Solar water and hot fill washing machine

ennisjim

Hi,
We have solar panels heating water and are looking for a new washing machine. It should make sense to buy a model which takes hot water but I was wondering if anyone has any thoughts on this, recommendations for models, etc.

Thanks

CJhaughey

Jim

Not many hot feed washing machines here in Ireland.
We ordered a Admiral/Maytag toploader from the UK, it takes a massive load 10kg and fills hot and cold.
Toploaders aren't for everyone but they are very fast.

Hotblack Desiato

I heard that the thinking behind cold-fill only machines was that modern machines use so little water, the hot water would barely get the chance to come all the way down the pipes. Also modern detergents are designed to work well at 30 degrees, never mind 40, in the 1970s people were still doing boil washes for cottons and linens, 60 degrees was for the synthetics, 40 degrees for wool!

If we turn on our kitchen hot tap, it takes a full minute for the hot water to reach it, and this is by no means a big house. So a hot-fill machine would be pointless for us. On a 30 degree wash, which is what we usually use, the machine probably uses more energy for the drum motor than it does for the heater.

Edit: found the article and it's worth a read.

(N.B. - As an interesting side note here, a lot of people seem to think that it's more efficient to use a hot fill as they have a tank full of hot water, a condensing or combi-boiler... wrong! It is actually cheaper to heat the water in the appliance and, with almost every modern machine, by the time it if full of water, all it's done is replaced the cold water in the pipework with hot water from the tank or boiler. It's totally wrong to think that this (or indeed a hot fill) is better in my opinion, common sense applies really.)

ennisjim

Thanks ninja900 - I have found similar advice, eg.
http://www.washerhelp.co.uk/buying-related_2.html#cl_q1
http://www.mtprog.com/spm/download/document/id/593 sections 6,7,8

Looks like a regular cold-fill it is then. Just means lots more hot water available, more soaks in bath, etc...

CJhaughey

I don't see your reasoning, If you have solar heated DHW as I do then to make maximum use of it you should have a hot feed washing machine.
I appreciate that in some houses it may take a considerable length of time to get hot water to the machine but if the water pressure is that poor then it will hardly have filled the machine with cold water in the 60 seconds.
All the arguments presented so far have dealt with hot feed in terms of Combi-boilers or gas/oil boilers not with the Use of Solar DHW.
It is a definate energy saver to use solar heated water for washing machines.
Try heating 5 or 6 litres of water to 40 deg on the stove and see how long it takes, thats a lot of energy you are using to heat the wash, and the rinse if you have warm rinse as well.
Solar heated water is not something that you save and store it is more efficient to use solar hot water in the morning and have the tank heat again in the PM as efficiency drops off as the tank temp rises.

Hotblack Desiato

CJhaughey wrote: »

I don't see your reasoning, If you have solar heated DHW as I do then to make maximum use of it you should have a hot feed washing machine.
I appreciate that in some houses it may take a considerable length of time to get hot water to the machine but if the water pressure is that poor then it will hardly have filled the machine with cold water in the 60 seconds.

It's not a question of pressure, it's the length of the pipework involved and the volume of water held in the pipe vs. the amount to fill the machine. If you have a long pipe run and a low-water use machine you can get little or none of the hot water actually entering the machine. So yes you are heating your water for free but just using that heat to heat up the pipe... while the washing machine still uses its heating element because it's only seeing cold water through the hot fill.

Edit: do any hot fill machines take HW for the rinse? I doubt it as it won't make your detergents work any better, and in a house with conventional HW it would be extremely wasteful.

tribesman

ninja900 wrote: »

It's not a question of pressure, it's the length of the pipework involved and the volume of water held in the pipe vs. the amount to fill the machine. If you have a long pipe run and a low-water use machine you can get little or none of the hot water actually entering the machine.

I understand your point as we've got this situation. We can get around it by running the hot tap in the nearby sink before starting the washing machine. The pipe is then full of hot water from the start of the fill.

ennisjim

Is there an issue with water from solar being too hot (eg. 60 degrees) and affecting certain fabrics/colours ? Do the machines which take hot fill ensure that cold water is mixed to meet the target temp (eg, 30/40 degrees) ?

byte

I'd expect it to mix them to acquired temp, to a certain extent anyway.

