Freezer uneconomical?

oxters

Hello

I have an ancient (40 years old) large chest freezer in my garage which is extensively used and has never missed a beat. Obviously it can't be efficient and recently I started to take part in an Energy Monitoring Project which gives a read out of my electricity use over a period of time. During the night when almost nothing else is on apart from 2 sky boxes on stand by, my use peaks every 45 minutes or so from 300 watts to around 700 watts having been at a higher level for around 15 minutes. The stat is set pretty low.

I am sure this must be the freezer motor cutting in.

My question is : How much more efficient would a new freezer be and would I recoup the outlay over a reasonable period of time.

Any advice greatly appreciated

Premier_2

You need to be careful here.

A freezer is essentially either on or off (apart from the initial high momentary consumption when the compressor starts)

My guess is that only the difference between 700W and 300W (i.e. 400W) is what the freezer is actually using (for the 15 minutes periods you speak of).

A new one will be more efficiecient, but not by much. It might use a little less electricity when the compressor is running, and improved insulation/better heat exchange may mean it runs a little less often.

I've no idea on the price of a new chest freezer (£300?) but your current one has lasted you 40 years (and still going strong) - you'll be lucky if one built today will last that long.

If it's not bust, don't fix it.

csnann

I don't know about chest freezers but I have been looking at fridgefreezers and new ones seem to use around half the energy my old one does!

dannymccann

I'm with Premier, lets say your freezer uses 400w for 15 minutes, 10 times a day. Over the course of a year that is (100w [400/4] * 10 * 365 / 1000) 365kWh, @ 8p/kwh = £29.20 in electricity a year. The cheapest chest freezer on Tesco is £305, and uses 248kWh (apparently), under optimum conditions etc etc, so £19.84 ish cost to run a year. Bear in mind it will also probably be a lot smaller than your Ice Age chest freezer.

On running costs alone you are looking at a saving per year of £10, meaning the cheapy Hotpoint would have to last 30 years to payback its price based on running cost savings alone - and you could bet your house that it wont last that long.

Sooler

Do you need a freezer at all? If you have a shop convenient then use that as your freezer, let them store the food, you just go in and buy it when you need it

Cardew

I have a large oldish(12 years?) Bosch freezer in garage.

Checking it with a power meter over a couple of weeks it uses 7kWh a week in winter and 8kWh in summer; so about 380kWh a year - £35ish.

I would think a 40 year old freezer would use a bit more.

So if it is working! keep it!

oxters

dannymccann wrote: »

, lets say your freezer uses 400w for 15 minutes, 10 times a day..

But that's the thing. By my reckoning it's cutting in a lot more than 10 times a day!

Anyway, I also have one of these individual monitors and I've hooked it up to the freezer and will check out its consumption over a 24 hr period and also over 7 days. The stat is at minimum and I think it's the stat that could be faulty/too sensitive.

If I could get that fixed I'd happily stick some polystyrene panels around it to improve the insulation (it's in the garage so who cares what it looks like?) It's a huge freezer and we buy up loads of stuff in the supermarket when it's reduced to give away prices so even if it's old and a bit dearer to run it's saving us a fortune (I hope - monitor will tell) I'm sure we'd be a lot more than £300 for a replacement. (It's a Philips by the way and they don't make 'em like they used to)
Many thanks for the replies so far, I've ticked the boxes.

Cardew

oxters wrote: »

But that's the thing. By my reckoning it's cutting in a lot more than 10 times a day!

Anyway, I also have one of these individual monitors and I've hooked it up to the freezer and will check out its consumption over a 24 hr period and also over 7 days. The stat is at minimum and I think it's the stat that could be faulty/too sensitive.

If the stat is faulty the compressor tends to run all the time - or not at all and you have a stinking mess inside. (Happened once when we were on holiday when power tripped out!!!)

Have you got a freezer thermometer - it should be around -18C to -20C.

Post back your consumption figures please.

oxters

Cardew wrote: »

Have you got a freezer thermometer - it should be around -18C to -20C.

Post back your consumption figures please.

Thanks for your interest Cardew

We do have a freezer thermometer but have been unable to locate it meantime!

You asked for the figs and here they are.

The appliance used 1.299 kwh in the 24 hour period 6pm - 6pm

I am with EDF on their fixed Price 2015 tarrif. in the North Scotland area @ 11.96p per unit inc vat. EDF tell me that 1 unit = 1 kwh and if that is correct my day cost is 1.299kwh x .1196p = .1553604p per day = £56.71 for a year.

My tarrif looks expensive at todays prices but if I have gambled correctly it may look cheap in 18mths/2years time?

Anyway assuming my sums are properly based and calculated, I am reasonably happy with the running costs given the age of the antique. I realise it will work a bit harder in the summer but even so as stated in above post it would take a long time to make back the outlay in cost savings on my use.

I will look around for some big flat polystyrene sheets to fix to the box as a money saving exper (iment.)

Would appreciate you checking/confirming my calculations?

Should have said it's about 450 litres capacity so it's a big sucker and a new one at John Lewis is £449

Cardew

Calculations are OK.

Yours uses approx 30% more than mine. However yours is considerably older.

Comet sell a slightly bigger one than yours 502 litres grade B efficiency that uses 496kWh pa. which using your figure of 11.96p/kWh would cost £59.32.

Swipe

My Norfrost small chest freezer draws around 120w when it kicks in