When my wife and I bought a new home, it came standard with an underfloor heating system. Since we’d never had one before I decided to do some research to figure out how it works and most importantly, to understand if it’s a safe and effective heating option.
Here’s what I found.
Underfloor heating is a safe and effective system in the home especially when the flooring is made of ceramic or stone tile or vinyl or wood as they transfer heat to the floor surface at a high level. Carpets and rugs are less effective at transferring heat to the surface.
Before you decide on whether to install an underfloor heating system in your current home or in a brand new one, let’s take a look at the pros and cons and why it might be worth considering.
How does underfloor heating work compared to other options?
An underfloor heating system involves laying electrical or water-heated elements on the ground and then covering them with the actual flooring itself such as tiles, ceramics or wood. When the system is turned on, the heating elements beginning heating the area above it and the flooring will begin to warm up, eventually reaching the floor’s surface.
The actual heating process itself involves three stages:
Conduction
Conduction is the transfer of heat through contact, in this case from the heating elements underneath the floor to the flooring substrate directly above it. This is typically a tile or ceramic surface, hardwood, laminate or vinyl in a home.
In the case of underfloor heating, the conduction occurs through the flooring surface which gets heated from bottom to top. Other examples of convection include a radiator, AC unit or boiling water.
Conduction is the slowest form of heat transfer which is why when you turn underfloor heating on, it can take some time before you feel the heat underfoot depending on what floor temperature you’re starting from.
Radiation
Radiation involves the transfer of heat from one surface to the next. In the case of underfloor heating, the heat is transferred from the bottom of the flooring surface eventually to the top.
Other examples of radiation include the heating of the earth by the sun and coal or bricks heated in a fireplace.
Radiation is the fastest mode of heat transfer and follows the conduction phase.
Convection
While convection is often referred to in cooking or when boiling water to make tea in a kettle, convection heating also includes a radiator which takes cool air from the bottom and pushes warm air out of the top.
In the case of underfloor heating, the heated air radiates from the flooring and circulates throughout the room since warm air rises.
What types of underfloor heating systems are available?
Underfloor heating is offered in three main types:
Electrical – Electrical floor heating is generally made up of mats which are rolled along the ground to cover the entire floor. The mats have electrical wires that when turned on, provide radiant heat through the flooring surface.
Water – A water-based heating system is referred to as a hydronic system. It uses pipes filled with water that are heated to distribute the heat and warm the floor radiantly.
Hybrid – A hybrid system may utilize another heating source such a a radiator or forced air system along with an electric or hydronic underfloor heating system. You may find in particularly large rooms or small rooms with little floor space, that underfloor heating is used as a supplemental heating source. In old or otherwise poorly insulated homes, a hybrid system may also be employed.
How does underfloor heating affect other heating sources?
Underfloor heating can replace other heating options such as wall heaters, forced air heating systems or boilers to heat a home in most cases.
A wall heater will heat the immediate area nearest the heater first as will a forced air system. The air then circulates throughout the room over time but there may be hot and cold spots as a result.
In that regard, an underfloor heating system offers a more evenly heated room since the entire floor is heated consistently.
Unless you have a poorly insulated home or a small room with little floor space, underfloor heating can usually replace another heating option for that room completely.
How long will an underfloor heating system last?
Manufacturers and installers refer to wires and piping used in underfloor heating systems as having a lifespan of 50 years. The thermostat can be easily replaced if needed and repairs to an underfloor heating system can generally be isolated and done as needed depending on the flooring type you have installed. Systems generally require little to no maintenance, too.
By comparison a furnace will generally last 15 years and perhaps longer if you’re lucky. A furnace also needs yearly maintenance at a cost and replacement of furnace filters every 3 months due to the forced air nature of the system.
With a forced air system you may also have to do air duct repairs, duct cleaning or duct replacement over time.
What flooring options work best with an underfloor heating system?
Tiles made of ceramic and stone and polished concrete or resin floors are the best flooring materials to transfer heat from an underfloor heating system to the floor. Vinyl, linoleum and solid and engineering woods are next best. Broadloom such as carpets and rugs score the lowest in terms of transferring heat.
Tiles additionally don’t crack when heated as they don’t expand or contract when the temperature changes. Tiles, stone and ceramics are also very good insulators of heat too.
With wood flooring, an underfloor heating system can change the moisture content of the wood. You should not reach a floor surface temperature of more than 27°C (81°F) to protect your wood flooring. Engineered wood tends to be the best wood option used in conjunction with underfloor heating.
Before you agree to have any flooring installed, check with the manufacturer to ensure that it is suitable for an underfloor heating system.
