Washing Machine or Boiler?

jeremycb

I have just been inspecting the plumbing in my house and noticed that the Washing Machine is only connected to the cold water mains. I know that it is possible to connect the machine to the hot water from the boiler.

Does anyone know if it is cheaper to heat the water in the machine or from the boiler?, I have an A rated machine and a new combi boiler.

Thanks for your help

p.s. I normally wash on 30 degrees except for nappies which I wash on 60.

mum2kathryn

If your washing machine has two water inlets (hot and cold) it will probably be cheaper for your boiler to heat the waer. However if there is only one inlet I don't know which works out cheaper, but the water coming from your boiler will be about 60 degrees, so that means where you normally do a 30 degree wash, the water will be hotter than needed (unnecessary energy use, and might shrink delicates!).

Hope that makes sense!

jillie1974

my mum told me to always use the cold water option as the machne will heat to exactly the right temp but from the boiler will be the temp from there. so i guess the cold option is the more money saving

ariba10

We have a dishwasher (Ten years old now) that only has a cold fill, but I conneced it to the hot tap.

No problems so far.

skr00ge

Depends on which is more efficient. If your boiler is efficient then through the hot water is the way. If you have an inefficient boiler then the electric element in the washing machine may be the way. Flip a coin for the answer.

At least the electricity in the element can be generated by renewable means. The gas(I assume) in the boiler once its gone its gone.

The other way is to ignore hot washes and live in slightly grey whites. Or buy some of the eczema skin disolving bio powders.

tr3mor

ariba10 wrote: »

We have a dishwasher (Ten years old now) that only has a cold fill, but I conneced it to the hot tap.

No problems so far.

Dishwashers tend to run at around 60C anyway though, so this isn't going to damage your plates.

I use the 30C and 40C washes most on my washing machine, so water from the boiler would be too hot for them.

Cardew

mum2kathryn wrote: »

If your washing machine has two water inlets (hot and cold) it will probably be cheaper for your boiler to heat the waer. However if there is only one inlet I don't know which works out cheaper, but the water coming from your boiler will be about 60 degrees, so that means where you normally do a 30 degree wash, the water will be hotter than needed (unnecessary energy use, and might shrink delicates!).

Hope that makes sense!

Most modern washing machines are now cold fill I believe.

For those with hot water input, it doesn't matter about the incoming hot water being 60 degrees as it simply mixes it with cold water to achieve the 30or 40 degree temperature required.

Modern washing machines use relatively small amounts of electricity to heat the water. For instance my 3 year old machine cold fill uses:

0.2 to 0.3kWh for a 30 degree wash(depending on cycle/load)
0.45 to 0.55kWh for a 40 degree wash
0.85 to 0.95 kWh for a 60 degree wash
1.9kWh for a 90degree wash

That consumption is for the whole cycle which includes the motor for washing/rinsing/spinning as well as the pump.

So the total cost of heating the water by daytime electricity for the 30/40 degree washes(which I am reliably informed is the majority of washes!!)is in the region 2p to 4p. So a hot water machine might save 1 to 2p a wash if you have a gas boiler.

absfabs

I think you also got to look at the distance from the washing machine to the boiler. I.e. how many litres of water will run through before the hot water reaches your machine? Modern eco machines wash with very little water, so you might waste hot water sitting in the pipes while your machine still has to heat tepid or cold water.
Cold fill only might not only be simpler but actually more economical.

mikeywills

All washing machines cold, and hot and cold feed can be run on cold only as they have their own independant heaters.

If you have a hot and cold feed model you can get a single to twin copper feed which will allow you to split the cold water into the hot inlet aswell. The advantage of this is your boiler will not have to fire quite so often to feed the washing machine and in the case of a combi not draw hot water away from other uses like showers!!

It is more energy efficient to have cold feed only, and elsewhere on the continent you have no alternative but cold feed only.