Electrification for homes with limited power connections

If you want to ditch gas but your home has a limited electrical connection, what are the options?

Here at Renew we encourage readers to eliminate their gas connections as soon as they can. Moving away from gas has so many advantages, including removing the gas supply charge, eliminating local greenhouse and particulate emissions, and greatly improved safety.

At time of writing, the gas supply charge varies from 27 cents to $1.65 per day, depending on your location, energy supplier and the plan you are on, or $98.55 to $602.25 a year. Only WA has typically cheap supply charges, as low as 15 cents per day on some seniors plans.

So, for most people, the supply charge savings alone are going to amount to several hundred dollars a year—a nice little sum to have back in your pocket.

Then, of course, is the elimination of greenhouse emissions and localised pollution—gas is a fossil fuel, after all. While you can’t see it (the particles are too small to see), burning gas produces not only CO₂ and the vastly more dangerous CO (carbon monoxide), as well as nitrogen oxides, it also produces PM2.5 particulates (particulates smaller than 2.5 microns, or 0.0025mm). These particulates are small enough to enter the bloodstream in humans when breathed in, and have been implicated in all sorts of health issues, from heart disease to cancer. Eliminating those risks should be a high priority for anyone with a gas connection!

And, of course, there is safety. Barely a week goes buy where there isn’t a house fire or explosion caused by leaking natural gas or LPG. A leak doesn’t take long to fill a room with an explosive mixture, with the inevitable violent result when the mixture is ignited by electrical devices or an open flame. The only thing stopping this happening is the single little rubber O-ring around the metal shaft of each gas burner control on your gas stove or heater—any seal failure will result in a leak. Why would you risk that?

Lastly is regulatory changes. For example, in Victoria, as of 1 March 2027, if a gas hot water appliance breaks and cannot be repaired, it must be replaced with an electric alternative. While Victoria is the first state to implement this requirement, we expect others to follow in the future.

So, you want to take that step and remove your last gas appliances, but you have one big problem—the electrical connection to your property isn’t adequate to handle several high-powered new appliances such as an induction cooktop, electric water heater and electric heating. So how do you get around this?

Heat pumps
Well, the last two on that list are easily solved by the same technology applied in different ways, and that technology is the heat pump.

Heat pumps don’t make heat, they simply take it from one place and put it in another. It’s what your fridge does (takes heat from inside the fridge and dumps it outside, which is why the fridge is warm on the outside) and heat pumps can be applied to pretty much any domestic situation where you need a source of heat—hot water, space heating and even clothes drying.

We have written a lot about heat pumps over the years, but briefly, a heat pump will typically move around four times more heat energy than the electrical energy it consumes (this is called the coefficient of performance, or CoP. In this example, the CoP would be 4). This is what makes them so economical compared to devices that produce heat directly from electricity, where the ratio is a straight 1:1.

The more efficient a heat pump, the less energy it uses for a given task, but with a restricted electrical connection, you need to look at not just the energy consumption and efficiency, but also the peak electrical load the heat pump presents to the grid. Generally, the more efficient the machine, the lower the power draw for a given output capacity rating.

Electric hot water
As mentioned, the most efficient all-electric hot water system is the heat pump, and the most efficient of those are the CO₂ (R744) units—the CoP is often around 5 for a CO₂ unit—followed by units that use propane (R290), which can have a CoP between 4 and 5.

If you live in a sunny location, you may be better off using a solar water heater—either a conventional thermal unit (with collector panels that gather heat directly from the sun) or a direct PV unit, which uses a dedicated solar array to heat the tank. Both of these systems will use a mains-connected electric element as a backup.

While the element may not see much use for much of the year, in the colder or cloudier months it may have to supply a good proportion of the hot water requirement. Often, the element fitted is in the range of 2400 to 4800 watts (with respective current draws of 10 to 20 amps), but you really don’t need something that large—and the same applies even for a standard electric storage water heater without solar input.

For example, a 1200 watt element, running overnight on off-peak electricity (when house demand is typically low anyway) for, say, eight hours, can produce 9.6kWh of heating—enough to heat 200 litres of water from 20°C to 60°C (excluding any thermal losses). So, even on a day where the tank starts off almost cold, a typically sized tank will be fully heated, or close to it, by such an element. Add in a few extra hours of heating in the middle of the day (from your solar or even free electricity from the Solar Sharer Scheme) and even a large tank can be fully heated from cold by a small element.

Remember, hot water is drawn from the top of the tank, where the hottest water is, so unless you are using an entire tank’s worth of hot water each day (unlikely), then the element should keep up easily and you should never experience inadequate supply of hot water.

A 1200W element draws just 5A continuously—a small load even for a severely electrically restricted home, showing that water heating is not the huge power demanding load that it has tended to be envisaged as—a simple bit of common sense and a reduction of element size, combined with a timer, can eliminate this issue.

