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Solar water heaters in Pakistan
Evacuated tube, electric and heat-pump water heating compared: what each needs, what it cannot promise, and why an installed quote is dated rather than a headline price.
Water heating is one of the largest winter loads in a Pakistani home. A solar thermal collector can carry much of it on sunny days, but it does not remove the need for a backup element, and it cannot store enough for a long cloudy spell. This page compares the common options, states the assumption behind sizing, and links to the calculator that turns your own numbers into a demand figure and a payback range.
Options at a glance
| System | Capacity | Example / nameplate power | Sizing assumption | Winter / cloud / backup limits | Price |
|---|---|---|---|---|---|
| Evacuated tube collector, 150 L | 150 litres | Backup element: check model nameplate; 1.5–2 kW is an example only | Up to 3 people at 40 L/person/day | Backup element for cloudy spells; freeze protection needed; cloud output is not guaranteed | Dated installed quote required |
| Evacuated tube collector, 200 L | 200 litres | Backup element: check model nameplate; 1.5–2 kW is an example only | Up to 5 people at 40 L/person/day | Backup element for cloudy spells; freeze protection needed; cloud output is not guaranteed | Dated installed quote required |
| Evacuated tube collector, 300 L | 300 litres | Backup element: 2–3 kW example only; check nameplate | Up to 7 people at 40 L/person/day | Larger roof area and weight; backup element; freeze protection needed | Dated installed quote required |
| Electric storage geyser | Model dependent; ask for specifications | 2 kW element example only; check nameplate | Tank sized to the household; heats on grid or solar | Works at night; running cost depends on your own tariff | Dated installed quote required |
| Electric instant heater | No storage tank | Often draws well above 2 kW; read the model nameplate | Sized to flow rate, not litres stored | High concurrent load; may exceed a small inverter or breaker | Dated installed quote required |
| Heat pump water heater | Model dependent; ask for specifications | 0.5–1.5 kW input example only; check nameplate | Works best in a warm, ventilated space | Needs suitable space; less effective in cold outdoor air | Dated installed quote required |
Sizing assumption
We use an illustrative 40 litres per person per day for hot-water demand. It is an assumption, not a standard or a measurement. Households with large families, long showers or a washing machine may use more, and water-saving fittings may use less.
Demand above 300 litres is a reason to ask for a custom design, not to squeeze a larger tank. The number of bathrooms matters too, because simultaneous showers can exceed what one collector and tank can deliver at a comfortable temperature.
What solar thermal cannot promise
- Cloud and rain: output falls sharply, and a backup element is normal.
- Freezing nights: some northern areas need frost protection or a drain-back system.
- Backup: an electric element keeps hot water available, but it uses grid electricity unless your PV covers it.
- Structure: a filled collector and tank add roof load. A qualified professional must check the mounting.
Temperature lift and climate change how much useful heat you get. That is why the calculator asks you for a temperature rise instead of applying a hidden climate factor.
Source: US DOE Building Technologies: heat pump water heaters.
Where we mention a heat-pump water heater, the source is a United States Department of Energy explainer. We do not present its performance figures as Pakistani measured data.
Request help with a solar water heater
Solar thermal sizing help
Ask ProChuno to help you find a supplier who can size a collector and tank from your household's daily hot-water use.
Qualified connector and structure inspection
For roof mounting, connectors and wiring, ask for a qualified technician and the manufacturer instructions.
Questions about solar water heating
How do I size a solar water heater for my home?
Multiply the number of people by an assumed 40 litres each per day, then pick the nearest standard tank: 150, 200 or 300 litres. Above 300 litres needs a custom design rather than a larger standard tank. Confirm with a site survey and your actual hot-water use.
Do evacuated tube collectors work on cloudy winter days?
They still collect diffuse light, but output drops sharply in cloud and rain, so a backup element is normal. Freezing nights need frost protection or drain-back. PVGIS winter radiation is a long-term model, not a forecast, so treat any winter output figure as an average rather than a guarantee.
Is an instant electric water heater the same as a storage geyser?
No. A storage geyser heats a tank slowly on a lower element, such as a two-kilowatt example. An instant heater raises water as it flows and can draw far more than two kilowatts, so check your wiring, breaker and inverter limit before treating the two as interchangeable.
How is the payback of a solar water heater calculated?
Payback is the installed cost divided by annual savings minus annual maintenance. Savings come from the share of water heating you actually cover with solar, priced at your own electricity tariff or avoided gas spend. If savings do not exceed maintenance, payback is unavailable, not infinite.
Why does ProChuno not publish a solar water heater price?
There is no substantiated current Pakistani price dataset we can stand behind, and prices move with import costs and model. The static tables therefore say a dated installed quote is required. Compare written quotes for the same tank size, collector type, backup element and warranty.