How much gas should a Atmos Multi 24/80 use?

[etherboy]

Yeah I know how long is a piece of string.... I have a Atmos Multi 24/80 about 5 years old and it's been regularly serviced last time by British Gas (who seemed pretty competent).

I have no complaints it heats up water and the central heating fine, but the gas bill seems rather high, on average for the past year we use 60kWhs of gas each day, which is twice the electricity we use and we cook, washing machine, dishwasher etc. with it (note all appliances are cold water feed - why is that?)

So the Atmos Multi is our only gas appliance.

Also is the water supposed to be heating up over night? it seems like the thing is on 24/7 and for the life of me I cant workout how to tell it to go to sleep from say 10pm till 6am.

just interested to hear from others partly to check I'm not doing something silly but it does occur to me that if the boilers fine may be the gas meters faulty in some way.

Appreciate any feedback.

 

[kbdiy]

What controls do you have - programmer, stats, motorised valves etc etc? What type of property is it - detached, semi etc? Solid or cavity walls (insulated or not)? Exposed or sheltered location? Do you have baths or showers - how often? How well insulated is the house? Double-glazed? Do you have any supplementary forms of heating or do you rely solely on the central heating?

We all have differing comfort levels so there is no real standard. Based on you average your total consumption for the year is around 21900 kWh - is that correct - your bills should tell you? What is your cost per month/year? Trying to average costs per day doesn't allow for a real comparison.

As you can tell from the long list of questions there are too many variables to give a stock answer.

 

[etherboy]

I'll try to answer as best I can:

Programmer - TP7000
Stats - sorry don't know
Motorised valves etc etc? - sorry don't know but I guess so.

property is detached - 4 bed
insulated cavity walls - yes
sheltered location -yes
Double-glazed - yes (A rating)
EPC B

Do you have baths or showers - how often? - showers once a day x2
Do you rely solely on the central heating? - pretty much yes.

As for bills we're paying £120 per month on a roughly 1/3 - 2/3 split so electricity is £40 per month and Gas £80.

Remember the Atmos Multi is the only Gas appliance and the central heating has been off between April and end September

 

[Agile]

Why do you think that is excessive?

It is actually significantly lower than most home bills for a four bed detached.

Most are around £1600 pa for gas and elect.

Tony

 

[kbdiy]

Yes I would agree that is quite an acceptable usage and comparable with my own.

 

[Agile]

Its well lower than average because of the very good insulation and particularly the cavity wall insulation.

Tony

 

[Dean744PiN5]

also things like time spent in shower make a difference, had a customer complain of high gas usage in the summer once, when questioned a bit further turned out their teenage daughter spent an average of 40-50mins a day in the shower

 

[kbdiy]

She must have been a very dirty girl

 

[Dan Robinson]

The Multi is a cracking boiler and I certainly wouldn't let British Gas within a mile of one.


The boiler maintains a permanent supply of hot water.

If you want to turn it off press the button on the front next to the orange light labelled "hot water".


But then you'll have cold water.

 

[flameport]

we use 60kWhs of gas each day, which is twice the electricity we use and we cook, washing machine, dishwasher etc. with it (note all appliances are cold water feed - why is that?)

If you are really using 30 kWh of electricity per day, you could certainly reduce that - it's 3x the average household use.
However if you are paying £40 per month for electricity, either you are not using 30 units a day or your electricity is less than half the price of anyone else.

The gas does not seem excessive at all.

As for cold feed only, then if you believe appliance manufacturers, then it is wasteful to use hot, as due to the small amount of water used in modern appliances, most of the hot water would never get to the appliance and end up in the pipes and the heat would be wasted

The other reason is that it is cheaper to make appliances with cold fill only.

 

[Agile]

There is a very big saving in manufacture cost for just cold fill.

So I don't really believe the manufacturer's biased figures!

You have to take into account that gas is a THIRD of the cost of electricity so a little hot water left in a pipe is of little consequence. Also its usually the same hot water that is ready to be used at the kitchen tap.

Lagging hot pipes is very worthwhile but only rarely ever done!

Tony

 

[kbdiy]

The theory behind cold-fill only appliances goes hand in hand with use of combi boilers rather than stored hot water systems. The theory goes that the appliance only heats water when required rather than using stored water which has been previously heated (therefore using valuable energy) and possibly re-heated by the appliance to bring it to the correct temperature again. Similarly a combi only heats hot water on demand rather than storing, hence the link.

This theory allows manufacturers to bolster their claims about the energy efficiency of their appliances.

 

[Agile]

If water is heated then energy is used.

If stored in a modern cylinder it loses perhaps 2 kWh per day. Not much.

People love to imagine that a combi only heats water when required. Well it does but they ignore the fact that it takes about 20 seconds to heat itself up. Or it can be set to stay warm using perhaps 2 kWh of power per day!

Furthermore a combi gets hot when in use and when demand is ceases it has to dissipate that heat. So not quite as efficient as people seem to imaging.

Furthermore few combi boilers are in condensing mode. Whereas most heat only ARE when heating up a cylinder!

You have to look at the wider picture!

Tony

 

[etherboy]

Thanks for the responses, it's appreciated.

I would have been helpful if Atmos published some efficiency figures for boilers in the same way cars quote things like 'miles per gallon', else how can you compare them?

Is it enough to state how much heat can be generated without saying how much power is used?

 

[kbdiy]

If water is heated then energy is used.

If stored in a modern cylinder it loses perhaps 2 kWh per day. Not much.

People love to imagine that a combi only heats water when required. Well it does but they ignore the fact that it takes about 20 seconds to heat itself up. Or it can be set to stay warm using perhaps 2 kWh of power per day!

Furthermore a combi gets hot when in use and when demand is ceases it has to dissipate that heat. So not quite as efficient as people seem to imaging.

Furthermore few combi boilers are in condensing mode. Whereas most heat only ARE when heating up a cylinder!

You have to look at the wider picture!

Tony

As I said, that's the theory and the story put about to justify it. I didn't say I believed it!