As one of our major Sustainable House Day sponsors, we asked the team at NatHERS to explain how the scheme is expanding and improving home energy ratings across Australia.
Do you ever wonder why advertising is full of pictures of smiling people appearing cool and serene, not a bead of sweat to be seen – certainly no unsticking noises when they get up from the couch – despite the blazing sun and heat haze outside? Or snug and toasty in their living room while a freezing gale howls outside. Then there’s you, huddled under a mound of blankets, teeth chattering, playing rock, paper, scissors to decide who has to brave the cold to let the dog in. Or lying as still as possible on the tiled floor, dripping with sweat, while the 2003 air-conditioner does a lot of clunking and whirring but very little else.
Whether you’re building a new home, or renovating an ageing home most people like to feel what’s known as thermal comfort. In Goldilocks-speak, that’s when your brain tells you that you feel not too hot, not too cold, but just right – even in the one room where the temperature can vary greatly in a day, let alone in changing seasons! Thermal comfort is a challenging thing to get right and it turns out it is also difficult to measure. So tricky in fact, that some of our best scientists are currently looking at how we can improve the accuracy of our measures of thermal comfort in home energy ratings.
It also happens that feeling comfortable in an indoor space is – not really surprisingly – really good for you! Unfortunately, thermal discomfort can be really bad. It’s hard to focus if you’re too cold or too hot. Throw in lack of sleep, and a downturn in your mood and the health problems begin to pile up.
If you’re like most people, you want your comfort, your health and also a bit of bang for your energy buck. Preferably keeping the upfront costs down while lowering your energy bills. The key to achieving a Goldilocks-state-of-bliss without breaking the bank? It’s all about efficiency.
You need to understand your home’s energy (thermal) performance so you know what changes and improvements will increase your comfort, preferably while saving you energy and money. That’s where the Nationwide House Energy Rating Scheme (NatHERS) comes in.
NatHERS has been around almost 30 years. It’s a national energy rating scheme that uses house plans and building specifications to measure a home’s energy efficiency. The Scheme gives the home’s thermal performance a star rating on a scale of 0-10 stars, based on the home’s design, structure and materials. Put simply – the higher the stars, the less energy you need to use (and pay for) to keep your house comfortable through heating or cooling.
Home owners can use a NatHERS star rating to compare their home to others across Australia, choose a new home, or improve an existing home. It also helps architects and builders compare the energy efficiency of different designs. This guides smarter design and building choices, such as changing the position of a home on a block, or using higher rated insulation, to help make a home more comfortable to live in and cheaper to run. NatHERS is now expanding to offer a ‘Whole of Home’ rating. In addition to rating the thermal performance of your home’s building shell, the rating will include information on the energy performance of common household appliances such as heating, cooling and hot water systems, lighting, pool/spa pumps and on-site energy generation (e.g. solar panels and batteries). This new information will help home owners better understand the energy performance of their appliances and how energy consumption impacts their bills.
If you’re like most people, you want your comfort, your health and also a bit of bang for your energy buck.
The new ‘Whole of Home’ (0 to 100) rating will sit beside the current NatHERS star rating (out of 10); the two will be shown together on an updated version of the NatHERS certificate. And in more good news, NatHERS’ new voluntary ‘In Home’ assessments mean existing home owners also have an opportunity to benefit from a better understanding of their home’s energy performance.
Until now, if you had an older home, getting a thermal performance rating could be a bit difficult. The original plans for these houses can be very different to what exists today and in some cases non-existent. No up-to-date house plans meant no assessment.
If you choose to have an ‘In Home’ assessment, an accredited assessor will visit and evaluate your home’s comfort level in hot and cold weather extremes, and the energy used by major fixed appliances such as air conditioners, heaters and hot water systems. The assessor will give you an energy rating certificate, along with information to help you better understand your home’s energy performance and suggestions on how you could improve it. Sometimes even something as simple as adding outdoor shading or using a draught blocker (door snake) can be enough to make a difference to both your thermal comfort and your energy bills.
Like the rest of NatHERS, the new ‘Whole of Home’ and ‘In Home’ assessments are designed to help you measure your home’s thermal performance, and point you in the direction of ways to improve it so you will no longer need that mound of blankets!
Better for your comfort. Better for your wallet. Better for your health. Better for the environment.