Hi,
I am wanting to get some thoughts on if it's worth paying the $1760 for the upgrade to 3 phase power on our new build or if its a waste of money.
Cheers
3 Phase or Single Phase Power for New Build
MrFizz on 11/07/2020 - 12:56
Comments
I do not and we won't have a pool, spa or anything like that which may draw large amounts of power.
Never going to consider a decent sized split system aircon/heater?
getting a 7kw aircon, electric oven, gas stove, hydronic heating. So a mix of gas and electric
@MrFizz: It's 2020. Don't build a new place without ducted AC.
It's a tiny additional cost on top of the building price, and is more efficient, cheaper in the long run (low maintenance), quieter, and better looking, than a bunch of splits.
And there are plenty of picky people like me who won't consider a house without ducted AC, so not having it can often reduce the value.
@ItsMeAgro: As someone living in south west Brisbane with ducted AC my opinion is almost diametrically opposed.
Why? Primarily because we use ceiling fans most of the time so a $15-20K AC installation seems overkill, a fault in the ducted AC can bring all cooling/heating in the house to a halt, and replacement of ageing ducting etc is expensive and a pain in the arse.
Some of those points may not be directly relevant to a new build, just depends on how long you stay on one place.
Our next house will preferably just have split systems in the bedrooms and one living area.
@MrFizz: For the usage you listed, you will probably never make proper use of a 3 phase supply. Single should suit you well enough. Unless you plan on getting an electric car in the future which you wanna charge up fast(er).
If you wanna run an induction cooktop, reverse cycle ducted air conditioning system, electric oven at the same time, you probably will be out of power on a single phase
Are you likely to get an electric car in the future.
I would like to but unlikely in the near future. It makes a big difference for this?
You will be forced to by government policies when fossil fuels cars are banned, as is planned in other countries
That's not gonna happen unless the government buys out all the oil companies up…
You can charge of a single phase, most home chargers are limited to either 10, 16 or 32 amps. You don't need 'high current' charging as you normally have lots of time to charge at home. But yes in my example below if you have lots of high power devices, then you might be getting close on a single phase with a EV.
Its also nicer to charge the batteries a little slower when home.
upgrade to 3 phase power
Your replies seem to say you have made up your mind already…..
Reasons for upgrading to 3 phase
- high current demand devices, pools, spas, large AC units, induction cooktops, multi ovens etc.
- Large solar feed in, each phase is NORMALLY (but not always) limited to 5kw, so on 3 phase you can export up to 15kw across the phases.
- WAY cheaper to do it NOW than later on.
Single phase will be limited to 60-80 amps depending on the area, so if you use high current demand devices, you might be getting close to this.
ie induction cooktop, plus 2 oven kitchen will pretty much use up one phase.
Thanks for all your help there.
Large solar feed in, each phase is NORMALLY (but not always) limited to 5kw, so on 3 phase you can export up to 15kw across the phases.
OP needs to work out whether they can fit in that many panels. Don't forget 3 phase inverters are always more expensive plus you need to have all 3 phases balanced.
Even on 500W panels to max out you need 39 panels. 1sqm per panel. Having that much roof, it is wishful thinking.
OP needs to work out whether they can fit in that many panels
You don't have to export at the limit, with single phase you are limited to 5kw, with 3 phase, 15kw. You could have a 8kw system and export it all, rather than export limiting to 5kw.
Don't forget 3 phase inverters are always more expensive
yes and no. It depends on what setup you end up doing.
Having that much roof, it is wishful thinking.
I looked at a place the other day for sale with 20kw on the roof, all pointing north. 2 story flat roof, couldn't see them from the ground.
This was basically 3 x 7kw systems. aka 3 inverters one for each phase.
You don't have to export at the limit, with single phase you are limited to 5kw, with 3 phase, 15kw. You could have a 8kw system and export it all, rather than export limiting to 5kw.
False economy. Why would you pay for 3 phase and export the extra at 10c?
I looked at a place the other day for sale with 20kw on the roof, all pointing north. 2 story flat roof
Flat roof. Have you seen new estates built with significant flat roofs?
This was basically 3 x 7kw systems. aka 3 inverters one for each phase.
That is stupid when you can get a single 3 phase converter. 3x single phase would cost significantly more.
Flat roof plus 3x single phase inverters. There is something seriously wrong with the owner.
