Intense scrutiny of hot water heaters has revealed that building policies could do with more flexibility to allow for new designs, researchers say.

A study by RMIT’S Centre for Design has for the first time had a look at the comparative impacts of gas versus electric water-heating systems in apartment blocks.

Alan Pears AM, Senior Lecturer in Environment and Planning at RMIT, said the results of the Life Cycle Assessment showed current policies favouring gas and gas-solar hot water systems may be short-sighted. He says it reflects the lack of a whole-system approach to measuring environmental impact.

“Context is the key to choosing environmentally-friendlier hot water systems and this research demonstrates why policymakers should consider a systems approach in regulation, rather than following product-specific rules of thumb,” Pears says,

“Because of their strong energy efficiency, point-of-use electric hot water systems could also be the choice to ensure future-proofing of developments, as future grid emission reductions combine with efficiency for strong environmental outcomes.”

The independent research looked at greenhouse gas emissions, water use, solid waste and cumulative energy demand and included the use of dynamic thermal modelling software. It was commissioned by a company that produces electric hot water systems using a new “direct energy transfer” method, rather than traditional heat exchange.

In their tests the researchers found in operation, point-of-use electric systems were up to 3.1 times more energy efficient than gas in a medium-density apartment block. The electric set-up was found to be 2.3 times more energy efficient than gas in the high-density building.

The report says that these energy gains will only increase as more renewable sources start to feed into power grids, which will allow electric heater systems to run ever more efficiently.

The full report is available here.