mending things

My existing programmable thermostat , a Honeywell CM67 started failing. Rather odd actually, it would happily run the default programme but would not let me reprogramme. Every time I put the unit into programme mode, it would let me make a few changes then freeze completely. I tried changing the battery, but no help. Oh well its lasted me 10 years and done good service. I was trying to decide what to replace it with. I looked at the heatmiser range, which have some interesting models including some that can be controlled over wifi i.e from your computer or externally from a phone. Turning up the stat while travelling home on the bus seems a nice idea. However the heatmiser range have to be counter-sunk into the wall , whereas my honeywell unit sits on the wall. I also have been in contact with the UK operation of Nest, the American Smart stat. It has many interesting features, and possibly I'll get on a trial, but that is some way off. I had a pressing need for a new stat, espe...

So in my previous blog I outlined how it's easy to log your consumption, how to convert everything to the same units (KwH) and a site - imeasure - which makes this a lot easier. If you do all of the above , or even some of it, you will see how much energy you use per week. Over time you may see trends, probably connected to the seasons. My household gas usage drops in the summer and rises in the winter - pretty predictable stuff. I'm going to park oil, as I don't have any experience of using heating oil, but much of what I describe will be similar for gas & oil. Separating the consumption of gas , in my case for central heating (CH) and hot water (HW), from electricty for a moment, it's worth thinking about what determines how much is used. for gas, it's used by a boiler. the boiler heats water in a heat exchanger which is pumped through the house, and diverted either through a coil in a how water tank (HW) or through radiators in the house. This is referred in...

A gadget which I think goes largely unnoticed by consumers and plumbers alike is the programmable thermostat. I have a Honeywell CM67 but the model has been superseded by the CM907. Worcester do a similar model- I'm sure there are others as good. You can get them for around £50 online at plumbing shops. There is a range called Heatmiser too, you can find these on Amazon.  These devices replace the room thermostat, which in many cases is the classic "clunk-dial" based on a bi-metallic strip. These old style stats are based on 19th century technology. Their strip is made up of 2 thin layers of different metals, bonded and when it heats up the strip bends due to the differing rates of expansion of the two metals and this forms the pole of a switch. Because of the phenomena of hysteresis, these types of system are slow to respond, and take too long for the stat to switch on or off. To compensate , they actually have a tiny heater in them and actually consume some power. The h...