Are you thinking about building a new home? Ever wondered whether to go for a 6- or 7-star home?

What’s the difference anyway? And how do you know which home is best for you? How can you make sure you find the right designer and builder? Someone who designs and builds sustainable and energy efficient homes?

The other day I had an interesting chat with a builder. Our clients had seen some of their finished homes and really liked them. 

So, they had asked me to get in touch with them. 

To find out if they are interested in building their highly energy efficient home.

The builders themselves had several green credentials. And on their website, it looked all great. Like they know their stuff.

But when I spoke with them, I asked them about the homes they have done so far. And what measures they have put in place, to make sure their houses were energy efficient.

The builder started talking about this amazing 6-star home they did. And that they had put in a rainwater tank. First warning signs for me.

I asked him how they had built the home. And they said that they built it with brick veneer. And that they made sure the sarking was done well. And that they used double glazed windows. 

Nothing wrong with double glazed windows or brick veneer. 

But, did you know? A standard double-glazed aluminium window performs as bad as a single glazed timber window. Not so special after all, right?

And not sure if you are familiar with the subject of sarking. 

Or should I rather say the issue of using sarking? 


If you use sarking on your walls and roofs you trap humidity inside your house. Which can lead to moisture build up and lead to mould inside your walls. 

Doesn’t sound that great, right?


When building a home, you need to make sure your walls are breathable. That the builder uses breathable membranes.

I’m not gonna start now listing the things you need to consider when building an energy efficient home. But I’ll put together a list of the things NOT to do when you want to build an energy efficient and sustainable home


1 Do not engage someone who does energy efficient 6-star homes
This is a contradiction in itself! A 6-star home is a house built to the minimum legal requirements. 

By no means is this an energy efficient home. 

Think about it like this. If they would skimp the insulation at one spot. The rating would fall below 6 stars. 

Oops. What? You might wonder. And yet, that’s what happens on most construction sites. There are many areas where insulation is missing or where gaps occur. 

Which is one of the reasons why most so-called 6 or even 7-star homes often perform rather like a 2- or 3-star home. 

But that’s a whole other story for another day. 


2 Do not go with a builder that wants to use Sarking
Sarking is a NO GO. Neither for your walls nor for your roof. You do NOT want to trap humidity inside your house. 

You might never see it. But it can lead to a whole range of illnesses. Like asthma, eczema and other autoimmune diseases, just to name a few.

Any membranes or wraps need to be breathable!

3 Do NOT use standard double-glazed aluminium windows
Not all double glazing performs well. Like I’ve mentioned before. A standard double-glazed aluminium window performs as bad as a single glazed timber window. 

If you go for double glazing, make sure you go for high performing double glazing. Either thermally broken aluminium. Or opt for timber or Upvc options. 

Ask for the actual window performance. You should aim for a u-value of 2.0 or lower. But never above 3.0. 

(The u-value measures the performance of a window system. The lower the u value the better performing a window. Many standard double-glazed aluminium windows sit around a u value of 4 – 4.5)


So, if you are thinking about building an energy efficient and sustainable home. 

Make sure that:

1 You don’t sign up for a 6-star home

2 Your designer and builder don’t use sarking on their jobs.

3 You don’t settle for ‘standard’ double glazed windows.


If you want to know more about HOW to design and build an energy efficient home, please contact us.