Building heating in hill towns without diesel
How a 3,000 m² hotel or office building in a hill town can heat rooms through floor heating, radiators and fan coils with heat pumps, and what it saves against a diesel-fired heating boiler.
▶Video: Space heating for buildings and farms
V13 · 2–2.5 minFloor heating, fan coils and air handlers, from homes to poultry sheds
Video coming soon01Problem statement
- Long heating season. Hill buildings need heat for five months or more, and diesel heating is one of the largest operating costs.
- Uneven comfort. Room electric heaters and oil radiators give hot and cold spots and poor control.
- Diesel supply in winter. Snow and road closures can disrupt diesel deliveries just when heating is most needed.
- Losses between fuel and process. Burning diesel in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference building is a 3,000 m² hotel in a Himalayan hill town with winter lows of −5 to 0 °C. It has floor heating in the lobby and restaurant, radiators or fan coils in rooms and a fresh-air unit.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Room and floor heating | Rooms 20–22 °C | 3,000 m² × 40 W/m² peak × 50% average × 14 h | 840 |
| Fresh-air heating | Supply air 20 °C | 2,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kgK × 15 K = 10 kW × 12 h | 121 |
| Storage and pipework standing losses | – | about 5% | 48 |
| Total useful heat | 1,009 | ||
Averaged over 14 running hours, the heat pumps need about 72 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 2 × SE-AH-37U (74 kW total) (SE-AH air-source heat pump) delivering 55 °C, covering the day's 1,009 kWh in about 13.6 running hours.
- A 2,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired heating boiler stays connected behind a normally closed valve as standby.
- Heat pumps charge a buffer tank at 45–55 °C, which feeds floor heating, fan coils and the fresh-air coil through separate pumped circuits.
- Floor heating runs on a mixing valve at 35 °C, which lets the heat pumps work at their most efficient.
- Radiators sized for 55 °C, or fan coils, cover rooms where floor heating is not practical.
- A weather sensor lowers the supply temperature on milder days.
Selected equipment
| Model | SE-AH-37U × 2 |
|---|---|
| Heating capacity | 37 kW each, 74 kW total |
| COP | 4.2 at A20 °C / W50 °C (data sheet T1) |
| Power input | about 17.6 kW total at rated conditions |
| Rating | rated 55 °C, 60 °C maximum, R410A |
| Supply temperature | 55 °C |
| Storage | 2,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the buffer tank follows a weather-compensated set point between 40 and 55 °C. TIC-201 sets floor heating supply at 35 °C through its mixing valve. Room thermostats control each fan coil, and TIC-203 holds fresh-air supply at 20 °C. The diesel boiler stays as standby for the coldest nights.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| CO₂ per year | – | – |
06Benefits
Even, quiet comfort
Floor heating and fan coils give steady room temperature without hot spots.
Less diesel to store
Heating no longer depends on winter fuel deliveries.
Cooling in summer
Reversible units can cool the same fan coils in summer.
Lower energy cost
Each kWh of electricity delivers about 4.2 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Heated floor area and construction
- Heating emitters installed or planned
- Lowest winter temperatures and heating season length
- Current heating fuel use
- Space for outdoor units and buffer tank
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Low supply temperature. Every 5 K lower supply temperature improves efficiency. Size emitters for 45 °C or lower where possible.
- Defrost and cold climate. Choose units rated for low ambient temperatures and size the buffer to carry heating through defrost.
- Freeze protection. Use glycol or drain-down protection for outdoor pipework in sub-zero conditions.
- Electrical. About 18 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. Air-source output falls in cold weather: about two-thirds of rated capacity at 5 °C ambient. Size on the coldest design day for northern sites.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.
Talk to us
Building heating in hill towns without diesel
How a 3,000 m² hotel or office building in a hill town can heat rooms through floor heating, radiators and fan coils with heat pumps, and what it saves against a diesel-fired heating boiler.
▶Video: Space heating for buildings and farms
V13 · 2–2.5 minFloor heating, fan coils and air handlers, from homes to poultry sheds
Video coming soon01Problem statement
- Long heating season. Hill buildings need heat for five months or more, and diesel heating is one of the largest operating costs.
- Uneven comfort. Room electric heaters and oil radiators give hot and cold spots and poor control.
- Diesel supply in winter. Snow and road closures can disrupt diesel deliveries just when heating is most needed.
- Losses between fuel and process. Burning diesel in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference building is a 3,000 m² hotel in a Himalayan hill town with winter lows of −5 to 0 °C. It has floor heating in the lobby and restaurant, radiators or fan coils in rooms and a fresh-air unit.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| Room and floor heating | Rooms 20–22 °C | 3,000 m² × 40 W/m² peak × 50% average × 14 h | 840 |
| Fresh-air heating | Supply air 20 °C | 2,000 m³/h × 1.2 kg/m³ × 1.005 kJ/kgK × 15 K = 10 kW × 12 h | 121 |
| Storage and pipework standing losses | – | about 5% | 48 |
| Total useful heat | 1,009 | ||
Averaged over 14 running hours, the heat pumps need about 72 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 2 × SE-AH-37U (74 kW total) (SE-AH air-source heat pump) delivering 55 °C, covering the day's 1,009 kWh in about 13.6 running hours.
- A 2,500 L insulated storage tank decouples the heat pumps from the process peaks.
- The diesel-fired heating boiler stays connected behind a normally closed valve as standby.
- Heat pumps charge a buffer tank at 45–55 °C, which feeds floor heating, fan coils and the fresh-air coil through separate pumped circuits.
- Floor heating runs on a mixing valve at 35 °C, which lets the heat pumps work at their most efficient.
- Radiators sized for 55 °C, or fan coils, cover rooms where floor heating is not practical.
- A weather sensor lowers the supply temperature on milder days.
Selected equipment
| Model | SE-AH-37U × 2 |
|---|---|
| Heating capacity | 37 kW each, 74 kW total |
| COP | 4.2 at A20 °C / W50 °C (data sheet T1) |
| Power input | about 17.6 kW total at rated conditions |
| Rating | rated 55 °C, 60 °C maximum, R410A |
| Supply temperature | 55 °C |
| Storage | 2,500 L insulated tank |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
TT-101 at the top of the buffer tank follows a weather-compensated set point between 40 and 55 °C. TIC-201 sets floor heating supply at 35 °C through its mixing valve. Room thermostats control each fan coil, and TIC-203 holds fresh-air supply at 20 °C. The diesel boiler stays as standby for the coldest nights.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| CO₂ per year | – | – |
06Benefits
Even, quiet comfort
Floor heating and fan coils give steady room temperature without hot spots.
Less diesel to store
Heating no longer depends on winter fuel deliveries.
Cooling in summer
Reversible units can cool the same fan coils in summer.
Lower energy cost
Each kWh of electricity delivers about 4.2 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Heated floor area and construction
- Heating emitters installed or planned
- Lowest winter temperatures and heating season length
- Current heating fuel use
- Space for outdoor units and buffer tank
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
- Winter minimum ambient at site
Design notes
- Low supply temperature. Every 5 K lower supply temperature improves efficiency. Size emitters for 45 °C or lower where possible.
- Defrost and cold climate. Choose units rated for low ambient temperatures and size the buffer to carry heating through defrost.
- Freeze protection. Use glycol or drain-down protection for outdoor pipework in sub-zero conditions.
- Electrical. About 18 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Winter output. Air-source output falls in cold weather: about two-thirds of rated capacity at 5 °C ambient. Size on the coldest design day for northern sites.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.