Which rooms can you install underfloor heating in?
Underfloor heating can be installed in any room in your home including the bathrooms, kitchen and in the basement.
A common place to install underfloor heating is in the bathroom since most people who work or go to school get up early in the morning and usually head straight to the bathroom to have a shower and get ready.
Having a warm room ready first thing in the morning is seen as very desirable and underfloor heating can help achieve this.
In the basement which is on the lowest floor of the house, it’s usually the coldest area in the home too. With heated floors, it can help to keep the foundation warm making it more comfortable to walk on even in winter. The consistency of heat from the floor heating is also preferable to a fireplace or air vents which warm one area of the room first.
Is underfloor heating expensive to run?
Natural gas is almost always cheaper than electricity and depending on where you live, might be as much as 30% cheaper. So heating a home with a gas furnace will be cheaper than an electric one all things being equal.
An underfloor heating system powered by electricity is on the other hand more efficient than a radiator or forced air heating system since it heats the entire floor of a room rather than heating the air. You also tend to set the thermostat of an underfloor system lower than you would the thermostat of a radiator or forced air furnace.
The warmth from underfloor heating is also spread throughout the entire floor whereas a radiator and air ducts heat the immediate area first and then slowly heats the rest of the room over time.
Underfloor heating systems are also normally run at a slightly lower temperature than radiator systems too which can also save energy costs over time.
Is it cheaper to leave underfloor heating on all the time?
During winter and cooler periods, manufacturers of underfloor heating generally recommend setting a minimum temperature and leaving the heater on at all times to maintain a reasonable minimum temperature level. This way it takes less time when warming up when heating is required.
Modern underfloor heating system use a thermostat just like your home already has. Some people turn their heat down at night using a programmable thermostat in winter to make it more comfortable for sleeping and to save on their heating bill. By keeping the thermostat at a minimum temperature, the heating will kick in when needed to maintain this minimum level and then heat up to a higher temperature in the morning.
The same principle applies with an underfloor heating system.
Check with the manufacturer of your heating system to be safe but they’ll most likely suggest a minimum temperature to set the system at. This way the flooring will be kept at a minimum temperature even during off periods so that when the system needs to turn on, it’s already at a warm level rather than having to heat up from a cooler one.
What can go wrong with underfloor heating?
There are several things that can go wrong with underfloor heating systems:
- Wires can get damaged causing parts of the floor heating to stop working.
- Pipes can get damaged which can also impact the heating system.
The good news is that using modern thermal imaging technology, a fault in a flooring system can be isolated and fixed without having to tear up a large section of the floor.
Another bit of good news is that when a system has been installed and tested properly, underfloor heating is widely regarded to be very efficient and high quality with few problems noted by owners.
Even in the case of a tiled system, one or more tiles that are removed can then be replaced after the repairs have been made to the specific area in question.
Pros and cons of underfloor heating systems
| Underfloor heating pros | Underfloor heating cons |
| Heats the people and objects in the room from the floor up rather than heating the air in the room as with other heating methods. | Expensive to install and must be installed in a new home or during a reno in an existing house which adds to the cost. |
| Air is not circulated so dust movement in the rooms is minimized. | Small rooms with less floor space might require a supplemental heating option. |
| Can replace radiators and other heating options. | Repairs can be expensive depending on what flooring you have if the system breaks and needs to be fixed. Tiles glued to the floor would need to be broken and then replaced after fixing. |
| Can choose between an electric, water or hybrid heating system. | A heat loss assessment should be done first – especially in older homes – to ensure that an underfloor heating system is capable of heating your house. |
| Provides very consistent heating in a room. | Underfloor heating may have an impact on floor height depending on what system you choose which could have an impact on some rooms such as bathrooms and door areas. |
| A system can heat one room, several rooms or every room in your house on multiple floors. | Installation times can vary depending on your chosen system if you’re retrofitting an existing home. |
| Adding a zoned heating function will allow each room to be separately heated to its desired level. | Rooms that are not insulated might require a larger system to keep up with heating the room. |
| You can run many systems on phone apps that also help to run the system in an energy efficient manner. | Larger rooms may require a bigger system to keep up with heating the room. |
Summary
Underfloor heating is a convenient and safe option to replace other heating systems such as forced air or radiators. If you’re concerned about airflow and dust being moved around your rooms with a forced air system, you won’t have that issue with an underfloor heating system.
Underfloor heating systems are also quieter than a furnace and distribute heat more evenly than forced air or radiator systems.
Looking for more information on flooring options? Check out my article to learn more about whether hardwood is healthier than carpet to start with.