Commercial hot water
How big a heat pump for your hot water?
From a small hotel block to a campus — 1,000 to 100,000 litres a day. You get the capacity in kilowatts, the storage tank to pair with it, the Sunniva model that covers it at your winter temperature, and what it costs to run against a geyser or a diesel boiler.
How much hot water
Pick what the building is, then set the numbers.
Hot water per day
6000litres
Number of guests
100
Litres per guest per day
60litres
Indicative — move it to the figure your own experience gives.
Water temperatures
The rise is what costs money, not the outlet on its own.
Incoming water temperature
22°C
Mains or tank feed. Colder in winter, and further north.
Hot water delivered at
55°C
Hours the machine may run
6hours
Sunniva sizes on a maximum of 16 hours a day, leaving the rest for defrost, service and the off-peak window. Fewer hours means a bigger machine for the same water.
Where it is
Air temperature drives both capacity and COP.
Nearest city
A starting point only. The slider below stays editable.
Design air temperature
15°C
The cool-season temperature the system still has to deliver at.
This is EVI territory. Below about
5 °C a standard air-source machine loses output quickly. The
SE-EVI range is published down to −20 °C and the selection
below reflects that.
The plant room
One machine or several, and whether you want a spare.
Standby machine
A standby is one spare machine of the same model,
piped in parallel and rotated with the duty units. It carries no load
in the sizing — the duty machines meet the duty on their own.
Most machines you would accept
4
A duty does not have to be one machine. Two smaller units often fit the load far more closely than one large one, and they stage better at part load. Set this to 1 if the plant room only has room for one.
What you pay for energy
Change these to your own tariff.
What heats your water today
The saving is measured against this one. The chart
still shows the others so you can see what they would have cost.
Electricity
9₹/kWh
Diesel
92₹/litre
LPG (commercial)
95₹/kg
PNG
55₹/SCM
Days of use per year
330days
Sizing margin
10%
Headroom for fouling, standby losses and ageing.
Comparison assumptions change only if you know why
Electric geyser efficiency
95%
Diesel boiler efficiency
85%
Diesel energy content
10kWh/litre
LPG boiler efficiency
90%
LPG energy content
12.8kWh/kg
PNG boiler efficiency
90%
PNG energy content
10.5kWh/SCM
Whatever figure you have — ours or anyone
else’s, installed. Nothing is sent anywhere until you fill in the
form below.
Grid electricity carbon
0.71kg CO₂/kWh
The Indian grid average. Lower it if you have rooftop solar or a green tariff.
Diesel carbon
2.68kg CO₂/litre
LPG carbon
2.98kg CO₂/kg
PNG carbon
1.9kg CO₂/SCM
Coal / biomass carbon
1.8kg CO₂/kg
Swings hugely with grade. Set it near zero for biomass, which is usually counted as biogenic.
Required heat pump capacity
—
The machines that cover it
—
Cost to run for one day
You would save
—
What it pays back, and what it stops
Pays for itself in
—
Carbon avoided
—
Want this sizing checked by an engineer?
Your name, phone and email go on the saved sheet and let our team confirm the selection against your actual draw-off pattern, pipe runs and tariff. All three are needed before the sheet can be sent or saved.
How this is worked out
- Heat needed = litres × 1.163 × temperature rise ÷ 1000. That constant is water’s heat capacity, 4.186 kJ/kg·K, in Wh per litre per °C.
- Capacity = the day’s heat ÷ the hours the machine may run, plus the sizing margin. A heat pump is not sized on peak draw — storage covers the peak.
- Storage is 2 to 6 times the hourly output, the rule printed on every Sunniva datasheet.
- Machine selection interpolates each model’s own published capacity and COP to your design ambient. SE-AH is published down to 5 °C; SE-EVI down to −20 °C, which is why the recommendation changes when you drag the temperature down.
- Where a duty asks for hotter water than the tested condition — SE-AH is tested at 50 °C outlet, SE-EVI at 55 °C — the panel says so rather than reusing the cooler figure.
- Litres per guest, bed or resident are indicative starting figures, not Sunniva standards. Move the slider to your own experience; the saved sheet records what was used.
- Payback is simple payback — the price you type in, divided by the annual saving. No finance, no maintenance, no discounting, and no price of ours is assumed or disclosed. Carbon is the displaced fuel’s emissions minus the electricity the heat pump draws, at the Indian grid average of 0.71 kg CO₂ per unit. Every factor is a slider, and the saved sheet records what was used.
- Indicative only. Draw-off pattern, static head, pipe runs and local code all affect the final selection — confirm with Sunniva Encon LLP before ordering.
Commercial hot water sizing
Sunniva Encon LLP
Calculated for
—
What you entered
Result
Required capacity
—
—
Running cost & savings
How this was worked out
Talk to Sunniva
SalesWhatsApp our sales desk
LinkedInFollow Sunniva Encon
YouTubeSee the machines running
Review usRate us on GoogleContact
+91 93213 65103sales@sunnivaencon.com
www.sunnivaencon.com
Office
C‑443, Oshiwara Industrial Centre Premises CHS, New Link Road, Goregaon West, Mumbai© 2026 Sunniva Encon LLP. The design and code of this calculator are our copyright. Results are indicative and offered in good faith — the method is set out above. Confirm the final selection with us before ordering.
