Open Source Content Management

Architect Peter Powell has an interesting post on GreenBuildingAdvisor.com about passive solar design principles. Powell, who say he's designed over 60 "passive solar homes" over the last 35 years, challenges some of the most widely held principles of passive solar design. The full post is here, but I've selected a few snippets and copied them below.

Powell advises against using trees to shade south-facing facades, writing:

Using deciduous trees to shade the south elevation in summer is a major design error. This is a myth that won’t go away. Don’t do it! This theory holds that deciduous trees and vines will shade south-facing windows in the summer and reduce heat gain, while in the winter, when the leaves are down, sun will be able to enter and heat the house. It doesn’t work.

The problem is that the limbs of any tree tall enough to shade the windows in the summer will significantly block the lower winter sun, even with the leaves down. In my area (central Pennsylvania), most of the leaves don’t fall until November anyway, after there have been many cool days and nights when the solar gain would have been useful.

 

He also says that getting your building orientation 100% perfect isn't necessary...

I keep reading articles about how to locate true south, using everything from computer programs to measuring shadows through different seasons. Just get a simple compass and correct for declination if you must.

Orienting a house east or west of true south by up to 20° will have no significant effect on solar performance. For example, I currently live in two virtually identical passive solar buildings, a residence and a studio. The studio faces due south and the residence faces 25° west of south. By the end of a sunny day, the overall solar performance of the two buildings is almost identical, with the house performing slightly better in the spring and fall and the studio doing slightly better in the middle of winter.

...and that it's okay for designers to specify more south-facing glazing than most rules of thumb allow:

The area of south-facing glazing area can comfortably be 15-20%+ of total floor area as long as there is adequate storage mass and “active” movement of the heat into the storage.

To maximize solar gain while minimizing overheating, immediately move the stratified heat into storage. Don’t rely on natural conduction and convection to move the heat.

Most rules of thumb for south-facing glazed area assume that the storage mass is located only in the south-facing rooms, and they assume direct conduction of the solar heat into that storage. This method is relatively slow and inefficient, except for the limited surface areas which are directly in the sun, and often results in overheating. It fails to take full advantage of the available mass in rooms remote from the sun, as well as the advantages that occur when heated air is moved through hollow masonry walls or hollow floor slabs to remote mass storage.

A house with a larger-than-normal glazed area (which could be 30%+ of the floor area of the south-side rooms) can still be comfortable and productive if solar heat is moved mechanically out of these areas and circulated into other rooms and, most importantly, directly into supplemental storage mass.

 

 

 

An article in the Guardian last Wednesday discussed a report by the Royal Academy of Engineering, which concluded that "eco-bling" such as wind turbines and solar panels will not help the UK cut carbon emissions quickly enough to meet the government's ambitious carbon reduction targets. That's hardly news - it's pretty obvious such technology is just part of the solution rather than a total fix.

The report also warns that a major step-up in the retrofitting of old buildings needs to take place.  Interestingly, it said the UK building industry would struggle to meet demands to make all new buildings zero carbon by 2020 because of a lack of skilled workers who understand how energy is used and saved in buildings. The report requested British government funding for a study to examine exactly how many workers would need to be upskilled in order to meet government building energy targets.

Reading the piece reminded of what appears to be a disconnect in Ireland regarding our ability to energy upgrade old buildings and to build low energy new ones. The construction industry clearly sees the retrofitting of old buildings as a major source of potential work in the coming years, and it has stressed time and time again that it has the skills needed to meet this challenge. It also sees the exporting of Irish construction skills as a potentially big area of work - with a green and low-energy reputation as one of the key thngs defining the Irish building brand.

But on the other hand, Construct Ireland has been hearing and seeing for years just how badly energy-related work in buildings can be: insulation not properly installed,  draughty gaps around windows and doors, badly-filled cavities, bad internal insulation jobs that lead to condensation and mould, crude heating systems and controls, building regulations not being met.

These problems are far too common, and to suggest we can immediately begin retrofitting successfully on a massive scale is naive.  The wider industry is still emerging from the property-boom mantra of quick new build with little focus on energy standards or retrofitting. Things are are improving of course, and the sustainable building sector has been at the forefront of the focus on quality.

Nonethless, what's clearly needed is a gradual approach to renovating our building stock with a focus on training, upskilling and standards first and a staggered rise in the number of buildings upgraded each year as standards improve.

