Saving energy: facts, figures and ideas required

[emordnilap]

Does anyone know of a place that has statistics on domestic energy consumption in these islands?

The reason is I'm trying to find out if our house is 'typical' or not. Our electricity consumption has declined over the last two years but I don't know whether we started high or not.

We're not exactly scraping the bottom of the barrel in our efforts to reduce energy consumption, but I can sense the bottom is there.

Following the installation of a larger but much better insulated hot water tank (because of installation of a solar panel) I've been round and insulated practically every hot water pipe that wasn't already insulated.

One of the last places in our house that uses a 'normal' (ie not low energy) bulb has been upgraded. We have a security light on a pir at the back and it had a 300 watt bulb in it. Fortunately it's rarely used and has lasted years. The new bulb (24 watt) is supposed to last up to eight times as long. The downside is the greater amount of technology and engineering involved.

Our compost toilet system is working well and has the bonus not only of saving gallons of water (and consequent emptying of the septic tank) but also saves the electricity driving our well pump.

We have more work to do on a north facing wall to help conserve heat and I need to capture more heat on the south side. Once that's done, we'll look at capturing wind energy.

Anyone got any energy-saving tips that wouldn't appear in run-of-the-mill lists?

[SunnyJim]

Wow. Sounds like you've done alot!

We have more work to do on a north facing wall to help conserve heat and I need to capture more heat on the south side.

How are you going to do that? After seeing Ken's light earth insulation projects, I'm thinking of putting a bit of light earth up on the back of our house to add to insulation.

I'm also thinking of some lambs wool stuffed 'curtains' that will sit between our windows and some internal shutters I want to make.... It's getting them all to fold up nicely that's foxing me at the mo.


edit: Also our bloody cat flap seems a weak spot. I don't know what to do about that. Maybe make a cat house in the garden for the cat?

[adam2]

Refrigeration can account for a fair proportion of electricity in an otherwise efficient household.
Replacement of a correctly functioning fridge or freezer may/may not be justified due to the cost and embodied energy of a new one.
Any new fridge or freezer should of course be a high efficiency one.

An off peak tarrif may be worth it if you use much power at night, or can shift much of your load to nightime use.

Infrared heat lamps are useful for local warmth, and despite the high cost of electricity, can save money compared to heating a whole room useing gas or other fuel.

[adam2]

double post deleted

[adam2]

edit: Also our bloody cat flap seems a weak spot. I don't know what to do about that. Maybe make a cat house in the garden for the cat?

Would it be possible to remove the existing cat flap, and make a new cat entrance via a porch, lobby, conservatory, or similar? Fit new cat flaps in the inner and outer doors, draughts being reduced by the use of two doors.

[emordnilap]

Wow. Sounds like you've done alot!

Thanks. A lot more to do...

We have more work to do on a north facing wall to help conserve heat and I need to capture more heat on the south side.

How are you going to do that? After seeing Ken's light earth insulation projects, I'm thinking of putting a bit of light earth up on the back of our house to add to insulation.

Our house is not suitable for that type of insulation. Our work to the north wall involves moving the door (and getting rid of its draughtiness) and enclosing it in a porch designed to capture early and late sun, plus inside the house constructing wainscoting insulated with sheeps wool (which we had left over from insulating the loft years ago).

The walls of the cottage are stone/rubble and so are difficult to deal with generally.

I'm also thinking of some lambs wool stuffed 'curtains' that will sit between our windows and some internal shutters I want to make.... It's getting them all to fold up nicely that's foxing me at the mo.

That's got me thinking - the wife is very handy with a sewing machine, making lots of her own clothes.

One project is to better insulate our windows (teak frames/retrofitted double glazed panes). I have mirrors at either side of the windows to improve the light, the reveals of which are angled like this: /—\. Shutters are a good idea but could compromise the light. Better curtains is probably quickest with shutters outside later.

Maybe the curtains could be stitched down their length creating a foldable pleat(s)?

As for the south wall, plans are afoot for a hothouse for food plants and a small conservatory, roofed to keep out summer sun but to capture low winter sun.

[emordnilap]

Refrigeration can account for a fair proportion of electricity in an otherwise efficient household.
Replacement of a correctly functioning fridge or freezer may/may not be justified due to the cost and embodied energy of a new one.
Any new fridge or freezer should of course be a high efficiency one.

Thanks a2. Our fridge/freezer is A++ rated, two years old! Still, there is room for improvement - one side could be further insulated. We have it set for 5/15 degrees, which is plenty cold enough. The recommendation is 3/18. I think we could bring the freezer up another couple of degrees. What do people think? It's a vegan household so there's practically no risk from food poisoning.

