In one form or another, underfloor heating has been around for a very long time. Only in more recent years, though, has it become as common practice as it is now. And, with the benefits not just limited to how good it feels underfoot, we’re not at all surprised. But if you’re still deciding whether underfloor heating is the right choice for your home, it’s worth learning a bit about the different types you can choose from and how they work.
THE BASICS
Underflooring heating is one of many methods to heat or partially heat an indoor space. It involves a system of pipes or wires (more on this in a bit) that are installed within or underneath the flooring and produce heat. This heat is then transferred into the flooring where it radiates into the rest of the room, or transfers further into furniture or directly into your body through your feet.
One great thing about underfloor heating is that it’s not visible, so there’s no need to have an ugly appliance disrupting your interior design.
IS IT WORTH IT?
The type of heating that’s best for your home will depend on a lot of factors, including your budget, heating needs, and energy source. However, there are some significant benefits that come with underfloor heating.
First, underfloor heating will heat the room more evenly than other options like radiators or central heating which can create cold spots. They’re also effective when heated to significantly lower temperatures than traditional radiators, reducing their energy usage.
On top of this, underfloor heating can be safer and healthier than other alternatives. Tucked neatly away under the floor there are no sharp edges or hot surfaces that people can hurt themselves on. As it doesn’t rely on fans or ducts, it also won’t spread airborne pollutants like dust mites or pollen. In bathrooms, it can even speed up the evaporation of moisture to reduce mould buildup.
Now let’s consider the level of flexibility that underfloor heating provides. It can be installed in as many or as few rooms as you’d like. And, even when throughout the home, it can run in zones, heating the rooms you’re using without wasting energy in the ones you’re not. Despite its name, it can also be installed in walls—although this may not be as efficient.
IN SLAB VS IN SCREED
Underfloor heating can be installed either in slab or in screed.
In slab heating is connected to the steel mesh of your home’s concrete slab before the concrete is poured. This means it needs to be installed very early in the build but will also be able to take advantage of the slab’s thermal mass to maintain heat. Keep in mind, however, that any damage that’s discovered after the concrete has been poured will require cutting into the concrete to access the heating system. In slab systems can be used in zones, but as the heat will spread throughout the slab, they’re more ideal for heating an entire home.
In screed, on the other hand, is installed in the thin layer of material (often a mix of cement and sand) that’s spread between the concrete slab and chosen flooring, like tile or carpet. For this reason, it’s installed much later in the build and can even be added with some relatively basic renovations. As an in screed system is closer to the surface, it will heat the room much faster. The heat is also less likely to spread throughout your concrete slab into the rest of the home.
At our Langsford Street project, our clients chose to install in slab heating in their bathroom, but in screed heating beneath brick pavers in the kitchen. While bathrooms typically have in screed heating under the tiling, in slab was the most appropriate here to allow for a completely tile-free bathroom that would be easy to keep clean.
ELECTRIC VS HYDRONIC
No matter whether it’s installed in slab or in screed, there are currently two different types of underfloor heating: hydronic and electric.
Hydronic
Hydronic underfloor heating uses hot water that circulates through a series of pipes. The water is heated through the hot water system with the help of a gas booster.
Hydronic systems are much more expensive to install but are then more efficient to run long-term. If installed in slab, keep in mind that the concrete slab will need to be thicker to allow for the extra space needed for the pipes.
Electric
Electric underfloor heating uses ultra-thin wires that heat up as electricity passes along them. It’s significantly more affordable upfront but then requires more energy to run (although this can be mitigated with solar PV).
It’s worth noting that electric systems can take quite a long time (a few hours) to heat up when installed in slab. However, some people have solved this problem by simply leaving it on all winter. This way, once it’s taken the time to heat up initially, all it needs to do is maintain that heat (which doesn’t require much energy).
Note how much thinner these wires are compared to the hydronic pipes above.
In our Vivaldi Street project, electric underfloor heating installed in screed was the best choice as it was only needed in the bathrooms.
TRADE SECRETS
To reduce the risk of damage to your underfloor heating system, make sure the layout of your room is well planned out before installation, and make sure your heating system won’t be under anything that will be fixed into the floor (the installation of which could damage the system). At Arklen, we also very carefully map all the pipes or wires for future reference.
We’ll install all in slab heating with an alarm that will alert us if a wire or pipe is compromised. This ensures any damage can be dealt with as quickly as possible.
If installing underfloor heating in a suspended slab, insulating under the slab will help reduce heat loss. At our Gooseberry Hill project, underflooring heating is installed in their kitchen, living and dining area which originally sat above an open parking area. A few years down the line, though, they transformed this space into a games room to accommodate a growing family. The addition of this room, with insulation, has noticeably improved the effectiveness of the underfloor heating.
The decision about whether to include underfloor heating and, if so, what type to include, isn’t an easy one. As builders, though, we’re here to help our clients make these decisions, and will always walk you through the pros, cons and costs of each option specifically for your project.
Photographers: Scott Wright Photography, Peter Ellery Photography, Dion Robeson and Arklen