Here’s the problem: Your business has a heat pump. It keeps the building warm efficiently and cheaply. But when the grid goes down for 16 hours in January, the heat pump stops — and so does your business.
Here’s the solution: A solar + battery system that powers the heat pump during blackouts. Not for a few hours. For the entire outage.
This guide shows you how to size a system that keeps your heat pump running — whether the grid is on or off.
First: The Cold Reality
If you’re running a business in Ukraine during winter:
- Temperatures hit -15°C to -20°C
- Gas heating may not be available (pipeline damage, shortages)
- Electric resistive heating costs a fortune to run
- A heat pump is the most efficient way to heat — but it needs electricity to run
Without backup power, a 16-hour blackout in January means:
- Building temperature drops below safe levels
- Water pipes can freeze and burst
- Inventory, food, or medicine can be ruined
- The business simply can’t open
This is not a comfort issue. It’s a survival issue for your business.
Can a Heat Pump Run on Battery Power?
Yes — but you need to size the system correctly.
A heat pump uses less electricity than resistive heating (by 3–4x), but it’s still a significant load:
| Heat Pump Size | Typical Power Draw | 16-Hour Energy Need |
|---|---|---|
| 6 kW heat pump | 1.2–2 kW (cycling, COP 3–4) | 20–32 kWh |
| 8 kW heat pump | 1.6–2.7 kW (cycling, COP 3–4) | 26–43 kWh |
| 12 kW heat pump | 2.4–4 kW (cycling, COP 3–4) | 38–64 kWh |
| 16 kW heat pump | 3.2–5.3 kW (cycling, COP 3–4) | 51–85 kWh |
Key insight: The heat pump doesn’t run continuously. It cycles on and off based on temperature. In a well-insulated building, the compressor runs maybe 40–60% of the time.
Real-world example (150m² office, good insulation, -5°C outside):
- Heat pump (8kW): runs ~8 hours total over 16 hours = 8h × 2kW avg = 16 kWh
- Other loads (lights, internet, 1 fridge): ~3 kWh
- Total for 16-hour blackout: ~19 kWh → needs a 20+ kWh battery
Sizing Guide: Solar + Battery for Heat Pump Backup
Without Solar Panels
| Building Size | Insulation | Min Battery | Recommended Battery |
|---|---|---|---|
| 80m² apartment | Good | 10 kWh | 15 kWh |
| 150m² house/office | Good | 15 kWh | 20 kWh |
| 150m² house/office | Poor | 20 kWh | 30 kWh |
| 300m² business | Good | 30 kWh | 40+ kWh |
With Solar Panels (Better)
Solar panels recharge the battery during the day, dramatically extending your blackout runtime.
| Building Size | Solar | Battery | Blackout Runtime |
|---|---|---|---|
| 150m², good insulation | 5 kW | 10 kWh | ~12 hours |
| 150m², good insulation | 5 kW | 15 kWh | 24+ hours (solar recharge during day) |
| 150m², good insulation | 8 kW | 20 kWh | Unlimited (solar covers daily use) |
That “unlimited” row is why solar + battery is the real solution. Once you have enough panels to recharge the battery during the day, you can run indefinitely — even in winter (panels still produce 20–40% of rated capacity on sunny winter days).
The Inverter Matters Most for Heat Pumps
Heat pumps have compressors. Compressors have high starting current (surge) — a compressor can draw 5–7x its running current for the first 0.5 seconds.
The wrong inverter: trips when the heat pump starts. Client calls you at 2 AM.
The right inverter: handles the surge without breaking a sweat.
| Inverter | Surge Capacity | Heat Pump Compat? |
|---|---|---|
| Deye | 2x rated for 10s, 3x for 1s | ✅ Excellent — handles even big heat pumps |
| Growatt | 1.5x rated | ✅ Good for small/medium heat pumps |
| Victron | 3x for short duration | ✅ Excellent (but expensive) |
| Budget inverters | Low | ⚠️ Many will trip on compressor start |
For installers: Always size the inverter 1.5–2x the heat pump’s running power. An 8kW heat pump needs a 10kW+ inverter. And always check the inverter’s surge curve against the heat pump’s LRA (locked rotor amps).
The Ideal Heat Pump + Solar Setup
For a Home or Small Office (150m², Ukraine)
| Component | Recommended | Estimated Cost |
|---|---|---|
| Heat Pump | 8kW air-to-water (Daikin, LG, or Mitsubishi) | €4,000–€6,000 |
| Inverter | Deye 10kW hybrid | €1,500 |
| Battery | GSL Energy 15–20 kWh LiFePO4 | €2,000–€3,000 |
| Solar Panels | 5–8 kW (12–18 × 450W) | €1,500–€2,500 |
| Total | €9,000–€13,000 |
For a Small Business (200m², Poland)
| Component | Recommended | Estimated Cost |
|---|---|---|
| Heat Pump | 12kW air-to-water (same brands) | €5,000–€7,000 |
| Inverter | 2× Deye 8kW (parallel, 3-phase if needed) | €2,400 |
| Battery | GSL Energy 20–30 kWh LiFePO4 (rack-mount) | €3,000–€4,500 |
| Solar Panels | 10 kW (22 × 450W) | €3,000 |
| Total | €13,000–€17,000 |
In Poland, subsidies help: “Czyste Powietrze” covers up to 66,000 PLN (€15,000) for heat pump + solar. “Mój Prąd” adds up to 6,000 PLN. Combined, these can cover 50–70% of the total cost.
What About Gas or Electric Heating?
| Heating Type | Cost to Run (16h) | Backup Power Needed | Verdict |
|---|---|---|---|
| Heat pump (COP 3.5) | €2–5 (electricity) | 15–30 kWh battery | Best — efficient + battery-compatible |
| Gas boiler | €8–20 (gas) | Only for pump (~100W) | Unavailable in many areas |
| Electric resistive | €12–30 (electricity) | Massive battery (40–80 kWh) | Too expensive to run on battery |
| Diesel generator + heater | €30–60 (fuel) | N/A (runs on diesel) | Loud, expensive, fuel shortages |
The heat pump is the clear winner. It uses 3–4x less electricity than resistive heating, which means you need 3–4x less battery capacity.
Winter Solar Production — The Truth
Clients often ask: “Do solar panels even work in winter?”
Yes, but less. Here’s what you can expect:
| Month | Production vs Summer | 5kW Array (Kyiv) |
|---|---|---|
| June | 100% | ~25 kWh/day |
| September | 65% | ~16 kWh/day |
| December (clear) | 25% | ~6 kWh/day |
| December (cloudy) | 10% | ~2.5 kWh/day |
The takeaway: In December, 5kW of solar produces maybe 3–6 kWh on a good day. You’ll still need a large enough battery to last through multiple cloudy days. But every kWh from solar is one you don’t take from the battery.
Bottom Line
- Heat pumps can run on battery backup — but you need 15–30 kWh for a full day
- Deye inverter is the best choice for heat pump backup (surge capacity matters)
- Solar panels are strongly recommended — they extend runtime to “unlimited” on sunny winter days
- Without solar: size the battery for 16h of heating + other loads
- With solar: a 15kWh battery + 5kW solar can power a heat pump indefinitely on most winter days
The best time to install this system was last year. The second best time is now — before winter arrives.
📌 Next: Solar Panel Types Explained — Which to Choose
📌 For installers: LiFePO4 Battery Guide — sizing for daily deep cycling
