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Any kind of renovation should include energy-saving measures

Fri, Mar 14, 2014, 10:46

When refurbishing and extending it makes sense to go down the sustainability route, after all there is little point in adding insulation and replastering if you still have draughts jetting through old windows and the roof.

Other reasons are to cut energy bills and save the planet, as well as helping Ireland achieve its target, set by EU legislation, to reduce energy consumption considerably by 2020 (with low to zero carbon houses from 2016 onwards).

If you’re building an extension or making substantial changes to an existing house (or converting another building into a home) you will need to comply with Part L building regulations, which are being tightened gradually. Although the regulations concerning retrofits are not as onerous at those for a new-build or, to a lesser extent, an extension.

Ways to save energy are to both cut down on its use as well as making your own power. Before you even start retrofitting or building, it pays to plan properly which may involve reconfiguring your living space to collect sun (free heat) and guard against the north wind. If you put service spaces, halls and stairs on the north side it will help to insulate living spaces from the chill.

Also, trees can help shelter a building from wind while protecting from the sun. Nature has designed deciduous trees brilliantly for this: their leaves in summer shading from the sun, and dropping in winter when we need all the light we can get.

When it comes to energy, you can both guard against energy loss with insulation, and gather your own off-grid sources. Both wind turbines (usually more effective in the countryside, although the neighbours might throw a hissy-fit) and sun-gathering PV (photovoltaic) panels to make electricity. Solar panels garner the sun’s power and air or ground-source heat pumps use heat from the earth or atmosphere to contribute to hot water and central heating.

Biomass boilers that burn wood-chip have the benefit of being carbon-neutral because the carbon emitted when trees are burned is roughly similar to that absorbed by trees that are growing; also wood is a renewable resource.

To stop energy loss and to keep the building at a higher “resting” temperature than freezing, which is familiar to many who own period buildings, you need to put in serious amounts of insulation: in the roof, to stop rising heat departing, in the walls and even floors. Up to 60 per cent of heat is lost through the building’s fabric in uninsulated homes.

Insulation needs to be planned and installed in a way that prevents thermal bridges, which are gaps that heat can sneak out of. Key points are in windows and doors, junctions between floors and walls, and walls and roofs, and holes for pipes and cables.

You can save water and cut down on costs (to be introduced soon) by collecting rain in barrels and installing grey-water systems that recycle water from sinks, rain and showers for use in gardens and toilets. Composting toilets cut down on water too.

The main considerations are the cost of any measures, the ease of installation and how long they take to repay the investment although their value to society and the planet outweighs financial value.

Joseph Little Architects blazed a trail when they designed Ireland’s first EnerPHit house in Monkstown, Dublin.

The Passive House Institute, understanding that passive house standards were too onerous for most retrofits (they are easier to achieve with new-builds), created EnerPHit, which is also very stringent, requiring a “deep” retrofit, achieving energy savings of between 50-90 per cent).

“The key thing is airtightness,” says Little. This has to be achieved at an early stage of construction work, when the building is a carcass and before services and finishes are added.

Many people aiming for EnerPHit standards are pressured out of it during building work, perhaps due to a tight building timetable. “In our case the client was fantastic, willing to rent that bit longer,” says Little.

The owner Pauline Conway wanted to make her house an educational tool as well as protect the world’s resources. Her patience and commitment allowed them to stop the build while they conducted further airtightness tests, when the first one failed.

After a few months they achieved the standard required. The builders are now taking their expertise to every new job even though the energy-saving requirements may not be as high.

“It has become part of how they build. Achieving airtightness has become a way that builders can prove they are good,” says Little. While the retrofit of the 111sq m Monkstown house was to EnerPHit standards, its 48sq m extension was built to passive house quality. This addition faces south and has sunpipes, rooflights and windows extended downwards to become patio doors.

There are also solar panels at the back of the house. In taking a low-carbon approach, many of the building materials throughout were made from timber, including triple-glazed windows and doors, and the insulation was recycled newspapers and wood fibre.

When the project was complete the BER of the house had risen from G to A3. And it does indeed provide an example.

“The construction industry needs many more examples of deep retrofit to a clear standard,” says Little, who admires the way that Germans set a goal and work towards it, something , he says, that we too need to learn.