Why is my house so cold in winter – and what can I do about it?

by | Aug 15, 2022 | Budget, Performance

Your house is supposed to be a warm and comfortable place – especially in winter. But unfortunately, that is not the case for many Australian homes: The walls are thin, the windows leak, and more often than not, there is no insulation in the walls.  This is not only highly uncomfortable for everyone living in the house, but can actually become a real health concern. That’s why we are taking a look at the most common reasons for cold homes – and what you can do to warm it up.


  • Health concerns from cold houses
  • How warm your house should be
  • Reasons why your house is cold
    • Poorly performing windows
    • Air leaks
    • Missing insulation
  • Conclusion: There is warmth in sight

Health concerns from cold houses

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Living in a house that can’t keep the inside temperature at a certain level is not only very uncomfortable, but can cause a variety of health issues. 

Cold houses can cause respiratory problems

When the temperature inside your home is lower than the outside air, your body has to work harder to keep warm. This extra effort increases stress on your lungs and heart, which can exacerbate asthma or other lung conditions, such as chronic obstructive pulmonary disease (COPD).  Your internal organs are also under more pressure when you’re cold—your kidneys have to work harder to regulate body temperature. While this may sound trivial in comparison to other ailments listed here, it’s important for homeowners who suffer from heart or kidney conditions that affect blood flow through their bodies in order to prevent further complications as a result of exposure—particularly during winter months when temperatures drop significantly outside.

Cold houses can cause mental problems 

Studies have found that cold temperatures can affect people’s moods and their ability to think clearly. This is because the brain needs oxygenated blood to function properly, which means it becomes distressed when exposed to low temperatures over long periods of time. Research has also shown that living in noisy, dark and problem-plagued homes increases anxiety, depression, and even loneliness. And housing flaws, such as mould, damp, or cracked walls, are also a major predictor of depression.  ? If you want to know more about the health threats of cold homes, we recommend you read the WHO Housing and Health Guidelines – especially chapter 4 on “Low indoor temperatures and insulation”.  So next time you tell yourself to suck it up and put another layer of clothes on, remember that this is not a long term solution if you want to keep your own and your family’s health a priority.

How warm your house should be

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The World Health Organisation (WHO) recommends that indoor temperatures should be at least 18°C. Unfortunately for many Australians living in houses with poor insulation, those numbers are difficult to reach. In fact, an ongoing national project by the community organisation Better Renting is currently investigating what the real indoor temperatures are this winter. Shockingly in one particular case, even with three heaters running in part of the house, one participating couple still couldn’t get their house up to more than 17 degrees.  If we take a look overseas to countries that experience way colder outside temperatures in winter than even the coldest Australian climate, we can only admire the numbers that are coming in for their homes. One study looked at how much heat is lost over the course of 5 hours inside homes in North and Western Europe when the outside temperature is 0°C. They tested 80,000 households and found that in Norway, the temperature only drops 0.9°C inside homes, with Germany being a close second with only 1°C temperature loss.

You can find the study here but beware, it was conducted in German!

Reasons why your house is cold

There are several reasons why your house is cold in winter, but we will focus on the areas that, in our experience, most commonly affect the home’s thermal performance. These are:

  1. Poorly performing windows
  2. Air leaks 
  3. Missing insulation

1. Poorly performing windows

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Poorly performing windows mean that warm air is escaping through the thin layer of (often single) glazing as well as gaps in the frames or seals, which then allows cold air to come into the room.  Single-glazed windows don’t insulate as well as double-glazed ones (which have two panes of glass separated by an air layer) or triple-glazed ones (with three panes). This means they will allow more heat loss through their glass surfaces. High performance windows also usually come with a special coating that reduces the emissivity of the glass. But window performance is not just up to the amount of glass panes – it is also about the material of the frame itself, as this can massively influence the heat transfer from inside to outside. Aluminium frames transfer more heat than wood or uPVC frames do because aluminium has a higher conductivity than other materials. Conduction is responsible for transferring energy from one source to another (like inside your house to outside). This means that if it’s cold outside, an aluminium frame will let more of the cold air into the house, because the cold transfers through the frame more easily. 

