Underfloor Heating Insulation

There are many types of underfloor heating insulation. At Underfloor Heating Systems Ltd we recommend the use of Polyurethane insulation covered with an aluminium foil.

Polystyrene insulation is not recommended as underfloor heating insulation as this is far too soft and the underfloor heating staples (clips) will not hold the underfloor heating pipework in place.

Also, Polystyrene does not have very good insulation properties compared to Polyurethane insulation.  Polyurethane insulation is the best insulation for wet underfloor heating systems.

Well known brands of Polyurethane insulation are Celotex and Kingspan. These insulation boards reduce downward heat losses, are easy to cut, hold the underfloor heating pipework in place and are very reliable boards.

Underfloor heating insulation can be used for both a concrete (screeded) floor and for a timber, suspended floor construction. See our underfloor heating manual for further instructions.

The height of the underfloor heating insulation will vary according to the current building regulations for your particular project. This will generally be between 30mm and 100mm depending on the underfloor heating project and the current building regs. Ultimately, the more underfloor heating insulation is used, the less the downward heat losses will be.

If a liquid screed is used, the insulation boards need to be taped together and a membrane fitted on top of the underfloor heating insulation before the pipework is fitted. The insulation boards must be taped together if normal screed is used.

Underfloor Heating Cost

Underfloor heating normally starts from £400.00 + VAT for a small area, up to around £12.00 – £14.00 per m² for the supply of larger underfloor heating systems.

The cost is normally between £4.00 and £6.00 depending on the size and location of the project.  Underfloor Heating Systems Limited supply underfloor heating systems all over Europe equally, our approved wet underfloor heating installers can also fit the systems across the UK and the European mainland.

All of our water underfloor heating packs include free delivery and come with a hand sketch or CAD drawing as an optional extra. Project info is also supplied for each underfloor heating water order, with a full set of our underfloor heating instructions.

Our approved underfloor heating installers offer free site visits anywhere in the UK.

All of our wet underfloor heating products are made to the highest possible quality and are used throughout Europe and the UK.

The running cost for an underfloor heating system compared to a radiator system will be lower as the water temperature is only in the region of 40 degree C, compared to a radiator system that will be running at over 70 degree C.

As there are many underfloor heating companies in the UK, the underfloor heating cost has been reduced.  The key is to look for underfloor heating companies that has been in business for over 10 years and use high quality European products.

Underfloor Heating Systems

It is important to avoid air pockets in any screed used for water underfloor heating systems.  Air pockets in the screed will not conduct the heat and the underfloor heating system will not perform to it’s optimum performance levels.

The normal mixture of screed used for wet underfloor heating systems is 4:1 sand/cement mix. Normally 65 – 75 mm screed is used on top of the underfloor heating water system.  If a liquid screed is used then this is normally 50 mm.

Never use the underfloor heating system to dry the screed.  The screed must be allowed to dry naturally.  This could take up to 4 – 6 weeks.

Always fit a DPM (damp proof membrane).

Our underfloor heating pipe spacing is normally c/c 200 mm for our wet underfloor heating system.  The underfloor heating pipe will normally come in 200 m pipe coils. Never use more than 110 m for one underfloor heating loop.

Our underfloor heating pipe is marked every metre, so it is easy to check how much underfloor heating pipe has been used for each room.

See typical underfloor heating project information below that goes out with every underfloor heating order;

Pipe spacing approximate c/c 200 mm.  Max loop length 110 m.    Try to use all the pipework supplied, but you will always have waste.  Just make sure you have enough pipe to come back to the manifold, the pipe is marked every metre.

Loop lengths are only approximates!  Read the instructions provided before installing the system.

Layout suggested is;

GF, MANIFOLD LOCATED IN CUP’D

Eight room thermostats (3 core + earth).  9 Circuit Manifold.

LOOP LAYOUT (ONLY APPROXIMATE LOOP LENGTHS)

LOUNGE – 100 M AND 100 M – ONE ROOM THERMOSTAT

KITCHEN/UTILITY– 100 M – ONE ROOM THERMOSTAT

BED3 – 50 M – ONE ROOM THERMOSTAT

HALL – 50 M – ONE ROOM THERMOSTAT

BATH – 25 M – ONE BATHROOM THERMOSTAT

BED 1 – 60 M – ONE ROOM THERMOSTAT

EN-SUITE – 25 M – ONE BATHROOM THERMOSTAT

BED 2 – 40 M – ONE ROOM THERMOSTAT

Underfloor Heating Water

Before installing our water underfloor heating systems it is very important to read the underfloor heating instructions provided with the order.

Check that the correct screed thickness and underfloor heating insulation is fitted before fitting the underfloor heating water pipework.

It is critical to check the floor finish, as too thick carpet or wood on wood is not a good solution for any wet underfloor heating system.

If you are installing our single room underfloor heating kit, the mixer unit should be located in the room it is serving or as near the room that is possible.

