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DIY Forum >> Electrical Questions >> economy radiators https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1291925413 Message started by scotspark on Dec 9th, 2010, 8:10pm |
Title: economy radiators Post by scotspark on Dec 9th, 2010, 8:10pm Hi Has anyone seen these or got any experience of these http://www.economy-radiator.com/ had a customer on the phone who is thinking of replacing storage heaters in a flat. I had suggested dimplex duoheat (which i haven't seen before either) just looking for bit of personal experience i am always dubious of website testimonials. |
Title: Re: economy radiators Post by CWatters on Dec 9th, 2010, 10:57pm All conventional electric heaters are 100% efficient. They all convert 100% of the electrical energy they use into heat. So I'm very sceptical of claims that one type of electric heater is more efficient than another. Modern oil and gas boilers are >80% efficient which is obviously less than 100%, however even taking that into account standard rate electricity is three times the price of gas and twice the price of oil on a like for like basis... http://www.nottenergy.com/energy-costs-comparison3 The figures that matter on that page are the "Pence per kWh (after boiler efficiency)". Electric heating only makes sense to me if you can use a cheap night rate like E7 or use a heat pump (GSHP or ASHP). But even using a heat pump that is 320% efficient the costs are only slightly cheaper than mains gas. So what they are really talking about is switching from E7+storage heaters to a standard tarrif of some sort. They have to work some numbers to see if their lifestyle makes that sensible. Some of the comparison sites have guides. |
Title: Re: economy radiators Post by big_all on Dec 9th, 2010, 10:58pm you as a electrition will realise there is no such thing as economy in electric systems a kw is a kw no matter how you dress it up electric is an expensive way off heating economic electrical heating means not enough heat at an expensive rate in general gas is around 4p a kw off heat after waste compared to around 10p a kw for lecky |
Title: Re: economy radiators Post by scotspark on Dec 10th, 2010, 12:53pm Unfortunately gas is not an option. Currently there is a storage heater in the hall and lounge, and a panel heater in each often 2 bedrooms. I had suggested replacing the 2 storage heaters with dimplex duoheat radiators which use a combination of off-peak and 24hr supply. They are also a bit more aesthetically pleasing. She has asked me to look at the radiators above which she found on the net. I am very sceptical about there claims about quality of heat being better than storage or panel heaters. I am also very sceptical about there claims about them working out cheaper to run than off peak though I do agree with them about many off the shortfalls with off-peak heaters. |
Title: Re: economy radiators Post by CWatters on Dec 10th, 2010, 3:01pm The more I look the more I want to cry. Take the example running cost here for example.... http://www.economy-radiator.com/images/pdfs/Example%20running%20costs%200710%201PG%20WEB.pdf The table appears to show impressive savings over a gas boiler but for starters their units are wrong. There is no such unit as a kw/day. They mean kwh/day. Then notice that they claim a gas boiler needs 103 kwh/day to heep the house warm compared to only 32 kwh/day when using their product. Why? It's the same house at the same temperature isn't it? Apparently not.... Look at the graphs. The temperature data for their product shows a remarkable stable temperature close to the ideal 21C. If you look at the graph for the gas boiler (wet) it appears to show the room temperature varying between about 25 and 28C. Hard to tell from their graph but it seem to be much hotter than 21C. No wonder the bills were higher with gas - the room stat appears to be set too high or perhaps it's faulty :-) I suspect even that isn't enough to explain the huge difference in energy consumption. Perhaps they are also assuming a very old very inefficient gas boiler that hasn't been serviced for years? They also assume electricity is £0.073 /kwh gas is £0.038 /kwh which is a ratio of 1.92 : 1. Notts say Electricty is currently £0.1295 /kwh and mains gas £0.0368 /kwh. That's a ratio of 3.5 : 1 so at best their figures are very out of date and by chance that favours electricity in the cost comparison. I'd also like to know why they say a storage heater produces "dry heat (bad for asthma)" whereas presumably their product doesn't? How does that work exactly? I've never seen a storage heater with a little reservoir that had to be emptied. Where does the water go? |
Title: Re: economy radiators Post by big_all on Dec 10th, 2010, 4:11pm some off these surveys include the cost off the central heating depreciation and some even include mantainance cost some assume all the units used will be off peak even though thats physicaly impossible other points to note is iff your stuck with electric your cheap units can be subsidised by the day units for example my brother pays 3p off peak but 24p peak i pay 10p all the time so if you have a lot off day units you could be paying more have a look at your actual use you may save money |
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