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  1. #1
    Join Date
    Aug 2008
    Posts
    54

    Stumped: How do I determine if a new furnace & heat pump is worth it?

    Hello, all-

    Total newbie here, although I've spent considerable time searching here trying to find the answers myself. I suspect that the answers I seek will help many others as well.

    I'll try to be brief, but don't want to omit details, so here we go. My thanks in advance to those willing to slog through and share their expertise!

    I have a 2800 +/- sf home in NY. It is 8 yrs old and equipped with a large Williamson forced air furnace (roughly 80% efficient) using a 1 gal/hour nozzle as well a Lennox 5 ton 11 SEER heat pump set to "change over" to oil at 45 degrees. On an annual basis I use about 850 gallons of oil, which at current pricing is about $4200/year (ouch!). I also use a Duro Dyne 2 zone panel and dampers.

    I have spoken to a few contractors, but remain puzzled at the inconsistency. The consensus is that my Williamson unit is oversized by a good 20% or so.

    Seeing as how I haver better uses for money then sending it to the Middle East nutjobs who don't much like us, I am pondering the following:

    1) Carrier Infinity ICS Modulating propane furnace w/ a 5 ton Carrier Infinity heat pump (their best).

    2) Same as above only with a Carrier oil furnace.

    3) Hallowell air to air heat pump

    4) Energy Kinetics EK1 boiler and TWO Carrier 3 ton units (This is already disfavored as the estimate was about 3 (yes THREE) times #1 above. I sense they want to out the kids through college on this ONE job.

    5) Do nothing other than set the change over on the Lennox to 30-35 instead of 45.

    I am interested in the best long term solution saving money, energy and more and am stymied at the choices: Propane vs oil, Carrier vs. Lennox vs. Trane vs. hallowell and on and on it goes. Despite many, many hours of research and calculating, I am stumped as to how to best approach the situation and see what make the best long term (5-10 years hence) approach. In short, I am not even sure I am asking the right questions and/or considering the right factors.

    Sorry for the rambling, but I'd greatly appreciate input as to the more reliable brands, propane vs oil and, of course, how to best calculate a pay back time. My thanks to all in advance.

  2. #2
    Join Date
    Feb 2007
    Posts
    190
    First when it comes to comfort you cannot go wrong with the Carrier Infinity in my opinion it is the best thing being made.

    Do you know what your local electric rates are. Based on what you are paying for oil I'm sure you can turn down the the oa lockout.

    Where are you located

  3. #3
    Join Date
    Aug 2008
    Posts
    54

    Good question and thanks- Should have mentioned this.

    Quote Originally Posted by rponson View Post
    First when it comes to comfort you cannot go wrong with the Carrier Infinity in my opinion it is the best thing being made.

    Do you know what your local electric rates are. Based on what you are paying for oil I'm sure you can turn down the the oa lockout.

    Where are you located
    I live about 1 1/4 hrs N of NYC in the "People's Republic of NY" as I like to call it due to the high taxes

    Current electric pricing is about 15 cents per kw.

    What is stumping me is how to calculate a break even., especially since those I have talked to all say my furnace is a good 20% over sized. In other words, if I spend $10 on new equipment, how do I determine what I would save, assuming generally constant weather & usage? The few contractors I spoke to tended to be evasive on this, leery of committing themselves. While I certainly don't expect exact figures, I didn't think it unreasonable to get written "ball park" estimates so I could see if it was worth spending many thousands. I seek the best long term value, not cheapest solution and am fine with a payback of 5-6 years more/less if truly warranted over the long term.

    Of course, the "oil vs. propane" debate is still there. That's a whole issue unto itself.....

  4. #4
    Join Date
    Feb 2007
    Posts
    190
    Is the 15 cents after taxes? I usually devide the the total bill by the KW used it gives you the real rate.

    In order to calculate the ballance point you are going to need the actual building load not the equipment capacity. I have this at my office but I'm sure someone will post it before tomarrow.

    As for the payback calculation. Speak with a Carrier Dealer they have a great OP Cost calculator to compare systems side by side

  5. #5
    Join Date
    Aug 2008
    Posts
    54

    Let's see if I can flesh out the details

    Never knew this was so complicated! Interesting, though.

    Quote Originally Posted by rponson View Post
    Is the 15 cents after taxes? I usually devide the the total bill by the KW used it gives you the real rate.

    This I do not know. The local utility gave me this figure to use.

    In order to calculate the ballance point you are going to need the actual building load not the equipment capacity. I have this at my office but I'm sure someone will post it before tomarrow.

    As for the payback calculation. Speak with a Carrier Dealer they have a great OP Cost calculator to compare systems side by side

    Now you know why I am confused and posted here. Not one dealer has mentioned this. I keep asking for details, but never get them. I'll have to ask about this. Thanks!

  6. #6
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    From a recent post of mine:

    Compare the cost of 1 million btu's of heat for various fuels (insert your own fuel costs and efficiencies for a more representative calc):

    Propane at $3/gallon, 90% efficient furnace:
    (1,000,000 btu / 91,000 btu per gallon) x $3 / .9
    = $36.63

    Electric resistance heat, electricity at 15 cents per kw-hr delivered:
    (1,000,000 / 3413) x .15
    = $43.94

    Heat pump, same electric rate, COP = 3.25 at 35F ambient:
    (1,000,000 / 3413) x .15 / 3.25
    = $13.52

    Oil at $4.25 per gallon, 80% efficient furnace:
    (1,000,000 / 139,000) x 4.25 / .8
    = $38.21

    ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++

    Your changeover temp for the heat pump at 45F seems way too high. I would start with 32F and see how it goes.

    Good luck.

