September on Doctors Lake, a dead condenser, and the quietest system we install

The call, the third week of September

The household lives on a wooded lot off the eastern shore of Doctors Lake, in one of the older Fleming Island neighborhoods where the parcels are large and the oaks are older than the houses. Their outdoor unit, the second one the house had worn out, quit on a 90-degree afternoon in the third week of September. They had two questions: could we get there, and was there anything that did not involve putting a third condenser on the same pad.

The first answer was yes, that evening; Orange Park is a little over an hour from our shop and no-cool calls in September are dispatched the same day. The second answer took a site visit and a tape measure.

What we recommended, and why

The house had three things going for it: an acre of open, sandy, damp ground; an electric bill from Clay Electric that climbed every summer with a system that was never quite big enough; and owners who planned to stay twenty years. That is the geothermal profile.

A ground-source heat pump moves heat into and out of a loop of pipe buried in the yard instead of into the outside air. In Clay County the ground a few feet down stays near 70 degrees year-round. On a 91-degree July afternoon the system is rejecting heat into something 20 degrees cooler than the air; on a 30-degree January morning along the lake it is pulling heat from something 40 degrees warmer. No outdoor fan, no coil for pine straw and oak leaves to clog, nothing on the pad for the next storm to flood.

We quoted a two-stage geothermal unit with a horizontal loop field, a new variable-speed indoor cabinet in the existing garage location, and a desuperheater to preheat the water heater as a bonus. We also quoted a conventional high-efficiency air-source heat pump, because a fair comparison is the only kind worth making. Financing with low monthly payments was available on either.

Ask whether a loop fits your lot

Installation week

• Day one. Locate utilities and the septic field, then trench the loop with an excavator across the open part of the lot. Sandy Clay County soil digs easily; the water table a few feet down is a help, not a hindrance.
• Day two. Lay and fuse the HDPE pipe, pressure-test the loops, backfill, and run the header to the garage wall.
• Day three. Remove the old air handler and the dead condenser, set the geothermal unit on the garage platform above the line Irma’s floods would have reached, connect the loop, the ducts and the drain, and flush and charge the loop.
• Day four. Start-up, balance the airflow room by room, program the thermostat, and walk the owners through it.

A smaller lot in Oakleaf or Lakeside would have meant vertical bores and a drilling rig for day one; the rest of the week looks the same.

Living with it

The first thing the owners noticed was the silence on the lanai. The second was that the house held 48 percent humidity through October without the thermostat being pushed below 76. The electric bill told the rest of the story over the following summer. Maintenance is lighter than on a conventional system: filter changes, an annual check of the loop pressure and the heat exchanger, and no outdoor coil to rinse. The loop itself is expected to outlast the house.

Geothermal is not for every Orange Park address. It wants land, a long ownership horizon and a budget that can look past the first year. For the households that match, it is the best system we sell.