Should you have particularly large hot water requirements, then upsizing to an 1800W element should cover any eventuality—1800W (7.5A) will heat 300 litres from 20°C to 65°C in around nine hours (excluding tank losses). It’s just a matter of doing a few calculations, making sure you have water saving devices and fittings to reduce hot water use, and installing the appropriate element in the tank, controlled by a suitable timer.

However, it’s not standard practice to use small elements in larger tanks, so you may have to gently persuade your plumber/electrician that such a setup will indeed work. Just show them the numbers (there’s a water heater calculator at omnicalculator.com/physics/water-heating that is simple to use.
However, manufacturers are now offering more flexible options, such as the Thermann Smart Electric Storage water heaters, which come in sizes from 80 to 400 litres, with elements starting at 1.8kW (the 1.8kW is available up to the 315 litre model).

Remember, as an example of using lower power inputs for extended periods, a direct PV hot water system is usually connected to a 2kW to 3kW solar array, which would average under 2kW input throughout the day, and yet it will easily heat a typical tank to the correct temperature over the course of a sunny day—which proves that the slow and steady method works just fine.

Electric heating
In gas-heated homes of yesteryear, it was common for massive gas heaters to be trying to heat a thermally leaky home, simply because, when the systems were installed many years ago, gas was cheap and so little or no thought was given to the efficiency of the home or the running costs of the heating system. Now that the days of cheap gas are over, a bit more effort needs to be put into heating options as homes transition to electric heating.

For an all-electric home with a limited power connection, the primary source of heating (aside from any passive solar gain, if your house happens to be designed and oriented correctly to take advantage of it, which most aren’t, and as much insulation and draught sealing as you can realistically undertake and which should be done first) will be the most efficient reverse cycle air conditioning you can get.

This means no ducted systems, as they are notorious energy hogs—heating an entire typical [leaky] home requires a lot of energy, regardless of the energy source. Instead, look at single- or multi-head split systems, which can have CoPs close to 5 or even greater, although this depends on the outside air temperature—even the best air conditioner will have a lower than rated CoP when the outside air is close to or below freezing, and will freeze up periodically and need to run a defrost cycle (because water from the outside air condenses on the outside coils and then freezes), during which time you get no heating.

So, selecting the most efficient units you can afford, not oversizing them too much (larger units generally draw higher instantaneous power, although they will cope better in very cold weather for a given space size to be heated) and being a bit selective about which parts of the home are heated, can greatly reduce the energy demand and maximum instantaneous power requirements.

Having said this, if you are renting and/or the home is particularly leaky, then space heating is not the most effective way to go—trying to heat a leaky home is like trying to fill a bucket that has a big hole in the bottom. You are better off with more localised heating using radiant heaters, either high temperature “bar” type heaters, or far-infrared panel heaters. Because these are plug-in type heaters, they will never exceed 10A of current draw, and most of the time you can run them at a lower setting.

Either type can still use a lot of energy if used excessively, but you can feel much warmer sitting in front of a 1000W radiant heater than having a 6kW reverse cycle air conditioner, drawing 1.5kW or more, running full blast trying to heat the entire space. After all, you really only need to heat yourself a lot of the time.

Radiant heaters have evolved somewhat in recent years. Far infrared panel heaters range from under 100 watts to 1200 watts or more, and produce a low level, very longwave infrared heat that penetrates well into humans for effective, subtle heating. A small under-desk 200W (less than 1 amp!) heater can easily keep you warm in a cold room.

Radiant bar heaters have also changed in recent years. While they are still common in older heater designs, nichrome (an alloy of 80% nickel and 20% chrome metals, hence the name) wire elements, which are prone to developing hotspots and eventual failure, are slowly being replaced by sealed glass carbon fibre filament heater elements. These use a spiral wound carbon filament “rope” contained inside a quartz glass tube. They don’t suffer from the fatigue and oxidation problems of metal-based elements and so have quite long lifespans. They can also be run at somewhat lower temperatures, producing longer wavelength infrared rays, which heat you better than the higher temperature units. The lower running temperature also means less energy is wasted as light, and they are sometimes marketed as “low glare” heaters. Further, rather than using multiple elements for different power levels, carbon fibre elements can be driven directly at different power levels—at lower powers, they barely glow at all, producing nothing but heat.

Many modern radiant heaters also have inbuilt timers, so they can be set to turn off after a set period, ensuring they are not left on accidentally. Remote controls are also now common.

So, if you decide to go for radiant heating, look for carbon fibre filament units, they are on par with wire element types cost-wise, but have a nicer feel and longer lifespan, although they can be harder to find.

Personal heating
As mentioned, in a cold, leaky home, the only option may be heating the occupants, not the space. While smallish radiant heaters can be used for this, you can reduce the energy consumption even further by personal heating using devices designed specifically to heat a person. Examples include heated floor mats, heated blankets and throws, heated cushions and even heated clothing.

