Thread: Hot water heat pump

I don't understand the analysis , and I am pretty good at understanding these things.
I did a "whole of life cost comparison" of element at Off peak 1 , bottled gas, and heat pump, and the element came out the best by a long shot.

I have been advised by a couple of electricians and plumbers not to touch the heat pump system as they are unreliable and that they do not work under about 4C.

The manufacturer's figures for energy usage for the heat pump produced MORE Kwh than when I did the actual calculation for my element system.

A lot have been sold for the RECs to sports clubs and caravan parks , and I recall the caravan park at Cape Hillsborough where they had 5 or 6 and only one was working at any time and it was noisier than a split system air conditioner which is what it is.
The heat pump also is very tall and would not fit under my house.

Your individual circumstances may well be different to mine, but you should do your own analysis before committing. I don't see any connection with solar power at all except for the RECs.

If you want the "feel good "factor that you are using less coal power, just remember that the generators have to turn all night anyway to run the light and refrigeration.
It would only be if your hot water system dropped the voltage in the grid so much that the producer had to start up a gas turbine or whatever that there is any incremental use of electricity. That is why they offer off peak.
Regards Philip A

Solar works well here,but a heat pump,wouldn't have one.

The ones i have seen are overly complicated,one repair and you have done your money.

Electric element and be careful with usage is the go IMHO.

Or solar if you live in an area where they work well,with a manual switch for the booster heater.

This is the second house we have had solar HW,our booster switch is used only a couple times each year,usually during cloudy weather in winter.

I had a heat pump hot water system on my house in Yass and was pleased with its performance. It gave me no trouble in the 13 years I lived there.

It was the Quantum model that came out just after they found that many people were not bothering to connect the electric boosting element, so they stopped fitting it. With two teenage children, we never ran out of hot water.

At the time, there was an analysis of different HWSs at Questacon, The National Science and Technology Centre in Canberra. It concluded that the heat pump was the most efficient, at that time and in that climate. It used to get a lot colder than 4C in winter there, but it didn't seem to create any problems.

When my off-peak here in Tuross died three or four years ago, I replaced it with a Dux heat pump. It is still going well.

I have found the heat pump to be convenient to install, efficient and effective.

I bought a 1 year old heat pump HWS from a Victorian country caravan park that had been sold a bunch of these by installers as mentioned by PhilipA below. They were too noisy for him and his patrons and cost more to run than the instant Natural gas ones they replaced and were going back in, one at a time. I paid around $1K for it instead of the new cost of $5K which made it quite worthwhile.

To make mine most cost effective, (as I have the good solar feed in tariff) it is time clocked to come on after sundown and shut off before 10pm as I like my peace and quiet at bed time. I didn't have off peak electricity metering as the house's original storage heater got replaced a long time ago by an instant LPG unit. My HWS is now backed up by flat panel HW collectors and a solar powered pump for some free heating over summer. I don't get much sun in winter as I live where I'm surrounded by big trees.

Now if you had a very low feed in tariff you could easily time clock one of these things to run during the middle of the day to use some of the excess electricity generated and you would not have to worry about the unit cutting out on frosty nights. My unit (a "Quantum" brand unit) does work in very cold conditions but goes into a regular de-icing maneuver which cuts its efficiency somewhat.

As for reliability, they do have loads more parts to go wrong and it wouldn't take much to wipe out any cost savings that it generated. My unit had a stuck compressor once and the manufacturer wouldn't even book an inspection appointment without draining my credit card in advance. I managed to get it running again with the scientific application of a thumping big hammer applied to the compressor case. Would I buy another? No idea, depends on how much I had to pay for one. This one's saved me loads of money but if it had been a new one I would still be recovering its purchase price, 6 years after its installation.

I would rate the cost benefit ratio in a similar way to the purchase of a diesel Disco instead of a petrol one. Both get you there, one costs more to run and the other costs you more to fix when it dies.

I have installed a lot of these as well solar hot water systems. I would only touch Quantum heat pumps ( I have this at my own house) or Apricus solar evac tube hot water.
The other brand heat pumps I have installed are Dux, Rheem, Siebel Oltron, and a couple of other that brand names have slipped my mind, we have had a LOT of trouble with all these, particularly the Rheem, out of the 20 odd of these we have installed, every one of them has died.

A site we work on have a heap of Quantum commercial heat pump HW units.

They have had quite a few fail,they were also badly installed,can't get panels off to work on them as they are to close to each other and against a wall.Some are also in plant rooms,so they have had to put extraction fans in to pull out the cold air.

They wouldn't be 5yrs old.

I looked at another one the other day the tech said had a refrigeration issue.Sure did,a refrigerant leak in the tank,second one with same problem in the last few months.Unit has to be replaced.

The site now realises they would have been better off replacing the old gas HW units with new gas units.

I think someone did a good salesman job on them

When mine dies, I will put the apricus system in, unless I sell the place first

Enter

Looking a evacuated tube solar for hot water before but ditched that idea when I visited several very well set up Heat Pumps homes with hydronic heating in Melbourne. Hot water year round and possibly free heating and hot water over winter got me costing the set up. With a solar array on roof for day time power.

The brands of heat pump is clearly an issue. Rheem seems to have a "Very Bad" rep! See Whirlpool green tech forum which has many people who have systems and opinions some of which are rubbish and some very helpful!
https://forums.whirlpool.net.au/forum/143

Several plumbers and architects I spoke with pointed me to Enter
The heat pumps are IMO very similar to air-conditioning split systems. In fact I would say they are the same in many ways. These are a known with decades of use and again IMO fairly to very reliable if you get the right one!

My current heating costs are gas for hot water and a ducted heating system. Renovating here and my 30 year old hot water and heating systems are in need of replacement so I hope to spend a bit to save a lot. It will be structured to allow replacement of parts so even if I get failures or not enough sun to run I will have back ups.

The tricky bit was finding the right people who are not just sales people.

Watching the battery ideas