It isn't a relevant example. Hardly anyone does flat roof and neither would people put a 3x single phase at least not now.
Flat roof. Have you seen new estates built with significant flat roofs?
There are more house designs out there than those you see in a cookie cutter estates.
That is stupid when you can get a single 3 phase converter
But you just said 3 phase units cost way more, so which one is it?
Flat roof plus 3x single phase inverters. There is something seriously wrong with the owner.
Such a narrow view of the world. If you had seen the place, it would all make sense. But you haven't and your narrow views limit you to the 'norms' of cookie cutter house design.
Will you ever sell?
If even one potential buyer cares about 3 phase, that might get you a slightly higher price.
Good point!
Never seen it on an ad unless for a commercial property used for manufacturing.
I didn't have this decision to make, but the last time I built a house I ended up thinking 'gee I wish I had…' for almost every thing I decided I wouldn't need.
It's easier to pay a bit now and not use it, then have to pay alot more later when you need it.
Buy once, cry once.
IKeep in mind three that there is usually a higher supply charge for three phase as well.
Also depending on your contract sometimes you are charged 3x the highest phase power not the sum of all 3 - this can be significantly higherHave lived in several properties with 3-phase, never had any extra supply charge for it.
there is usually a higher supply charge for three phase as well.
Source?
Phase 3 is meant for commercial use, is this a commercial property?
If it's a commerical property, OP can use one of the phases to power the "red light" out the front :P
240v that bad boy, only tools get 3 phase at home
3 phase.
It doesn't cost much extra on a new build, it is substantially more if you want to upgrade later.
Whatever you put in to make it 3 phase, you will get back in resale.
Minimal additional ongoing cost.
Problem is, it can be a small new build on a 300sqm block with 4 BR and 2 bathrooms which means single phase is enough.
Or you talking about a new build on a 1000sqm block and it is 600sqm floor space.
At OzBargain what seems like a bargain isn't if you put it into correct context.
It is easy to spend other people's money, key strokes are cheap, hard cash isn't.
I'd agree that you may as well get it (when I built in 2009 it was only about $600 extra) but I didn't bother. I got a quote recently on upgrading to three phase which came in at about $1500 so it's not significantly more.
It's a good idea for a larger solar system but otherwise, it's not really necessary for most users. I have an induction cooktop, pool, three split system air cons (including a 7.2kw/8.0kw) and I've never had any power issues running all three at the same time.
I understand what you are saying but there is false economy out there.
Solar - the payback is short if you can get a grant + you use the power. A 6kw system generates about 18KwH per day in winter. 5Kw is the feed in limit on single phase. After rebate in Victoria probably cost $1k which makes a no brainer. Without a rebate would cost about $5k to save (18kwh x 365 x 0.2 per KwH) payback will be 3 - 4 years. If you go twice the size it is an extra $5k but whether you use that or sell it back at 10c per KwH. At 10c payback would be 8 years.
Some people talk about future proofing but home appliances have got more energy efficient, it is just people have scaled up. Instead of buying the 2Kw air con for the lounge they've decided to get the 7Kw to cool down faster or build bigger lounge rooms. Each to their own (people can decide) but let me point out people are consuming more yet we live on a planet that isn't getting any bigger.
You're naive in believing in energy efficiency, it's all about induced demand. Looks at the computer electronics, we used to be awed at pentium 4 or 4g speed but it just never stop there, a 20 year old mobile phone probably only need a recharge once a month with today battery but most phone nowadays barely last over a day despite being a lot more energy efficient in terms of pure functionality (talk and text). Same goes for household energy, electric car is one of such foreseeable sucker of power, next minute you'll see a 3 phase instantaneous electric hot water that will draw nearly half of today's single phase limit.
I got a quote recently on upgrading to three phase which came in at about $1500 so it's not significantly more.
Was that all up including the power company costs to run a new line in etc and the fuse board upgrades etc?
Seems very cheap.
Unless I'm misunderstanding something - the power company doesn't need to do anything in terms of running the line from the street to my house. My electrician said he'd open up the services pit on the footpath and attempt to run it through the existing conduit and if he could, then it would be about $1500. Naturally if you need to dig a trench, new conduit etc that will increase the cost but my electrician was confident it would be fine, as my house was built in late 09. I didn't bother though - I'm quite happy with 6.48kw of solar panels (5kw inverter due to single phase limit) and never have any power demand issues.
