Smart Heating

I posted back in July about the idiocy of the governments Green Deal scheme. I vowed to have nothing to do with it (at least in its current form) but I have been making a few changes in the last few weeks to try and reduce my energy bills.

The first of these was a replacement tumble dryer. Tumble dryers are notorious electricity hogs and the best way of reducing their cost is to dry clothes outside. This is not always possible and, given the climate we live in, the tumble dryer is still the least worse solution to a house full of damp clothing for 8 or 9 months of the year. Our existing tumble dryer was actually an emergency purchase (it was a Christmas Eve dash to a branch of Comet on the other side of Edinburgh several years ago) but it had become increasingly noisy over the last few years and I suspected that it wouldn’t stand up to our heavy use for too much longer. I measured it’s energy consumption on a full cotton load at 2.49kWh. Given that I wasn’t going to waste any money on a Green Deal assessment I spent the difference of an AA rated “heat-pump” dryer which uses a refrigeration style closed loop to heat the clothes rather than a separate electric element. I measured a similar load on this and the full cycle took 0.97kWh – a massive 61% saving over the old dryer although still 0.97kWh higher than drying it on the line.

The second item I went for was a replacement duvet. I bought our last Winter duvet 12 years ago when I first bought the larger size of bed. I had the feeling that this wasn’t as warm as it could be and I read on a website that a synthetic duvet has a life of 3-4 years. This may have been exaggerated as the website was selling new duvets but I decided to invest in a down duvet. The difference is remarkable and it really makes having a heating free bedroom at night a possibility – no more cold feet for me. This also got me to research one other area: Is it possible to heat a home in a more controlled manner?

Manual TRV

Our central heating system has three main control systems: a timer on the boiler which determines whether the whole system switches on or not, a thermostat located in the hallway which (theoretically) allows the temperature for the whole house to be set and individual thermostatic radiator valves (TRV pictured) which switch off the hot water supply to their attached radiator when the temperature reaches a particular point. This is a fairly typical set-up and it should help to limit the amount of heat that is wasted by heating excessively or at inappropriate times. However, I have found that this works better in a more modern house or, at least, one which is built in a consistent manner with similar use of the rooms. Our house just isn’t like that.

I had a look around to see what was available and one system (and there are other similar ones) was British Gas’s Hive system. On the face of it this sounded like a great idea: a central heating system that could be programmed and controlled remotely. The system costs £200 to install and is one that comes under the banner of the internet of things: essentially domestic appliances that are connected to the internet and can be controlled remotely and integrated with other devices. In the case of Hive it is connected to  a mobile phone and could, in theory, allow for heating to be switched on or off depending on the location of the phone. The problem with this is that it rather assumes single person occupancy and it only really takes control of the central timer and thermostat: one of which I am quite capable of switching on and off myself (if no-one is in, the heating goes off) and the other is about as effective as a chocolate teapot.



Programmable TRV

What I have actually chosen is a bit less connected (at least at the moment) but should be a lot more effective. I’ve bought several programmable radiator valves – in my case the Pegler Terrier i30. These devices replace the existing TRVs (this should be a simple DIY job as the old on is unscrewed and the new one replaces it) and they take over the role of the timer, thermostat and TRV for each individual room. This allows different temperatures to be set for each room depending on usage and time of day. If the room needs to be warmer (or cooler) at a particular point the temperature can be changed up or down using a slide wheel or remote control and the valve will return to the pre-determined temperature at the next programmed timer event.

So far, I have fitted these to two of the bedrooms, the living room and the dining room. I had intended to fit them to all of the bedrooms but as the design of the valves vary some of the older ones do not have an appropriate fitting – which is annoying. As it is, I intend to replace the other valve bodies with a standard ones although I think I will get our local neighbourhood plumber to do that as it will become wet and messy if I fit them. The other slight annoyance I’ve found with them is that he motors in the valves are slightly noisy, so in the bedrooms it is advisable to set them to come on roughly at the time one would be waking up anyway: given that my new duvet is like sleeping in a furnace, that shouldn’t be such a problem.

In terms of cost savings, Pegler have done a case study in which they estimate that a house will save 30% of their heating costs by using these valves. I suspect that is rather high but I would estimate that I would only need a 10% saving to cover the cost of the valves. However, much like loft insulation, the real benefit of energy saving devises like these is not so much in the cost saving as in the improvement in comfort. I’ll probably get a much better idea of how effective they are in the Winter.