  7. #7
    Join Date
    Aug 2008
    Posts
    54

    Thanks, Gary-- Much appreciated

    Much appreciated. I am getting a few estimates & will see what the gang here thinks.

    Quote Originally Posted by gary_g View Post
    From a recent post of mine:

    Compare the cost of 1 million btu's of heat for various fuels (insert your own fuel costs and efficiencies for a more representative calc):

    Propane at $3/gallon, 90% efficient furnace:
    (1,000,000 btu / 91,000 btu per gallon) x $3 / .9
    = $36.63

    Electric resistance heat, electricity at 15 cents per kw-hr delivered:
    (1,000,000 / 3413) x .15
    = $43.94

    Heat pump, same electric rate, COP = 3.25 at 35F ambient:
    (1,000,000 / 3413) x .15 / 3.25
    = $13.52

    Oil at $4.25 per gallon, 80% efficient furnace:
    (1,000,000 / 139,000) x 4.25 / .8
    = $38.21

    ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++

    Your changeover temp for the heat pump at 45F seems way too high. I would start with 32F and see how it goes.

    Good luck.

  8. #8
    Join Date
    Jun 2008
    Posts
    80
    Check out this heating cost comparison calc. It may help you mix and match different types of HPs with your oil furnace or propane as backup versus just your oil. Its not perfect, but you can personalize your fuel costs to give you a ballpark. I'm no expert so I stress the ballpark part. This spreadsheet requires you to estimate usage of your system, so play around with best and worst case scenarios.

  9. #9
    Join Date
    Aug 2008
    Posts
    54

    Might it be possible to re-post the link? It is not coming up.

    Quote Originally Posted by dac122 View Post
    Check out this heating cost comparison calc. It may help you mix and match different types of HPs with your oil furnace or propane as backup versus just your oil. Its not perfect, but you can personalize your fuel costs to give you a ballpark. I'm no expert so I stress the ballpark part. This spreadsheet requires you to estimate usage of your system, so play around with best and worst case scenarios.
    Not sure what is happening, but every time I click the link it comes up empty. Might be my luck again!

    So far I've gotten a Carrier Infinity estimate, Hallowell pricing and just today met with a Lennox dealer. I ruled out an "Energy Kinetics" system 2000 as it was priced "stupid-high". It and 2 smaller Carrier HP units were TWICE the Hallowell and some THREE times the Carrier Infinity oil furnance/Infinity HP quote. I'll pay for a good job, but am not sending someone's kid to 4 years of college on ONE job!

    I've dealt with this Lennox dealer before. They proved decent to deal with in the past. So far they recommend an XP14 5 ton 16 SEER HP and O23V oil furnace to replace my Williamson dinosaur and yr old Lennox HP29 11 SEER HP. They estimate $2k annual savings a current pricing. Much depends on what the actual quote is.

  10. #10
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    For a heat pump in New York, you want:
    - 9 HSPF (heating seasonal performance factor).
    - Full heating btu's at the 47F rating. A 5 ton nominal unit should be 60,000 btu's, not less. Some system combinations are weak on heating btu's.
    - As low a change-over temp to the oil furnace as possible. Start with 32F and see how it goes.

    Good luck.

  11. #11
    Join Date
    Oct 2007
    Location
    KY
    Posts
    59
    You already have the right kind of setup. Heatpump / furnace backup is just great for comfort. Look at one of the different calculators to determine the economic switchover point - it will be much lower than 45F even with an 11 SEER unit. There is a personal decision to make about the comfort balance point. Nice warm air out of the vents feels better than what the HP will deliver at lower temps. Having an oversized furnace may not be a reason to spend money - you are only using it when temps are low and you need the heat. Since it is only 8 yrs old, it is probably at least 80% - which people are still installing to go along with the dual fuel systems. As has been recommended, changing that lock out temp down to 32F will go a long way to reducing you energy costs. I don't believe you will save a great deal by switching equipment. When the current equipment goes bad is the time to do the upgrade. You may have another good 10 years life in what you have now. It probably won't be cheaper then, but it may well be a whole lot more efficient.

  12. #12
    Join Date
    Sep 2003
    Location
    Portland.OR
    Posts
    311

    Smaller nozzle???

    Yes a gallon an hour is a bunch..

    Why not just have your service guy go to a .65 or .8 gall/hours??
    Thats so simple to do...

    Do you have lots of insulation??? LOTS.. look at the new codes.
    Here in Oregon, its 24 inches of fiberglass in the attic...... how much do you have....
    Insulation pays back ALL the time in ANY SEASON.

  13. #13
    Join Date
    Aug 2008
    Posts
    54

    A smaller nozzle was suggested, but the Mfgr, Williamson, said such was "a bad idea"

    Quote Originally Posted by fixitguy View Post
    Yes a gallon an hour is a bunch..

    Why not just have your service guy go to a .65 or .8 gall/hours??
    Thats so simple to do...

    Do you have lots of insulation??? LOTS.. look at the new codes.
    Here in Oregon, its 24 inches of fiberglass in the attic...... how much do you have....
    Insulation pays back ALL the time in ANY SEASON.
    This was suggested to me, but the Manufacturer, Williamson, said to NOT do it, supposedly since such would disrupt and eventually harm the unit--or so they said. They seemed sincere.

    I amy well do nothing as I called the tech dept at Lennox today who told me my old unit can easily go down to 25, albeit a bit less efficiently than the new ones. This is about the same as the new ones to boot. Yes, it would run at 16 vs 11 SEER, but the HSPF was only incrementally higher (8.5 vs. 7.2) and in their words "not worth it". They suggested I get a few more years out of the unit and see what happens then.

    I appreciated their honesty and may try a year with the set point changed from 45 to 25-28 and see what happens. Still doing some research, but perhaps Lennox is right.

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