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  1. #1
    Join Date
    May 2011
    Posts
    38

    Adding heat pump to existing furnace

    We'll be deciding soon on which contractor to go with. However, all of my estimate so far includes replacement of our propane furnace with a new 80% propane furnace. The current 80% Bryant propane furnace is about 17 years old and is functioning properly. If this is the case, would I not be able to just add on a heat pump to my existing system? Would cost savings not be significant by doing so? Or is it a question on the combined efficiency of the system? I was hoping to spend about $ but it looks like it will be 3x my planned budget.
    Last edited by beenthere; 05-20-2011 at 05:53 AM. Reason: price

  2. #2
    Join Date
    Feb 2011
    Location
    Cloverdale,Ca
    Posts
    316
    Would you spend 15k on your car? Spend the money, have a comfortable, efficient home in witch to enjoy years of good nights of worry free sleep. Or spend 5k and limp that jalopy tell the wheels fall off. Just depends how you want to spend your life.

  3. #3
    Join Date
    Sep 2008
    Location
    VA
    Posts
    1,768
    Most people who go from a furnace to a heatpump complain that the air is too cold. Well, yes the air is not 140, but it is still warm enough to complete the job, to warm the home.
    Dual fuel is a very effective way to gain efficiency. Many new thermostats can now integrate all the necessary functions.
    However, 17 years on a standard 80% furnace is closer to is final flutter, than it's first flame. Typically, mid-grade furnaces last 20 years. It can still demonstrate the apparent signs of normal operation, but could have a failing heat exchanger.
    If you're going to get a new system, then go with one that will save you the greatest amount of money in utility payback, for the amount of time you plan on spending in your current home.
    We've had some customers that actually have such a dramatic savings in utilities, they are able to transfer that savings to their monthly payment on thier new system. In ten years or less, many systems can pay for themselves, if installed and matched properly.
    If you plan on being in the current home only a short time, then have the furnace thoroughly inspected and install the heatpump as you've planned. It's quite simply an investment.
    "The only true wisdom is in knowing you know nothing" Socrates

  4. #4
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,903
    The furnace could have 3-7+ years left; I would keep it if the heat exchanger is in good shape.

    Won't gain anything unless you upgrade from 80% to 95%.

    If you live in a cold climate, the furnace will carry most of the heating load. Heatpumps which are sized for cooling start losing ground at 25-40F OD.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Question LOCATION LOCATION LOCATION ...

    Quote Originally Posted by cold55 View Post
    We'll be deciding soon on which contractor to go with. However, all of my estimate so far includes replacement of our propane furnace with a new 80% propane furnace.

    The current 80% Bryant propane furnace is about 17 years old and is functioning properly. If this is the case, would I not be able to just add on a heat pump to my existing system?
    Would cost savings not be significant by doing so?

    Or is it a question on the combined efficiency of the system? I was hoping to spend about $ but it looks like it will be 3x my planned budget.
    It's rather meaningless to provide a comment without knowing location, current monthly energy costs and utility rates.

    Al$o, Energy Audit might be appropriate.

    You might be anywhere in South or North America ( or even Asia)
    for all we know.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  6. #6
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Before you make any decisions, you should have a contractor that does load analysis assess your system, do the load analysis and then educate you as to your options.

    Bryant makes 80% gas furnaces that are multi-staged with variable speed blowers. They also make 90+% gas furnaces with the same or better features. The staging is all about comfort while the V/S blower is for both added comfort and lower utility bills (electricity).

    The HP could be added to either the existing furnace or a new furnace but IMO, you'd be much better off to match the equipment so you can document its performance. Read the attachment and proceed accordingly. You'll be glad you did.
    Attached Images Attached Images
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  7. #7
    Join Date
    Jun 2010
    Location
    Philadelphia PA
    Posts
    2,190

    Dan nailed the answer

    How much does a BTU of Heat Pump heating compare with Propane?

