First Month With Sanden Heap Pump

TL;DR: This thing is purely awesome!

An ordinary day’s power consumption of the Sanden Heat Pump unit, marked in red lines

It’s been almost a month since my Sanden heat pump system being installed.

The unit is scheduled to start running after 9AM. It probably should start a bit later than that because my solar system can barely produce 900w of power at 9AM in late winter, if it’s sunny of course. I think it should start in the afternoon so even if it’s cloudy winter day the solar system can carry the heat pump without struggling.

But looking at the home energy chart, the heat pump probably consumed less than 2kw each day given we do a few hot showers and do other daily cooking and cleaning routines, so it’s not a big deal at all even if I don’t have solar.

Water is pre-heated and stored in the well insulated steel water tank, so at the nearest tap the hot water is almost instant, even more instantaneous than my old gas one. Guess it takes a few seconds for a gas heater to warm up its heat exchange pipes which obviously not needed by the water tank.

The unit is almost silent when it’s running. I can only identify its noise when I’m within 5 meters with it. If I’m in my kitchen, I can certainly tell if the fridge is working but not the heat pump which sits just outside of the kitchen wall.

This heat pump also works like a good combo with my induction cook top. For instance when I start to cook some noodle, I use hot water from the water tank, which is an instant boost from 10°C to 60°C. This saves me some time waiting for the water to boil and also some energy thanks to heat pump’s very high thermal co-efficient, ie. only 1/6th energy is used to heat water to 60°C, then 100% energy to heat up to 100°C.

Now I only hope this thing runs reliably and won’t have a break down. Fingers crossed 🙂

1-Step Away From Fossil Fuel: Sanden Heat Pump

Sanden Heat Pump Hot Water system freshly installed

After weeks of waiting, thanks to lock downs in Victoria, I finally have a 315L Sanden Heat Pump installed, replacing my who-knows-how old gas instantaneous water heater. The job has been done professionally by SolarFlow, kudos to the team!

I can label myself an environmentalist who keeps trying to minimize my own carbon footprint but this heat pump is also a logical and economical decision.

First of all, a heat pump works like a reverse air conditioner: it extracts heat from the outside and heats up inside. In other words, unlike gas or old school electric water heater, heat pump doesn’t use energy to generate heat but only transfer it. During my little research on heat pump products, I noticed that amongst all heat pumps Sanden stands out as the most efficient one: with 1 unit of energy consumed it can transfer up to 6 units of energy, a 600% coefficient of performance(COP)! This means comparing to my gas water heater which probably has <60% of efficiency the heat pump is a tenfold more efficient. And high efficiency means less running cost.

With solar panels the perk of being an electric appliance is that when the sun is shining, the heat pump runs(almost) for free. Just to be clear, I still need to pay for water regardless weather. With a rough calculation, I paid about 500 dollars a year for hot water with the old gas heater, so this heat pump can possibly pay for itself in 10 years. ( I found it interesting when it is a V8 diesel SUV no one asks if it will pay for itself later but people do ask this question if it’s renewable related products )

Fingers crossed though, the tank is warranted for 15 years but the heat pump itself only has 6 years of warranty.

The temperature of the hot water out of the tank feels like 60°C, which means it needs to mix with some cold water to achieve a comfortable temperature, so the 315L tank practically can supply me much more than 315L of hot water depending on the desired temperature.

Last but not least it’s also quieter when running. I could definitely tell if the gas heater was running 5 meters away from it, but won’t be so sure about the heat pump.

Overall I’m quite pleased with this upgrade 🙂

Real Life Cost of a Tesla Model 3

It’s been a bit more than 2 weeks since I got my Model 3 as a result of my impulse-buying, so as an end user I think I’m qualified to do some cost analysis and projection based on the first 1000km I’ve done with the car.

Disclaimer: The following analysis is based on my calculation with my personal data. “Your mileage may vary”. Also this is only concerning money, all those driving experience and zero emission bluff are safely ignored here.

The major saving for driving a Tesla is from the running cost, ie. ‘fuel’ cost. Though the Model 3 Long Range claims a nice 657KM range for a fully charged battery, when I do school runs with AC set to a comfortable 20 degree, the estimated range is about 540KM, which translates to roughly 15kwh/100km.

If I replaced an EV with a Tesla, the saving won’t be great. Fortunately the one got replaced is a 3.0L Diesel SUV which has an average 8.3L/100km fuel economy( and I believe that’s a pretty good one among 3.0L SUVs).

Then the saving per 100km depends on the electricity and diesel fuel prices. There isn’t any way to get around the diesel price, ie. I always fill my tank at nearby petrol station. I just grab the “Don’t pay above” price from RACV‘s data and it’s 132.8c today. The Diesel SUV costs me AUD 11.02 per 100KM.

For electricity however, there are ways to save money: midnight electricity is usually cheap, and it can go even cheaper if charging with solar power during the day. So here’s a table for cost saving grouped by different source of electricity.

