Gas HWS or Heat Pump HWS

[Grumpy John]

Earlier this year we had 6.6Kw of solar panels with a 5Kw Inverter and using the PowerPal App we have noticed a reduction of energy consumption even with the onset of winter and the cloudy conditions. We currently have a 7y/o 135 litre gas hot water service and with the current rebates available I was wondering if it would be worth getting a Heat Pump HWS. I have heard that the compressor can be noisy, so any feedback from any members who have gone down the Heat Pump HWS track would be appreciated.

[Chris Parks]

We had a very early Siddons and the heat exchange panels used to vibrate when the pump was running but the newer ones may not do that now. I liked it because in effect it was a quick recovery system that did not cost much to run.

Edit, I just looked at the link, ours had the pump and motor on top of the tank and now I see they are using separate compressors so Ignore me.

[Grumpy John]

Thanks for the quick reply Chris. How long ago did you did you install your heat pump HWS?

[Chris Parks]

GJ, see my edit. Looking back I think it was the thick end of 30 years ago which seems unbelievable now. It had to go because a house was built next door and it never saw sun and I guess the early ones did not have great performance in those conditions and it was running constantly. At first I thought it had a gas leak but no luck there so we changed back to an OP system. Prior to the shading problem it always worked well.

[Mr Brush]

We've just finished rebuilding our house lost in the bushfires of Jan 2020, which was an excuse to update a few things. 6.6kW of solar on a perfectly north facing roof, and a new Sanden Heat Pump HWS. We had a Quantum Heat Pump HWS in the original house, placed inside the garage - very reliable and energy efficient, but a bit noisy. The Sanden is a split system (tank is undercover in garage, compressor outdoors in services area), uses CO2 refrigerant so works well down to much lower temperatures. So far the Sanden is brilliant - almost totally silent, and apparently only uses 900W when running flat out.

Sanden is apparently the "Rolls Royce" of Heat Pump HWS (Japanese made), but definitely worth the spend compared to the old Quantum (which I believe are now made in China).

[aldav]

Had to have a laugh when I looked at the link. How is a heat pump non-electric? Those new spit setups certainly look a bit different to what I was familiar with.

[Mr Brush]

We rebuilt on the same slab, to much the same house design. I was all set to just get a replacement Quantum heap pump HWS (just a tank with all the compressor gubbins sitting on top) as it could go in the garage in exactly the same spot as the old one. Slight snag....Quantum have changed from a non-flammable refrigerant to a flammable one, so under no circumstances can the unit now be placed in a garage. Game over - called Sanden, and their split system suited perfectly.

[Beardy]

I have installed a number of heat pumps but not the current split type models. Didnt have any issues with them but personally I would probably stick with a gas storage unit if you have natural gas available.
They are cheap to buy and uncomplicated, the heat pumps are fine when they are running but are still a more complex unit with more potential issues and are quite expensive should you need to replace it and have no subsidies available to you ( which is most likely the case)

If you will still need gas connected for other household appliances do you think you are going to be better off financially changing?

[Grumpy John]

I have installed a number of heat pumps but not the current split type models. Didnt have any issues with them but personally I would probably stick with a gas storage unit if you have natural gas available.
They are cheap to buy and uncomplicated, the heat pumps are fine when they are running but are still a more complex unit with more potential issues and are quite expensive should you need to replace it and have no subsidies available to you ( which is most likely the case)

If you will still need gas connected for other household appliances do you think you are going to be better off financially changing?

I think you've raised a very valid point Beardy, i.e. very expensive to replace if there is no subsidy available. We still have/need gas for the cooktop and ducted heating, so my other option is an instantaneous system.

I'm just trying to second guess the cost of different energy supplies moving forward. The initial purchase price, while important, can be recovered by cheaper running costs.
We haven't had a clothes dryer for quite a few years now, but just bought a new heat pump model because it is so efficient to run, that's what made me think to go for a heat pump HWS when the old one packs it in.

[Bohdan]

An alternative solution is to install an electric storage unit with a solar power diverter. This will heat your water with any excess solar electricity that you are not using rather than dumping it into the grid for very little $$.

If you do go for a heat pump model the solar diverter will heat the water whenever you have surplus power.

[rwbuild]

I have an LPG gas instantaneous that is run by 1 D cell battery and it costs me a new battery every 3 yrs and $127-50 per qtr for the gas + annual rental fee for bottles of $60-00. 3 person household

[Chris Parks]

An alternative solution is to install an electric storage unit with a solar power diverter. This will heat your water with any excess solar electricity that you are not using rather than dumping it into the grid for very little $$.

If you do go for a heat pump model the solar diverter will heat the water whenever you have surplus power.

I looked at doing this a while ago and the price was stupid, so much so I doubt it it would have been paid back in my lifetime.

[Bohdan]

I looked at doing this a while ago and the price was stupid, so much so I doubt it it would have been paid back in my lifetime.

He already has the solar system, some have diverters builtin, so the only cost could be the electric hot water tank and wiring so I assume you are planing a very short life.

[Chris Parks]

He already has the solar system, some have diverters builtin, so the only cost could be the electric hot water tank and wiring so I assume you are planing a very short life.

I've got the solar with a Fronius inverter and data manager and to do it properly I was quoted around $1200. I believe there are cheaper options but they don't work as well but I really don't understand the ins and outs of it all and if anyone can clarify the differences it would help.

[Beardy]

If you were looking at running an electric storage heater off solar you would want to make sure you have plenty of excess solar capacity, I think the heaters are 3.6 or 4.2 KW that will be getting drawn from your system plus you are buying electricity to run the boost side of things when the sun don’t shine.
I am a bit out of touch with these as they were not allowed on new house builds until recently as they didn’t meet BASIX requirements