Heating water

Did you know that since the 1st January 2006 nearly all domestic boilers sold in the UK have been gas condensing boilers. They are super efficient due to the way they use the heat from the exhaust gases to further heat the water. James Watt would have been proud.

This post was originally going to be dedicated to gas condensing boilers but the National Energy Foundation have an excellent article telling you everything you need to know. If you have recently installed a gas condensing boiler please let us know about your experiences by leaving a comment below - are there any pitfalls we should be aware of? I have been told that it can take a minute for hot water to come through the taps and this can waste quite a lot of water. I suppose you could use this water to rinse dirty dishes or you could save it in a large jug to put on the garden.

As you can tell I don't have a gas condensing boiler because I only have electric and I am on an Economy 7 tarriff. This tarriff is rated so that off-peak electricity (between the hours of midnight and 7am) is a quarter of the price of on-peak electricity. However, on-peak electricity is rather expensive. I believe this is an attempt by the electricity companies to smooth out the peak of electricity demand during the day and the trough of low electricity usage overnight. You can't just switch off a power station when nobody is using it, so encouraging people to do their washing and heat their water overnight must use up electricity that would otherwise be wasted.

There are a whole host of other problems associated with Economy 7 tarriff but I'm not going to discuss them here.

Here's a little description about the hot water tank that is installed in my flat. It is well insulated with foam and has two immersion heaters installed. One is supplied by electricity between the hours of midnight and 7am and is placed at the bottom of the tank. If left switched on permanantly it would heat the whole tank but only using the cheaper electricity for seven hours every night. The other immersion heater is supplied by electricity 24 hours a day but is positioned half way up the tank. I presume this is supposed to be used as a booster to supply half a tank of hot water during the day if the rest has been used up.

Given that I rarely use a full tank of hot water each day it seemed wasteful to be using the Economy 7 tarriff every three nights or so, especially as it only took about an hour to heat up the tank. So I've had a timer installed on the 24 hour elecricity supply which only heats up half the tank and only for one hour in the morning just before I wake up. Now I only use 7 hours of Economy 7 electricity per week to heat my water and I don't have to remember to switch the hot water on and off every few nights. This is especially good as I often forgot to switch it off meaning that I'd end up using lots of expensive on-peak electricity for no reason whatsoever.