Energy Usage comparison - Large Convection oven vs. Small Counter Top ovens

IRCA

Hi all,

I have a large combo electic oven (Smeg) and gas hob (5 burners). The Oven is guzzelling electricity and as I can't aford to replace the whole thing (still want to keep the gas Hob), I am considering buying a small convection oven, around 20-25ltr capacity for the counter top, big enough to roast a chicken for example.

Does anyone a) Know or b) can point me to a resource with comparative energy consumption data for small vs large ovens as described? And which would generally be more efficient?

Currently the large oven takes approx 2 hours to cook an 1.8 KG chicken.

Any advice appreciated.

Thanks

Amateurish

By using this .. http://www.esb.ie/esbcustomersupply/residential/energy_efficiency/appliance_calculator.jsp
An average electric oven is 1kW approximately. Gas cooker oven 2.5kW.
So its costing you at most 2hrs * 2.5units * 19 cent/unit to cook your chicken. 1 euro. Possibly less than 40 cent.
There's no counter top unit listed so I reckon a microwave/oven combi is closest to what youre thinking of? At 1.6kW the two hour cooking time will cost approx 60 cent.
however...I think the small unit is bound to bleed heat out quicker so the element will be turned on for more of the cooking time. It is entirely possible it will use more electricity to cook the same meal.
Personally I think you will be a long time making back the extra expense.
Maybe have a look at the old oven and why you think its hard on power. Are seals in place where they should be?

10-10-20

Oven efficiency depends on the loss of heat over its time in use.
Simply, given two similarly sized units, a well insulated oven will be more efficient than a poorly insulated one.

But, should a small unit be tested alongside another larger comparable unit with similar insulation, the smaller unit will be more efficient as the surface-area for heat loss is less on the smaller unit.

So, in effect and given the assumptions above, the smaller should be more efficient.

Unfortunately, I don't believe that these standards are well tested and it would seem that all ovens are given an A-rating regardless of the insulation, but I'm open to correction on that!

It's also worth noting that the appliance label isn't a guide to the working consumption of the oven over time. A 2kw oven may initially draw 2000w of power, but once up-to-temperature the thermostat will turn the heater-element off and the oven will remain 'at temperature' for a period. Hence, the cumulative power of the oven won't be 2000w for that hour, but more likely just over 1300w or so, depending on the insulation.
Gas ovens by their nature suffer a significant loss as they require a vent to provide a source of fresh air to the flame, so unfortunately this causes the oven to be very effective at heating the room as well as the cooking chamber.

BryanF

OP, buy an energy monitor
you shouldn't have to pay more than 50€
once you get used to it you can clearly identify (at any given time) the base load in your house and by turning on and off appliances see their energy consumption. I find mine reasonably accurate and it has caused me to be very selective when buying any new electrical purchases.