FAQ's

Underfloor Heating Frequently Asked Questions

The following are some of the questions most commonly asked by customers. If you have a question that is not covered here, please contact us.

  1. What is a CU Heating mat?
  2. How wide are the mats?
  3. How simple are the mats to install?
  4. Which underfloor mats are right for me?
  5. How do I choose the correct size of mat for my installation?
  6. What is CU Heating cable?
  7. How simple is underfloor heating cable to install?
  8. Underfloor heating mats or cable?
  9. How safe are underfloor heating mats and cable?
  10. Can I install on any subfloor?
  11. Can mat systems be installed under laminate, wood or plastic floor?
  12. Will my floor level be raised?
  13. Is it possible to estimate the running cost?
  14. Is it necessary for an expert to install underfloor heating mats and cable?
  15. Will I need any other materials to install an underfloor heating mat or cable?
  16. Can I tile directly on top of your mats or cable?
  17. What type of control is required with CU Heating mats and cable?
  18. How can I test my CU Heating system?
  19. What is the temperature of the tile surface?
  20. Can CU Heating systems be used for total heating in the room?
  21. Is it possible to control the floor heating system?
  22. How quickly will my floor get warm?
  23. Have you got any instructions for the tiler?
  24. Why insulate?
  25. What thickness of insulation board do you recommend?
  26. Are your mats and cable guaranteed?

 



1. What is a CU Heating mat ?
- Top

A heating mat, with a 3mm thick twin wire heating cable pre-mounted onto commercial grade fiberglass mesh that holds the heating cable together to simplify installation.

It has a self adhesive side which is extremely sticky to allow for easy fixing to the sub-floor. The adhesive extends to the cable loops that run along each side of the mat.

All mats have been tested in accordance to National and International Standards for Safety. Our mats comply with rules regarding the EMC (Electro Magnetic Compatability) and fulfil the ICNRIP guidelines and regulations with regards to EMF (Electro Magnetic Fields).

The heating element is produced with three layers of electrical insulation and an earth braid, making it suitable for use in any room.

Manufactured in a wide range of ready made sizes with the supply lead wire at one end only, it is supplied on a roll for quick installation – and offers maximum flexibility to the installer; easy to plan and easy to lay and suitable for large or small areas.

• Perfect for applications in bathrooms, kitchens, conservatories and more;

• Suitable for ceramic, natural stone, slate, marble, limestone, terracotta etc;

• Lifetime warranty;

• Available in three power outputs of 150 w/m², 160 w/m² and 200w/m²

• Rated at 160 w/m² and 200w/m² is ideal for conservatory concrete floors and rooms where faster heat up is required.

Simple to install and great for renovation projects, as well as new builds.


- Updated: January 2020



2.How wide are the mats?

When they are run side by side, each one is designed to cover a width equivalent to approximately 500mm.

- Updated: January 2020


3.How simple are the mats to install ? - Top

 

Installing a mat is ideal for the DIY enthusiast or an approved installation contractor.

Only a pair of household scissors are needed when cutting the fiberglass mesh. THE HEATING ELEMENT MUST NOT BE CUT.

Each mat is fitted with a supply lead wire at one end only. You don’t need to worry about where the mat ends, just cut the mesh and turn it any way to fit your floor space.

The mat has a self-adhesive backing which is extremely sticky to allow easy fixing to the sub-floor. The adhesive extends to the cable loops that run along each side of the mat.

The heating elements can be easily detached from the fibreglass mesh to assist installation around awkward shapes and obstacles.

You can combine more than one size of mat to cover the total floor space and with multiple circuits the lead wires must be connected electrically in parallel.

Two or more mat sizes can be combined together if required.

Full installation instructions can be downloaded on the website in pdf format.

An installation instruction booklet is available on request.

- Updated: January 2020



4. Which Underfloor Mat is right for me? - Top

Our Foil 150w/m² is the safest solution for direct contact with a wooden subfloor.

This situation is extremely common in many new homes and apartments and our 150w/m² Foil Mat provides a perfectly heated carpet, wood orn laminate floor.

Our 160w/m² mat should always be installed on concrete floors, tile or stone floors in areas like kitchens or bathrooms.
Our 200w/m² mat should only be installed on concrete floors, It is ideally suited for conservatories or areas that require primary heating.

