[David Olivier]

North America has differences from northern Europe. Many well-known cities in the NE USA are 10-15 degrees nearer the equator than English cities. Blue skies are more common in winter than they are in N W Europe.

This winter insolation makes a huge difference to the heat consumption for a given set of U-values, air leakage and for a given level of thermal capacity (assuming south-facing glazing).

Also the difference in energy performance between heavy and light construction increases (heavy consumes less) as one moves nearer the equator and/or to a climate with more moderate outside temperatures. Louisville, Ky. has a mean annual temperature of 14.6 degC it seems. Southern England averages about 9.5 degC. Big difference.

I don't think the UK has ever tried to teach the rest of the world to build well. That would be rash, given where Canada or Sweden had got to by 40 years ago.

I too find the UK treatment of thermal mass simplistic. I'm writing a book which may help rectify this.

[David Olivier]

I think objections to LPG are inconsistent if the alternative of an ASHP is likely to prove undersized and need resistance heat top up, with greater CO2 emissions. Even without resistance heat, its emissions look level with or higher than LPG and don't forget in the long term it's as possible to make a renewable version of gas as to make renewable electricity.

Also why should other electricity users who only run lights and appliances and heating controls off it have to pay to reinforce the cables of the rural national grid? At their present size some of these would probably melt if most buildings used heat pumps. Most of it was sized for a peak demand of around 1 kWe per dwelling not 2 or 3 or more kWe.

See THE GREEN ELECTRICITY ILLUSION written 8 years ago on this site somewhere and points still mostly valid.

[David Olivier]

Merely some action in the civil courts would be better than nothing.

In several continental European countries, if the space heating bill greatly exceeds the stated amount (usually assuming the building is 20 degC all winter) the tenant can sue the landlord or the owner can sue the contractor or designer.

I had some clients with a house like this in 2009 – a reasonable oil bill might have been £600/year, the actual bill exceeded £3,000/year – but they weren't interested in going further. It was undertaken on a direct labour basis; it wasn't from a volume developer. Moreover, as Building Control was one of the parties who had wrongly-advised them, the other being their architect, there wouldn't be much possibility of a prosecution of anyone else by Building Control !! The only possibility would have been civil action.

[David Olivier]

An excellent paper.

Not even I had realised the extent to which results sent to Building Control are “altered”. A building inspector recently told me results had been significantly improving and he seemed to be quite positive.

To get any sense of the trend, someone will have to return and re-test a random sample of modern buildings constructed in 2002, 2004, 2006, 2008, etc. The Building Control database is probably as useful as Andrex.

David.

[David Olivier]

Maybe this comes too late but I cannot see the reason for heating with electricity made from natural gas (and a little coal) instead of heating with LPG using a £2.5-3k condensing boiler. Both are fossil fuels and the theoretical COP of perhaps 3.5 from the GSHP comes at a price of many £1,000s extra. I understand that the capital costs of heat pumps have increased now that they must be sized to meet the whole peak heat demand.

Several contacts and clients have houses which are thermally-efficient enough to be heated by a few cylinders of gas in a normal winter, i.e. not needing a bulk tank.

In urban areas with natural gas, by this design feature one could risk spending more money initially for a heating system which emits more CO2 and increases the running costs.

Please read The Green Electricity Illusion elsewhere on this site to explain why if you are grid-connected then your CO2 emissions from heating electrically are not affected by the presence of a renewable electricity source on your roof or in your garden.

[David Olivier]

MEV? Very under-hyped, unlike most systems, but neutralises the background air infiltration up to a point.

Used in all new Swedish buildings from 1978 until they went more for MVHR, with their builders unlike ours being apparently able to construct very airtight buildings without much effort i.e. <1 m/h @ 50 Pa.

MEV = unwise if you have open-flued appliances e,g woodstoves within the heated space.

I've seen 1950s semis. in which both houses have had their chimneys removed and tiled over at some point in the last 50 years. Good idea for all all chimneys I think, unless they are “Listed”.

[David Olivier]

Hello Peter

I suspect that if you check with the mfcr. you will find that the U-value has the product in a vertical position!! This is just one of the bizarre assumptions that European companies get away with.

Rooflights seem to be so poorly-insulated that for my house I made my own. It's modelled on the two-part construction used in the 1st Canadian Advanced House in Brampton, 1989. In Scandinavia it would be described as 3+1 glazing.

I think the NFRC in the USA has published some true in situ U-values for sloping glazing in their climate, under design conditions, as has the ASHRAE Handbook. Needless to say they are worse than European quoted figures.

I suppose it might still work out, inputting the true U-value of this product, and benefiting from the gains of natural light, but there could presumably be a downdraught if the U-value including the installation psi-value is too high.

So far I haven't detected a downdraught from mine. I'm writing a book on the house and will probably give the details in there.

Regards

David.

[David Olivier]

Tariq

Weather compensation is explained by these installers ecotechnicians.co.uk. If you're near enough to London where they're based it might be worth paying one to visit and do some fine tuning or even suggest modified controls for a condensing boiler which should be run with low water temperatures 24/7 not as hot as possible for two periods/day.

Or I know a retired mechanical engineer in Essex if any use but he'd similarly want a consulting fee to sort out someone else's heating system (He achieves a measured 96% efficiency using a condensing boiler on the existing radiators).

It should be more valuable with UFH. Without it there tends to be a regular fluctuation in room temperature. caused by too much heat entering the floor at once.

Surely a condensing boiler shouldn't need a thermal store for the space heating. Gas can be burned very precisely on demand, as the bills from well-designed and installed systems all bear out although it would ne nice if they were the rule not the exception.

David

[David Olivier]

I recently looked at the warming to date on the Met Office records for London and the rural W Midlands. and plotted some graphs. There seems to have been little more than a 0.5 K warming in the last 60 years at Shawbury. The London site I looked at, Heathrow, has it seems been affected by suburbanisation which can cause an apparent warming rate much higher than the true figure.

I think it is a lot more important to ensure that weather files are valid for the typical weather we have experienced over the last 30-60 years. Until winter 2009/10 I heard people saying that the climate was warming so much that we should be using new, much less severe different weather files, only to change their mind after December 2010 which was comparably cold to January 1979 or December 1981.

I also note that the Met Office has revised its models recently as well.

[David Olivier]

Why is a new house designed other than with typical continental controls of weather compensation and continuous heating?

Compulsory across the Channel, so rare here that some heating installers don't understand the concept.

[David Olivier]

A group of people have known of this risk ever since we attended a talk given by Eddy Verhelle from Belgium in 2007. He was extending his earth-sheltered house and found that none of the insulation materials whether XPS or cellular glass had performed as advertised by the mfcr. They had been eaten into holes and/or were soaking wet.

He found an absolute lack of cooperation from all insulation manufacturers whose products he had used.

One of us did a thorough web search and this showed that vermin risks to insulation especially rats/mice and glass fibre were publicised by several US and Canadian government organisations many years ago. Much less awareness in Europe even now (2012).

David

[David Olivier]

I or any Canadian or US window company could tell them how to make glazing with the U-value of eight panes of glass and the weight of a single 4 mm pane. Clue … just buy some mass-market US windows and take apart the sealed unit, where you will find 2 to 2.5 mm heat-strengthened glass.

If they care to buy my book in due course, they can learn more for a lot less than several million Euros!

[David Olivier]

Or insulate the 60 mm cavity?

[David Olivier]

In the rest of Europe they use cranes!!

[David Olivier]

I'd try to get components from Sweden where MEV was compulsory in new construction 35 yrs ago

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