We're back in the Construct Ireland offices, and hard at work on getting our January issue to the printers. Because of that there won't be much action on the website over the next week or two. I've trawled through a variety of websites and picked out various new year stories - many of them reviews of the year gone and predictions for the year ahead. Hopefully something will grab your attention.

From Jetson Green: top ten green stories of 2009, top ten shipping container projects of 2009, 19 green building innovations of 2009, 62 innovative green homes of 2009

From Green Building Advisor:  top ten energy efficiency stores of the past decade, Minnesota retrofit programme's popularity exceeds funding

From Inhabitat: themes from a decade of architecture, green design predictions for 2010, tiny solar PV cells look like snowflakes, Google unveils apps that monitor deforestation and home energy use

From Treehugger: the year in green modern homes, UK ecovillage gets government grant 

Some other interesting stories this morning: some interesting letters to the Guardian about green technology, important milestone reached in national smart meter plan, sales of energy efficient boilers on the increase in the UK

Construct Ireland takes its Christmas holidays from today, we'll be back on January 4. The next issue of the magazine hasn't gone to the printers yet but will do early in January - it'll contain articles on various retrofit projects, the ESB's home insulation scheme, a striking new low-energy build in Sligo, international green buildings and a huge profile of the Cloughjordan ecovillage project in Tipperary, among much else.

Here a few links to keep you going until then. Happy Christmas.

New solar shingle hits the market: Jetson Green

Vacuum insulated windows: Green Building Advisor (note US sites like this use R-values to demonstrate thermal performance instead of U-values - to convert divide one by the R-value and then multiply by 5.682)

When customers challenge the wisdom of smart meters: Green Building Advisor

New York City backs off retrofit requirement: Green Building Law Update

Green roofs suck up CO2: Treehugger

Green building comes of age: CS Monitor

 

 

 

 

 

I blogged last week about plans by the British Conservative Party to introduce a pay-as-you-save scheme that would allow consumers to energy upgrade their homes and pay for the work over time on their bills.

An article in the Guardian by the party's energy and climate spokesperson Greg Clark offers more detail. Clark writes:

That is why I set out our green deal – an ambitious plan to give every home in Britain an entitlement to energy efficiency improvements up to £6,500 in value. Every homeowner would be entitled to an independent assessment of what energy efficiency work is worthwhile and would save money.

They then get an entitlement to have these improvements carried out immediately by a kite-marked installer at no upfront cost. The cost of the work is repaid over 25 years via the home's energy bills.

The assessment will ensure that the measures carried out will be those where savings in energy bills are greater than the cost of repaying the amount borrowed. That means that families will be able to make their homes more efficient, pay back the cost over time, and still save money from day one.

He adds:

Yesterday we took this policy a step further. We announced that the mayor of London and 14 local councils, covering between them more than 6m homes, have agreed to pilot our green deal scheme should a Conservative government be elected next year.

Importantly, these local authorities have local expertise and knowledge, and will help us to roll the green deal out on a street-by-street basis, targeting first those people most in need of cutting their fuel bills and heating their homes.

As well as helping more families, a properly national scheme has other advantages. It could directly create 36,000 jobs in installing and surveying, with a further 42,000 jobs indirectly created in the energy efficiency supply chain. And because we are committed to apprenticeships, we will ensure one in 10 of the new direct jobs created by the green deal are to be "green apprenticeships" – over 3,500 new apprenticeships in total.

Interestingly, Clark criticises the (UK) Labour Party's plans for a pay-as-you-save scheme, claiming it will help only 500 families over two years. And that does seem to be the case - see details of Labour's plans here.
 

Two big home energy upgrade stories to report on this morning.

As the climate change talks continue to stutter in Copenhagen, UK Conservative Party leader David Cameron has pledged to kick start £20bn of home energy retrofits in the UK if his party is elected to government next year. According to the Guardian, six million British households would each be offered £6,500 of energy efficiency measures.

Cameron is proposing a pay-as-you-save type scheme, under which households would pay for the upgrades through resulting savings on their energy bills. Patrick Wintour and Nicholas Watt report:

Cameron's plans for a multibillion-pound investment in energy efficiency are part of a strategy to make environmentalism relevant. Companies such as Tesco would lag lofts and insulate walls, then share the resulting savings in electricity bills with householders over a minimum 15-20 years.

The councils that have struck deals with the Tories would not only offer insulation packages, but also identify the streets most in need of help. A household with the most basic package of measures could expect to see savings of £360 a year on its heating bills, with an energy-efficiency provider putting in an initial investment of £1,500. Some of the savings would go towards repaying the upfront costs of the improvements. Households saving £360 a year would need to pay £120 towards the £1,500 investment, but would keep the remaining £240 a year for themselves.