CJhaughey

I am not sure about other types of machine but I know ours mixes it to give a warm wash.

Cuauhtemoc

This came up a while back.

Basically from looking into it LG are the only company still doing hot fill machines from what i can see. Don't know there reputation but heres a link

and previous Thread..

That link doesn't seem to work atm but this is their global site. 8kg A++ Link

CJhaughey

There are a lot of manufacturers selling hot fill washing machines and I expect more to join the fray as solar becomes more common.
Electrolux have a front loader which is hot fill and specially designed for solar usage.
And Admiral which may not be for everyone due to the large size and top loading have a hot feed washing machine.
Older machines had a dual feed but it is uncommon now, worth checking for though.
Heres a long discussion of this exact topic which has workarounds if you are that way inclined.

momec

you can get a constant supply of hot water at any hot tap if you put a return supply back to your cylinder from the tap . you might need a small circulating pump an a couple of non return valves or if you've a good plumber he should be fit to set it up on a gravity system . it works well for me anyway and it is done in every hotel that way .

Hotblack Desiato

A 'hot leg' system is VERY wasteful of heat, unless you go to extremes of insulation, and probably even then. Solar heat may be free but it's not plentiful enough in this country to waste! and you don't want to be dumping heat from the pipes into your house in summer anyway.

ennisjim

I wonder if the argument that the hot water still in the pipes after the fill is wasted makse sense. I would have though that there would be a couple of litres of hot water involved (pipe run for me is about 4 metres). My tank is 300 litres so 2 litres 'wasted' doesn't sound like a big deal, especially if the solar can reheat the 2 cold litres 'for free'. Or maybe I'm missing something. The alternative is to heat with electricity which sounds wasteful.

ircoha

Interesting thread, input from CJH et al top class as usual:)

The original dual feed clothes washers were set up such that the HW inlet only opened for washes above 60C.
I presume the modern ones don't have this constraint but it is worth checking.

I presume Solar HW could also be used in the dishwasher.

chipclub

I have a 5 year old Hotpoint washing machine that has a hot feed. I don't know if it saves any money on the heating costs but it certainly saves time on the wash when the machine does not have to heat the water.

td5man

chipclub wrote: »

I have a 5 year old Hotpoint washing machine that has a hot feed. I don't know if it saves any money on the heating costs but it certainly saves time on the wash when the machine does not have to heat the water.

Any updates on this thread as i'm looking for dual feed washing machine.

byte

I don't think you'll get one anymore. I've not seen one in at least 5 years now and I work in the trade.

The time saving mentioned by chipclub is moot really, as the new machines take longer due to using considerably less water than the older dual feed machines.

Here's a good link as to why having a hot water pipe is pointless.
http://www.ukwhitegoods.co.uk/help/buying-advice/washing-machine/2965-hot-water-fill-for-washing-machines-again.html

whizbang

You dont need a 'Hot feed' machine.
Most machines dont give a toss what temperature the inlet water is.
If it isn't hot enough after fill, then it turns on the heater until it is. If you fill it with hot water, then the heater doesn't turn on.
Put a thermostatic valve in the water feed if you dont want too much heat.
You can use a recirculating thermostatic valve if you really need a specific temperature.
Simplest:
Put a flow control valve in the hot water inlet, then play around with the feed flow for a few washes, until your happy with the temperature.

whizbang

After you have digested the post by Byte, first thought is, Don't you tend to put on a wash at the same times every day, and wash the dishes, fill the kettle, and lots of other kitchen things at the same time ?
-Point is there probably will be hot water in the pipes to start with. Only your own usage will tell.
btw point 3 is wrong. its the expansion in the tap components that slows the flow.

td5man

whizbang wrote: »

You dont need a 'Hot feed' machine.
Most machines dont give a toss what temperature the inlet water is.
If it isn't hot enough after fill, then it turns on the heater until it is. If you fill it with hot water, then the heater doesn't turn on.
Put a thermostatic valve in the water feed if you dont want too much heat.
You can use a recirculating thermostatic valve if you really need a specific temperature.
Simplest:
Put a flow control valve in the hot water inlet, then play around with the feed flow for a few washes, until your happy with the temperature.

I think id need to fit a thermostatic mixing valve as the water is so hot that you cant put your hand in it