Getting from G to B: how to make an old house more energy efficient

There’s a lot more to selling or renting a property than simply doing a spring clean and putting it on the market; letting potential buyers know how energy efficient your home is, is not only advisable but is also a necessary requirement.

A Building Energy Rating (BER) certificate measures the efficiency of a dwelling by calculating the CO2 emissions and KWh/m2/yr of the property. It covers energy use for heating, ventilation, lighting and hot water and is calculated on the basis of standard occupancy. So those with a good rating will be energy efficient and have the lowest utility bills.

It is measured using DEAP software (dwelling energy assessment procedure) which calculates all the heat gained from solar gains through windows and roof-lights and from using appliances. It also calculates the heat losses through the wall, floor and roof and then figures out how much heat is needed to keep a house warm and the water hot and how efficient the heating system is.

The rating is on a sliding scale from A to G – A1 being the best and G being the worst and is based on the UK SAP rating. Completed by a registered BER Assessor (these can be found on www.seai.ie ), it is a necessity for anyone who is putting their property on the market.

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"You are required to get a BER rating when you are selling or renting your house, and the rating is valid for 10 years," explains architect Darragh Lynch. "A more energy efficient house is cheaper to heat; it is indicative of a better build quality, is less draughty and is more comfortable.

“It is also worth pointing out that the BER rating only measures the performance of your building fabric using a universal set of criteria for occupancy, hot water use, etc. It is because of this that we are able to compare BER ratings nationally, but it is not the same as your actual energy usage. Very often your energy habits can save you much more money than insulating your house, but this is a different thing than BER ratings.”

Engineer and registered BER assessor, John Neylon from Ennis, Co Clare, says there are some simple methods to improve your BER rating and in turn make your property a more attractive prospect to potential buyers or renters.

“There a number of ways in which to improve your BER rating, some are more expensive and time heavy than others, but a few simple things will get you on the right track,” he says. “The first thing to do is to cosy-wrap your house – in the same way as you would put an extra jumper on, give your house an extra layer. If you have cavity walls, get them pumped up (with polystyrene beads) – and if your house is older, it will need dry lining. A layer of mineral wool in the attic is also very beneficial, but the walls are a big factor.

“The next thing to do is to get rid of open fires and put in a stove – it may not be as atmospheric as a roaring fire, but a stove will make a huge difference to the heating in your house as a fire is only 30 per cent efficient compared to at least 70 per cent efficiency with a stove. This also applies to new boilers which can be up to 95 per cent efficient and will definitely save on your heating bills.”

The cost of the getting a BER rating for your house varies depending on its size and the reason for the rating – so an energy upgrade may cost between €200 and €400, but a rating for a new house could be more expensive.

Darragh Lynch, who will be speaking on the topic at the Ideal Homes Show next weekend, says there are lots of ways to improve the energy efficiency of your home – he agrees with John Neylon that increasing insulation is vital.

If you are insulating you should also consider air tightness and ventilation

“The attic is the best place to start and 300 to 400mm of insulation will give a very good U-Value (standard of energy passing through a material),” he says. “Insulating your walls is next best – pumped cavity insulation is quick and easy and doesn’t need any changes inside or outside – but it’s only as good as the size of your cavity. Internal dry is next on the list but you should get advice on potential thermal bridging (the difference between an insulated wall and uninsulated wall which may cause condensation problems and mould growth). External wall insulation is also a very good solution but it is more expensive that the other methods.

“You should also consider more environmentally sustainable insulation products such as cellulose, sheep wool or wood fibre. Insulating under a concrete slab is something you can only do once, when you are building, but if you have a timber floor you can also add insulation (but make sure to provide adequate ventilation).”

The Dublin-based architect says it’s also important to draft-proof doors, windows and floors and implement other small changes which can make a difference – and for some home-owners a grant may be available.

“If you are insulating you should also consider air tightness and ventilation,” he says. “This involves sealing gaps that air can leak out of and providing a designed ventilation system. And if you are replacing windows make sure to get triple glazed with airtight seals and thermal breaks.

“You could also replace your light fittings with low energy LED bulbs which are long lasting, use very little energy and are available in lots of different fittings to suit every application.

“But if you are doing (a lot of) work to your house, make sure to apply to SEAI for grants which are available for energy upgrades. However, it is important to get good advice as some upgrade works can have un-intended consequences which can affect your comfort and health.”

• Darragh Lynch will be discussing the topic at the Ideal Homes Show on Friday April 20th at 14.00.

www.idealhome.ie

www.seai.ie

www.darraghlynch.ie