The other import saving comes from the 0 maintenance of a Tesla car. Like I stated in my previous click-bait style post, A Tesla car doesn’t need to see a mechanic. For my diesel SUV, there is a major maintenance every 20,000km and a minor one between the major ones and we usually do more than 20,000km a year. Also there were cost to replace parts such as coolant or catalytic converter so for the sake of simplicity I’ll put AUD 1500/year as an average cost and the real figure could be easily bigger.

Some common cost both ICE and EV cars have are ignored, such as rego, insurance, AC filter and tyre, etc. costs.

Electricity SourceRateSaving/100kmSaving/yr(25,000km)Combined Saving
Home/Grid off peak17cAUD 8.47AUD 2,118AUD 3,618
Home/Solar power10.2cAUD 9.49AUD 2,373AUD 3,873
Super charger42cAUD 4.72AUD 1,180AUD 2,680
25,000km/yr is much higher than average but we have decided to do school runs with a car thanks to covid

On the other hand, a Tesla costs a premium and my Model 3 Long Range figure is almost AUD 90,000. My SUV can be sold for at least AUD 20,000, so it’s an AUD 70,000 expense out of my pocket. Depending on finance options, below is a list of overall saving(combined saving – loss to interest)

Finance OptionRateLossOverall Estimated Saving
Cash + 1 year Term1%AUD 700AUD 1,980 ~ 3,173
Cash + Offset2.2%AUD 1,540AUD 1,180 ~ 2,373
Car Finance2%AUD 1,400AUD 1,280 ~ 2,473
Thanks to the super low interest rate, having a term deposit is the worst thing to do.

Of course there’s a possibility that someone bought 35 BTC with AUD 70k a few years ago, and that definitely is the best investment. But other than that, buying a Tesla this year actually saves me a few thousand dollars a year.

EDIT: Another faction is depreciation of the car’s value, here’s some simple research I did with Obviously all cars depreciate and it’s best to not own one if possible 😀 but looks like Tesla depreciate slower based on samples from the past 5 years.

ModelDepreciation/yrPrice When NewLoss/yr
Tesla Model S 75D 2016~7%AUD 158kAUD 11,840
BMW 4 435i F33 2016~11%AUD 128kAUD 14,840
Cash~1.68%AUD 90kAUD 1,518
The depreciation rate was calculated roughly based on 2016 car price when new and used car price found in Cash depreciation rate is the average inflation rate of 2016 – 2020


Never Buy a Tesla

I just got my Tesla Model 3 delivered last week and I’ve added a few hundreds of KMs to its odometer. Frankly it’s largely a disappointment and I’ll state my reasons here.

First, it doesn’t have a ‘start engine’ or ‘ignition’ button at all! More to that, it doesn’t have an engine either, only electric motors. So I sit on my driver seat and shift the gear to ‘D’ with the right lever, and stepped on the acceleration pedal and it just went forward quietly. Also during acceleration there’s no delay, the instant torque is true, and there’s no gaps between gears normally with an auto-transmission car. Quite strange.

And when I said ‘quietly’ it’s really quiet, like awfully quiet. Imagine going through a parking place, the pedestrian in front of my car won’t notice given good hearing ability. I might need to roll down my window and yell ‘Excuse me’ out loud. This won’t be a problem with a normal car at all, not to mention the cars with mufflers removed.

All the buttons and dials on a car’s dash are replaced by a big tablet mounted at the center. This proved to be hard to use during driving because I need to look at the screen to see where to touch. As an alternative there are voice commands like “take me to work”, but who would talk to his car?

As the engine is replaced by motors, there’s no need for turbo, gear box, clutch, etc., so there’s no need to go to a mechanic to replace engine oil, spark plugs, air and fuel filters. Actually there’s no need to see a mechanic at all. This makes harder for me to see my mechanic friends. But maybe in 2 years I still get to see my friends at tyre shop at least.

I have to admit charging the car in the garage is very easy, just like I charge my phone at night, but with a much bigger plug. The wireless charging bays for mobile phones are a nice touch too. But again, feels like I lost the opportunities to go to petrol stations, where I can buy other nice stuff too.

And zero carbon emission? That’s just advertising right? Besides if the government doesn’t care about the environment, why should you do?

After all, I think this Tesla car is just a glorified tablet bundled with seats and wheels. However if you still insist to buy one here’s a referral link. How does this work? If you buy a Tesla with this link, you and I will each get 1500KM of super charge for free, a silver-lining of this disaster(but again, I have solar power, ie. free power, so this will be less incentivising).

Just kidding, I absolutely love this car 🙂 My mate who read my post said I don’t need to state the bloody obvious.

EDIT: My cat just expressed his disappointment too: He used to enjoy the warm hood of my previous car and it can be warm for hours after it’s parked. Now the new one is dead cold!