maintain vs replace

Discussion in 'Maintenance and Troubleshooting' started by Dennis, Jan 21, 2011.

  1. Dennis

    Dennis New Member

    Does anyone have a suggestion? I'm trying to decide whether to maintain an old geothermal, replace with a new one or change to natural gas.

    Is there a site or source you’d recommend to do a btu evaluation? I have a 1981 4 bedroom contemporary 2 1/2 floor home of nominally 3700 sqft, with 6” thick
    walls and soaring (9-22) ceilings in the 250 sqft hall and 4-500 sqft living room. This makes “sqft” of limited value; is there a cubic foot calculation? I just bought the home and have been shocked by the cost of heat and A/C in our first 6 months. The home has open system geothermal Florida Heat Pumps, 4 and 5 tons, I think. I don’t know what has been replaced over the 29 years, but I just replaced the fan and the well pump recently. With the estimated life of a 1981 system, I know it’s time to upgrade. My problem is that, without even adequately heating, or air conditioning to extreme, my electric bills have peaked at $1500 per month and average out to about $1050. Could a new, more efficient geothermal make enough difference to merit the expense? Please feel free to transfer this to the blog if you prefer..and know how. Or if you instruct me how I can register and post it, I’d be happy to.

    Thank you for your intelligent and reasoned replies to the other members of the blog.
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I think

    your best bet is replacement before the tax credits end. If the units are original to the home at thirty years old they owe you nothing. Check the "Find-a-pro" section hre for starters. Now would be a good time to consider tightening the envelope,too.
  3. Dennis

    Dennis New Member

    upgrade question

    Thanks, Custis. Do you have a idea of the way to translate eer and cop into actual relative costs? If the old system is EER of about 15 and the new one is 28, does that mean actual costs of air conditioning would be cut about 1/2 with an upgrade? Is that similar for COP and heating? I've heard that geothermal pumps are much more efficient than other systems in the A/C mode it "much" better than natural gas for heating? any idea how much?

    Thank You!
  4. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    A BTU is A BTU

    The issure becomes how much does it cost to move it where you want it. There are comparisons out there for the differant fuels, their cost and how many BTUs per unit of measure.

    If I could tell fortunes or see into the future I would be rich and some place warm instead of freezing here in Cleveland..
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Find a competant geo repair company and start there. I don't know where you live, but your bills sound higher than they should be regardless of system age or electric cost.
    Sounds like you are running on 100% auxiliary on the east coast.
  6. Dennis

    Dennis New Member

    Thank you. It does seem high. I hope there's a reasonable answer, since i'm very pleased with the home and location. I don't think it's the resistance heat, since the circuit breakers are off, which I assume is sufficient to remove their input. It seems geothermal is still the oddity here in Toms River. I do have one contact to try.
  7. Bergy

    Bergy Member Industry Professional Forum Leader

    With two old "open loop" units the heat exchanger may be fouled. Do you have access to any maintenance records? Open loop systems require periodic back flushing of the heat exchangers.

    With systems close to 30 years old you would, more than likely, be better off upgrading to new units with a FULL 10 year part and labor warranty.

  8. geome

    geome Member Forum Leader

    Try the dealer locator for the brands you are interested in. In the Water Furnace web site, I found 3 dealers within 18 miles of Toms River. I'll wave to you on our way to Beach Haven later this year. :)

    Will Waterpirate go that far North?
  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    You can also look through the dealer section here and check the International Ground Source Heat Pump Assoc. certified installer list (google igshpa).
  10. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    My gut suggests that efficiency of new vs 30 YOA equipment may be as much as double.

    A perverse result of that is that in heating MORE open loop water may be needed since high efficiency units add less operating power to total heat capacity. Open loop water is sometimes relatively expensive owing to well pump power.
  11. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Not my experience. Most of these systems still could perform at 3 + COP. The flip sides are:
    They are usually oversized which means they can consume extra kw on top of the lower efficiency (owing to poorer designer education and an irrational aversion to aux. coils). They also are often oversized to the duct systems as well.

    Older heat exchanger technology gets less btu's out of a like amount of water meaning greater pumping cost.

    Single stage vs 2 stage requires more pumping as well, adding to op cost.

    This again is a reminder that COP does not necessarily equate to op cost on a 1 to 1 ratio.

    I think all of us agree that you would benefit from updated equipment in all areas of comfort and energy usage, however a competant repair company may by you some time to prepare for the expense and let you build a trusting relationship with your new geo guys.

  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'll defer to Joe on that since his experience trumps my gut.

    I should have been more clear - nameplate efficiency may have doubled but installed efficiency may not. When I looked at FHP 5 years ago their advertised efficiencies did not compare well with WF or CM - I may have incorrectly extrapolated backward based on that. FHP has since come out with a line comparable to WF and CM.

    Even with decreased op costs, ROI on a complete swap out may be long.

    There may be charge, waterflow, or scaling problems causing excessive use of resistance heat and severely limiting cooling output, driving up your bills.

    My practice with new customers with older equipment problems is to try to find a way to limp the old stuff along for a time while they prepare financially for the hit.
  13. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Dennis, glad you found your way to the forums. Hope all of this info helps.
  14. Dennis

    Dennis New Member

    Excellent suggestions!

    Thank you, Geo Bloggers.

    Your analyses for my 30 year old system's reduced efficiency restores my hope that a new geothermal system MAY perform well enough to bring my utility bills down from the stratosphere!

  15. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I'm disturbed if you think I suggested starting with a new system.
    I want your guys to start with a heat load of the house and a design expectation for existing equipment and a diagnosis/repair if it is not performing well. Only then can you answer your question of repair vs replace.

Share This Page