Gas vs Diesel fire's

caitlyn_1989, Apr 29, 2:52am
Looking at fires for a new house. help ???

comadi, Apr 29, 3:24am
Gas is cleaner for the environment.

aredwood, Apr 30, 6:39am
Have a look at what LPG is per Litre next time you are at a petrol station. LPG is still cheaper than diesel even if you are paying road tax on it as well. And Natural gas is far cheaper again.

Also please get an energy efficient gas fire. As there are no min efficiency rules for gas fires. If there were at least 1/2 of the gas fires available today would be illegal to sell. Only consider an inefficient one (which would be intended for decorative only use) if you are also installing an efficient central heating system in the house.

lythande1, Apr 30, 1:55pm
Diesel sure isn't cheap these day. and dirty.

tiny15, May 1, 5:52am
I think a litre of diesel would give you a lot more heat than a litre of gas, so maybe its not so expensive as it first looks, gas also gives off a lot of condensation. but i guess gas is real easy if you have gas mains in your street

aredwood, May 2, 7:45am
Sorry but LPG gives off more heat than Diesel. Also burning any hydrocarbon fuel releases moisture. So an unflued diesel heater (yes they exist) will be just as likely to cause condensation problems as a unflued LPG heater. So the solution is to use a flued heater. So the moisture goes outside through the flue.

Have a look at http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html In NZ what we call LPG is a 80%/20% mixture of Propane and Butane. (so you will need to have a look at both in my link.) And Methane = Natural gas.

tintop, May 2, 3:59pm
Ah - yes. But how do prices per unit of heat compare ?

johotech, May 2, 4:25pm
Diesel is cheaper by far. Compared to my bottled LPG costs, it would be about 60% of the cost roughly. Doesn't mean I would have a diesel heater in my house though.

According to my rough calculations:
LPG 20c /kWh
Diesel 12c /kWh
Heatpump 6.25c / kWh (@25c/Kw and COP 4)

tintop, May 2, 4:41pm
Thanks Joho. There is a comparison on the Consumer.org website - but it looks like my subscription has run out :(

But I remember that LPG was the dearest, and a wood burner with free firewood was the cheapest, with the others in between.

Heatpump here - used it for the first time a couple of nights ago. ( now that the house wiring has been sorted :) )

johotech, May 2, 4:49pm
I checked the consumer survey. Roughly backs up my figures.
Rough figures from their graph:
Heatpump 5.5~12c /kWh
Natural Gas 7~13c
Wood burner 9~24c
Diesel 18-21c
LPG (flued) 19~23c

My figures in the post above are the cost for the fuel only and don't take into account the efficiency of the heater itself. I guess it is possible they found that Diesel heaters aren't efficient.

tintop, May 2, 4:56pm
Cheers - Yes, my memory has not completely rotted away!

Our previous place we had a multi fuel stove, ( A Wagener Butler) but used to burn free macrocarpa. Very useful - esp with quite frequent power outages.

ira78, May 3, 11:28pm
If they're only going by cost per kilowatt hour of the fuel heatpumps should be rated at the kilowatt hour cost of the electricity. $.20-.25/kwh.

Wish I could heat my house with uranium. That works out to roughly $.000004 per kilowatt hour for the fuel. :)

melonhead1, May 3, 11:41pm
Diesel has a far higher energy density than Propane. You'll use far fewer litres of Diesel than propane to do the same amount of heating.

tintop, May 3, 11:47pm
Weight for weight Propane is better than Diesel.

http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html

tintop, May 3, 11:51pm
Heatpump 6.25c / kWh (@25c/Kw and COP 4)

johotech, May 4, 2:32am
No, they are giving figures for the cost per kWh of heat produced, not energy used.

tintop, Jan 18, 10:06am
It occurs to me that the lowest heating cost ( but capital intensive ) is to use a couple of heat pump hot water storage cylinders heated up at spot rates during the late night/early morning, and then use the stored heat as needed in the evenings.

Might do some sums on it later :)