Where does the heat in the house escape? This is an important question that many ask themselves, because if it is possible to eliminate heat loss, it is possible to make significant savings in heating! So, let’s take a look at some of the basics behind it: what should be done to stop heat loss in the house? In which order ? What offers the best cost-benefit ratio?
What you will learn
The thermal envelope
About 25% of the heat produced by your heating escapes through the roof of your health home.
About 35% of the heat will escape through walls and gaps, in and around windows and doors, and about 10% of the heat will escape through the floor. Together, the roof, walls (+ windows and doors) and the floor constitute the thermal envelope.
If you can slow down this movement of heat from inside the house to the outside environment, passing through the thermal envelope, you can significantly reduce your energy bills. In modern houses, building regulations state that houses must be built for this purpose. But how do you adapt these solutions to older homes?
Prevent heat from coming out through the roof
Install insulation in the attic. This is the first step in improving the energy efficiency of a health home: it is really cheap, easy to do, and can pay off in two years or less.
You’ll need to decide if you want a warm attic or a cold attic, and what exactly you want to do with the attic (e.g. do you want to store boxes up there and be able to move around in them?)
In addition, you need to decide on the insulating product you want to use: mineral wool, sheep’s wool, rigid insulation board, or even newspaper. There are many options to consider.
Prevent heat from coming out through the walls
Walls generally come in two forms: solid walls and cavity walls.
Typically, properties built before 1930 have solid walls and those built after have cavity walls.
Cavity walls are incredibly easy to insulate – all you need to do is inject an insulating material into the walls, which slows down the movement of heat. This operation is inexpensive and worth doing, with a relatively quick return on investment.
If you have solid walls, things are more complicated, as there is no cavity that can be filled in, so the walls must be insulated either from the outside or from the inside. This operation is expensive and, on the outside, it involves siding (you will therefore lose the aesthetics of the brick, for example). If you opt for interior insulation, you will lose some floor space.
Thewall insulation is worth doing as it represents the greatest source of heat loss.
Windows: important, but not as much as you might think!
In older homes, people absolutely want to replace them with double glazing in order to stop heat loss and keep their homes warmer.
There are two things to consider: First, think about the glazing area of your health home in relation to the wall area. Normally the area of the walls is much larger than that of the glazing, so always target the walls first.
Second, double glazing is expensive, and can take many years to pay off. I have the example of my parents’ house dating from the early 1900s, which has many windows. The cost of replacing them would only be amortized by the heating savings in about thirty years …
That’s not to say it’s not worth doing, as double glazing will improve health home comfort by stopping heat loss, cold drafts, and improving sound insulation. However, from a financial point of view, other measures will have to be considered first.
Draft protection: inexpensive and quickly pays for itself
Sealing is often overlooked, but consider an open fireplace in your health home. Cold air rushes in, and the expensive hot air that your radiators have created can simply go up and out through the chimney. This can be avoided by making your health home draft proof.
Caulking can be installed around doors, windows, attic hatches, floor slats, etc.
How to prevent heat from escaping through the floor
Standing on cold, drafty ground is uncomfortable, but you can fix it! Insulating the floors will prevent heat from escaping, but if you are looking for something more, you can install underfloor heating in conjunction with a traditional boiler or, better yet, a heat pump. This will allow you to heat the house and get rid of radiators for good! Insulating floors is a relatively straightforward process, and like walls, there are two main types: solid floors and hanging timber.
Small mention of U values
When you study the issue of your health home’s energy efficiency, you might come across the term “U-value”. Do not be afraid of it, it is simply a loss of heat.
The lower the U value, the better. Thus, an unfilled cavity wall can have a U-value of 2.0 W / m2, while filling the cavity can reduce the U-value to 0.2 W / m2.
With these few tips, you should be able to optimize your insulation. If in doubt, you can also get a thermal imager that will allow you to detect temperature differences. This is expensive equipment, but most health home improvement stores rent it out today. There is then the possibility of calling in a professional who can establish a complete diagnosis.
When the insulation is optimal, you can then focus on the most efficient heating methods to optimize your energy consumption.