Will nZEB mean lower household bills?

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nZEB stands for nearly Zero Energy Building so does this mean home buyers benefit from tiny energy bills?  …it depends!

In 2010 the European Union issued a directive that by the end of 2020 all new buildings and homes should use almost no energy and that a considerable part of the remaining energy needed, should be met with renewable energy. Each member state decides how this should be implemented  and defines what ‘nearly’ means. The Irish Government is implementing the directive through revised building regulations for homes which are proposed to come into force on 1st April 2019 … just a couple of days after Brexit!

This means that any dwelling receiving planning permission after 1st April  should meet the nZEB standard. After 2020 all homes irrespective of when they received planning permission should achieve the new standard. However many of the better home builders will meet the standard before this date.

But what does nZEB mean in reality based on what is in the proposed regulations? It should result in homes on paper that are 70% more energy efficient than the homes we were building during the last boom ten years ago and for typical homes this means an A2 energy rating so is a very substantial improvement …if they are built right!

We have been on a journey to get there. The Green party in government from 2007 to 2011 drove the agenda updating the building regulations for energy efficiency twice in 2008 and 2011 meaning that the next step to nZEB as defined by the Irish Government is no longer a huge leap.

But will it result in ‘nearly’ no bills? Not quite! There are lots of reasons why energy bills could remain high depending on the path the home builder chooses to meet the regulations so one nZEB home may not be the same as another.

Higher heating bills could be down to poor workmanship. Poor application of the building regulations often mean the home does not perform as well as it should, because small details in both the design and construction of the different junctions of the home are not fully right such as tiny gaps left in insulation, little gaps left around pipes, poor commissioning of heating systems etc.

Also not all designs are equal and the regulations require the architect to improve the efficiency for that particular design. A mid terrace home or apartment is already inherently efficient,but a  detached sprawling dormer bungalow is inherently inefficient because of the exposed surface area so nZEB will make a bad design better but not as good as an inherently efficient design.

Under the proposed nZEB /building regulations the home builder can also choose to skip installing a properly commissioned  ventilation system that would guarantee good indoor air quality if  their homes have a higher level of air infiltration rate (ie are leakier) based on an air tightness test reading of above 3cum/msq/50pa. If your homebuilder chooses this route,they must also install twice as many  ‘hole in the wall’ type vents, to meet background ventilation requirements. This means that not only could the  home be so drafty that there may be no reduction in heating bills, but the home could suffer from very poor indoor air quality and mowld growth.

Water efficiency is also weakly regulated under building regulations and inefficient sanitary ware could really impact your energy bill, as water needs to be heated for showers, and the more water you use the more you need to heat. With a family of teenagers water efficient showers will  help keep bills under control. Some showers can use anything up to 26 litres a minute or more of expensive hot water, whilst the most efficient can be down to a remarkable 3 litres per minute. This is why all new homes should be fitted with  European water label  A rated taps and showers.

One thing to remember is that the building regulations do not cover appliances or other electronic equipment that you purchase after you occupy the home ,so if you still have a large bill, part of it could be down to inefficient white goods such as washing machines, computers, large screen televisions and the real energy guzzlers – clothes driers.

Under the revised regulations the renewable energy system should provide 20% of the fixed energy requirements of the home, but this does not count the non fixed energy requirements such as appliances and the many electronic gadgets in our homes. The builder may also choose to install a larger renewable energy system as it is sometimes a cheaper way of complying with buildings standards than by ensuring that they get the basic fundamentals right, like insulation and good workmanship. This may do your bills no good, because an extra PV panel on the roof could  be exporting the electricity when you are out of the house, whereas good workmanship would actually keep you warm at night. Remember there is currently no Feed in Tariff for exported electricity in Ireland.

Therefore it is the particular pathway by which the homebuilder chooses to comply with the new regulations that will largely determine how low your bills will be. And of course the size of your bill   will  also be down to how you use the house and the number of people in the home as the BER can only make assumptions based on the size of the house and number of bedrooms. Finally utility companies will continue to charge  hefty standing charges plus VAT no matter how little energy you use.

This is a good  reason to seek out homes with Home Performance Index certification, as it looks for an approach that benefits you the most, in reducing bills and looking after your health. It requires water efficient showers and taps, assesses the skills of the design team and the construction team to minimise the risk that the home does not perform. It insists on real attention to detail on how insulation is installed and requires proper sealing against drafts which causes poor performance.  A properly designed and commissioned ventilation system must always be installed. It encourages the home builder to supply the best A+++ rated white goods. But beyond this it looks at many other issues that will cut your bills, like location potentially saving you thousands each year in car costs.

The best way of ensuring that  the ‘nearly’ in your nZEB home might just be near enough, is if you also insist it is a Home Performance Index Home!

This little video explains the key dates that home builders must be aware of in the implementation of nZEB