Underfloor Heating Costs
There’s a lot of mixed information out there in regard to electric underfloor heating running costs and for obvious reasons. There are so many variables at play during installation that, in truth, no one system will run exactly the same as another. Every single home is different so there are no easy answers or figures set in stone. All projects will be working to their own set of specific conditions. Though it’s impossible to give exact figures that will be true for any system, this article can provide some insight into potential long-term running costs and how they stack up against other heating methods.
What can influence how running costs are calculated?
With any heating system, there are a number of factors that determine how much they will cost to run and how effective they will be. Here are some of the main elements that can determine the efficiency of an electric underfloor heating system:
Installing the right insulation can make your electric underfloor heating system up to 50% more efficient and makes a huge difference to overall running costs. Insulation prevents any heat generated from being lost through the substrate below and instead pushes it upwards into the room above. No electric underfloor heating system should be installed without adequate insulation because without it, you’re looking at much longer heat-up times and higher energy usage.
The type of floor covering you decide to use with your system will have a large impact on its efficiency and heat-up times. Tile and stone make the best floor coverings due to their excellent conductivity – they warm quickly but are also slow to cool, and can reach higher temperatures than other materials. Vinyl makes a good option as it heats quickly, but also cools rapidly. Wood and carpet, however, have much slower heat up times which means that you will use more energy getting the room up to a comfortable temperature. Carpet in particular acts as an insulator and will make any system much less efficient, so you can expect to pay a lot more in running costs if this is your intended floor covering.
As with any heating system, the greater the area, the more energy you’ll need to use to keep it at the right temperature. Underfloor heating systems are no exception to this rule, so if it takes 84.3p to heat using a 10m² kit for four hours, it will be over double the amount to heat a 25m² room at 210.8p.
Room Insulation & W/m² Used
It’s not just floor insulation you need to consider when fitting an underfloor heating system. Inadequate room insulation is a primary cause of higher running costs, because draughty rooms lose heat much quicker than rooms with insulation up to modern standards. Lower w/m² systems will struggle to maintain the temperature of poorly insulated rooms, resulting in a system that only works as floor heating – a common problem with underfloor heating systems that have been retrofitted in period properties. Higher w/m² systems are better for high heat loss rooms, but the increased amount of cable used for tighter spacing means that the long-term running cost may be more. That being said, choosing a w/m² that is too low is never advised as it will struggle to maintain comfort temperatures, constantly drawing energy as it tries to battle the heat loss of the room. You can also install higher w/m² systems in rooms with standard insulation, and as more of the heat is retained, the room will get to temperature in less time with no real difference in energy costs – in the same way that a higher wattage kettle uses the same amount of energy to boil water as a lower wattage kettle, despite getting the job done in half the time.
Frequency of Use
Many systems are installed with the intention that they will only be used occasionally, or only used at a low level, to take the edge off nippy floors when the weather gets colder. If this is the case for your project, you’ll likely find your running costs much lower than forecasted, as your usage will be infrequent enough to make little difference to your bills. Underfloor heating will always cost a little more if you use it in short bursts, because it will need to heat up from cold every time, so you may find it more efficient to keep your heating on for longer periods of time at a set level. You should also bear in mind how hot you want your rooms when using underfloor heating as a primary heat source. The higher your chosen temperature, the more power your system will need to use to maintain temperatures, and the less often the thermostat will switch your system off.
Finally, another vital aspect you need to be mindful of is what price per kilowatt hour you’re paying for your electricity. The calculations made below were based on the average UK price from February 2015 – 14.05p/kWh – but yours may be lower or higher than this figure. Checking to see whether you can get a cheaper tariff is always advisable, and if you’re going to be using your underfloor heating frequently, it’s definitely worth pursuing to make sure you’re getting the best deal.
We would always advise getting an assessment of your home completed by an energy efficiency expert before purchasing an underfloor heating system. Call us on 080 246 1875 to discuss how BlueTech Energy can help you.