Why do we use so much energy

Owain_Moneysaver

Turn CH thermostats down.

Fit water saving shower heads. Showers on submarines are 15 seconds water to get wet, soap up, then 30 seconds water to rinse.

Use the cooker less, plan menus so you only have one pot on or the oven is full.

NigeWick

Martyn1981 wrote: »

total gas consumption pa is about 7 to 8,000kWh.

Three bedroom bungalow with wife and myself. 3725kWh gas & 2400kWh electricity here, and, we've just had a condensing boiler fitted so hopefully gas usage is going to be lower. Cooking & showering is electric and the 4kW solar PV provides hot washing up water from early May to late October. Another cost is the wood burning stove in the lounge as we like the look of the flames. About £100 per year for the wood plus £50 for the chimney sweep.

[Deleted User]

michaels wrote: »

By my maths 19000kwh should be enough to heat 1200l per day from 10c to 40c at 80% efficiency - can anyone comfirm this?

No that's MJ you've calculated not kWh, heating 1200l by 30% at 80% efficiency uses 52.5 kWh, which is about £6.25 on my tariff. (1kWh = 3.6MJ)

Martyn1981

jack_pott wrote: »

No that's MJ you've calculated not kWh, heating 1200l by 30% at 80% efficiency uses 52.5 kWh, which is about £6.25 on my tariff. (1kWh = 3.6MJ)

Hiya, if you multiply 52.5 x 365 you get ~19,000.

NineDeuce

michaels wrote: »

So any tips on how to work out how much energy each bath and shower needs? I can compare monthly gas use in summer and winter although need to adjust for the pc diverter replacing some gas in the summer.

This suggests that hot water may be 1300kwh per month in summer, not sure about cold water temperature and whether seasonal dofferences in this are important (I guess average increase from 15 to 40 in summer would need 40% more in winter if it were 5 to 40 would suggest using an average of 20% more). This gives about 19000 owh per year for hot water and 13000 for space heating.

Now I need some data to see how this compares to other houses of a similar size and water usage.

You can get such information from the Carbon Trust website.

The average spend on gas and electricity is around £900 per year. I imagine this is for a family of 4.

A human uses 150 litres of water per day, this including washing themselves, dishes, toilet flushes, drinking water.... everything... but you say you are using 150 litres in a bath alone....

I think that there are targets from organisations such as the Carbon Trust to reduce this to 130 per day.

You wont get a lot of heat loss if your pipes are well insulated. It just seems that you are using a lot of water.

Further to your original post, you do not need to heat to 22 degrees per day. Buildings do not require to be heated until temperatures outside drop below 15.5 degrees. You can save as much as 7-8% on your heating bills by reducing your temperature by 1 degree. You could probably drop your heating demand and put a jumper on.

Also, why do you need to set it to be on all day? Set timers on your heating controls or manually control this more effectively. 17 degrees at night also seems a bit odd. Is this really necessary if you are in bed asleep?

8 showers seems a lot. However, showers use about half the amount of baths.

Cardew

NineDeuce wrote: »

17 degrees at night also seems a bit odd. Is this really necessary if you are in bed asleep?

Heating we heat 24/7 to 21-22C in the day (6AM - 11PM) and with a night min of 17C.

OP's house is well insulated so I doubt if there are many nights in the year where the house temperature would drop by 4C/5C to 17C in 7 hours.

My heating is also set to 21-22C in the evening and drops to 18C at 9.30pm and back up to 21C at 6am for 2 hours. I have a thermometer that displays the minimum temperature reached outside and inside. IIRC last winter the internal temperature never dropped to 18C, so the heating never kicked on overnight.

michaels

Cardew wrote: »

OP's house is well insulated so I doubt if there are many nights in the year where the house temperature would drop by 4C/5C to 17C in 7 hours.

My heating is also set to 21-22C in the evening and drops to 18C at 9.30pm and back up to 21C at 6am for 2 hours. I have a thermometer that displays the minimum temperature reached outside and inside. IIRC last winter the internal temperature never dropped to 18C, so the heating never kicked on overnight.

Thanks

Not sure if it gets down below 17 at night, I suspect the heating probably only comes on if the outside temperature falls below zero.

