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IanR last won the day on May 13

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  1. What does "thermal mass" mean to you? It's not got a definition that everyone agrees on, and there's no units for it, making it open to interpretation. A masonry skin, outside an insulated cavity, and therefore outside the thermal envelope could be considered "thermal mass". Similarly a poured concrete raft, sitting atop an EPS former and therefore within the thermal envelope could also be considered "thermal mass". The effect of both is to dampen the diurnal temperature variation, and assist the insulation in stabilising the internal temperature of the house. Concrete sitting inside an EPS sandwich would be just as effective as if it were either fully inside or outside the insulation layer.
  2. Hi Jake, welcome! Sounds like you could be an asset to the Forum, and hopefully you can pick up some titbits along the way.
  3. For timber windows, the current U value requirement (1.6) is carried forward into the new regs until 14.06.2023, so makes no difference if you read the old or new regs (for timber windows only)
  4. It didn't look like a structural element to me, looks like a frame within the fenestration. Can you get away with calling the glazing frameless in the scenario?
  5. I believe so. Part L1A, Page 25, New fabric elements in an existing dwelling https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1057372/ADL1.pdf
  6. If you are not sure of the spec, then you will need to go to the manufacturer. However, Is it not the whole window value that needs to be under U 1.6, not just the glass?
  7. Your loads appear typical, so a typical connection should be sufficient. At the time I requested a connection I was told 20kVA was "typical". Because I was requesting something untypical, and they knew I was a home owner and not an electrician, they wanted me to prove the load size with a (I think it was called) diversification calculation. This was the total loads connected x a factor (ks factor?) that allowed for them not all being in use at the same time. Different connected items seem to have different ks factors. In the end I just got the electrician to speak to them and they accepted what he told them without the need for any proof. Edited to add. 3 phase may be an advantage though, allowing more than a 3700kw solar PV connection, without DNO approval and for EV charging at above 7kW.
  8. The Quote from Network Power reads as if the £2,819.60 is the whole cost for the new 100kVA Transformer, rather than just my 45kVA portion of it. On top of this there was £3,300 to install 130m of 3 phase cable from the telegraph pole to my kiosk, in a trench that I dug, and make the connection, plus other amounts for reinforcing the local overhead lines from transformer to telegraph pole, +++ Total cost was £7,600.
  9. Are they charging you the whole cost of a new 200kVA transformer? For a new 3 phase, 45kVA connection, I was charged £2,819.60 to upgrade the pole transformer from 50kVA to 100kVA, back in 2016. Here's mine. I feel like putting my name on it! Lot's of other charges for the connection. Total bill was over £7K iirc.
  10. It's not about who is quoting you. It's about the property's space heating requirement being 57,225 kWh. On your property, with cost effective measures, you could get this down to around 8,500kWh. Whether it's heated by gas or electricity, the property needs the same amount of heat energy inputted to maintain the required temperature. A 90% efficient gas boiler(s) will meet that requirement with 63,583kWh of gas, or an 481% efficient GSHP will meet it with 11,897kWh of electricity.. @ 7.37p per kWh of Gas and 28.34p per kWh Electricity, the heat pump will be cheaper to run day-to-day, but if you design, engineer and build better and get the 57,225 kWh energy requirement down to 8,500kWh both options would be much cheaper to run and install. I believe there is around a £2,750 per year cost save by improving the energy efficiency of your house. The parts of the build that improve energy efficiency should have a 50-60 year life, but even if you only considered a 25 year life then that's a £68,750 budget for energy efficiency measures.
  11. Simple, cost effective steps could vastly improve your proposed building's energy efficiency. My property is a modest ~450m². But, as a barn conversion, has a large volume, circa. 1650m³. That would be similar to yours if you had an average 2.8m ceiling height. My space heating and hot water could be comfortably met with an 8kW ASHP. I did oversize my heat pump to 12kW, wanting a faster re-heat on the hot water, but that has proved entirely unnecessary. My annual space heating requirement is around 6,400 kWh. Hot water is around 10,000kWh, which combined, needs around 4,000kWh of electricity at a SCOP of 4.
  12. Is that space heating and water? For a GSHP they may have used a SCOP of 4.5, which would mean a roughly 60,000kWh annual energy requirement for heat and hot water. Unless you are providing hot water for 10, or have included a swimming pool, you could easily get that figure down to sub 20,000kWh annual energy requirement. GSHP install cost do not make the small efficiency increase over ASHP worth it. An ASHP install cost should be in the region of £5K to £10K more than the equivalent gas install, and you can get £5K back in a BUS grant.
  13. But they're not. My local gas standard rate is 7.37p and Electricity is 28.34p Gas boilers are, say, 90% efficient. An ASHP needs a SCOP of 3.46 to be in parity. For me, ASHP is cheaper to run day-to-day, even without considering not having to pay the gas standing charge. Inflationary pressure will remain higher on gas than electricity going forward, for many reasons. Over time the swing will be more in favour of electricity.
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