Solar vs Heat Pump Water Heaters

Solar water heaters and heat pump water heaters are the gold standards for renewable energy water heaters. They are both proven technologies that have been widely used for over 30 years. They are also storage tank systems, which mean they can provide good water pressure for large households. Below is a quick summary of our overall review for both systems:


However there is a reason why many hotels, country clubs and residences in Singapore are using heat pump water heaters over solar heaters and it has everything to do with our climate. Heat pumps have a higher efficiency than solar heaters in Singapore.

Compared to conventional storage heaters which are powered by pure electricity, heat pumps and solar primarily use renewable energy such as free heat in the air or sunlight. On clear sunny days, the performance of solar heaters could be higher than that of heat pumps. But there are few such days in Singapore.

Our tropical climate, cloudy skies and frequent rains cause solar water heaters to draw against their 3000 watt backup heating elements often, effectively transforming them into high power consuming 150 lit electric heaters. More on sizing for solar heaters: ‘Why are solar heaters so large?

Initial cost

This is the cost of a suitable heat pump or solar heater for a family of four:

  • 60 lit heat pump – $2800+ ROI 4 years
  • 150 lit solar – $5500+ ROI 8 years

More on sizing for solar heaters: ‘Why are solar heaters so large?

Renewable systems get a lower rating here because the average initial price that a homeowner in Singapore pays for a normal water heater is around $300 to $500. Renewable energy water heaters are fitted with higher technology components, hence the price difference.

Running cost and Return on Investment (ROI)
Although the initial cost is high, the running cost is incredibly low. You can expect to breakeven on your 4th year for heat pumps. Solar water heaters cost more so we estimate around 8 years to fully recoup your costs. The lower ROI for heat pumps also makes it more popular in Singapore.

Ease of Installation

Solar heaters must be installed on the roof of a building, preferably on a south-facing wall. The roof of the house should be tall enough without obstruction from sunlight. Panels and tanks are separate and installation time is longer, around 6 hours.

Heat pumps are not limited to the roof and can be placed anywhere in the house. However, they cannot be situated in tightly enclosed areas as they need to absorb heat from the environment. Heat pumps come as a single unit with no separate components and installation is plug and play, approximately 3 hours.


Solar panels need to be professionally cleaned from the rooftop every 6 months or dust that settles on it will affect its efficiency.

Heat pumps are as hassle-free as regular electric water heaters, where there is no additional service required.


Heat pumps and solar heaters are both great renewable energy water heaters but they don’t perform the same way in different environments. In temperate climates like Europe and America, solar heaters can be quite popular, but in tropical climates where there is an abundant supply of heat all year round, heat pumps are the undisputed preferred choice.


Further reading:

Other popular comparison articles:

  1. Gas Heaters vs. Electric Water Heaters
  2. Instant vs. Storage Water Heaters

Other interesting heat pump features:

  1. Digital panel
  2. Memorizes your bathing patterns


Why are solar heaters so large?

Renewable energy water heaters such as solar and heat pumps are sized differently from regular electric heaters. This is because renewable heaters generate heat slowly; their large sized tanks are used as ‘tank reservoirs’ to store free energy so users can draw from a larger ‘battery’ which won’t run out when required.

Tank sizing for an average family of 4:

  • Electric – 40 lit
  • Heat pump – 60 lit
  • Solar – 150 lit

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Amanda Zhong

Amanda Zhong

Amanda is the bookish personality of AOS Bath. She loves reading in quiet places over a good cup of tea. Like her other Gen Y peers, she has a penchant for advanced technology that delights and engages people.
Amanda Zhong

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