Oven preheat - solar?

Meatballs

Has anyone measured oven electricity usage during warm up and maintaing temperature or run the numbers on this?

Wondering if it's worthwhile preheating oven before the sun goes down.

Any heating losses in winter presumably count to house heating so fairly energy neutral, but maybe not cost neutral compared to gas/ASHP.

Also would be handy to know on agile tariffs. Cheaper to heat up multiple hours early?

Verdigris

No. But I do know that using a Panasonic Combi-oven is far more efficient. In the twenty minutes it takes to warm up a conventional oven I can have cooked and eaten my dinner with a combi-oven.

I realise this only really applies to one or two people eating. If you divide the wasted heat over a family then it doesn't look so bad.

It is, of course, wise to use solar when it is available. However, in summer, when there is solar available late in the day you might not fancy a hot meal. The oven won't stay hot from mid afternoon to dinner time in winter.

Merlin139

Verdigris said:

No. But I do know that using a Panasonic Combi-oven is far more efficient. In the twenty minutes it takes to warm up a conventional oven I can have cooked and eaten my dinner with a combi-oven.

We do exactly the same, Only time we use normal oven is when we want to cook bigger items like large joints or a Turkey at Christmas.

Using it now.

QrizB

Meatballs said:

Has anyone measured oven electricity usage during warm up and maintaing temperature or run the numbers on this?
Also would be handy to know on agile tariffs. Cheaper to heat up multiple hours early?

It seems unlikely, at least for a conventional oven. My gas oven is cold within an hour of turning it off.

I guess if you had an oven full of bricks like a storage heater (or eg. a fancy Everhot stove) then it might be more practical.

Verdigris

There is very little insulation in conventional ovens because they want to maximise capacity but are constrained by the "built-in" dimensions. Even with good insulation the hot air will disappear when you open the door. As QrizB suggests, some thermal mass might help out but you've still got to "cook" that brick, which may use energy that could be more usefully employed elswhere.

Meatballs

Verdigris said:

No. But I do know that using a Panasonic Combi-oven is far more efficient. In the twenty minutes it takes to warm up a conventional oven I can have cooked and eaten my dinner with a combi-oven.

I realise this only really applies to one or two people eating. If you divide the wasted heat over a family then it doesn't look so bad.

It is, of course, wise to use solar when it is available. However, in summer, when there is solar available late in the day you might not fancy a hot meal. The oven won't stay hot from mid afternoon to dinner time in winter.

I wasn't suggesting turning it on and then off when it reaches 200C. I was thinking more along the lines of heating it up to temperature and the energy costs then associated with maintaining, say, 200C for 2-3 hours.

Verdigris

As I said in my later post, ovens aren't generally well insulated. If you want to heat the kitchen oit may be useful.

Meatballs

Just realised my smaller oven is not hardwired so I can do a quick experiment if I can be bothered to move the fridge...

Laycity

Our slow cooker has been dragged from the back of the cupboard and given a new lease of life since we got solar and battery. Prep at lunch time and put on approx 2pm, uses a lot less than a 3Kw oven and can use any available solar excess.

Meatballs

0.326kWh to heat to 200C (11mins)

10 minutes of maintaining temperature 0.11kWh so 0.66kWh every hour.

I think I've proved to myself it's a long way from being viable (unless you were on direct electric heating in the house and it was cold anyway) 😅

silverwhistle

Yep, not worth it, but certainly you need to use an oven to it's full once as you get it to temperature. Yesterday I did sour dough crackers, pecan pie, roasties, wild boar joint with root vegetables and sour dough breads at different temperatures going both up and down.

Today  I used some of the leftovers so made a mushroom sauceon top of the wood burner, and baked a potato in the stove itself. Like others I also use a slow cooker at times which is an easier way to harness solar power.