If you are thinking of staying with gas and only having it for a new HWS. A lower cost option to consider?
You are going to need to pay for a gas fitter to install the new HWS. One of our urban family did this several years back as the best option. For a small extra cost at the same time the gas fitter disconnected the town NG gas and installed a connection point for a gas bottle 36kg, instead. Just be sure to purchase an LPG version HWS.
It is worth comparing the cost of the two options. We run our HWS in one property on town gas and another on bottles. We use just over two 36kg bottles a year. The saving in the first year paid for the gas fitter. The daily service charge in Brisbane adds around $300pa to the gas bill for zero usage. Our last 36kg bottle cost $142 delivered and swapped by the truck driver. We use a 9kg swap and go, the BBQ spare when the 36kg runs empty, via a changeover tap. Or you can have two large 36kg, Which would add $30 in our area pa for the bottle hire.
If you have a gas cooktop they can be changed over to LPG by replacing the jets, one per burner. They are the size of a cig butt and a regular spare part, you can purchase yourself. The change should take less than 30 mins. Make good use of the gold plated gas fitter.
Doing the same for an oven may not be so cost effective. It may need the oven removed for access, at which point for older ovens the whole burner may require replacement. A $200-300 job all up.
Thanks, Mark. I have not yet decided. it may be that its the old gas stove which is grossly inefficient. I did get one quote to change over to electric and it was going to break the bank. I’m having the old gas stove removed next week sometime (local gasfitter/plumber who has very reasonable rates) and after I have cleaned up around and under the stove, will decide which way to jump. IN the meantime I can make do with portable appliances. I’m still interested in heat pump for hot water. will see what the quote tells me. Managing this stuff on a pension is not an easy task.
Understood. The gas fitter will be a useful sounding board about your gas options. The heat pump quote should include a guide to annual electricity consumption for comparing running costs, to help with your decission.
Well, they were quick, and coming tomorrow to quote. Must confess I am terrified, I know its going to be horribly expensive and I may just stick with what I have, but at least I’ll have some idea.
P.S.
The Australian give web site suggests an electrical power saving of up to 60% when compared with conventional resistive HWS systems. The online suppliers all seem to claim up to 80% and a probable ‘second coming’.
Choice has not tested Heat Pump HWS systems. Although @phb posted a link to Canstar Blue, and a link to a broader Aust Govt HWS resource.
One of the key factors in determining the cost benefit of a solar PV array is the capacity you have to use your own power rather than buy it or sell it cheaply. This requires you to be able to move your use to the bright part of the day. This might be doing the washing or running the dishwasher then. Heating water fits into that quite well.
A 12 or 15 evacuated tube array connected to a small tank with electric booster element is another option worth considering. If the element is 2.4kW, you can just plug it into a power point, no need for additional switchboard work.
It’s generally sunny around where I live, so we don’t even need the booster element. With a 30 tube array + 250l tank (with no electric heating element) we have had hot water every day for more than 18 months, but do have short showers, and generally aren’t big users of hot water.
Back when it used to rain more often there were a few days per year where the water was a bit cooler than comfortable, but we did generally have longer then 2min max showers then too. These days 1-2min showers are the norm, until we get some decent rain.
Generally my recommendation is for evacuated tubes for sunny locations, and heat pumps for cloudier areas.
I think for places like Melbourne with cloud and heavy frosts it is recommended to upgrade to a more expensive Heat Pump with a defrost cycle or auxiliary electric resistance heater (1.5kw common). The efficiency or COP also decreases in colder environments. Reducing the benefit slightly over winter months.
P.S.
I suspect with a 210l Heat Pump HWS starting at around over $3,300 plus installation, it may be difficult to justify spending the extra if it is replacing a gas HWS. It’s a $4,000-$5,000 investment that might pay off for a family home over five years. Much longer if you are single and trying to make every dollar count.
If a heat pump is run off mains grid power or you choose a gas HWS the difference in carbon footprint seems minimal. But much better compared to an electric resistive HWS on mains power. Of course the evacuated or flat plate collector solar systems or a solar powered electric are the low carbon best options.
Electric Ignition Instantaneous Gas HWS are a good option if you have no issues with power outages. The power ignites and controls the temperature so you don’t have to install an extra tempering valve. If your gas system is compliant it is a cheaper option for replacement in the future. If you put in a temperature controller at you shower it will reduce gas usage and help prevent the how water fluctuating or cutting out if you adjust the taps. Gas boosted Solar Hws have a bigger outlay and more components to be replaced but only use gas when their is no hot water from the solar, cheaper and more efficient than the electric boosted systems to run. Gas storage Hws will have a pilot flame on constantly and this will fire up when the hot water in the storage tank drops below a certain temperature, using more gas than the instantaneous.
Look into Stieble Elton heat pumps, they have some of the best back up warranty service that we have experienced as plumbers, the product is outstanding. The newer model have got rid of the anode, so no need to get this checked every couple of years. Bosch have also had excellent warranty service, not sure how their new heat pumps perform.
The electric ignition instantaneous units you do. Other option is a Bosch Hydropower Units that don’t require an electrical connection - but you do need a high performance Tempering Valve with them.
Yes, I am wondering whether there is an interim solution where I can somehow use the PV system to heat water during the day rather than using entirely gas. Then worry about heating/cooling later.
I don’t know if its even possible to connect my existing HWS to the solar PV, or if I will need a new one - either gas or electric assist.
I used to have a Bosch instantaneous gas heater with auto electric ignition, it had 2 D cell batteries, no electrical connection required. It was an older model though, purchased around 1995.
It isn’t connected directly, but the PV system feeds all loads in your house, up to its current output- best to time your water heating to highest PV system output.
At home, like @gordon we have a Bosch instantaneous gas HWS now 4 years old. We have a convenient power outlet, but considered the battery option for power outages. However we also loose the house pump so no point. The Bosch works fine. No need for a remote temperature controller as the Instantaneous gas HWS delivers a constant temperature, to the current AS. Best to have the Instantaneous HWS near the kitchen and shower, which may be easy in a small dwelling.
Our Shower is a good 18m from the Bosch. We never see temperature fluctuations, or need to adjust taps even when another tap is opened. The pipes are lightly insulated. The benefit of installing a remote temperature controller may be more to the benefit of the local plumber and electrician, rather than a saving in a small amount of gas used. For one person more so.
We found installing the Bosch instantaneous gas HWS very effective, with just a short tee of the supply to the kitchen, and another short pipe to the existing HWS. Finding a gas fitter was the hardest part.
At our other abode, our gas storage HWS has a tempering valve which is an everyday plumbing fitting. They are neither rocket science or high tech. Bosch also have recommended options for their Hydropower instantaneous units.
Hi Gordon, We have a plumbing company and receive a lot of calls from clients with the hot water cutting in and out in the shower. Quite often this can be caused by them not being used to using instantaneous hot water systems and continually adjust the water. Bosch had extended warranties at one stage if you installed a controller with the unit (not sure if this is still current as they are taking their electronic ignition units off the market). The cost of the controllers is quite reasonable if it extends the life of the unit.
