Electric underfloor heating running costs

12 Apr 2016

With the price of fuel increasing year on year, the running costs of any heating system becomes an important consideration. This article speaks about the costs of running electric underfloor heating and how to reduce them. 

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Table of running costs

The table below shows the average running cost of different rooms within a family home. The calculations are based on an average cost of electricity of 14 pence per kWh and the room being well insulated (ideally up to current building regulations), including the appropriate floor insulation.

Room Bedroom 1 Bedroom 2 Bedroom 3 Bathroom & Hall Living Room and Kitchen
Room Area 12m2 16m2 18m2 12m2 26m2
Heated Area 10m2 12m2 14m2 10m2 22m2
Running Cost /  hr
(Constantly on)
21p 25.2p 29.4p  21p 46.2p
Average Daily Cost 63p - 126p 76p - 152p 89p - 177p  63p - 126p  128p - 256p

The average daily costs are based on keeping a room warm for 12 hours and with a 25% - 50% duty cycle. Matting is based on a 150W/m2 model with a Rayotec digital thermostat and either Insomax or Palziv. 
These figures should only be used as a rough indicative figure. The running costs vary depending on heat loss of the room, outside temperature and desired indoor temperature. 

What affects the running costs?


Insulation
By far the most important thing that affects running costs is the heat loss of the room. Always insulate the floor, roof, walls and windows to the highest level possible. 
 
Height of room
Rooms with vaulted ceilings need more energy to heat them up due to the higher volume of air. However underfloor heating is much more effective at heating rooms with high ceilings when compared to radiators. The heat of the radiators (convectional) tends to heat the top of the room before it reaches the bottom. Underfloor heating actually heats the area where people stand and sit making it more fuel efficient.
Room Height and Running costs of Electric Underfloor Heating
Heat loss through extractor fans & draughts
Bathrooms or toilets with extractor fans will suck out all the warm air making the heating stay on for longer. Draughty rooms let the warm air escape also, increasing the amount of heating required. Open fireplaces also can increase heat losses considerably.

Desired temperature of room
The warmer the room the more energy is required for heating. It is best to keep rooms to the standard temperatures of 18C for bedrooms & hallways, 21C for living spaces and 23C Bathrooms.

Period of Heating
The longer you heat up a room the more it will cost. Each room should only be heated when it is being used to reduce running costs. 

 

What can I do to reduce running costs of my underfloor heating system?


(1) Insulation
  • New Concrete floors: For a new concrete floor, insulate the subfloor with as much insulation as possible and install insomax insulation on top of the screed.
  • Suspended floors: In a suspended wooden floor insulate with a good quality foil faced insulation between the joists to reflect the heat upwards.
  •  All floors: Always insulate with Palziv, Insomax or the Ultra Backer boards insulation. Insomax comes in various thicknesses  - try to use the thickest possible.
  • Cavity Wall insulation: Many UK homes do not have cavity wall insulation. Typical costs are just £150-£350 with a typical payback in just 2-3 years. It is an absolute must to reduce fuel bills.
  • Loft insulation: By increasing loft insulation from 100mm to 270mm you can further decrease your energy bills with minimal costs (typically £100-£300).
 
(2) Control
Good control is key to reducing fuels bills. All Rayotec underfloor heating systems are “zoned”. This means that every room or open space will have its own thermostat. This allows you to have full control with each room on the correct temperature. By having a digital programmable thermostat this added level of control becomes incredibly easy.


Cost of Electricity vs Gas

Although the cost of electricity is currently higher than the cost of gas they are getting closer in cost. Generally a wet underfloor heating system will have cheaper running costs but can be considerably more expensive to fit when compared to electric underfloor heating.

The future of energy production is also all based on creating electricity (wind and solar farms and nuclear).

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