Meanwhile Barack Obama has called on the US Congress to provide more financial incentives for homeowners to upgrade, describing insulation as "sexy stuff" - yes I'm serious, see the report. "“The simple act of retrofitting these [old] buildings to make them more energy efficient … is one of the fastest, easiest and cheapest things we can do to put Americans back to work while saving families money and reducing harmful emissions," Obama said. 

Rising energy use in buildings contributed to an increase of 1.5% in overall energy demand in 2008, despite the economy contracting by 3% over the same period, a new report from Sustainable Energy Ireland (SEI) reveals today.

As it says on the tin - if you know of any other interesting stories please do share.

Gormley to set targets for carbon emissions reductions today: Irish Times

UK boiler scrappage scheme to help 125,000 householders upgrade their gas boilers to new, high efficiency models - sounds like a much better idea than a car scrappage scheme to me: Guardian

Cloud computing recommended for energy efficiency: Energy Saving Trust

Green architect Malcolm Wells dies at 83: New York Times

Self destructing bacteria could be key to better biofuels: Inhabitat

UK houses spending more on going green: Guardian (some figures on this here)

Copenhagen climate talks should put big focus on retrofitting existing buildings: ereleases

UK cannot meet carbon reduction targets unless commercial sector embarks on massive retrofit drive: Telegraph

Can windows perform better than walls in energy terms?: Green Building Advisor

We all know the three Rs of waste, but reducing and recycling often get a lot more attention than reusing. But now a report from the UK's Bioregional Development Group and construction waste reclamation body Salvo has re-iterated that reusing materials offers greater environmental benefits than recycling.

Via Treehugger.com, BioRegional's Jonathan Essex says: "Pushing reuse clearly shows the benefits that reuse brings over recycling. For example, if we reclaimed 50% of reusable iron and steel the carbon savings would be equivalent to taking 29,000 cars off the road - and that's for just two materials. Yes, reclamation is currently more labour intensive than recycling which makes it more expensive, but it creates green jobs and products that often have a higher value than recycled - for instance reclaimed bricks are worth much more than bricks recycled into aggregate."

The report - available here - makes some key recommendations to British policy makers: create a "reuse champion" to direct investment in new capacity and R&D, provide information to the public and work with government to promote reuse; invest in storage and re-processing capacity for reuse of construction products; set targets for the reuse of construction waste and support reuse through planning policy; incentivise reuse and reclamation by adding materials to the EU emissions trading scheme; and direct landfill revenues to reuse before recycling.

Anyone interested in this topic should check out our article Deconstruct Ireland - it's all about designing buildings for disassembly and reuse.

When I covered the Serve project in North Tipperary for the latest issue of Construct Ireland, one thing struck me: how difficult it is to convince householders to upgrade their homes. Serve is an EU-funded sustainable energy project that is grant-aiding home energy upgrades alongside the Home Energy Saving (HES) scheme in North Tipp - more info on Serve here.

The idea of Serve is to get householders to undertake the basic insulation and heating upgrades under HES -  and then go further with additional measures under Serve. Between HES and Serve homeowners can get up to 70% of the cost of an energy upgrade - but it's still a hard sell.

When I interviewed Paul Kenny from the Tipperary Energy Agency, he said most homeowners were reluctant to upgrade, and that those in houses built post-1990 were particularly disinterested. Many believed their houses to be energy efficient. Of course this generally isn't the case - according to SEI's latest stats, most building energy ratings (BERs) for existing dwellings fall between a C and a G rating.

So how should energy upgrades be sold to householders? If the experience of Serve is anything to go by, even the introduction of Pay As You Save - a scheme that would enable homeowners to energy upgrade their homes and pay for it over time on their bills, spending nothing up front - might not be enough to convince a lot of people.

A first step is to make homeowners aware of the energy performance of their homes. An idea proposed by Construct Ireland, whereby BERs must be displayed on all property advertising, is included in the current programme for government. This would ensure that BERs are prominent in newspapers, on property websites, on street signs and hoardings. It should make us all much more aware of the energy performance of typical Irish homes. After all, if my neighbor is selling her house and I see she has a D, E or F rating, I'm more likely to realise that my own home's performance must be similar and think about upgrading.

But clearly this is just one step towards making people aware of the energy performance of their home and convincing them to renovate. What else can be done to entice homeowners?