How to change hot water heating from gas to electric?

[colinMackie]

Situation: 10kw of solar is being installed on my roof Williamstown Victoria. I have separate gas heating and gas hot water systems. The latter is showing end of life symptoms i.e. brown hot water.

The 10 kW will far exceed our electricity requirements until i load it up with heavier electrical appliances in a time-of-day intelligent manner.

Questions:

What's the best solution  (price/subsidy output for variable solar input, output for variable environmental conditions), for hot water in my case? Assume 4 bedroom 2 storey home.

When the sun doesn't shine and it's cold can i still have hot water?

Do heat pump hot water systems boost with regular resistive heating in cold conditions?

Are heat pump HW heaters better than regular resistive heaters for price and return on investment?

Do heat pump hot water systems also heat or cold the home?

Is noise an issue with best pump systems?

[EricL]

Hello @colinMackie 

Welcome to the Bunnings Workshop community. It’s wonderful to have you join us and thank you for sharing your question about changing your hot water heating from gas to electric.

Let me try and answer some of your questions. I have a hot water solar system installed in my house and when there is no sun, my whole family must remember to press the boost button for the mains electricity to kick in and heat up our water. 

If you're planning to use solar-generated electricity to power a heat pump hot water system, the approach is still feasible. In this case, the heat pump would be an electric-powered system that uses electricity, including the excess solar energy from your 10-kW solar installation, to heat the water. 

Hot Water When the Sun Doesn't Shine? Yes, a heat pump can provide hot water even when the sun isn't shining. Heat pumps extract heat from the surrounding air, which means they can work in colder conditions. However, their efficiency may decrease in very cold temperatures.

Some heat pump hot water systems have a backup resistive heating element that can be used during extremely cold conditions or when the demand for hot water is high. This ensures you have hot water consistently, but using the resistive heating element will consume more electricity. It’s important to find out if the unit you purchase has this feature.

Heat pump hot water systems are generally more energy-efficient than regular resistive heaters. This means they can provide better returns on investment over time by reducing your energy bills. The initial cost of a heat pump system might be higher, but the savings over the system's lifetime could outweigh the initial investment.

Heat pump hot water systems are designed primarily for heating water and are not typically used for cooling or heating homes. 

Noise can be a factor with heat pump hot water systems, but modern units are designed to be quieter than older models. The noise level can vary depending on the specific brand and model. 

When choosing a hot water system, consider factors such as upfront costs, ongoing energy savings, system efficiency, and the specific needs of your household. I suggest consulting with local experts who can assess your home's requirements and recommend a suitable solution for your home.

Here are links to discussions regarding solar power:

• Feedback on new solar system by @TonyJ
   
• Poll: Do you have solar panels?
   
• Solar Power Back Up Batteries. by @Andy_Mann 

Let me call on our experienced members @MikeTNZ and @CSParnell for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[CSParnell]

Hey @colinMackie an electrician will have to do a maximum demand assessment to make sure your mains can handle the load of the electric hot water heater, even know you have solar maximum demand still has to be calculated. From there if there is enough capacity on the main cable a new circuit can be run out to the hot water location and the  the plumber can disconnect the gas hot water and connect the electric one and the sparky will hook up power and carry out final tests.