What proportion of the cost if running an oven is used in getting it up to heat? It always seem to me that it takes one hell of a lot to get it up to, say, 170, but from then on it only cuts in intermittently.
So what is the difference between:
Cost of heating oven to temperature plus keeping it hot for 15 mins.
and
Cost of heating oven to temperature plus keeping it hot for 45 mins.
(I'd still guess that the pre-cook in microwave would be cheaper. But possibly by quite a small margin. I certainly find our microwave itself gets quite warm in cooking potatoes for a few minutes.)
Talking about the kettle, I am amazed how many folk still use a kettle to make a cup of coffee or tea. Shove a shovel of coffee granules ( I just tip the required amount direct from the jar being a former lab. chemist and still able to assess volumes), zap the microwave (90 seconds in our unit of
850W) and bingo. If tea, then similar but teabag inserted after heating! Shorter time than in the kettle, not heating the kettle with minimal energy heating the turntable.
I agree with all but part of the last paragraph. When we were younger and my wife was a housewife by choice staying at home with the kids, I was out working both in and outdoors. I would come home in winter, from a warm comfortable car to find the house unbearably warm. Now that the kids are adults, she helps get disabled kids to and from school, walks the dog several times a day and can cope with the house at a lower temperature than me!
Why oh why can she not understand that closing doors between rooms conserves the heat? I'll come home to find that virtually all doors are open and that the CH is working hard!
There's a toxin in potato skins which is destroyed by cooking. However, microwaving doesn't cook the skins well enough to do so, so there's a risk you'll end up eating some.
Yeah, but it's still not right though, probably because the skin gets sort of surface crispy, but you don't get a nice properly thick and crispy skin like what we like in this house
Are Kill-A-Watt meters sold there, they are very accurate and good for testing loads over days like refrigerators to see actual usage. They record hours and Kwh used. Of coourse you use Cfls and flourescents not incandesant lights.
Re our loft insulation. The insulation is only the depth of the ceiling joists as the loft is boarded onto the joists. For storage use only - heat not required up there. The front and rear dormers ( full house width ) flat roof insulation depth is not known - there may be none as the house was built in 1968. I think this would be difficult to remedy unless anyone has suggestions. Could Kingspan the ceilings I guess but have full wall height fitted furniture so an alternative would be preferred. This has also made me think about the small triangular lofts that form part of the ceiling for some downstairs rooms and part of the lower walls for some 1st floor rooms. They are small though and I have had difficulty even crawling into the space in years past.
All our rads have TRV's except the one in the room where the stat is. We don't like or need warm bedrooms so the heat there is just background and doors are shut during the day. The programmable room stat is set at its lowest setting ( 5 deg C ) overnight ( from 10 pm weekdays ) so effectively the heating is off overnight. During the daytime heating needs are mixed as the 3 members of the family have varying work/university hours on different days. The stat is set for just about comfortable in the later morning/afternoon with a temperature boost for the evening when it's certain that one or more will be home.
The tumble drier was new 12 months ago and is A energy rated and it is used on its humidity sensing setting. IE when the clothes are dry and the exhaust contains no/negligible moisture it switches itself off. I now remember why we bought it 12 months ago and it was because of our energy bills last winter - our 20 yrs old tumble drier was still working OK at the time. The link to a drying cabinet/room with a dehumidifier is very interesting - wish I'd seen it 12 months ago.
Re cooking. Our 5 yr old range cooker is 1m wide and has only one oven cavity which is full width. The electric oven has developed a problem this past month or so in that it is intermittent in operation. Turns out that it is a common fault with this manufacturer on this range cooker. My wife is pressing for its repair but I think I might delay so that she gets into the habit of using an alternative where possible. It's a big oven to heat for small items like potatoes or pasties. We have a new but unused electric steam cooker that has been in the loft for about 3 yrs since it was bought as a present for us. Should be good for several veg at once as opposed to 3 or 4 gas rings burning. We have a pressure cooker that the wife doesn't use as much as she used to. It, of course, can cook several veg on just one gas ring. Our freezer is about 18 months old, can't remember the energy rating offhand but I chose one with thicker than usual sides assuming insulation there. Our fridge is about 20 yrs old and maybe needs an assessment on its consumption.
The washing machine and dishwasher have both been replaced in the past 4 years or so. Don't know their energy ratings though - should get the handbooks out if I can find them. In the washing machine my wife does hotish washes, don't know what temperature will have to ask and asses.
Hmm - on looking at the assumed ( guessed and still to be measured ) 100mA consumption for the bell transformer I guess I was a bit pessimistic. 24 W of iron loss - it would definitely run hot.
