Sunshine7

It's chilly here in Perth now in the mornings... I have the option of using the portable mains gas heater or the reverse split cycle system.

I know that I could probably answer my own question by switching on each appliance and watching the respective meters for a while (then finding out the costs per unit), but I was just wondering if anybody has a firm opinion on the matter ( a firm answer would be even better)? Which is cheaper to run in general?

Heat-wise, both are very good, very quick to heat up space so it really just comes down to cost. Thanks

EvannTel

As will ve cheaper in my experience.
Historically my as was 60 per month averaged over the year but electric was at least 100 without heating.

pompeyblonde

Gas all the way!! and warmer!

ozzieeagle

Quite a complicated issue since inverter system came out. IE: Heat Pumps. After trawling through lots of information over the past year whilst I made a decision re heating after my reno, I found to my surprise that it's probably neck and neck between the most efficient Gas heating System and the most efficient Electric inverter systems. Basically you need to know how the heat pumps work to get your head around this. I do know that a 5kwh inverter system only uses around 2kwh of input electricty but ouputs 5kwh of heat.

It actually comes down to the average mean temperature of where you live. If you live in an area where the average is around 12C in the winter then Electric inverter system are cheaper. If its less than 8 degrees then Gas is cheaper. Melbourne is probably an area where it would be close to even. Sydney with it's higher mean tempreatures would probably mean that inverter systems are cheaper to run. Tasmania would be cheaper for gas, if it wasnt for the fact that it has the cheapest electricity prices in Aus.


There are pages and pages of this information on Whirlpool site by people that work in the heating and cooling industries and its a hell of a lot more complicated than it first looks.

One thing for sure, you can generate your own electricity.... It's a damn sight harder to create your own usuable gas.

I'm presently having real issues over a Gas Hot Water system that I have to change. I should be buying the Electric heat Pump system... however they are damn expensive. Whereas I know I'll regret it if I buy the cheaper swap over Gas hot water system.... especially if I end up getting my electricty producing solar panels.


Long term, Gas has had it's day.

iamthecreaturefromuranus

I miss Holt's Bitter. Never had any problems creating my own gas in those days.

ozzieeagle

LOL.... although when I reread what I typed before pushing "The Button" I added the word usable.

iamthecreaturefromuranus

ozzieeagle

Just rechecked on Whirlpool and found one of the threads that goes into this subject in detail.

Looks like Reverse Cycle Air con is quite a lot cheaper than gas to run.

http://forums.whirlpool.net.au/archive/1698083

KJCherokee

When you buy electricity you pay for it in 'units' where 1 unit = 1 kWh i.e. an appliance using 1 kW operating for 1 hour uses 1 unit of electricity. 1 kW is 1000 Joules per second, so 1 kWh is equivalent to 3.6 MJ. Everything you pay for is usable (we won't go into power factors here!)

When you buy gas you are charged per MJ (megajoule) - but since your gas meter measures volume, this is converted to energy (MJ) using a conversion factor determined by the gas supplier. This is usually based on the Gross Heating Value which assumes that all the energy available in the gas is usable: since the combustion of gas produces water (as vapour) which is usually exhausted a percentage of the GHV cannot be used. This means that, unlike electricity, you don't use all the energy you pay for. Bear this in mind when doing cost comparisons.

Typically the usable energy is around 90% of the GHV.

phat-dave

gas everytime!

instead of the stupid carbon tax to lower emissions... idiot gillard should make every house built from 2012 have access to natural gas and give rebates to convert your house rather than relying on air con/heaters throughout winter/summer that use dirty old coal power stations.

ozzieeagle

A 5Kwh per hour Solar system will run most houses including their reverse cycle systems, and makes them totally self sufficient. Those systems are also coming down rapidly in price.... Around less than 12K now. They would surely be close to carbon neutral.

DadAgain

5Kw system going in to our house next week...

We expect to pull a $200 income per qtr and have no problems with our minimal use of the ducted air con. (I think we turned heating on perhaps on 1 evening last year, cooling 12 hours most nights for 3 months in summer)

KJCherokee

Some of the posts here have confusing use of units - this may sort things out.

Electrical equipment is rated in kW, not kWh. The rating shows the (maximum) rate at which it uses electricity when it is turned on.

5kWh per hour = 5kW - the hour per hour is unnecessary.

In all SI (metric) units energy is measured in joules and the rate of using energy is measured in watts, where 1 watt = 1 joule/second. So a kWh is the amount of energy required to produce 1kW continuously for 1 hour
=1000 joules/second x 3600 seconds = 3.6 MJ (megajoules).

kWh is what you pay for, kW is the rate at which you use it (or supply it from solar panels etc).

phat-dave

even better! except the solar rebate is gone as off next month isn't it?

ozzieeagle

Yes which has halved the price of Solar systems. 5Kw Systems were over 20K less than 18 months ago.

The simple fact is a 5Kw solar system is enough to power the majority of large households in Australia..... Even in cold old Melbourne.

I'd rather be self sufficient and have a small upload to the grid than rely on Government subsidies. Doesnt matter what happens to the price of electricty once your self sufficient.