A 200w/m² mat provides a faster heat up than a 160w/m².

- Updated: January 2020

 

 

 



5.How Do I Choose the Correct Size of mat for my Installation ? - Top

Plan the installation.

Draw a general view of the room and mark the area which will be covered with heating elements. Take measurements of the room. Avoid heating under units and sanitary ware as this can cause heat blockage and it is unnecessary to heat these areas anyway.

Always start by measuring the FREE floor area available to apply the heat.

In a bathroom the FREE area is the floor area without the bath, shower, toilet, washbasin and any units -10%.

In a kitchen the FREE area is the floor area without the kitchen units and appliances -10%.

Select the size of the mat below the actual FREE area available e.g. if the FREE area is 7.6m² you should select a 7m² pack, for 4.2m² a 4.0m² pack and so on.

Ensure that the mat will fit into your room as it is not possible to cut the heating element.

Bear in mind to leave a minimum 50mm unheated gap around the room perimeter when calculating the heated area.

- Updated: January 2020

 



6.What is CU Heating cable ? - Top

A twin wire heating cable supplied on a reel with the supply lead wire at one end.

The cable heating element is produced with THREE layers of electrical insulation and an earth braid. It is designed to meet European and International Class 2 safety standards, and is suitable for use in any room.

• Perfect for applications where extra flexibility may be required with the layout, especially in smaller or awkward areas with obstacles, such as en-suites, shower rooms and bathrooms.

• Suitable for ceramic, natural stone, slate, marble, limestone, terrecotta etc.

• Lifetime cable warranty.

• Can be installed to match power outputs in the range of 120 to 200 w/m².

The dual wire construction ensures electro-magnetic emissions are practically eliminated making it safe for children to play on the heated floor.

It is installer friendly with a 4m long supply lead wire at one end only.

There is no need to get the two ends of cable back to a termination point.


- Updated: January 2020

 

7.How simple is underfloor heating cable to install ? - Top
Our cable is ideal for any DIY enthusiast or approved installation contractor.

The ultra thin profile of the cable is ideal for renovation projects, as well as new builds.

The cable requires more time to install than the mats but it can provide the installer with extra layout flexibility, especially in smaller areas with obstacles, such as en-suites, shower rooms and bathrooms.

A table provides a guide to the floor area permutations at various watts density and cable spacing.

You can combine more than one size of cable to cover the total floor space and with multiple circuits the lead wires must be connected electrically in parallel.

Once the control position has been decided, the size of the cable can be chosen..

More than two cable sizes can be combined together if required.

Full installation instructions can be downloaded on the website.

An installation instruction booklet is available on request.

- Updated: January 2020

8.Underfloor Heating Mats or Cable? - Top
The heating mat is a heating element mounted onto a fiberglass mesh that holds the heating cable together to simplify installation. This is the easiest system to install.

Although underfloor heating cable requires more time to install than mats, it can provide the installer with extra layout flexibility, especially in smaller areas with obstacles, such as en-suites, shower rooms and bathrooms.

Cable systems are labour intensive and this problem increases with the size of the floor area, which can result in installation mistakes.

Cable systems will generally require a cover of levelling compound prior to tiling because of the tendency for the cable to move during the tiling operation if it is not secured to the floor properly.

However, it is easier to control the movement of the heating element in smaller areas. Also, when metal fixing banding is used as a means of fixing the cable to the floor, the element cable can be made much more secure by this method compared to fixing tape.

- Updated: January 2020
 

9. How Safe are Underfloor Heating Mats and Cable? - Top
 
Perfectly safe!

All mats and cables have been tested in accordance to National and International Standards for safety. Cables and mats comply with rules regarding the EMC (Electro Magnetic Compatability) and fulfil the ICNRIP guidelines and regulations with regards to EMF (Electro Magnetic Fields).

Heating elements are produced with THREE layers of electrical insulation and an earth braid, conforming to industry specifications.

Because of the dual wire construction of the heating element there is only one cold lead to connect and electro magnetic emissions are virtually eliminated making it safe for children to play on the heated floor.

- Updated: January 2020

 


10.Can I Install on any subfloor ? - Top
Yes

Undetile heating can have any one of our mats. 200w/m² is ideal for primary heating, whilst 160w/m² is perfect for secondary heating.