    The idea of Dual Fuel is pretty attractive, I would replace both units if you can afford to do so
    You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!

  8. #8
    Join Date
    Sep 2006
    Location
    Montana
    Posts
    983
    IMO, unless it is physically impossible, it is pointless to replace an 80% furnace with another 80% furnace, especially when running on LP. If you live in a cold winter climate, I would replace the furnace with a 90%+ furnace. Depending on where you live would determine whether a heat pump is a good investment or not. If you live in a warmer winter climate and the heat pump would do the majority of the heating, then replacing the furnace with another 80% furnace would make sense. Whichever route you go, a variable speed blower would be a good investment, whether you go 80% or 90%. At 17 years of age, I would recommend replacing the furnace. Please tell us where you live so we can give you some better advice on what would make the most sense.

  9. #9
    Join Date
    Jun 2009
    Location
    Albuquerque NM
    Posts
    2,485
    Quote Originally Posted by cold55 View Post
    We'll be deciding soon on which contractor to go with. However, all of my estimate so far includes replacement of our propane furnace with a new 80% propane furnace. The current 80% Bryant propane furnace is about 17 years old and is functioning properly. If this is the case, would I not be able to just add on a heat pump to my existing system? Would cost savings not be significant by doing so? Or is it a question on the combined efficiency of the system? I was hoping to spend about $ but it looks like it will be 3x my planned budget.
    Ordinarily I'd say let's see your energy rates, but propane is never cheap so this is almost a no-brainer.

    I would suggest a new 80% furnace (1-stage ECM or 2-stage VS) with heat pump for a dual fuel system. In moderate temps the HP will do all the heating, much cheaper than propane. Then the furnace only runs on colder days.
    Last edited by garya505; 05-20-2011 at 12:19 PM. Reason: typo

  10. #10
    Join Date
    Oct 2002
    Location
    Northeast Tennessee & Alaska
    Posts
    108
    I say, “Educate the customer and let them make the decision”.

    So…

    It will cost you less in the long run to have the whole thing done at the same time. However, if finances require, it is perfectly OK to have the heat pump added to your existing furnace. But know this, you are nearing the end of your furnaces useful life. When? Who knows. Could be two days after the install or years from now (that gamble is yours). The questions you might ask yourself are: (1) Can I afford to do the whole thing now? (2) Will I better be able to afford to do just the furnace at a later date; most likely by surprise (equipment rarely schedules its demise with the homeowner)? (3) Will waiting, save me more money than the added labor that I will incur in having the furnace replaced later? (Remember, you do not know how much longer the furnace will last)

    Last thing, if you decide to wait, what I tell my customers is this; start planning NOW for the inevitable. Setup a savings account, buy savings bonds, bury a shoebox in the backyard or SOMETHING. But do not wait and allow yourself to get caught off guard or you will regret not changing the furnace when you could.

    Good luck!!

  11. #11
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    If reusing the old furnace, a heat load calc is all the more important. It is absolutely necessary to determine the airflow of the existing furnace to determine if it's properly sized for the proposed HP. Going with new across the board allows for matched equipment and ultimate comfort, provided it's all properly sized. If the budget allows, stepping up to a 90+% furnace would enhance your savings. You could possibly end up saving enough between the two systems (gas furnace & heat pump) to nearly pay the monthly note on a loan.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  12. #12
    Join Date
    Jun 2009
    Location
    Albuquerque NM
    Posts
    2,485
    I started down this raod a couple of years ago. Thought I could just add the heat pump, then decided the old furnace was such a noisy clunker (I called it "the beast") I would replace it, even though it was only about 8 years old. But, if your furnace is still working fine, and isn't oversized, and doesn't have any other problems, go for it. With a dual fuel system the furnace wouldn't get used as much anyway.

  13. #13

    Thumbs up

    Skippedover, your PDF Ho To Selet An HVAC Company is EXTREMELY helpful!! Thank you

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