New house heating and hot water questions

cnagra

Hi,

I have moved from a house with a combi boiler to a house with a water tank upstairs. The new house has 4 bathrooms, but at the moment only 2 are used. Here are my questions...

1) For enough hot water for 3 showers in the morning (7-8am), what time should the hot water be turned on and for how long for?

2) Is it better to convert my hot water tank to a combi boiler. (We have quite a few radiators and taps).

3) Is it cheaper to turn on the hot water and the heating at the same time?

4) Should the electric switch near the water tank every be switched on?

Thanks in advance for any answers

smcqis

1. It is impossible to say without knowing how many rads if any are switched on, efficiency of boiler etc Every house will be different, trial and error is the key

2. Depends on how the current system works, can you afford to switch to combi, whats your long term plans with the house. Are 3 showers taken at the same time or one after another?

3. It would be cheaper to run just the one, but if you need heat you need heat. The less rads to warm up the quicker the water will, so maybe turning off rads in rooms not frequently used.

4. I assume you mean the immersion? I use this in the summer to wash dishes etc as it takes good half hour to get warm water in our house using the oil so i just use immersion which is pretty instant for us instead of wasting oil

cnagra

Thanks for the reply...

1. In the morning we don't always have the heating on. It depends how cold we think it will be in the morning. If we do have the heating on then it's about 13-15 radiators that are on.

I didn't know having both the heating and hot water on the same time effects when and how long to put the hot water on.

The boiler is 9 years old.

2. The showers are all taken at different times in the morning, but between 7.30 - 9.00am. The house is quite large, which is putting me off going to a combi.

3. I have done this thanks.

4. I am not sure if it is immersion. There is a box attached to the side of the tank. This has a wire coming out of it which is attached to a switch. This switch has been off since I moved in. I guess this is backup for hot water just incase the gas isn't working?

Thanks again for the reply!

alleycat`

Hi,

From the sounds of it:-

In the airing cupboard for the system you'll have (probably) a pump, the tank (with a small thermostat on the front), a small square box (divertor valve) and the switch you've mentioned (for the immersion).

On that basis:-

The switch should be off unless you want to use the electric to heat the water tank (rather than the boiler).
Inside the tank is the equivalent of a giant kettle heating element and that is what the switch is for.

Electric is more expensive than gas (assuming you are on mains gas) so use the boiler to heat the tank rather than the immersion.

With Oil, or other heating sources you'd have to work out the cost per kwh and work out which is cheaper.

How we do it:-

We put the timer on for the boiler to heat the hot water twice a day.
Once at about 5am for 30 to 40 minutes and again at about 4pm for the same amount of time.

That gives us enough hot water for showers, baths, washing up etc throughout the day (2 adults, 1 child).

I think the only time this system might not work is if you have people taking long, long showers and long hot baths.

The heating, at this time of year is just set to come on via the thermostat (rather than timed).

During the rest of the year the heating is set to off but the hot water times remain pretty much the same (although the tank heats up faster / loses less heat in summer).

You can have both the hot water and heating on at the same time but the divertor valve will split the the heating between the hot water tank and the central heating rads.

Obviously that means two sources are removing heat from the system at the same time and means neither works as efficiently whilst this is happening.

Once the tank reaches temperature the thermostat on the hot water tank should close the divertor and it'll go back to just rads again.

Not sure if that helps but it should give you a general feel for how the system works.
The rest is a bit trial and error.

cnagra

thanks 'alleycat' that's great.

Thanks for the answers guys..