All-electric, all measured.
No natural gas. No ductwork. Six inverter-driven heat pumps, three outdoor compressors, and an envelope tight enough to hold sixty-five degrees in a Midwestern winter on partial load.
Natural gas was removed for health, environmental, and operating-cost reasons. With the upgraded service and a tight envelope, the heat pumps run efficiently — and the gas connection (and its monthly fixed charge) simply isn't there.
First efficiency, then production.
Most "green" retrofits start by adding solar panels to the same leaky envelope, the same gas furnace, the same century-old wiring. The result is a renewable supply tax-credited onto an unchanged demand — and a roof full of panels working overtime to make up for what the house keeps losing.
We took the opposite path. Reduce the demand first; produce later — or never, if it's not needed.
| Phase | Done at 346 Corona | Result |
|---|---|---|
| 1 · Reduce | Tight envelope · two insulation layers · radiant barrier · new Energy Star windows · all-new plumbing and wiring | Heating and cooling load cut to a fraction of an inefficient comparable. Measured average 712 kWh/mo total. |
| 2 · Electrify | All gas removed · multi-zone heat-pump HVAC · heat-pump water heater · induction-ready electric kitchen | Every joule the house consumes can come from the grid — and from the grid's cleaner future. |
| 3 · Produce (optional, future) | Roof and 200 A service ready for a small PV array — sized against the already-reduced load. | An owner who later chooses to add panels can target full energy independence with a much smaller, cheaper system than the original house would have required. |
Why the order matters: cut the load by a third and you cut the size of any future solar array by the same third. Solar is most powerful when it's pointed at a small, predictable demand — not used as a band-aid on a leaky one.
Six zones, three compressors.
| Zone | Capacity | Configuration | Model |
|---|---|---|---|
| Primary bedroom · 2nd floor | 12,000 BTU | Concealed duct | Senville Sena 12/HF |
| Upper floor (×3) · kitchen · half bath | 12,000 BTU | Multi-head | SENA-12HF-ID16 |
| Main level · open space | 18,000 BTU | Concealed duct | SENA-18HF-ID16 |
| Flex room · downstairs bath | 9,000 BTU | Concealed duct | SENA-09HF-ID16 |
All units are inverter-driven cold-climate models from Senville's AURA line. Equivalent units are sold by Carrier and other major manufacturers.
Quieter, cleaner, more deliberate.
Forced-air systems circulate dust and allergens, lose energy through duct runs, and are loud. The house was built without them — instead, every room has its own zone, controlled when and where it's needed.
The removed ductwork freed the basement: ceiling height now exceeds seven feet.
What it costs to run.
| Supplier | Plan | Rate | Modeled monthly * |
|---|---|---|---|
| AES Ohio (default) | Standard | 8.6 ¢ / kWh | ~ $118 |
| Direct Energy | 12-month fixed | 6.59 ¢ / kWh | ~ $97 |
| Energy Harbor | 12-month fixed | 6.55 ¢ / kWh | ~ $97 |
| Public Power | 9-month fixed | 6.49 ¢ / kWh | ~ $96 |
| Clearview Electric | 7-month fixed | 5.79 ¢ / kWh | ~ $89 |
* Modeled at a conservative 1,000 kWh consumption plus AES Ohio's $31.48 delivery charge. Real measured consumption was 712 kWh/mo. Rates as observed in 2024; the deregulated Ohio market means rates change — and can be shopped.
A sensor sat in the living room for a year.
February 2024, a representative cold month in Oakwood: average outdoor temperature in the low 30s, indoor sensor average 67.2 °F, minimum 60.6 °F, maximum 74.8 °F. Thermostat set 65 °F. Some zones idle.
A house that holds its temperature, costs roughly a hundred dollars a month to run, and goes carbon-neutral the moment you choose a green supplier.