@akyeeeahdude: If its true, it is a steal!! I only ask as I'm not sure about QLD, but in VIC everything back from the meter (including the meter) is normally looked after by the grid wholesaler for disconnect/connect etc. Your electrician isn't allowed to just hook up the extra phases to the street.
Plus you'll need a meter replacement from single to 3 phase, and some balancing of the loads by moving circuits around to spread the load over the phases in your power panel.
Its a strange mix, the wholesaler will disconnect your power, the electrician can do most of the work etc, the wholesaler comes back to inspect and if happy they reconnect.
The wholesaler will be the ones connecting and at least inspecting the line being ran between the street and meter.
I went through a single phase mains upgrade when adding a 32amp load, the electrician found finding out my cable between the meter and street lines was a mix of 40amps internally and 80amp external, on a 80amp breaker. The external cable from the street was replaced at some point. Lucky it was picked up before maxing out that poor little cable.
A quick google seems to say QLD has similar fees for these services on top of the electrician
https://www.energex.com.au/__data/assets/excel_doc/0010/8362…
Service upgrade. For example, an upgrade from single phase to multi phase and/or increase capacity. Excludes work on metering equipment (if required). Overhead ~$1000
We have a 300sqmt (living area only) house with reversa cycle ducted air-con to 7 zones and a separate 2.5Kw split system. In-ground pool and solar each running 1Kw pumps, as well as your normal house-hold appliances. All on a single phase supply with no issues.
That is because you don't run everything together at once. A lot of people are just jumping at shadows.
I do quite enjoy the idea of paying $1,500 so they can get extra 10Kw of solar export at 10c - 12c per kilowatt like solar panels and inverters grow on trees.
How would you possibly know what our situation is to make such a wild claim??
FYI, on a summer day we will typically have the aircon running at full steam, both pool pumps running, 2 refrigerators running, (at least) 2 TV's and 2 PC boxes running.The comment wasn't specifically pointed at you. Simply put electricals don't work out loads on the basis that you have every appliance running at once.
I did not ask you to give details. In addition you don't have a typical family usage therefore it goes to show single phase is enough and most people are just having a laugh going for 3 phase.
If given the choice I would do it purely for solar feed in.
No, if that happened I would just make up a battery bank.
You would but would the OP make their own power bank.
Just double check with your electricity supplier if you will be billed a standing charge for each phase/meter. If yes, then not worth it.
just pay for and be done with it, with new build almost certain the cable main will run underground and if it is to be upgraded in future, it can cost 5 times as much if dig up required
We've just built a house - 250m2. We have ducted AC (the largest single phase system was sufficient), a spa and electric oven (which are never all on at the same time),gas cooktop, along with a 6.6kw solar system and solar hot water.
Cost to upgrade was quoted at about $1700-2000 - it wasn't worth it for something we will never need.
3-phase. Though it didn't cost me any extra. Though I did pay $2700 to have it run under the road instead of back overhead.
Ducted aircon is only worth it if your house is inefficient. We have a 300sqm house with just a single 9kW reverse cycle aircon split. We put in underfloor electric heating in the bedrooms and bathrooms and ceiling fans in all bedrooms. Means there is no ducting, means clean ceiling space, no dust buildup in ducts. Keeps the living envelope of the building better sealed for better heat/cool retention. A big ducted system would only be used to compensate for poor quality inefficient build.
Pretty typical in this country where people would pay $4k for ducted heating but wouldn't pay for double glaze or better insulation.
Double glazed will cost 10 times of that
Three phase- Future proof your investment.
Didn't know home appliances are going 3 phase? If anything homes are getting more energy efficient not less.
Or just expecting to be growing vegetable hydroponically?
3 Ø, because you (or a future owner) might want to get into metalworking and install a lathe/mill, and secondhand 3 Ø equipment is often "given away" by factories closing down
If you are considering a decent solar system, then yes. You get a single 3 phase meter so no extra cost.
Thanks everyone for your insights. Genuinely appreciated.
We decided to get the 3 phase power upgrade. No, we don't need it now but I am pumped at the idea of getting an electric car down the line and I believe when we sell the house in a number of years, 3 phase power will be more in demand due to there being more electric drivers on the road.
Cheers!
Do you have any 3-phase equipment ?