Search the Community

Recently our boiler was broken. Whilst we awaited it being fixed we were using two gas fires we hardly ever use. One of them has a pilot light which I leave turned off as it is rarely used, but turned on at this point. I looked at my Octopus app and saw we were using gas. I was surprised as the boiler was broken and thought that there was something wrong. Then I remembered the pilot light. It appears that the pilot light used around 3.5kWh of gas a day. That is 1300kWh a year or around £90 a year in gas. It is pretty small compared to our gas bill, but would be equivalent to 10% of the assumed gas usage in the price cap calculation. Boiler is fixed and the pilot light is turned off. So I am not wasting 3kWh a day, justing using 300!

So last couple of months we've averaged 11kWh of Gas per day and 10kWh of electricity per day. Somewhat disappointed that this is that high given that our only gas usage would be for our system boiler to heat our 300L hot water tank to about 56C and every single lightbulb in the house is a low energy LED (bar one actually, in the kids bathroom - which is a halogen). I haven't insulated the tank yet, so will do that this month, but I've at least insulated the pipes. Electricity seems high, though I do work from home and we do a lot of laundry as we have two young kids and we watch a lot of TV. How's your energy usage at the moment? Particularly interested to hear from those who also have a gas heated hot water tank. I've now turned the thermostat on the tank down to about 53C to see what difference this makes. It's difficult to know the exact temp it's set to as the analogue dial shows 45C and 65C and then two equally spaced increments in between which should be equivalent to 51.67 and 58.33.

There are two views about what happens when you use a large induction ring and a smaller pan. Assuming everything is equal and the pan is large enough to turn the ring on. Will the ring use the same amount of electricity if it was a large pan or a small pan. I.e. as the pan does not cover the entire ring, will the same amount of electricity be used even though the whole ring is not covered. Whilst it seem easy to answer I have found many conflicting opinions.

An Excel spread sheet has been used to calculate the heating and cooling. One thing also calculated is that at peak energy the bungalow requires as much for the heating in the winter as for the cooling in the summer! So the hottest part of the hottest day and the coldest part of the coldest night need about the same amount of power! This is mainly because of the solar gain through the windows. The calculations were compared with what has been used for heating and it is reasonable good. The calculated heat requirement is down to -8C although I cannot find records here of colder than -5C. It is assumed that the ASHP will supply all heating and hot water when required. (hopefully mainly hot water heating from excess PV power) There is a back up immersion in the buffer tank but I hope to never use it. The cooling is another thing all together. The ASHP manufacturer informed us that if you run the cooling through the radiators below about 19C this will cause condensation - They were right. When running the ASHP in the summer in cooling mode at 18C the radiators began to get wet because the warm air was being cooled and the cooler air could not hold as much moisture.( the buffer tank also started to do the same and this has to be sorted as well) This is what is know as the dew point! Water coils are now designed to be added to the MVHR ducts to overcome this problem by cooling the air entering the building. The MVHR will be boosted with cooling to the east end of the building, or the west end of the building ( no south windows) when there is strong solar gain. As a trial the ASHP will be left on 24 hrs to see the effects. The temperature of the heating water produced by the ASHP will be turned down to the lowest setting which keeps the desired room temperature. Anything else let me know

Hello - Asking for a friend - no, seriously? I am. He has contacted me as he is becoming concerned about the high amount of electricity he seems to be using on a monthly basis. I have asked him for more details but at the moment he says he has an ASHP and a Hot Tub. Does anyone have any experiences at this stage of the two being run and resulting in high levels of energy usage? Last month he used 819kwh and already this month he has used 253kwh. There is only him and his wife at home!! Any thoughts would be welcome. Thanks in advance.

I'm sticking this here as I've been asked the question via PM, and rather than just give an answer to one member, I thought it might be more useful to stick the answer somewhere were others can also read it. Back when I was first looking at doing some rough "what if" type comparisons, between different build systems, windows, insulation and airtightness levels etc, I wanted a fairly quick way to be able to change one element, say the wall U value, or the efficiency of the MVHR system, and see what impact it had on the overall heat loss of the house. This model was never intended as a substitute for something like PHPP, which is very comprehensive, it was just intended to give a rough idea so that I could see the scale of some of the changes, and work out where best to spend our limited budget. Having written the spreadsheet for our build, others expressed interest in using it, so I tidied it up and let others have a copy. Because lots of people seemed to want to use it, and also because it generally seemed to give results that were within 10% or so of more complex models, like PHPP, I put a copy of the spreadsheet up on our website, as a free download: http://www.mayfly.eu/wp-content/uploads/2017/01/Fabric-and-ventilation-heat-loss-calculator-Master.xls This post is a set of very brief instructions on using this spreadsheet. First some health warnings. It was never intended to give an absolutely accurate prediction of heat loss, and as such it takes no account of solar gain, wind or incidental heat gain from occupants and appliances. As a consequence it is generally a bit pessimistic, in that it will usually tend to slightly overestimate the heating requirement. This is not necessarily a bad thing, as it can be useful to have a bit of heating capacity in reserve for exceptionally cold weather. To use the spreadsheet, you first need to gather all the data needed to complete the white cells. Most of this should be self-explanatory from the notes in each section. The U values, for example, should be the true U value of the component, including any additional thermal paths, so the window U value needs to be the Uw value, not the Ug value, and the floor U value needs to be adjusted for any thermal bridging around the periphery. All the areas are the internal wall, floor and ceiling/roof areas, not the external ones. The model does not account for geometric thermal bridging at corners, but in a well-insulated house this effect should be very small, anyway. Some of the most difficult to obtain data can be the mean daily air temperature and the mean minimum daily temperature, for each month. This data is available for your location on the Met Office website, but posting a link seems a bit fraught, as the Met Office keep changing their website and this makes any link out of date fairly quickly. All I can suggest is that you work your way through the historic data on the Met Office website and find that closest to where you live. Once all the data is filled into the white cells on the spreadsheet, you should get some numerical data in the green cells, plus two graphs will appear. The graphical data is often the most useful. First, there is a basic heat loss versus outside air temperature plot (the Heat Loss Vs Delta T plot). You can use this to determine how much heat the house will need to maintain the room temperature that you put into the spreadsheet (it defaults to 20 deg C, but you can change this to whatever you feel comfortable with). The red line is the total heat loss, the other lines are there so you can see which elements are contributing the most to the total. If you want to know how much heat the house will need in order to maintain a temperature difference between inside and outside of 20 deg C (say a 20 deg C room temperature when it's zero deg C outside), then just go up vertically from the 20 deg C point on the horizontal axis until it meets the red line, then go across horizontally from this point to the vertical axis and read off the heating needed in watts. The other plot shows the heat loss per month, and this one can be a bit confusing, because, like the other plot, it takes no account of incidental heat gain, from solar heating, appliances, occupants etc. The best way to use this is to print it off and pencil a horizontal line across where you think you wouldn't have heating on. For example, If you turn your heating off in April/May and on again in September/October, then draw lines across at about the point where these dates cross the other lines and call that your "no heating" point. The mean heating needed for each month will then be the difference between those lines and the values on the plots. You can quickly work this out by just noting the amount of incidental heat gain, indicated by the pencilled horizontal lines, and then subtracting those values from the monthly values. Be aware that this is really a very rough estimating tool, as there will be big peaks and troughs in daily temperatures within those months that will effect the heating required. In most respects, the heat loss vs delta T plot is more useful for sizing a heating system. Hopefully the above should make some sense to anyone trying to use this tool.