks, if I understand the regulations.

    The new refrigerants are less detrimental to the environment, too.

    Check with the utility company to see if any rebates are available...I had a new boiler and WH installed and got back $1100.
  3. Mort

    Mort New Member

    Messages:
    83
    Location:
    CA
    If it's the same shop that put refridgerant into a leaky system to begin with I think I'd look elsewhere for future repairs or replacement of the system. Being a twenty year old system, it likely uses a coolant that is no longer manufactured (ie freon) and is usually only available recycled at a pretty steep price.

    I was in you boat a few years ago with a sixteen year old system and replaced everything (well, had it replaced). The new system works better and is less expensive to operate and the rebates from the gas and power company covered 15% of the cost.

    Mort
  4. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    If it's 20+ years old I think I'd replace it with a new 13 seer unit. You will save money in the short run.
  5. hans_idle

    hans_idle New Member

    Messages:
    51
    Location:
    Princeton Junction, NJ
    Thanks for the info. I looked up the rebates that the utility company might offer (didn't know they did that), and it looks like I might be able to get a couple hundred from them.

    The only question I have at this point is how expensive it might get. I'll have to get some contractors over here to see what it might cost. I'm inclined to do the furnace and a/c all at one time, but not sure if that will be $2000, $5000, or $8000.
  6. Mort

    Mort New Member

    Messages:
    83
    Location:
    CA
    When I replaced mine about four years ago it was around $4500 for a 13Seer (mind is blank but 3 ton rings a bell) variable speed unit with new furnace. It was a pretty R&R type job....no wall type modifications were necessary. I'd expect the prices today would likely be 20% higher (at least)

    Mort
  7. hans_idle

    hans_idle New Member

    Messages:
    51
    Location:
    Princeton Junction, NJ
    Mort,

    Forgive my ignorance, but was that an A/C unit AND a furnace, or just the furnace? I didn't quite catch all the terms.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,323
    Location:
    New England
    A furnace typically supplies heat and a fan. To get cooling, you add a cooling coil and compressor, but still use the fan on the furnace. The controls on the furnace are smart enough to not turn on the furnace heat source while cooling is called for (except in some specialized situations where you need tight control over humidity levels where then they run the a/c to remove moisture, and then re-heat the air if it is too cold for comfort).
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