150w/m² is the safest solution for direct contact with a wooden subfloor and is the only option when the floor level is critical.

This situation is extremely common in many new homes and apartments and our 150w/m² mat provides a comfortingly heated carpet, wood or laminate floor.

160w/m² mats should always be installed on concrete floors for comfort/secondary heating,
 
200w/m² mats should always be installed on concrete floors where primary heating is required, especially in a conservatory.

- Updated: January 2020
 

11.Can mat systems be installed under laminate, wood or plastic floor ? - Top
Yes, but only our foil systems!

Constant wattage systems can damage these floor specifications, with a few exceptions. Our 150w/m² foil mats are specifically designed for installation under laminates/carpets. Our other systems should not be placed under these surfaces.

Please consult CU Heating for responsible advice based on worldwide experience.
 
- Updated: January 2020
 

12.Will my floor level be raised ? - Top
Barely.
 
Our 200w/m² and 160w/m² mats are only 2mm thick.
 
Whilst our 150w/m² Foil mat and insulation is only 5mm in depth.

- Updated: January 2020
 

13.Is it possible to estimate the running cost? - Top
Yes

The running costs of the mat and the cable is between 0.5 - 2 pence per square meter per hour.
 
But there is a real pay-back with insulated floors in terms of the energy consumed.

CU Heating recommend the use of insulation in the floor and insulating backer board whenever possible.

Insulation will improve the heating efficiency, provide faster heat up time and save energy.

- Updated: January 2020
 

14.Is it necessary for an expert to install underfloor heating mats and cable ? - Top
Installation is ideal for either a DIY enthusiast or approved installation contractor.

The electrical supply must be protected by a correctly sized RCD (Residual Current Device), either at the mains or a fused spur.

The system connects to your household wiring and it is recommended the final mains electrical connection is made by a qualified electrician.

A full set of installation instructions are provided with each pack. Call 0800 023 2628 for any assistance on Monday to Friday between the hours of 8.30am and 5pm.

Full installation instructions can be downloaded on the website in pdf format.

An installation instruction booklet is available on request.

Care should be taken when planning the installation on larger floor areas due to the higher electrical loading required. A separate power supply may be required.

- Updated: January 2020

15.Will I need any other materials to install an underfloor heating mat or cable ? - Top
Before installing our mats or cable you should prepare the subfloor. Clean the floor and prime with a coat of PVA, a water based adhesive primer. This will also help the tile adhesive and/or levelling compound to bond with the subfloor.

Any good tile or hardware outlet will supply PVA primer.

Our mats have a self adhesive backing which is extremely sticky for simple fixing to the sub-floor. The adhesive extends to the cable loops that run along each side of the mat.

Flexible tile adhesive and fillers are required e.g. latex, acrylic or polymer based. These will compensate for any tile movement and possible cracking caused through expansion and contraction. A flexible grout should also be used.


- Updated: January 2020
 
 

16.Can I tile directly on top of your mats or cable? - Top
Using a flexible adhesive the tiling can be carried out as a single operation directly on top of the mat or cable.

Allow a depth of adhesive sufficient to lay the tile and encapsulate the heating element with no air gaps.

Always use a plastic trowel to avoid damaging the heating element.

In cable installations, take care not to dislodge any of the cable from its fixed position when applying tile adhesive.


- Updated: January 2020

17.What type of control is required with CU Heating mats and cable? - Top
We have many system controller options available.

Our Push-Button range is available in white, silver or graphite.
While our Digital Touch-Screen thermostats are available in onyx black or pearl white.

Our thermostats are also sold separately to offer extra controllers if required.

- Updated: January 2020
 

18.How Can I Test My CU Heating System ? - Top
Follow the instructions provided.

Basic electrical tests are required at the various stages of installation and the results should be recorded on the guarantee card provided.

Check before installation, immediately after installing and before putting the heating into operation.

Test for cable continuity and its resistance (ohms), as well as the resistance of the sensor cable.

Also, measure the insulation resistance value as required by BS7671 - the minimum reading should be 10 megohms regardless of element length.

Record the results on your guarantee card.

Consult your electrician.

