Have Geo Bids - Plotting Next Move

Discussion in 'General Discussions' started by Blake, Feb 6, 2009.

  1. Bergy

    Bergy Member Industry Professional Forum Leader


    Please do not tell people that a "properly designed" system will not need backup heat. In eastern Iowa we, "as a rule", require twice as much energy to heat a home as to cool one. Bearing that in mind, our systems become a balance of economics and comfort. AFTER we have done a detailed heat gain/heat loss on the home, we tailor the system to provide our client with the most economical system possible for THEIR home. GENERALLY speaking, our designs meet 93% to 98% of the required Btu's at design temp of -5*. The strip heat only has to make up 2% to 7% of the run time. Experience has shown a system capable of providing 100% of the heating load will be OVER-SIZED for the cooling load. Also, how often does a system provide only 100% of the load? It will either provide too much or not enough Btu's. We can design a system capable of heating to -30*(An all time record low for us) but at what cost in dollars AND comfort for the client? Every HAVAC contractor here knows the amount of time spent BELOW design temp for their area is minimal. The added cost of up-sizing the geo and adding another loop RARELY is justified.

    I don't know if Colorado's design criteria is the same as Iowa's. If I don't know that, you can bet Joe and JoAnn Homeowner doesn't know either. Remember, what holds true in one part of the world may not hold true in another.

  2. Jim Bellings

    Jim Bellings New Member

    Not to mention....

    I agree with needing back up heat strips. Also important to note that when going from a 5 ton to a 6 ton unit the efficiency on most brands drops considerably. I just quoted a job where another contractor bid a 6 ton without heat strips. I proved that my 5 ton with 10 kw heat strips will save about 150 to 200 bucks a year. Not to mention my 5 ton geothermal puts out 52k of heat vs. the other brands 6 ton doing 54k of heat. My program had calculated that heat requirements were 74k btu of heat for the house at 9 degrees outdoor temp and 70 inside....my 5 ton 52k btu of heat was going to have the aux heat come on 1 percent of the time. So definitely need to be careful!

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