1
Commercial hot water
How big a heat pump for your hot water?
From a small hotel block to a campus — 1,000 to 100,000 litres a day. You get the capacity in kilowatts, the storage tank to pair with it, the Sunniva model that covers it at your winter temperature, and what it costs to run against a geyser or a diesel boiler.
How much hot water
Pick what the building is, then set the numbers.
Hot water per day
6000litres
Number of guests
100
Litres per guest per day
60litres
Indicative — move it to the figure your own experience gives.
Water temperatures
The rise is what costs money, not the outlet on its own.
Incoming water temperature
22°C
Mains or tank feed. Colder in winter, and further north.
Hot water delivered at
55°C
Hours the machine may run
6hours
Sunniva sizes on a maximum of 16 hours a day, leaving the rest for defrost, service and the off-peak window. Fewer hours means a bigger machine for the same water.
Where it is
Air temperature drives both capacity and COP.
Nearest city
A starting point only. The slider below stays editable.
Design air temperature
15°C
The cool-season temperature the system still has to deliver at.
This is EVI territory. Below about
5 °C a standard air-source machine loses output quickly. The
SE-EVI range is published down to −20 °C and the selection
below reflects that.
The plant room
One machine or several, and whether you want a spare.
Standby machine
A standby is one spare machine of the same model,
piped in parallel and rotated with the duty units. It carries no load
in the sizing — the duty machines meet the duty on their own.
Most machines you would accept
4
A duty does not have to be one machine. Two smaller units often fit the load far more closely than one large one, and they stage better at part load. Set this to 1 if the plant room only has room for one.
What you pay for energy
Change these to your own tariff.
What heats your water today
The saving is measured against this one. The chart
still shows the others so you can see what they would have cost.
Electricity
9₹/kWh
Diesel
92₹/litre
LPG (commercial)
95₹/kg
PNG
55₹/SCM
Days of use per year
330days
Sizing margin
10%
Headroom for fouling, standby losses and ageing.
Comparison assumptions change only if you know why
Electric geyser efficiency
95%
Diesel boiler efficiency
85%
Diesel energy content
10kWh/litre
LPG boiler efficiency
90%
LPG energy content
12.8kWh/kg
PNG boiler efficiency
90%
PNG energy content
10.5kWh/SCM
Whatever figure you have — ours or anyone
else’s, installed. Nothing is sent anywhere until you fill in the
form below.
Grid electricity carbon
0.71kg CO₂/kWh
The Indian grid average. Lower it if you have rooftop solar or a green tariff.
Diesel carbon
2.68kg CO₂/litre
LPG carbon
2.98kg CO₂/kg
PNG carbon
1.9kg CO₂/SCM
Coal / biomass carbon
1.8kg CO₂/kg
Swings hugely with grade. Set it near zero for biomass, which is usually counted as biogenic.
Required heat pump capacity
—
The machines that cover it
—
Cost to run for one day
You would save
—
What it pays back, and what it stops
Pays for itself in
—
Carbon avoided
—
Want this sizing checked by an engineer?
Your name, phone and email go on the saved sheet and let our team confirm the selection against your actual draw-off pattern, pipe runs and tariff. All three are needed before the sheet can be sent or saved.
How this is worked out
- Heat needed = litres × 1.163 × temperature rise ÷ 1000. That constant is water’s heat capacity, 4.186 kJ/kg·K, in Wh per litre per °C.
- Capacity = the day’s heat ÷ the hours the machine may run, plus the sizing margin. A heat pump is not sized on peak draw — storage covers the peak.
- Storage is 2 to 6 times the hourly output, the rule printed on every Sunniva datasheet.
- Machine selection interpolates each model’s own published capacity and COP to your design ambient. SE-AH is published down to 5 °C; SE-EVI down to −20 °C, which is why the recommendation changes when you drag the temperature down.
- Where a duty asks for hotter water than the tested condition — SE-AH is tested at 50 °C outlet, SE-EVI at 55 °C — the panel says so rather than reusing the cooler figure.
- Litres per guest, bed or resident are indicative starting figures, not Sunniva standards. Move the slider to your own experience; the saved sheet records what was used.
- Payback is simple payback — the price you type in, divided by the annual saving. No finance, no maintenance, no discounting, and no price of ours is assumed or disclosed. Carbon is the displaced fuel’s emissions minus the electricity the heat pump draws, at the Indian grid average of 0.71 kg CO₂ per unit. Every factor is a slider, and the saved sheet records what was used.
- Indicative only. Draw-off pattern, static head, pipe runs and local code all affect the final selection — confirm with Sunniva Encon LLP before ordering.
Commercial hot water sizing
Sunniva Encon LLP
Calculated for
—
What you entered
Result
Required capacity
—
—
Running cost & savings
How this was worked out
Talk to Sunniva
SalesWhatsApp our sales deskLinkedInFollow Sunniva EnconYouTubeSee the machines runningReview usRate us on GoogleContact
+91 93213 65103sales@sunnivaencon.com
www.sunnivaencon.com
Office
C‑443, Oshiwara Industrial Centre Premises CHS, New Link Road, Goregaon West, Mumbai© 2026 Sunniva Encon LLP. The design and code of this calculator are our copyright. Results are indicative and offered in good faith — the method is set out above. Confirm the final selection with us before ordering.
1