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I can't see a reason
Some people have designed for 8 l/s.cap for years or even lower if the occupation at that density is intermittent.
If you design a system with poor ventilation efficiency you need more than 8, it's regrettable if this has been factored into Part F.
1 May 2012 at 8:46 am in reply to: Re: Re: A National Insulation Scheme instead of more banker bailing? #38103It should be in line with the policies set out in LESS IS MORE too.
BTW Caroline Lucas MP is advocating QE to help the productive sectors of the economy and not go into bankers' pockets or the stock market. I think Keynes would have approved too.
On EPCs I lose count of the number of people who have been given an E when it should have got a B – or vice versa.
Indeed. I've just looked at some figures which suggest to me that a Canadian HRV of ~1979 was as energy-efficient – i.e. it had as low a specific fanpower – as the best available today in Germany. Why no great progress?
I think most people in Germany would acknowledge that Canada had the Saskatchewan Conservation House long before they had the Passivhaus Standard.
Here is another report
ow.ly/a2P6bJd
If 5 p/kWh is the cost, that is less than heat from an oil or LPG condensing boiler
20% of the UK has no piped gas.
I put my concerns to BRE and was told that convenience to commercial designers outweighed precision, or similar sentiments.
I do not believe that PHI has thoroughly checked the data. If they had, they probably wouldn't be keen on calling ten mild years “climate” when the Met Office has 50-100 years of records for many UK sites. While the data with PHPP for B'ham was clearly not an accurate long-term average temperature the new data for “the Midlands” appears to make a larger error in the opposite direction.
I can't see how gas heat pumps can easily give a COP of 4.
It's hard enough with elec ones in which the elec is generated from gas in CCGT power plants at only about 40% overall efficiency (generation and distribution losses, HCV.)
I've just looked at this data for the Midlands and it relates to ten mild years, 1996-2005.
Not a very good guide to the future (or even to winters 2009-10 and 2010-11)..
30 December 2011 at 2:58 pm in reply to: Re: Re: Non-PVC screened cable (bending it around corners) #38301EMFs (especially M), extra protection for data / TV cables, etc.
Fire resistance is desirable but not essential, it tends to be a by product of avoiding PVC. However the more flammable sheathing or insulation materials, such as XPE, are if anything harder to bend than silicone rubber.Read The Green Electricity Illusion, I suggest.
Yes, without the right flows some rads will overheat the rooms and some will underheat – usually in the most distant part of the circuit
Balancing the flows is critical. You probably don't even need TRVs on all rads – saving money – if the system is balanced and weather-compensated. Only on a few rads. in rooms subject to occasional high solar or electrical gains.
30 July 2011 at 11:41 am in reply to: Benefits of cavity wall insulation and external wall cladding #38047Is this really true, that you used cellulose fibre to fill a cavity wall, in which the outer leaf is naturally damp and rain occasionally runs down the inside of the outer leaf?
It will be papier mache by now.
I think having accepted the constraint of Logstor A/S pipework the point is to design the system with pipe sizing and layout consistent with a low percent losses (like 8-10 not 20-25 percent).
The flow and return temperatures can be lower than the orthodox values of 80/40 degC (although even higher temps. are common). Also 2×32 mm pipe may be excessive in most of the network as iit can carry typically 100 kW. That is is potentially enough heat for 30 small houses of high insulation standards, depending a great deal on how the hot water supply is arranged. If you use considerably smaller pipes, you get a moderate reduction in heat loss.
If you find the agent doesn't asnwer questions, why not try dealing direct?
If a house has natural gas, installing an ASHP plus a woodstove and maybe electric resistance water heating seems an expensive way to make clinmate change worse and double or triple the number of space heating/DHW systems you need. Why do it?
Similar with a rural house with space to store LPG, in my view. That plus solar has emissions well below an ASHP (note solar plus an ASHP doesn't make much sense for technical reasons, too long to go into here.)
As for the overheating, if it has 150 m2 of south glazing, does it have 750 m2 of floor area? Have you done any analysis with PHPP, either by yourselves or a consultant?
Suffice it to say decent building designs in central Europe (e.g. Vienna, July average 21 degC) can be kept comfortable in heatwaves, so I think something has gone significantly wrong if people are facing overheating in almost the coldest summers anywhere in the EU.
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