I'd say this is the source of a lot of your heat loss. Due to a leak I had to replace the ceiling over one flat-roofed bedroom, I took the opportunity to replace both and insulated between the joists with 60mm Celotex leaving - I forget now - maybe 20mm air space above. These rooms are now warm all of the time with the TRVs at 4 rather than cold with the TRVs at 6. A noticeable improvement.
Only three ways to retrofit to a flat roof AFAIK:
Wait 'til it needs replacing and do it externally then (going from cold roof to warm roof, probably)
Tear down ceiling, insulate with Celotex/Kingspan between joists, reboard & replaster. Messy, expensive. Need at least 60mm Celotex to be worthwhile: building regs probably require at least 100mm maybe 150 in new builds, anything over 100mm is probably overkill in our lifetime for a retrofit.
Fix new joists to existing ceiling (transverse to existing for ease of fitting) insulate tight to ceiling, board and plaster. Less messy, but reduces ceiling height by 75 - 125mm, expensive.
No grants available for flat roof insulation, despite it being greater source of heatloss than walls or loft: indicates how poor the cost/benefit ratio is. However, in your situation it may be a disproportionately high contributor to heatloss giving you a much better payback: with me it's marginal. It would be more comfortable with insulation (fewer cold spots) but I'm not putting a monetary value on comfort.
BTW: If it's snowed with you today keep an eye on your roof and your neighbours' to see where the snow goes first - that's a good indicator of poor insulation. If a neighbour with a similar property keeps their some much longer, ask them what insulation they have. Or maybe they're away skiing.
On Wed, 04 Feb 2009 20:31:17 +0000 someone who may be Geoff Lane wrote this:-
That may mean they are doing their job. One of the disadvantages of these valves is that they are not in a good location to sense room temperature well, even before they are covered by furniture or curtains.
Some of the thermostatic valves in my house are at least 20 years old. They still do their job well. The one in my hall brings the radiator on at full output for a while, as the hall warms up it achieves a steady state with the radiator at low temperature.
Same in my bedrooms, with the TRVs set to about 1 (I like the temperature at about 14C). It seems that if the CH is firing quite frequently, due to cold weather, the TRVs don't open up so much because they're kept warm from the pipe, but if the CH fires perhaps every 60 - 75 min. the valves open more as they've cooled down. Perhaps better on the outlet? Also 'reversed', so that the cap is horizontal and less affected by the heat?
I thought the principal toxin in spuds was solanine, isn't oxalic acid what is in rhubarb leaves? (Though oxalates are produced in some fungi infected potatoes.)
(Ignoring artificially applied substances like the post-harvest fungicide thiabendazole (which does not get destroyed by oven or microwave cooking).)
But I would like to see some references to potatoes and microwaves.
Surely the whole point of the TRV is to restrict the flow, so that less water flows and the radiator emit less heat !
The suggestion that the radiator attain the same high temperature would surely infer some timing factor, rather than a temperature regulation or am I seriously missing the point ?
Yes, although that is a US-specific brand name I believe. There seem to be an ever increasing number of different makes/types of these appearing here, and they can be found for well under £10 if you look around.
FYI the house here is a late 60s open plan semi, with two adult occupants 24/7. Back boiler central heating, electric cooker, no tumble dryer, Economy 7 electricity; computers on 20/24 and router
24/7.
Be aware that Nov-Dec-Jan is the possibly costliest period for heating; almost half the annual gas bill is accounted for here by these three months, 6000 out of 14000 kWh annual.
I've just checked the spreadsheet for Nov-Dec-Jan: Gas £226, electricity £114. Annual use is 14000 kWh for Gas, 3500 kWh for electricity.
What brought the electricity bill down noticeably was having the kitchen updated a couple of years ago, and replacing the cooker, fridge, and freezer with modern ones (fridge and freezer became a fridge/freezer).
ISTM that your gas usage isn't too far out of line for a back-boiler system, but you don't say whether you have this type or a modern condensing one.
As others have said, go for the costliest items first, likely to be tumble drier, cooker, and washing machine on the electricity side, and taking the sensible steps as have been mentioned with the central heating - but keep in mind these are the costliest heating months anyway.
Turning off things like the router are likely to be more of a pain that it's worth - if someone's working late, or starts early, and the router isn't up and running, then it becomes a nuisance that you'll happily pay a few pounds a year to avoid.
Be aware that 'energy ratings' on appliances can be a con - washing machines have now gone cold-fill only, to boost their ratings despite using more electricity than before. It all hinges on what is defined as 'efficiency', which isn't necessarily the same as reducing your bills.
Also be aware that 'switch' websites don't always give you the full range of options. The Equitable Billing Company refuse to pay fees to switch sites, so don't appear on them. Their only tariff is a 'social' one, the same for every customer, none of these confusing 'deals' like the main suppliers, and no expensive 'Primary Day Units' for electricity or 'Expensive Tier' for gas. Do your suppliers have these? See if Ebico's price comparisons would help you:
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