Energy ratings for tumble dryers

Sterlingtimes

I having been trying to get my mind around published energy ratings. Are they really meaningful?


I have created a small table to look at the most expensive and the cheapest dryers in each category. We have the Indesit (highlighted in yellow). I have just bought a plug-in monitor to measure usage (which I adjudge to be very high, perhaps 21 cycles per week) over a time period. I know I am not going to change family behaviour to adopt other methods of drying.


Given that I may get a generation contribution from Solar PV, irrespective of outlay which machine type would be my best selection?


.

Andy_WSM

I'd say the White Knight gas dryer might offer the best running costs.

Gas is approx 1/3 to 1/4 of the price of electricity, so although it uses the same amount of energy as the Grundig heat pump model it will still be a lot cheaper to run.

tunnel

I have an AEG heat pump which is easily catered for via my solar(even in light cloud), no point paying for energy if the solar can provide it free

Sterlingtimes

Thank you, Andy and Tunnel. The two plug-in meters arrived today: one for washing machine and one for tumble dryer. I will run those for a month. My thought is that the tumble dryer gets through about 2200 kWh a year of electricity perhaps £250. That will shortly be tested.


Ignoring solar, a highly efficient machine could save half of that: £125 per year.


Now it's a matter of considering the possible solar-contribution.

Sterlingtimes

Measurement of the laundry appliances is in progress. The initial indication is that the B rated tumble dryer will consume 2200 kWh a year and the A++ rated will use 1100 kWh. So laundry accounts for 40% of my electricity usage. Mrs Sterling is a heavy launderer attending to human, horse and dog laundry.

Without solar contribution, I would be guided towards a gas tumble dryer a raw 4/6 saving, but with solar I would be guided to an A++ electric tumble dryer with a raw 3/6 saving.

But the current dryer is relatively new and performing well. The payback on a A++ replacement could be seven years or more.

I am inclined to wait until the end of my first solar year to evaluate the solar contribution to the household.

zeupater

Sterlingtimes wrote: »

Measurement of the laundry appliances is in progress. The initial indication is that the B rated tumble dryer will consume 2200 kWh a year and the A++ rated will use 1100 kWh. So laundry accounts for 40% of my electricity usage. Mrs Sterling is a heavy launderer attending to human, horse and dog laundry.

Without solar contribution, I would be guided towards a gas tumble dryer a raw 4/6 saving, but with solar I would be guided to an A++ electric tumble dryer with a raw 3/6 saving.

But the current dryer is relatively new and performing well. The payback on a A++ replacement could be seven years or more.

I am inclined to wait until the end of my first solar year to evaluate the solar contribution to the household.

Hi

I don't know how much electricity you expect to have spare ... aren't you already expecting to divert generation to DHW and that you've calculated that showers alone consume over 7000kWh so something's got to give somewhere ...

Anyway, averaging over 10 full cotton loads per week, every week of the year .... don't you have any lightweight fabrics for when the sun shines?, or is it that it never does where you live?, but then, why invest in solar in the first place ? .. ..... anyway, considering that we're talking solar & horses and washing have you considered employing the low tech solution which many others have used for millennia, that being a simple washing line .... keep the Indesit, buy MrsS a £10 length of plastic as a Valentines present (I'm sure she'll appreciate it !)and (only if she needs it) write her a personalised instruction manual ... you'll still need the dryer for the winter, but still save a fortune ....

2200kWh on tumble drying and 7000kWh on showers, then there's base-load, washing machine (for all that washing) and everything else ..... you're not looking at buying a Nissan Leaf to soak up all of the spare generation are you ? ....

HTH
Z

Sterlingtimes

zeupater wrote: »

Hi

I don't know how much electricity you expect to have spare ... aren't you already expecting to divert generation to DHW and that you've calculated that showers alone consume over 7000kWh so something's got to give somewhere

The showers, of course, use gas as a primary source. So if the laundry grabs most of the solar generated power, that's excellent. I'm getting to grips with numbers. Mrs and Master Sterling will undoubetely do their best to use all of the generated power available. Thank you, Sterling.

zeupater

Sterlingtimes wrote: »

The showers, of course, use gas as a primary source. So if the laundry grabs most of the solar generated power, that's excellent. I'm getting to grips with numbers. Mrs and Master Sterling will undoubetely do their best to use all of the generated power available. Thank you, Sterling.

Hi

In a standard 3 person household, your diverted energy should provide the majority of DHW for around half the year thus changing your primary source assumption ... of course, silly shower heads like the tropical rainstorm ones we used to have simply pour all of this collected energy down the drain very quickly ....

The standard BRE calculation for average DHW consumption is worked on something like 25n+40 (where n = number in household)litres /day of 60C water provision, so for 3 people somewhere around 120litres/day, that's probably about 2200kWh/year of heat provision, or about 6kWh/day .... in the summer a proportional diversion device and a 4kWp system should easily cover this demand if the DHW cylinder capacity is large enough to buffer a couple of consecutive dull days ....

I know exactly where you're coming from, when we started to try to become more energy efficient we also had no real clue where what we bought was going .... just open up a spread-sheet and start measuring actual draw/consumption with simple plug-in meters - it'll take some time to get your data, but it'll be your data .... you'd be surprised how different the figures will be to the published 'standard cycle' information and some of the rubbish available from on-line calculators ...

HTH
Z

Smiley_Dan

How easy is it going to be to time the drier so it comes on, and is at the point of using the most electricity, when the sun is shining?

If they are anything like washing machines or dishwashers in terms of the distribution of power load (sorry, I won't allow TDs in the house so I have no idea how they work), they will use a lot for a short period of time, then not much. This is why, when considering the household generation contribution, the kWh total usage is not fully enlightening.

It may be easier to get a DHW diversion device as above and use the energy for showering, assuming a well insulated hot cylinder.

Sterlingtimes

Smiley_Dan wrote: »

How easy is it going to be to time the drier so it comes on, and is at the point of using the most electricity, when the sun is shining?

If they are anything like washing machines or dishwashers in terms of the distribution of power load (sorry, I won't allow TDs in the house ...

The crux of the problem here is that I can work on getting the technology right but I cannot finely control the behaviour of the house occupants, e.g. impose showering windows and durations, dictating washing and drying times.

I know that currently I use 8,000 kWh (£1,000) in electricity per year, and 26,000 kWh (£1,000) in gas per year.

The best I can do is to get energy efficient technology, appeal to the family and hope that somehow solar PV makes a dent in these numbers.

Sterlingtimes

zeupater wrote: »

Hi

I know exactly where you're coming from, when we started to try to become more energy efficient we also had no real clue where what we bought was going .... just open up a spread-sheet and start measuring actual draw/consumption with simple plug-in meters TH
Z

Thank you. It's quite an iterative process, but as you say generic internet figures do not work. I am starting with the obviously heavy consumption devices first. Gas use during the summer must approximate to the hot water consumption (having a little regard for gas cooking).