Personal heating not only draws very little power—for example, a typical heated blanket may max out at just 150 watts—they also have safety features such as overheat sensing and, often, timers that switch off the heating after a set time.

While personal heating has the drawback that the air in the room stays cold, which can pose a health problem for some people due to issues such as condensation, there are situations, especially in older homes, where it’s just not possible to have effective space heating that’s within the occupant’s budget due to the high levels of continual heat loss in the home. Also bear in mind that most condensation happens on windows—you can greatly reduce this issue with something as simple as bubble glazing—bubblewrap stuck directly to the glass to insulate it.

Cooling
When it comes to cooling, you have the same options as any other home—air conditioning or fans.

If you installed a high efficiency reverse cycle air conditioner for heating, then you probably have a reasonably thermally efficient home and so already have a capable cooling system. If you went with another form of heating then you may be best fitting a small reverse cycle air conditioner in a single room to create a cool refuge for those extreme summer days and use high efficiency ceiling or floor fans for general comfort. Even something as low power as a Coolzy personal air conditioner is enough to create a cool refuge, unless the home is a complete hotbox nightmare. If this is the case, then you are going to have to improve the thermal performance of the home, and stick with fans and minimal clothing to stay as cool as possible.

Of course, the amount of cooling will depend on the house’s thermal performance, level of shading, and location. Don’t underestimate the efficacy of good shading—keeping the heat out means there’s no need to remove it at all, so a few well-placed shade sails and screens can make a huge difference to the thermal comfort of a home, greatly reducing the need for large, power-hungry air conditioners.

Cooking
One of the largest instantaneous electrical loads in an all-electric home—and one of the biggest roadblocks to going all-electric—can be the cooktop. With the move to induction, typical maximum loads can be up to 7000 watts or more, depending on the cooktop. This means that the cooktop may need a dedicated circuit rated up to the entire capacity of a power-limited home—32A to 40A.

Obviously, this isn’t possible, and it’s not even legal to install circuits that large in homes with such limited power connections. So, how do you get around this?

Well, for a start, it usually isn’t necessary. Many induction cooktops are installed with more circuit capacity than is required. The Australian wiring rules (AS3000, specifically, table C5) provides a recommended circuit size (in amps) for cooktops of different maximum power, taking into account that users will almost never use all of cooktop zones at maximum power and, if they do, it would not be for very long. This means that many induction cooktops only need a 20A circuit, but many electricians don’t seem to know this!

Another possibility is a portable induction cooktop, which is designed to plug in to a 10A powerpoint. Being limited to 2300W, they are no different to any other high power intermittent load, such as a powerful vacuum cleaner or other appliance.

But, what if you want a full four-burner integrated cooktop unit? Well, there’s a solution for that now too, in the form of power limited induction cooktops.

These look like a standard cooktop but are designed to limit their power draw to just 2300W by sharing the available power between the in-use burners using a bit of electronic smarts to send the heat where needed without exceeding a total current draw of 10A. These units are marketed as “low power induction” or “induction with power phasing” or similar marketing speak. They are easily recognised as they come with a standard 10A, three-pin power cord and plug. There are several manufacturers of these units including Omega and Haier, and they are now readily available from most appliance suppliers.

If you have been told by your electrician that induction is impossible in your home due to the lack of a capable electrical connection, just point them at these cooktops as they need to be aware of them.

Ovens present a particular problem—built-in ovens can draw as little as 2000W or up to 10,000W depending on size and features. For power restrained households you may have to compromise and get a lower power unit. Alternatively, don’t go with a built-in oven at all, use a benchtop unit instead as they are limited to 10A. You can also do a lot of oven cooking in an alternative appliance such as a microwave oven or air fryer.

Electric vehicles
One of the biggest steps in the electrification journey is the shift to an electric vehicle. While it’s nice to have a 3.6kW or even 7kW charger for your EV, the fact is that, for most people, it really isn’t necessary—the average person travels less than 50km a day, or about 8kWh to 10kWh of charging per day.

Generally, your EV will charge either during the day from excess solar, or at night from a cheap electricity tariff when there are few other loads on the house’s electrical supply. Many EV owners simply use the plug-in portable charger (often called a “granny” charger) that came with the vehicle, which is usually rated at 10A (2300W) maximum. You can even get plug-in chargers with adjustable current ratings—my portable charger can switch between 6A, 10A and 15A, for example.

You may also be able to charge at work if you use your car for commuting, or at the local shopping centre when you do the weekly shopping, or even at a nearby fast charger, if you are willing to pay the somewhat higher electricity tariffs applicable to most fast charger stations.

Smart appliances
Part of home electrification with a limited power connection is the prodigious use of timers and smart controls to limit when certain devices can operate, and to avoid operational overlap of loads that would exceed your connection limit.

