Rural Heating & Cooling - Electrical Vs. LPG

Hi All,

I am keen to get your thoughts and advice on building a home to connect a rural property near Geelong, Vic that only has town water and electricity available (no natural gas). I have been reading a lot online in regards to the different options and it's pretty overwhelming. I hope that by having this discussion we can also help others who are in a similar situation.

In terms of the house build, it is on a 5 acre property just outside geelong. It will be a 4 bedroom house likely with 3 rooms rented out (meaning high use of heating and cooling).

Overall, the heating and cooling categories to consider are:

- Water heating
- General Heating
- General Cooling
- Kitchen appliances (cook top)
- Kitchen appliances (oven)

In terms of chosen items for each category, I have chosen the following thus far:

- Water heating: Still no clear choice as yet. LPG sounds very expensive and I looked at heat pump water heat (HPWH) given it's very efficient but not so for the colder Vic climate. Maybe go something solar? Something else? Your thoughts would be really appreciated!

- General Heating: I'll go wall mounted heaters in the rooms with reverse AC in the master bedroom and reverse AC in the kitchen/living area. Wall mounted heaters are very cheap to run and I'm not keen on a central system given they heat a lot of the house unnecessarily (even with different zones)/house mates who could have it on all day.

- General Cooling: I'll have fans in each room and reverse AC in the master bedroom and reverse AC in the kitchen/living area.

- Kitchen appliances (cook top): Induction cook-tops sound like the go. Reviews and discussions have been generally positive.
- Kitchen appliances (oven): I'll likely go electrical if I can keep everything else electrical so no need for LPG at all. Keen for your thoughts.

If anyone could chime in that would be a huge help!

Cheers,
Luke

Built on a rural property in alpine country, with the only service being electricity. Our solutions:

Water heating - evacuated tubes solar, boosted by electricity

General Heating - the Sun, supplemented by heat pump hydronic heating.

General Cooling - fans, but now considering some supplementation.

Kitchen appliances (cook top) - induction, plus with an LPG wok burner.

Kitchen appliances (oven) - electric (buy anything but pyrolitic and you are wasting your time - literally)

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Why haven't your thoughts considered PV with possible/probable energy storage and go all electric?

You need to spreadsheet the likely demands and look to future trends.

We have recently gone from mixture of gas and electric to all electric.

Heating/cooling is all reverse cycle except bathroom where we have a wall mounted fan heater

Ran our hot water heat pump through last winter in Dandenong, Victoria with no problems. . . . we got a biggish tank and only run the heat pump from 2.00pm to 4.00pm when we are normally generating enough power from our rooftop solar.

I have always preferred electric ovens to gas ovens and I like our new induction hob much more than the old gas hob.

LPG should be avoided at all costs as it is currently the most expensive form of heating.

As arcadelt has insinuated, much of your general heating should be done by the sun (as it's free), & powerful.

What we're talking about here is "passive solar design". Orientating your house correctly, to enjoy the benefits of northern sunshine in your living areas in winter.

More can be found here,

http://yourhome.gov.au/passive-design

To take advantage of this you need appropriate length northern eaves, not a large verandah to the north. Save them for the east, west & south.

As you're doing additional space heating can be done with reverse cycle AC.

Make sure you have a well-designed roof for solar PV, with a large north facing area. Not lots of little triangles, which is often the case in Australia. PV panels facing north will produce the most power. Panels facing east will produce more in the morning, panels facing west in the afternoon (which can be useful in summer afternoons/evenings).

Solar thermal hot water is quite expensive, & will produce much more hot water in summer than in winter. Often in winter it will produce nowhere near enough hot water & will require a lot of boosting, while in summer it will produce more heat than required, wasting that additional heat.

Just about everyone says you're better off investing that money in additional solar PV. As it can be used to power much more than hot water, & any excess be sold back to the grid.

As you've noted, heat pumps are less efficient in cold weather. Though is think they should still be fine in most of Victoria, except the Alpine. Locating the heat pump on the northern side of the home (where the air will be warmer on sunny days) will improve efficiency somewhat (I have no idea if this is recommended or not).

The cheap (installation) option that some are choosing is to use an electric (element) storage tank, heated during the day with solar PV electricity. You'll need a good sized PV system for this.

Have a look on Whirlpool's Green Tech forum for info about this, & solar PV.

https://forums.whirlpool.net.au/forum/143

I wouldn't touch LPG. It's expensive (unless you use very little gas), & bad for the environment

Very good points. I have selected a house (Metricon Kalarney 24) that has north facing living areas and am orientating the house north.

I have included eaves in my estimates and will need to use the yourhome.gov website to calculate the size of the eaves and size/position of the windows.


Interesting point as I was talking with a goodguys sales rep and given my lot is limited to single phase at 40 amps, he recommended a Westinghouse 90cm Dual Fuel Freestanding Cooker as the oven is only 15 amps and the stove top can be converted to LPG (no natural gas connection to the property). I have read 2x9kg bottles can last a few months for a family when they are just running the stove top. If I run full electric on the stove top I'm thinking I'll hit my max amps of 40 once I am running AC / washing machine / a few power tools in the shed etc.


Interesting choice on the heat pump. I was looking into the heat pump + PV solar which sounded great but a large initial capital outlay. I did read a compromise can be getting a standard electric hot water system, despite expensive to run, and then installing PV solar on the roof when the budget allows it.

What do you reckon?


Yep - I have been considering exactly that!

To heat a HWS from PV generated energy, a good option is to install a hot water relay to a compatible inverter. This makes the inverter divert excess solar generation to the HWS once a set point above the HWS element size is triggered. For best efficiency, the HWS element size should be decreased so that the inverter diverts energy earlier, giving greater utilisation and longer diversion.

For further details, seek the advice of an industry professional.

Also, don't forget to have an EV power outlet installed. The times they are a changin'.

As advised by SaveH2O, a hot water relay is a good idea. I haven't looked into them in about 12 months, but last I looked the stand alone ones (like Catch Power I think) were very expensive, up around $1,000. So may never pay themselves off. But there were relay add-ons to your solar PV inverter. Fronius, which is a well regarded inverter had the add-on for maybe around $600 from memory?

Also as mentioned, reducing the size of the electrical element in the storage tank is a good idea, to either 1.8 or 2.4kW. The lower size of element means it will take longer to heat, but there's less chance of using expensive peak grid electricity when your solar PV isn't producing enough electricity to power a full sized electric element.

Again, there's a good thread on Whirlpool Green Tech discusses ho electric hot water storage powered by solar PV, & the use of relay devices (there's even a very cheap DIY kit from the UK).