New house with Combi boiler - hot water is SO much higher than old house with system heating, why?

good_thyme

Looking for a bit of advice here please.

In January we moved from a house with a regular boiler and cistern to a house with a combi boiler and we are shocked to see how much we are spending on gas. In the cold months we put it down to getting used to how we heated the rooms and to be fair it was a cold and miserable winter and spring.

But in the last few months there has been no heating on at all so the gas has only been used for hot water and showers (old house had an instant electric shower). We are currently using almost twice as many units of gas than at our old house. In the old house in the summer we'd heat the water for 2 x 3/4 hour sessions and that was plenty to last the day.

We've had a shock with this so we've taken steps to cut down the usage but would like to know if there is anything else that we can do. So far we have cut the water temperature on the boiler to 55 degrees from 60 degrees and have timed the showers. We are home all day so we are always using just a little hot water to rinse a mug or wet a dishcloth etc, etc so this means that we are firing up the boiler to heat just a little bit of water. This has to stop and we are trying very hard to remember not to automatically turn on the hot tap but to default to using the cold tap unless we really need hot water for hand washing etc. 

Is there anything else we can do to get the gas usage for heating water under control?

Qyburn

Some combi boilers have a feature where they keep the hot water bit preheated, even even when you aren't drawing water.  Normally that can be switched off, it might be called "Eco" or similar. If you let us know the model boiler someone will be able to advise.

FreeBear

Turn the hot water temperature down even further. During the summer, 40-45°C is plenty, and the risk of legionella is next to zero. The incoming water will have been treated by the water company, and it isn't sitting in pipes long enough for bacteria to develop.

If you only have a relatively small amount of dirty dishes each day, use the kettle to boil water for washing up.

How old is the combi ?

Real old boilers have a pilot light that is on 24/7 and can get through 1500-2000kWh of gas every year. Shutting the boiler off during the summer months (and just turning on for bath nights) will cut gas consumption noticeably.

good_thyme

Thank you for the advice so far 

The boiler is only a few months old, it's an Ideal Espirit Eco 2

Reed_Richards

When I had a combi boiler there was a long pipe run between the boiler and most of my hot taps.  So every time I ran a hot tap, a lot of hot water was left in the supply pipe.  If I didn't use that tap for a while afterwards, this water would cool and so the energy used to heat it was wasted.  I'm sure that lead to reduced efficiency.

Netexporter

How many kWh was your old electric shower using? Have you factored that into your gas usage for water heating?

Flugelhorn

Qyburn said:

Some combi boilers have a feature where they keep the hot water bit preheated, even even when you aren't drawing water.  Normally that can be switched off, it might be called "Eco" or similar. If you let us know the model boiler someone will be able to advise.

we switched that off on a boiler - we were only in the property at weekends and realised the boiler would be firing up when we weren't there to keep the preheated bit up to temperature. we have always washed hands in cold water - do no big deal there and TBH having to wait for the water to warm up a shower is no problem

badmemory

I very rarely use my hot water tap.  Normally by the time it has run hot I have turned the tap off so it really isn't worth it.  Is your washing machine etc cold water fill & if it is is it plumbed in correctly.

FreeBear

I see that the Ideal Esprit has a preheat mode - Press the button, and a little blue light should go out. That will save you a bit of gas if preheat had been enabled.

p00hsticks

good_thyme said:

We are home all day so we are always using just a little hot water to rinse a mug or wet a dishcloth etc, etc so this means that we are firing up the boiler to heat just a little bit of water. This has to stop and we are trying very hard to remember not to automatically turn on the hot tap but to default to using the cold tap unless we really need hot water for hand washing etc. 

We use the cold tap for just rinsing out mugs etc, and heat water in a kettle for doing a bowl of washing up - quicker and more efficient than waiting for hot water to come through the hot tap. 

Qyburn

good_thyme said:

Thank you for the advice so far 

The boiler is only a few months old, it's an Ideal Espirit Eco 2

Among it's features it lists ..
"Fast hot water response through domestic hot water preheat"

Try with that switched off, i think this is the correct manual (page 3) ...