Installed a 20kW Generac standby generator in Uxbridge: full permit process and winter performance

We live in Uxbridge in a rural setting on the Oak Ridges Moraine. Our power goes out 4-5 times per year — ice storms, summer derecho events, equipment failures on the rural distribution line. We finally installed a standby generator last year after a 72-hour outage that killed our chest freezer contents.

What we needed: The house is 2,800 sqft with a 200-amp panel, electric water heater, two-stage heat pump (18,000 BTU), and a separate panel for the detached workshop. We needed whole-home coverage.

Unit selected: Generac Guardian 20kW (natural gas, air-cooled). Run on the same natural gas line as our furnace and range — NG line was already at the house, just needed a tee and extended run to the generator pad.

Permit process: Two permits required — ESA electrical permit and TSSA gas permit. The Generac-certified installer handled both applications.

ESA permit: 8 days to issue. Inspector came for the automatic transfer switch installation (before energizing) and for final. The ATS was wired into the main panel — inspector checked the interlock mechanism, verified the load shed contacts (we set the generator to shed the EV charger and workshop sub-panel under high demand), and checked the bonding.

TSSA gas permit: 6 days to issue. Gas fitter extended the 3/4-inch gas line 32 feet to the generator pad, installed a manual shutoff valve at the generator. TSSA inspector came for final — tested for leaks, verified the regulator and pressure.

Concrete pad: Required by Generac installation manual — 4-inch pad, 36x60 inches minimum for this unit. Concrete contractor: $680.

Cost breakdown:

  • Generac 20kW unit (supply): $5,800
  • ATS (200-amp, whole-home): $1,200
  • Electrical installation (ATS, load shed wiring, ESA permit): $3,400
  • Gas line extension and connection (TSSA permit): $1,600
  • Concrete pad: $680
  • Total: $12,680

First full winter review: Experienced two outages — one 6-hour, one 4-hour. Generator started automatically both times within 15 seconds. Ran everything normally including the heat pump. Weekly self-test runs without issue.

Annual service is $220. Worth every penny.