Cost comparison data

Discussion in 'General Discussions' started by dher1029, Apr 20, 2009.

  1. dher1029

    dher1029 New Member

    I am considering switching from my current 15 year old gas / hot water system to a geothermal system for heat, hot water and air conditioning. I have the duct work already installed for the current air conditioning system.

    I currently spend $2,000 per year for natural gas that only provides heat and hot water. I also spend $2,000 per year for electricity that covers all electrical use; 3 Ton air conditioner, floor heat in bathroom, 8 foot electric heater in breakfast room plus all the cooking, lighting, entertain,ment and computing stuff.

    I am looking for a web site that will let me see the potential changes in these amounts if I switch to the recommended WF system.

    Obviously my gas costs will drop precipitously. And some heat and AC costs will drop out of the electric bill. But the electric bill will also rise due to the operation of the new WF equipment.

    Any place you can direct me for answers; or do you have any experience observations to make?

  2. a0128958

    a0128958 Member

    I was in the same situation as you: gas for heating and hot water, electricity for A/C and everything else. Replaced 15 year old Lennox 2-speed 5 ton A/C unit and 120 KBTU/hr furnace in July 2007 with WaterFurnace Envision 2-stage variable speed units (8 tons split across 2 units) connected to a closed vertical loop. Dallas climate. No DeSuperHeaters hooked up.

    Here are some multi-year charts to help you, showing before and after effect on electricity and natural gas consumption.

    Electricity Usage Since Year 2000: KWHUsage.jpg photo - Bill Neukranz photos at .

    Natural Gas Usage Since Year 2006: NGUsage.jpg photo - Bill Neukranz photos at .

    Total Electricty + NG Cost Since Year 2007: HVACCost.jpg photo - Bill Neukranz photos at .

    Again, GSHP installation was in July 2007. The change in utility consumption is dramatic.

    Best regards,

  3. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    See "No free lunch"

    It did not do well either.

    One gets what one pays for.
  4. Guest

    Guest Guest

    You might look into changing the breakfast room and bathroom floor to using nat gas heat (perhaps using water from your gas water heater).

    As much as I am in favor of GSHPs, the payback is long where natural gas is available.

    If you use electric/propane/fuel oil or are in a mostly air conditioning climate - definitely use GSHP.
  5. Bergy

    Bergy Member Industry Professional Forum Leader

    Strange advise

    Are you suggesting an "open" radiant loop with the domestic water? If so, That's bad advise. Radiant and domestic DO NOT play well together and should NEVER mix.

    Payback is relative. Electric rates vary widely across the country and between providers. In eastern Iowa one customer may pay 0.09 cents/kwH and his neighbor may pay 0.04 cents/kwH in the winter to run the geo.

    Why do you think GSHP mostly lends itself to "an air conditioning climate"?
    GSHP's are in use from the arctic circle to the equator.

  6. dher1029

    dher1029 New Member

    Thanks for your data; it helps to see what others have experienced. Can I assume that you had a satisfactory experience with the WF Envision equipment?

  7. a0128958

    a0128958 Member

    Dave, exceptionally so (satisfied with WaterFurnace equipment).

    WaterFurnace advertises its Envision models with COPs at or above 5 and EERs at or above 30. I set up a performance monitoring system ( Web Energy Logger: ) to, in part, see if indeed my WF equipment performs to the claims (it does).

    My excellent WF equipment performance, though, is highly dependent on having adequate loop water exchange (in my case bore hole field performance) and adequate secondary flow (in my case air duct performance). This dependency, by the way, is not unique to WF - all GSHP equipment, regardless of manufacturer, particularly need these two things.

    Many will say here, and I'll agree, that installation and design, done correctly, is an imperative to achieving equipment performance claims.

    And satisfaction with HVAC equipment goes beyond whether or not it's performing to it's technical capabilities. It also includes if you're comfortable with the air in the structure. And this is highly dependent on having the equipment sized properly - too small or too big may technically perform properly but you'll still feel unsatisfied with the resulting air characteristics. If you can get it, a Manual J analysis goes a long way toward getting the equipment sized properly.

    Good luck!

    Best regards,

  8. Guest

    Guest Guest

    > Why do you think GSHP mostly lends itself to "an air conditioning climate"?

    That's not what I said.

    The economics (not the technical feasibility) of any system depends on the cost of the alternatives and the cost of money. Yes, these vary, but in general, nat gas is less expensive per btu than propane/electric resistance/oil heat. So GHSPs compares better (ie, more often has a positive and quick ROI) to the latter ones.
  9. Waukman

    Waukman Member

    Here is another set of data points for electric usage. The attached file shows the electric usage since 2001. I live in Wisconsin and prior to GEO we heated with natural gas. We also used 5 window a/c units.

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