- Updated: January 2020
 
 

19.What is the temperature of the tile surface ? - Top
This is between 25-27°C in accordance with the BSI guidelines for comfort heating. BSI Code of Practice CP:1018 - Electric Floor Warming Systems specifies a maximum floor surface temperature of 27°C
- Updated: January 2020

20.Can CU Heating systems be used for total heating in the room ? - Top
Yes, but it will depend on a number of factors such as the insulating properties of the room.

For example, heat losses in conservatories are much greater than internal rooms. To achieve total heating in conservatories a cable in screed system is the most practical solution with the cable buried up to 50mm below the subfloor surface – and then it is only possible if the heat loss can be replaced and you have planned your floor levels accordingly: each installation is different.

CU Heating offer a design service for total heat requirements as the concept differs from comfort heating - simply call 0800 023 2628.

Internal rooms with good quality 'u' values can achieve total heat with CU Heating systems in the right circumstances.

Each case is different and depends on the 'u' values, size, air movement, volume and position of the room.

It is a fact, that higher loadings do not mean you can automatically have total heating.

One system does not fit all.

CU Heating provide a design service for total heat - simply call 0800 023 2628 or email your details.

- Updated: January 2020
 

21.Is it possible to control the floor heating system ? - Top
Yes by using a thermostat

A programmable thermostat combines the time-clock function within the thermostat whilst offering additional features. The main feature of a programmable thermostat is the ability to set different temperatures at different times of the day – known as comfort levels. They can be set to sense combined floor/room sensing or floor sensing only.

Our controller range is rated at 13amps and this enables direct switching of loadings up to approx. 2900 watts.

Higher loadings must be switched by a suitably rated contactor, a relay - or alternatively split the heating into more than one heating zone each operated by its own thermostat.

In bathrooms the thermostat control MUST be mounted outside the bathroom.

Air temperature control can be useful in a conservatory where the air sensor will override the floor heating control, helping to reduce the high air temperatures caused by a combination of floor heating and sunshine on the conservatory.

- Updated: January 2020
 

22.How quickly will my floor get warm ? - Top
This depends on the subfloor and its insulation properties.

A cement subfloor will be slower without a thermal barrier, as a percentage of the installed heat is absorbed into the floor (approx. 30% on a concrete floor without insulation).

As a rule of thumb, a warm floor can be attained in less than forty minutes when insulating backer boards are installed.

Insulated screeds and concrete floors will take up to 2 hours and uninsulated concrete floors may take anything up to 5 hours to reach the required floor temperature.

To make the best use of the system, insulation should be installed, either below the subfloor or as a layer of insulating backer board, OR BOTH.

- Updated: January 2020

23.Have you got any instructions for the tiler ? - Top
If our matting or cable system has been covered with a layer of flexible levelling compound prior to tiling, observe the drying time recommended by the manufacturers before tiling over.

A thin layer of levelling compound will provide protection for the heating mat or cable from mechanical damage. However, this step is not compulsory and you may decide to install the tiles in a single operation directly on top of the mat or cable.

It is OK to walk in stocking feet and kneel on the heating mat or cable, but avoid contact with sharp objects.

DO NOT drop tiles onto the heating surface as this could damage the heating element.


- Updated: January 2020
 

24.Why insulate ? - Top
Systems rated at 160 w/m² and 200W/m² are installed on uninsulated concrete floors with good results both in conservatories and internal rooms. However, due to the thermal dynamics involved, a cold uninsulated concrete subfloor will absorb up to 30% of the heat load down into the floor.

Without insulation the heat up rate is slower and running costs are higher. It is a fact however, that many installations have critical floor levels and a layer of insulation is not practical.

To make the best use of the system, insulation should be installed, either below the subfloor or as a layer of insulation backing board on top of the subfloor, OR BOTH.

Insulated floors pay for themselves over time with energy saved.

- Updated: January 2020
 

25.What thickness of insulation board do you recommend ? - Top
This can be restricted by the floor level of your installation.

10mm is fine in most cases and is our most popular size.

The time to heat up a tiled floor will hardly be noticeable, whether a 10mm board, 20mm board or thicker board is used.

- Updated: January 2020

26.Are your mats and cable guaranteed? - Top
All systems are backed by a manufacturers lifetime guarantee.

Ask your installer to complete the guarantee card supplied with your system. If this is not completed, the warranty is not valid.

- Updated: January 2020

CU Heating provide full design and engineering support on all applications - simply call 0800 023 2628 or email: sales@cuheating.co.uk