Duane Bozarth wrote:
wrote:
I'm in the process of selecting a company to install a geothermal unit,
but we've received contradictory information. I'm hoping this group can
shed some light on the situation.
We've had 2 companies come out and give estimates with 2 more lined up.
Interestingly enough one company based the size of the unit on cooling
demands, while the other based the unit on heating demands. If we go
with cooling it will be equvilent to 3.5 tons, whereas heating is 5
tons. I"m not sure who to believe. Does anyone have any advice or
experience?
Where are you located? Could judge better if had some idea of the
climate.
If there's a marked over/under-sizing on either side performance will
likely be less than satisfactory. I'd be particularly worried about
undersizing heating capacity in a cold climate, however, as if you don't
have sufficient capacity there you'll be forced to run on auxiliary
("emergency" in some nomenclature) heat for perhaps extended periods.
This will easily negate any hope of ever recovering the initial higher
installation cost by lower operational costs.
Had WaterFurnace installation in TN Valley--was very successful at
operational cost-effectiveness relative to air/air heat pump
conventional A/C unit. That area is, of course reasonably moderate both
summer and winter, w/ summer cooling demands normally just a little
higher than winter.
I'd get some more input...did the estimators run actual heat load
projections or were they simply "back of the envelope" estimations?
Authorized WaterFurnace installers have detailed estimating/sizing
programs. Other sources of information may be your local power
company--many have programs for cost share for energy-efficient
alternatives.
I live in Southern Maryland, Waldorf (20601) to be exact. It's about
35 miles south of DC. Both companies are WaterFurnace Installers. THe
company that suggested we base the size on cooling load walked through
the whole house measuring windows, rooms, doors, and inspected the duct
system. He back and said we have 45,000 BTU for cooling and 95,000 BTU
for heating. If we put in a cooling load system, the threshold for
heating would be 27 degrees. Anything below that we would have to use
back up heat.
The second company walked through the house and looked at our current
system. He didn't measure anything. He is to call me this week to go
over his estimate... but told us we would install based on heat load.