cost of hot water heated by gas.

jennifer56

I was working out how much various things cost and was wondering what the daily cost or gas usage was for a modern combi boiler with no stored hot water to heat enough water for 2 showers and a bath.

I have warm air heating, which I like, and a Janus water heater which heats a hot water tank. The Janus heater has a pilot light, which is on all the time, obviously.

I know how much gas the pilot light uses as I went away on holiday and forgot to turn it off, it uses 3 kWh a day costing approx 10p which is £36.50 per year.

When the heating is off and the heating pilot light as well, we were using 21 kWh of gas per day which in a year is 7665 kWh which costs me £260 if I make a yearly calculation just using that figure.

Then I subtracted the cost of heating for the winter from the total yearly bill of £540 (18500 kWh) and this costs £280 for heating for about 8 months of the year.

So what do other people pay for their hot water? more or less than £260? for 2 showers and a daily bath and washing dishes?

I also pay £420 per year for electricity.

Jennifer (who has too much time on her hands since retiring)

notbritishgas

Cannot help you with the cost of a combi boiler to heat water but can say what my costs are with a convential condensing one heating a cylinder full of water.
In the summer the hot water takes 1 hour to heat the full cylinder and that lasts all day. The gas used per week is just under 2 imperial units, lets say about 60 kwh per week which is about £2 per week, £100 per year. So daily use is less than 10kwh.

Cardew

There are two factors to consider:

Firstly the overall efficiency of your Janus heater(including pilot light) compared to a Combi boiler.

Secondly the loss of heat from a hot water tank. Modern well lagged tanks are tested to a British Standard and, with a full tank of 65C hot water, lose around 2kWh in 24 hours(you might have the figure stamped on your tank)

However that heat is not lost as such as it heats the house. For that matter the heat from a pilot light is also not 'lost'.

I suspect that a new combi might shave up to £100 a year off your annual costs; probably less!

Given a new combi will probably cost a couple of thousand pounds to install, I would not think it makes economic sense to replace your present system; especially since new combis have a very poor long term reliability reputation, with repairs costing £hundreds.