An off peak tarrif may be worth it if you use much power at night, or can shift much of your load to nightime use.

I'd thought of that but we use virtually no power at night, just the fridge/freezer, radio alarm and the wireless internet antenna outside. The computer is never left on over night but the small amount of heat generated in the antenna stops condensation (and besides, it's a relay to a neighbour).

Do passive infrared detectors use any power when the lights they control are not lit?

[adam2]

Frozen food will keep at temperatures up to about minus 10 centigrade, though the storeage lifetime is severly reduced compared with the recomended minus 18 centigrade.

With fresh food, any temperature below room temperature will improve the keeping qaulities of food, though the lower the temperature the better. 3 degrees will preserve the food better than 5, and 5 will be better than 8, and so on.
PIRs do use power when off, typicaly about one watt, less in some designs.

[SunnyJim]

edit: Also our bloody cat flap seems a weak spot. I don't know what to do about that. Maybe make a cat house in the garden for the cat?

Would it be possible to remove the existing cat flap, and make a new cat entrance via a porch, lobby, conservatory, or similar? Fit new cat flaps in the inner and outer doors, draughts being reduced by the use of two doors.

This is what we have, sort of. We have a cat flap from back door into covered but cold 'corridor' between house and garage. Then another cat flap to the outside world. I think the temp difference between inside and out make the drafts, rather than it being a wind driven pressure thing....

It's also a conducting bridge too isn't it? With a single plastic sheet as the 'door' it certainly feels colder than the surrounding wood door.

Maybe I'll make a DIY double glazed cat flap out of 16mm triple wall polycarbonate or something

[tomhitchman]

here is some data from the association of electricity producers:

http://www.aepuk.com/need_info.php#3

"How much electricity does the average person use?

The average person in the UK uses 1,930 'units' or kilowatt hours (kWh) of electricity per year. The average household uses 4,478 units of electricity. Total domestic electricity demand is 115,526,000,000 units, or 115,526 gigawatt hours (GWh), approximately 30% of the UK's total demand. The total domestic and industrial electricity demand in the UK is 340,043 GWh. One gigawatt hour is one million kilowatt hours."

And from an energy advert in the guardian april 2007 "average annual gas consumption = 20500kwhs"

I think averages are a difficult guide since it does not take account of differences housing stock.

[emordnilap]

here is some data from the association of electricity producers:

http://www.aepuk.com/need_info.php#3

"How much electricity does the average person use?

The average person in the UK uses 1,930 'units' or kilowatt hours (kWh) of electricity per year. The average household uses 4,478 units of electricity. Total domestic electricity demand is 115,526,000,000 units, or 115,526 gigawatt hours (GWh), approximately 30% of the UK's total demand. The total domestic and industrial electricity demand in the UK is 340,043 GWh. One gigawatt hour is one million kilowatt hours."

Thanks. That makes us higher-than-average users of electricity on an individual basis. I suspect that heating water via an immersion heater in summer is the killer. I will continue to monitor our energy consumption in the light of our recent solar panel installation. It'll be interesting to see what difference it makes.

One upside to our electricity consumption is that it's around 85% wind generated, according to our utility bill.

[RenewableCandy]

For space-heating energy there's a doc from the Stockholm Environment Institute (2003) which quotes 13,993 kWh per HH per year (on page 22). Of course a typical HH is only 2.4 people or somesuch, so if you're over-the-odds that's why. The figure for HW from the same doc is 5139 kWh.

Chateau Renewable burns 20,000 kWh for heating and HW together per year. But there are 4 of us and still a fair bit of insulating to do.

[SILVERHARP2]

I’ve done most of the simple stuff but at the back of my mind is replacing or putting carpet over downstairs wooden/tiled floors with lots of the multilayer reflective insulation underneath. A bigger project is building a 2 story glass conservatory covering the back of the house (s/w facing). And another one is getting some kind of partition setup in the living room which was originally 2 rooms, not sure on the cost benefit of these but if they had a benefit regardless of the cost then the house would be all the more comfortable

[maryb]

re the cat flap, you can get flaps which only open in response to a signal emitted by a small transmitter on the cat's collar (assumes your cat will wear a collar, of course). This cuts down a lot on draughts but probably wouldn't stop it being a cold bridge.

[Andy Hunt]

You could install a 'catlock' - like an airlock for cats, with an evacuated chamber for insulation.

But your cat would have to wear a space suit then.