Gas values (price and heat)

[akist]

I was trying to determine whether it is cheaper to use patio gas cylinder and a space heater, than an electric heater, to heat a room.

It turns out that the price is :

13kg patio gas refill = £55
patio heater = 12.5kW with 0.945kg/h draw
cost = 32p/kWh
space heater = 10.25kW with 0.74kg/h gas draw
cost = 30.5p/kWh

My electric is being charged at 37p/kWh (plus daily fixed charge).

So, patio gas is a bit cheaper, but if you factor in the inconvenience of lugging around gas bottles vs an extension lead, electricity wins.

********

Then I thought, what if I could tap on the mains gas supply, as we had in my previous house, there was a gas fire place connected to the gas mains.

Gas is being charged at 12.6p/kWh. How do I convert m3 of gas (as per meter reading) to weight of gas (as per gas bottle)?

 

[Madrab]

1x m3 of methane = ~ 0.671Kg

 

[Rodders53]

Don't.

Such heaters just push loadsa water into the rooms and need ventilation from outside to supply oxygen.


NB portable domestic log heaters should only use Butane I have read, and will be the clip on regulator type provided with such fires. Patio gas is Propane and clip on regulator a different size.

Natural gas fires are not very efficient either, lots of heat wasted up the chimney.

 

[Notch7]

since you will need a window open to avoid dying of carbon monoxide, I doubt the patio heater would be cheaper.

Somebody in my village used a portable gas heater instead of central heating, he had a fire, got serious burns, house had to be gutted top to bottom.

 

[Harry Bloomfield]

My electric is being charged at 37p/kWh (plus daily fixed charge).

So, patio gas is a bit cheaper, but if you factor in the inconvenience of lugging around gas bottles vs an extension lead, electricity wins.

You also have to factor in, that burning gas needs additional ventilation, plus it generates lots of moisture - whereas electric heating needs no extra ventilation. The extra ventilation, means there is even more expensive heat wasted.

 

[Harry Bloomfield]

Natural gas fires are not very efficient either, lots of heat wasted up the chimney.

Surprisingly, they claim to be 86% efficient, so only 14% up the chimney.

 

[akist]

1x m3 of methane = ~ 0.671Kg

Based on this conversion it works out as 15p/kWh.

burning gas needs additional ventilation, plus it generates lots of moisture

since you will need a window open

need ventilation from outside to supply oxygen

I forgot about that...

 

[Rodders53]

Surprisingly, they claim to be 86% efficient, so only 14% up the chimney.

Some may claim that --- others are 50% https://www.screwfix.com/p/focal-point-blenheim-brass-rotary-control-inset-gas-multiflue-fire/95952

 

[Madrab]

Only the glass fronted and OF convection LFE gas fires can claim a higher efficiency. We have an open fronted convection LFE that runs @ 68 efficiency. The glass fronted ones can run >80% efficiency. Of course these are claimed efficiencies in a perfect world/setup.

 

[fixitflav]

Gas is being charged at 12.6p/kWh. How do I convert m3 of gas (as per meter reading) to weight of gas (as per gas bottle)?

You already have the relevant figures - p/kWh for patio gas and natural gas. But if you do want to compare p/kg for the 2 gases, don't forget natural gas CV/kg is about 10% higher than propane.

 

[ianmcd]

your propane heater cant run on NG different gasses at different pressures

 

[Harry Bloomfield]

Some may claim that --- others are 50% https://www.screwfix.com/p/focal-point-blenheim-brass-rotary-control-inset-gas-multiflue-fire/95952

That type of gas fire has a reputation of being horrendously inefficient. A radiant version is much more efficient.

 

[gas112]

Dont forget heat going up chimney is not completely lost it heats up the fabric of the building and can warm rooms the chimney passes through