If you want to learn more about the different types of windows, we have a full article about window performance as well as an in-depth episode of our podcast that you can listen here.

Solution for poorly performing windows

If you have single-glazed windows, the solution to this problem is to increase your energy efficiency by upgrading to double glazing. This will help insulate your home and reduce heating costs. If your window frames are wooden, you can actually reuse the frames and just increase their thickness to allow for double glazing.  If you have single glazed aluminium windows, we recommend installing high performance windows that can help reduce heat loss and condensation problems in winter months. They also work well at keeping out unwanted noise when compared with standard double glazing but ensure that they are installed correctly as this will make all the difference in terms of their effectiveness! This means making sure that you seal all around your window and don’t allow any unwanted air to pass through a gap between your window frame and your wall.  If you think that upgrading some or all of your windows might be something for you then speak with your trusted window supplier who can offer advice on what would be best suited to meet both cost and energy saving requirements within your property.

2. Air leaks

Air leaks can waste energy and contribute massively to a cold home. They can also cost you hundreds of dollars per year, which is why you should seal air leaks in your home as soon as possible. There are many reasons why air leaks occur:

  • Walls, windows and doors aren’t sealed correctly
  • Insulation around pipes, vents or power outlets is missing or damaged
  • The external building wrap has not been taped and sealed correctly

Solution for air leaks

If you’re trying to figure out how to seal up air leaks, having a blower door test combined with thermal images done should be your first order of business. This will help pinpoint where your air leaks are occurring, and hence which areas you should be focusing on most with your rectification efforts. ? During a blower door test, the home is depressurised to a pressure difference of 50 pascals. The system will then indicate the air changes per hour (ACH), so how much air is being lost over the course of an hour. Combined with thermal images, this is the most reliable way to identify air leakage, missing insulation, and thermal bridging defects. Book your blower door test now!  If you have access to the building wrap of your house (the insulation between exterior walls), you should also make sure it is properly taped down and seal any gaps with blow-in insulation or other materials.  And of course, if the blower door test indicates that there is insulation missing in some areas of your home, you should have insulation installed. 

3. Missing insulation

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Insulation helps keep heat in and cold out by creating an air barrier between the outside world and the inside of your home. You can add insulation to walls, ceilings and floors. In some cases, however, there may be no insulation at all in a wall or room! When you’re looking for missing insulation in your house:

  • Check corners where two walls meet each other are properly sealed with caulk or foam sealant;
  • Look for gaps around windows;
  • Check for areas of missing flooring (if you live on a concrete slab) or ceiling panels (if you live in an attic);
  • Check power outlets

Solution for missing insulation

To identify areas of missing insulation, you can use thermal imaging to take pictures throughout the house. You’ll want to focus on corners, walls and ceilings that are poorly insulated—and if you see any dark spots in these areas, that means your home is losing heat through them. If there are obvious gaps between walls and floorboards, you can fix them with blow-in insulation. This material works well because it’s easy to install—all you have to do is insert it into the space between your walls and floors, then leave it alone until the winter comes around again! If there aren’t obvious gaps between surfaces in your house then consider adding more insulation directly onto each wall instead.

Conclusion: There is warmth in sight

You don’t need to suffer in the cold. There is warmth in sight, and help is available. Start your journey to a more comfortable home by having a professional energy audit done to identify ways you can improve your home’s efficiency and reduce heating costs, before you start sealing those gaps and upgrading your home to a more comfortable – and healthier – temperature.  And that’s it! We hope you now know why your house is so cold, and what can be done about it. If you have any questions or concerns about any of the topics we’ve discussed, please don’t hesitate to reach out to us. Our team would love nothing more than to help you get comfortable at home again!

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