All-Electric Readiness Check: engineer's guide
All-electric conversion replaces gas boilers, gas water heaters, and gas cooking with heat pumps, electric water heaters, and induction. Success depends on electrical service capacity and building envelope quality.
Open the All-Electric Readiness Check →
What this calculator does
The tool checks eight readiness criteria (envelope, service capacity, DHW method, cooking, HVAC, controls, roof for PV, regulatory) and returns a readiness score.
Formulas used
- Electrical capacity check:
Capacitymargin = (Iservice,new - Iservice,old) / Iservice,old - Heat pump capacity at design temperature:
Qhp = COPdesign × kWelec
Variables
- Iservice,new, Iservice,old = service ampacity before/after
- COPdesign = at the lowest design outdoor temperature
Worked example
Scenario: 3-bedroom apartment currently 60 A service, gas boiler, gas cooking.
- Convert boiler to 9 kW heat pump → add 40 A
- Convert cooking to induction → add 30 A
- Convert DHW to heat pump water heater → add 15 A
- Total new demand ≈ 145 A — upgrade to 200 A service required
- Verify main incoming supply and metering room capacity
Common mistakes to avoid
- Missing heat pump derating at low outdoor temperature
- Ignoring service capacity constraint
- No storage buffer for heat pump defrost cycle
- Skipping envelope upgrade before HVAC change
Frequently asked questions
Ground-source or air-source heat pump?
Ground-source higher COP but 2 to 3x capex. Air-source practical for most retrofits.
Backup electric coil?
Yes — for defrost and low-temp lockout, sized at 30 to 50% of heat pump capacity.
Standards and references
ASHRAE 90.1, LEED, WELL
Related tools on this site
Open the calculator that pairs with this guide: All-Electric Readiness Check.
Verification note
This guide is planning support only. Final design must be verified against the applicable project specification, authority requirements, manufacturer data, and the standards cited above. Consult a licensed engineer for construction-issue calculations.