Heat Pump for EV-Charging Households UK 2026

Typical UK domestic electrical supply:

• Standard single-phase: 80A or 100A from the DNO (network operator).
• 80A supply: max ~19 kW continuous (80A × 240V).
• 100A supply: max ~24 kW continuous.

Typical UK 3-bed peak load (without heat pump + EV):

• Lighting + appliances + cooking: 3-5 kW average peak.

Adding heat pump (typical 3 kW peak):

• Total: 6-8 kW peak. Within 80A capacity comfortably.

Adding EV charger (7 kW continuous):

• Total with heat pump: 10-15 kW peak. Approaches 80A limit (18-19 kW).
• Brief peaks (kitchen + cooker + heat pump + EV) can exceed 18 kW → fuse trip.

Solution priorities:

1. Smart-tariff scheduling to avoid concurrent peak operation.
2. Load-balancing EV charger (throttles when total household load high).
3. Consumer unit upgrade if needed (32A dedicated breakers + RCDs).
4. Supply upgrade from 80A to 100A if budget allows.

Intelligent Octopus Go (RECOMMENDED for EV + heat pump):

• Cheap rate ~7p/kWh from 23:30-05:30.
• EV charges overnight at cheap rate (Tesla, MG, Hyundai etc all integrated).
• Heat pump cylinder reheats during the same window.
• Daytime: standard rate ~26p, no peak avoidance needed.
• Combined household saves GBP 800-1,400/year vs flat tariff.

Octopus Cosy (alternative if EV doesn't need overnight charging):

• Multiple cheap windows: 04:00-07:00 + 13:00-16:00 + 22:00-00:00 at ~10.5p.
• Peak 16:00-19:00 ~37p (AVOID).
• Heat pump runs preferentially in cheap windows.
• EV charges during cheap windows (manual / smart-charger scheduled).
• Slightly higher operating cost than Intelligent Octopus Go for typical EV usage.

Octopus Agile (advanced users):

• Half-hourly variable rates.
• Best for households with home automation (Home Assistant, etc.) that can dynamically schedule loads.
• Potential for GBP 1,500+/year savings but requires technical setup.

Consumer unit upgrade (almost always needed for combined heat pump + EV):

• Most pre-2010 UK consumer units lack dedicated breakers for the required 32A heat pump circuit + 32A EV charger circuit.
• Upgrade to a modern dual-RCD or RCBO consumer unit (BS 7671 compliant).
• Cost: GBP 700-1,500 typical.

Supply upgrade from 80A to 100A (often justified for combined households):

• Application to your DNO (UKPN, Western Power, etc.).
• Free for the application; install cost varies by region.
• Typical: GBP 300-900 for 80A → 100A swap (DNO does the meter + main fuse).
• Worth it for: combined heat pump + EV + induction cooker + electric shower household; future-proofing for 5-10 years.
• Not needed for: smaller homes (<150m2) with single EV + smaller heat pump (<7 kW peak).

Three-phase supply upgrade (rare in UK domestic):

• Required if combined demand exceeds 24 kW continuous.
• Common in farms, large country houses, multi-EV households (e.g. 2x EVs + heat pump + workshop).
• Cost: GBP 5,000-15,000 + extensive work (new meter + supply route).

Scenario A - Already have modern (post-2015) consumer unit + 100A supply:

• EV charger + smart-tariff registration: GBP 0-200 admin.
• Load-balancing CT clamp: included with EV charger.
• Net cost: GBP 0-200.

Scenario B - 80A supply + older consumer unit:

• Consumer unit upgrade: GBP 700-1,500.
• Supply 80A → 100A: GBP 300-900.
• EV charger + smart-tariff registration: GBP 0-200.
• Net cost: GBP 1,000-2,600.

Scenario C - 60A or older supply + 1980s consumer unit:

• Full consumer unit replacement: GBP 1,200-2,000.
• Supply upgrade 60A→100A: GBP 500-1,200.
• EV charger + setup: GBP 0-200.
• Net cost: GBP 1,700-3,400.

For households with all four (heat pump + EV + solar + battery), a smart-energy router coordinates everything:

• SolarEdge Energy Hub: GBP 2,000-3,000. Manages heat pump scheduling + battery dispatch + EV charging from solar excess.
• Solax X3 Pro + Givenergy Gen 3: similar capability, slightly different ecosystems.
• Sunsynk Sun-X: cost-effective option for combined systems.

Coordination logic:

• Solar excess → battery storage (priority 1).
• Solar excess → EV charging (priority 2).
• Battery discharge → heat pump during peak window (priority 3).
• Battery discharge → household + EV continuation (priority 4).

1. Adding 7 kW EV charger without consumer unit check = risk of trips when heat pump + cooker + EV all draw simultaneously.
2. Standard variable tariff for combined household = paying 26-30p/kWh for both heat pump + EV. Switch to Intelligent Octopus Go ASAP.
3. Scheduling EV + heat pump cylinder reheat at same time on Cosy = both compete for the same cheap-rate window. Stagger them (EV 23:00-05:00, heat pump cylinder 04:00-07:00).
4. Non-load-balancing EV charger = no dynamic throttle when heat pump is at peak. Fuse-trip risk.
5. Forgetting to register the EV with the tariff = Intelligent Octopus Go doesn't auto-detect EV charging. Manual integration via Ohme / Zappi app.