Results 1 to 6 of 6
  1. #1
    Join Date
    Aug 2008
    Posts
    54

    Can one estimate how much fuel/energy new equipment would use compared to old?

    I continue to mull new equipment to replace my 9 year old oil fired hot air furnace & Lennox heat pump, especially since there appears to be an unusually good opportunity for better pricing due to a lack of business for even experienced contractors.

    The general consensus among all contractors I've spoke to is that the old furnace is substantially over sized. It has a non-changeable (per the Mfgr.) 1 gph nozzle thus resulting in an approximate 111,000 BTU/hr output (138,800 x .20 efficiency loss). Only 2 of the several dealers I contacted would do a true calculation. Both came up with a +/- 56K cooling load and 75K heating load. Guess which dealers I would use?

    I am contemplating switching to propane via a Carrier Infinity system & ICS 58MVC furnace plus a 5 ton 25HNA9 heat pump and comfort 2 zone control. Propane is in the lead since oil is, IMO, likely to be harder to get as the years go by due to global BS, more maintenance intensive, less efficient and far dirtier. I also like the variable/multi staging aspects due to comfort and possible increases in efficiency. Why fire 111K btu when all we need is, say, 60K?

    So, here is my quandary: Is it possible to determine based on past usage how much fuel/energy a new system WOULD have used were it installed in years past? I ask this since it is impossible to predict future conditions, but do think one can ask "Well, if I had this installed last year what would I have used?", which then answers the "So, is the investment in new equipment worth it? question.

    I figure if I can see a payback in roughly 4-6 years, assuming similar fuel pricing in the future, it's worth it. I'll invest for a longer term benefit, but can't see spending 5 figures just to switch equipment color!

    Background details: 2800 s.f. open foyer colonial in NY, 9 years old w/ R19 walls, R 30+ attic, Anderson low E glass and quite a few windows. Average annual oil usage: About 850 gallons. Total electric bill is about $2400/year. Obvious energy loses/holes already plugged.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    It would take 1,116 gallons of LP at 95% efficiency to equal the heat you get from 850 gallons of oil at 82% efficiency.

    So multiply curent LP and oil cost to those gallons, and you will see which of those fuels will cost less. And how much.

    To figure the savings with a dual fuel system is a little harder.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Go to the Carrier website. There's a calculator in there that will do the number for you on whatever combination you care to make, as long as you have the cost and usage figure. What' you're descirbing with the gas/electric HP is call Hybrid Heat by Carrier/Bryant. That's what you want to compare with.
    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!

  4. #4
    Join Date
    Aug 2008
    Posts
    54

    Hmmm... Thus assumes I would use the same number of gallons. Hopefully I'd use less.

    Quote Originally Posted by beenthere View Post
    It would take 1,116 gallons of LP at 95% efficiency to equal the heat you get from 850 gallons of oil at 82% efficiency.

    So multiply curent LP and oil cost to those gallons, and you will see which of those fuels will cost less. And how much.

    To figure the savings with a dual fuel system is a little harder.
    It is indeed harder, hence my query. While 850 gallons of oil does equal 1116 of propane, I was hoping to see how much LESS a new system would use. In other words, if my clunky and oversized furnace used 850 gallons of oil last winter, how many would a new system have used?

    If a newer, better sized and far more efficient system would have used only, say 400 gallons of propane, albeit with a larger elec bill due to increased heat pump use, would there be a net savings?

    If I assume past precedent to be somewhat predictive of the future and I use 850 gallons on average of oil and $1400 of electricity what WOULD I have used?

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    Making some assumptions.
    54% of your heating hours are at 40° and above. Total HP KWH usage 5,166.
    46% of your heating hours are at 40° and below. Total oil usage 390 gallons, at 82% eff.
    Converting oil to LP usage, it comes out to 512 gallons of LP, at 95% eff.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Aug 2008
    Posts
    54

    Damned if I can find that on the carrier site.

    Quote Originally Posted by skippedover View Post
    Go to the Carrier website. There's a calculator in there that will do the number for you on whatever combination you care to make, as long as you have the cost and usage figure. What' you're descirbing with the gas/electric HP is call Hybrid Heat by Carrier/Bryant. That's what you want to compare with.
    I spent some time looking and must be blind. Couldn't find it in the least.

    Any ideas or might I impose on you to post a link? Thanks--

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event