Lesson Two: Insulation, Energy Leakage and Drafts
Where do you start with insulation?
Insulation is like putting a blanket on yourself, it helps keep you warm and best practice is to have continuous insulation so to not create any thermal bridges. We know many Kiwi homes have little to no insulation, old styles of housing such as villas rarely have any insulation and the newer ones do, but generally only in between studs in the floor and roof.
If we could create an insulation wish list (if such thing exists) we would ask for continuous external insulation - basically a big warm blanket wrapped around the outside of our house. This method is a smarter way to insulate as it stops thermal bridges and creates a healthier home that is warmer, dryer and more comfortable to live in.
What can you do if you live in a villa?
So, you have a beautiful (old) villa that looks the part, but it has zero insulation?
Here are a few things you can do:
- FLOOR - invest in underfloor insulation, which is installed under the floor beams, another vapor permeable membrane should be added with this which will ensure you don’t have moisture, allowing the ‘house sweat’ to escape.
- WALLS – there are options, either in between the studs or applied continuously to the outside (preferred). The latter option means your weatherboards stay in place, the membrane is applied to prevent water getting inside the house, followed by the insulation and framing which holds the exterior weatherboards.
- ROOF – again the preferred option is to insulate the outside. Many Kiwi homes have a steel roof, so adding an insulation layer outside of that is a good idea – this also allows you to have a usable attic!
Why aren’t our homes insulated?
It’s not always a case of our homes not being insulated, but more so a case of what standard of insulation. The Healthy Homes Standard mandate that underfloor and ceiling insulation must be installed in a home, and in 2021 similar mandates will come into effect around heat pumps or heaters in the home.
If my home is insulated why is it still cold?
We know we can stop warm air escaping through the roof and the floor with insulation, but what about the walls? With no insulation in the walls thermal bridges are created and heat that would otherwise be contained gets sucked out of the walls. And while walls generally have a good R Value (amount of energy that goes through a thing ie. wall, window, door), windows do not. Therefore, as soon as the air hits the window (or an uninsulated wall) it is lost – this is known as energy leakage.
What can I do to reduce energy leakage?
The best way to reduce energy leakage is to identify where the energy (heat) is being lost and find a solution to reduce the amount that is escaping. A blower door test is a method used by building specialists to identify exactly where the air is escaping from – specific bedrooms, holes or no insulation in walls, low performing windows etc.
To block drafts in the house you can use draft stoppers or install foam strips to seal the door ensuring the air doesn’t leak out. If you can increase the R Value (amount of energy that goes through a thing) and make sure air isn’t escaping through a nearby gap you will help reduce air leakage and drafts in your home.
Fun fact: energy leakage also occurs in power points in your walls – but don’t worry about these too much, spend time on the bigger picture!
Is trapping heat causing moisture in your home?
Your house needs to breathe, just like you. But not through the gaps we have discussed. We need to ensure our home has adequate ventilation, which does not mean just opening the window. Sure, you can ventilate this way but it’s not as good as a mechanical option and you will be cold in winter!
Mechanical ventilation – think bathroom or kitchen fans. If these aren’t already installed in your house, you can purchase a cheap fan for your bathroom or kitchen to ensure you are removing that moisture.
TIP: Turn your bathroom fan on while showering and leave on for 30-60mins afterwards, this will continue to remove and draw out all the moisture.
In summary
You can heat your home well, but unless you insulate properly it is like sleeping with a blanket only covering your legs. Locate where energy leakage is occurring and try increase the R Value – use draft stoppers or seals to minimize loss through doors and windows. Or if you want the ultimate answer to insulation – aim for continuous external insulation.