Generally, in order to leave enough overhead for the common household appliances like fridges, kitchen appliances and entertainment equipment, you will need to ensure that the “background” load, i.e. the load that happens without you controlling it, such as water heating, operates at times of least demand—usually overnight in off-peak hours.

Making sure that all of your appliances can fit safely within your home’s maximum power rating might take a bit of planning, and the judicious use of programmable timers and some smart energy control.

Smart energy management
However, for homes with limited connections, some form of home energy management system may be required to limit maximum power draw, so that you never exceed your connection’s capacity. These can range from simple systems designed to provide you data so that you can manage your consumption in real time, through to advanced, integrated systems that can control any number of fixed loads to keep total load within the connection’s rating. We won’t go into details of energy management systems here as it can become quite involved, but such systems are commonly known as EMS (energy management systems) or HEMS (home energy management systems).

Note that a HEMS is not the same as a home automation system. The former is more about data gathering to reduce consumption, costs and emissions, while the latter is more about implementation and control of electrical loads, regardless of the reasons for doing so. The two systems are often integrated to enable a specific outcome, such as to maximise comfort, energy efficiency or, in the case of this article’s subject, to limit maximum power draw.

However, as far as we could find out, there hasn’t been much development of systems specifically to limit grid load to a specified limit using these systems, and so it may be a bit of a learning curve for you and your electrician/installer to develop a system that works for your situation.

Energy storage
While your grid connection may be limited, you don’t necessarily have to power all of your loads from the grid directly. Energy storage can provide supplemental power at times of high power draw to allow you to power heavier loads without overtaxing your grid connection.

With such a system, the battery would charge from solar or off-peak grid power when house demand is low, with the battery stepping in at certain times to provide those high loads when needed.

However, there are limits to what can be done using this method, as wiring regulations require that your grid connection still be able to run all loads if the battery goes flat or is otherwise non-operational.

One way around this is to wire the system such that some loads are connected purely to the battery’s output, and so become unavailable if the battery is flat.

Electrical upgrades
This is one of the more obvious solutions—to simply upgrade you home’s electrical connection to meet your requirements—although this article was written to address ways to avoid this expense. But if it becomes a requirement for your electrification journey, it may involve moving to a heavier duty single-phase connection, say 63A or 80A, or even going the whole hog and upgrading to a three-phase connection (generally, domestic dwellings are limited to 80A connections per phase, so it’s usually not possible to go past 80A, or in some cases, 63A).

A single phase upgrade may mean a new cable from the street to the house, plus a new service fuse (the fuse in the box mounted on the side of the house where the street cable enters the house). Cost and difficulty will vary depending on cable length, whether you have an above ground or underground electrical connection, and even your energy company.

The wiring to the house’s breaker panel may also need upgrading, as most likely will the panel itself—many homes have a panel with minimal spare space for extra circuit breakers for additional circuits as you add more electrical devices.

All of this will need to be assessed by your electrician and you or your sparkie will need to talk to your electricity company as to whether an upgrade is even possible.

There may also be other reasons why an upgrade isn’t possible, especially if you live in a flat or townhouse where the connection to the site limits the allowable connection to each dwelling.

Regulations
The Australian wiring rules (AS3000) sets expected loads for specific situations (number of lights, power points, cooking and water heating devices etc). There are several online calculators based on the wiring rules that allow you to calculate your likely (and legal) maximum load that can make deciding on your next move to electrification much easier:
ausinet.com.au/maximum-demand-calculator
jcalc.net/maximum-demand-calculator-as3000

There are a number of derating requirements in the wiring rules as well. For example, short, intermittent loads are acceptable up to the maximum circuit rating, but long term loads such as EV chargers, for example, should have a 20% derating applied. For example, a 230V, 20A (4600W) circuit should be derated to 3680W for long-term loads.

Ideally, the wiring rules would be available to everyone free of charge, rather than having to be purchased (the AS3000:2018 wiring rules document costs around $273 in digital form!). At the time of writing, a change to the availability of the rules to the general public is being considered by the federal government, but it has yet to occur, so you will need to consult with someone who has a copy of the rules and understands their requirements—your electrician.

Conclusion
For many homes, full electrification may be difficult without some careful planning, appliance upgrades and some level of load control and/or automation. And, if unavoidable, you may need to upgrade you connection to the grid. But the advantages far outweigh the hassle of getting there, in both reduced energy costs, reduced domestic greenhouse emissions, and flexibility of energy sources, especially when you add solar and energy storage to the mix.

Resources
Getting off gas toolkit: gettingoffgastoolkit.com
Rewiring Australia: rewiringaustralia.org
Green Building Council Australia: gbca.au
New Victorian electrification and efficiency standards and regulations: tinyurl.com/47xwfb9u
NSW Climate and Energy Action website: energy.nsw.gov.au