Will it cost much to have my gas oven on all night in the UK?

August 11, 2017 9:18 AM

Will it cost much to have my gas oven on all night in the UK?

I’m from Canada and used to electric ovens and Canadian electricity prices, so I have a potentially odd question: If I set my gas oven to gas mark 1 or 2 and have it on for 12 hours, will that cost much? Like, how much higher will my landlord’s gas bill than otherwise? Are we talking pence or pounds or even more?

posted by chudmonkey to Home & Garden (14 answers total)

Everywhere I have lived (albeit not in the UK) gas has been far less expensive than electricity.
posted by slkinsey at 9:24 AM on August 11, 2017

It all depends how well the oven seals, but I'd say that at a low level, it's using at most 1kW, so 4p an hour. So I'd say 50p a time is realistic.
posted by ambrosen at 9:26 AM on August 11, 2017

This is extremely dangerous. Gas ovens don't have safety features to avoid carbon monoxide poisoning. It's also very inefficient.
posted by caek at 9:28 AM on August 11, 2017 [16 favorites]

Hasn't everyone in the world switched from carbon-monoxide-containing coal gas to safe natural gas?
posted by artistic verisimilitude at 9:34 AM on August 11, 2017 [8 favorites]

I may have left my gas oven on overnight a time or two after pulling the pizza out.

It doesn't cost that much - gas is really cheap, and ovens don't run all the time unless you have the door open.

But you can figure out the cost pretty easily. A therm is 100,000 BTU. Here, it's about $.30/therm so my 25,000 btu oven will use 1 therm every 4 hours and 12 hours will cost about a dollar.

That being said, unless you're using the oven and attending to it, it's dangerous to leave it on - CO is dangerous and of course, there is a fire hazard.
posted by Pogo_Fuzzybutt at 9:41 AM on August 11, 2017 [3 favorites]

Yeah, if you have a well sealed house, leaving an oven on for extended periods could cause carbon monoxide buildup, but if you live in a relatively drafty place it isn't likely.

Natural gas burns fairly cleanly, so unless there is a lack of oxygen due to the environment or a poorly adjusted oven burner, the risk is low. If you're actually watching it, you can easily see the difference between a yellow oxygen starved, carbon monoxide producing flame and a fully blue completely burning natural gas flame.

Many of us grew up in houses that had open flame gas space heaters for winter heating and managed to live through it without carbon monoxide poisoning.
posted by wierdo at 10:07 AM on August 11, 2017

I think ambrosen is about right with the cost, but I will add that most gas ovens are not too accurate at temperature control, several hours at gas mark 1 may actually be more like gas mark 3 or 4.
posted by Lanark at 10:34 AM on August 11, 2017 [1 favorite]

Your landlord is also obliged to have a carbon monoxide detector and annual gas safety checks. Hopefully those are in place, but I'd say that even without, it's very unlikely that this is dangerous.
posted by ambrosen at 11:16 AM on August 11, 2017

artistic verisimilitude: "Hasn't everyone in the world switched from carbon-monoxide-containing coal gas to safe natural gas?"

What an outlandish idea. Carbon monoxide comes from the incomplete combustion oxygen and hydrocarbons, regardless of their origin. Of course it can come from burning natural gas. Look.

Carbon monoxide detectors are fairly inexpensive and good to have around.
posted by exogenous at 11:17 AM on August 11, 2017 [3 favorites]

Not that outlandish, domestic gas at one time was synthetic and contained a significant % of CO at source, hence the "suicide by head in oven" trope. But yes, these days the CO risk is only from incomplete combustion.

For what its worth, published recipes which call for a low overnight roast don't include any special warnings that I've noticed, presumably on the assumption that you won't be sleeping in the same room as the oven.

I concur on the cost estimate above, and the legal requirement for landlords to fit CO detectors.
posted by wilko at 11:33 AM on August 11, 2017 [2 favorites]

Response by poster: Thanks everyone! I’m making Devonshire cream, and it needs low, steady heat for 10-12 hours. I’ll crack the window in the kitchen to minimize CO danger, but the house does have detectors and a full complement of safety sensors and equipment so I’m not worried. If this is my last-ever post and you hear about a house fire in Stretford, Manchester just know that I died doing what I love: imagining scones.
posted by chudmonkey at 11:49 AM on August 11, 2017 [28 favorites]

If it's a one off (as opposed to "my boiler is broken and this is my plan for heating the house") it's not going to cost like hundreds of pounds and it's highly unlikely the landlord would notice.
posted by EndsOfInvention at 12:28 PM on August 11, 2017

As a data point we have an unvented gas fireplace in our house, along with a gas range. We have a carbon monoxide detector in the same room as the fireplace. We were told that running the fireplace for several hours should be safe (considering the size and draftiness of our house) but if we started seeing condensation on the walls we should open a window for fresh air. One very cold Christmas (where every gas burning thing was going at once) we did, in fact, see condensation on the walls, but that didn't present enough of a CO concentration to set off the alarm.

You should be OK. If you notice everything getting damp you might have a problem.
posted by fedward at 1:33 PM on August 11, 2017

My understanding of making Devonshire cream involved letting it sit for 6 to 12 hours (depending on room temperature), then heating it until rings form on the surface, removing it from the heat and leaving it in a cool place for 12-24 hours. As described here.

I've not heard of a recipe that involves heating it for 12 hours, so you may not need to worry about running the oven overnight?
posted by knapah at 4:45 PM on August 12, 2017