WE heat all day because my wife is at home all day and I work 3.5 days/week so the house is occupied. We could wear jumpers and do more but I like warm. My question is more about whether we are using too much energy for the heating /bathing we do than whether cutting down would save money (which obviously it would).

There seems to be different figures for bath and shower water use, some say 80 for a bath, others 150 and one site suggested 100, 200 or even 300 depending on bath size and depth.

Similarly showers depends on shower type and length. Ours is mains pressure but has a fairly small (and I suspect low flow) head and due to our carp water supply company the pressure is low especially in the mornings when everyone else on the street is showering. I will measure flow rate and shower length at some point. I suspect there are some fairly long showers taken but would have thought this would balance out with the shorter ones. With a 180l tank (at 60 degrees) and a 20kw boiler we have never run out of hot water yet.

Am I right in thinking 60 degrees is needed to reduce legionella risk? (All the bath/shower taps are thermo mixer so no scalding risk)

NineDeuce

Cardew wrote: »

OP's house is well insulated so I doubt if there are many nights in the year where the house temperature would drop by 4C/5C to 17C in 7 hours.

My heating is also set to 21-22C in the evening and drops to 18C at 9.30pm and back up to 21C at 6am for 2 hours. I have a thermometer that displays the minimum temperature reached outside and inside. IIRC last winter the internal temperature never dropped to 18C, so the heating never kicked on overnight.

That just doesnt make sense. If you recognise that temperatures throughout the year then you cant say that your heating comes on/off at particular times.

The OP says that the heating is on 24/7, so there are no timer controls. Therefore, time has no bearing.

And this is still kind of besides the point. You dont need to heat a house to 22 degrees, especially when the outside temperature is mild.....

NineDeuce

michaels wrote: »

Thanks

Not sure if it gets down below 17 at night, I suspect the heating probably only comes on if the outside temperature falls below zero.

WE heat all day because my wife is at home all day and I work 3.5 days/week so the house is occupied. We could wear jumpers and do more but I like warm. My question is more about whether we are using too much energy for the heating /bathing we do than whether cutting down would save money (which obviously it would).

There seems to be different figures for bath and shower water use, some say 80 for a bath, others 150 and one site suggested 100, 200 or even 300 depending on bath size and depth.

Similarly showers depends on shower type and length. Ours is mains pressure but has a fairly small (and I suspect low flow) head and due to our carp water supply company the pressure is low especially in the mornings when everyone else on the street is showering. I will measure flow rate and shower length at some point. I suspect there are some fairly long showers taken but would have thought this would balance out with the shorter ones. With a 180l tank (at 60 degrees) and a 20kw boiler we have never run out of hot water yet.

Am I right in thinking 60 degrees is needed to reduce legionella risk? (All the bath/shower taps are thermo mixer so no scalding risk)

" We could wear jumpers and do more but I like warm"....

Bizarre. In other words, "how can we cut down on heating while not doing anything to cut down?" If jumpers werent designed to keep people warm then why would anyone bother wearing them?


"There seems to be different figures for bath and shower water use, some say 80 for a bath, others 150 and one site suggested 100, 200 or even 300 depending on bath size and depth."

Again, this doesnt make any sense. If you want to cut down, then dont fill it up so much. That's the message. The 150 litres per day is an average figure of water use per day, irrespective of different bath sizes.

Your post is titled "Why do we use so much energy". Answer - because amongst other things, you prefer to have the heating on instead of putting on a jumper for free and you like to fill the bath up to twice the average.

michaels

NineDeuce wrote: »

" We could wear jumpers and do more but I like warm"....

Bizarre. In other words, "how can we cut down on heating while not doing anything to cut down?" If jumpers weren't designed to keep people warm then why would anyone bother wearing them?


"There seems to be different figures for bath and shower water use, some say 80 for a bath, others 150 and one site suggested 100, 200 or even 300 depending on bath size and depth."

Again, this doesn't make any sense. If you want to cut down, then don't fill it up so much. That's the message. The 150 litres per day is an average figure of water use per day, irrespective of different bath sizes.

Your post is titled "Why do we use so much energy". Answer - because amongst other things, you prefer to have the heating on instead of putting on a jumper for free and you like to fill the bath up to twice the average.

OK. My actual question is do we use too much energy given our hot water and heating profile- i.e. is our home efficient given our usage or should I look into whether there might be an issue with boiler efficiency or insulation efficiency?