Gas vs. All-Electric: The Modern ADU Default

A quiet revolution: most new ADUs being designed today are all-electric — no gas line at all. Here's why, and when gas still earns its place.

The case for all-electric:

• Skip the connection cost. Extending gas to a detached ADU runs $2K–$8K. All-electric spends that on nothing — the money simply stays in your pocket.
• Modern electric appliances are excellent. Heat pumps heat and cool in one unit efficiently; heat-pump water heaters sip energy; induction cooktops outperform gas burners in speed and control (chefs are converting — tenants will cope).
• Code is pushing this way anyway. California's Title 24 energy code strongly favors electric heat-pump equipment; many compliance paths effectively assume it, and some jurisdictions restrict new gas hookups. Designing all-electric makes energy compliance easier, not harder.
• Simpler forever. No gas plumbing, no combustion venting, no CO concerns from the unit's own appliances, one less utility relationship.

The honest counterpoints:

• Load calc pressure. Electrifying everything adds electrical demand — the panel-capacity question from lesson 7.3 gets bigger. (Efficient heat-pump equipment softens this significantly versus old-style resistance heating.)
• Gas is already there. For garage conversions where a gas line practically touches the structure, using it costs little.
• Preference. Some owners and tenants genuinely want gas cooking. It's your project.

The practical default: all-electric for detached new construction; case-by-case for conversions where gas is adjacent. If you do run gas, run it once, properly sized, with the meter's capacity checked — undersized gas plumbing feeding two homes is its own flavor of surprise.