The single room pack can take the heat from the main radiator circuit or it can be used with a two port valve an independent control with a 2 port valve.  Independent control is the best solution for any water underfloor heating system.

It is important to check that the boiler has enough heat output to cope with the water underfloor heating system.  Normally the boilers in the UK have plenty of extra output, or they are oversized, so this is not an issue.

It is best to install an automatic by-pass valve by the boiler.  This should be standard practice anyway as most boiler manufacturer would demand that a by-pass valve is fitted.

Copper or plastic pipework can be used to connect our single room pack to the primary flow and return of the heating system.

Underfloor Heating Water

If for some reason the flow meters on the underfloor heating flow manifold are indicating low flow rates, check the below;

- Is the underfloor heating pump set on full speed, ie number three.  Is the underfloor heating pump pumping the correct way, ie towards the underfloor heating flow manifold?  Is the flow and the return connected the correct way to the primary heating circuit?

- Check that their is no air in the underfloor heating water loops.  This is the most common problem with any wet underfloor heating system – ie air in the loops.

- What about rubbish in the underfloor heating mixer?  If the underfloor heating mixing valve is full of dirt, there will be no flow rates going into the underfloor heating loops.  The best solution is to clean the underfloor heating mixing valve.

- Has the underfloor heating loops been adjusted to the correct settings?  Call us here at Underfloor Heating Systems Ltd or see our technical manual on how to adjust the water underfloor heating loops.

If the water temperature is not correct to the underfloor heating water system, check that the system has been working for 24 hours and check that the heating source is providing enough warm water into the wet underfloor heating mixing valve.

If one of the rooms are not getting warm, then check that the correct actuator is doing the correct room thermostat for the wet underfloor heating system.

Normal flow rates to each water underfloor heating loop is approximately 2 l/min.

Wet underfloor heating

When connecting the 16 x 2 Henco multilayer pipe to the wet underfloor heating manifolds use the 16 x 2 mm Euroconus fittings.

Cut the underfloor heating pipe straight with the pipe cutter supplied with the order, fit the nut and the split ring over the underfloor heating pipework.

Use the calibration tool to re-shape the underfloor heating pipe and fit the insert into the underfloor heating pipework.  Finally connect the Henco pipework to our water underfloor heating manifolds.

It is very important that the water underfloor heating system is filled, flushed and pressure tested the correct way.  Please see our underfloor heating installation manual for guidelines. Each underfloor heating order is supplied with a full set of underfloor heating installation instructions.

Check that the boiler is working and the hot water system is operational.  All concrete floors must be dry before the underfloor heating water system is operated.

It is very important to fill and flush the flow and return pipework from the boiler to the underfloor heating system before the heating is operated.

The wet underfloor heating system will normally operated at a pressure of 1.5 bar.  The underfloor heating pump can be set to run at speed three.

If there is no flow rates to the underfloor heating loops, check that the underfloor heating Grundfos pump is working and that the actuators are open.  There could be air in the underfloor heating loops or the underfloor heating mixing valve could be blocked with rubbish.

Underfloor Heating Mixing Valve and Underfloor Heating Pump

Here at Underfloor Heating Systems Limited we use Reliance Water Controls underfloor heating mixing valves for our wet underfloor heating systems.

The underfloor heating pump is made by Grundfos.

The underfloor heating mixer is the ThermoMix mixing valve, one of the best mixing valves on the market.  The underfloor heating mixing valve can be mounted to the left on the underfloor heating manifold or to the right on the underfloor heating manifold.

The control pack that consists of the underfloor heating mixer and the underfloor heating pump can do up to 14 Kw underfloor heating output.

If the property is built to current building regulations, the underfloor heating pack could do up to 180 – 190 sqm floor area, ie 1000 m of multilayer pipe.

It is important that the pipework from the heating source to the underfloor heating mixing valve is flushed, as else there is a risk of dirt entering the underfloor heating water mixing valve and this could cause poor flow rates to the water underfloor heating manifolds.

The underfloor heating mixer can be adjusted from 35 degree C to 65 degree C.

The underfloor heating pump is a 25/60 pump, this is the same as a 15/60 pump.  The only difference is that our underfloor heating pump is black and the normal Grundfos pump on the market is red.  The reason for this is that our black underfloor heating pump is only sold to OEM’s and the red Grundfos pump is sold to merchants.

Wet Underfloor Heating Installation

The normal procedure for installing wet underfloor heating is as below;

1. Fit the underfloor heating insulation.  Check that perimeter insulation has been fitted.  Tape all the joints.

2. Install the water underfloor heating manifold on the wall and connect the underfloor heating water pump pack to the manifold.

3. The underfloor heating wiring centre can also be fitted above the underfloor heating manifold.

4. Now, install the Henco underfloor heating pipework 16 x 2 mm as suggested in the project information, hand sketch or the CAD drawing.

5. Fill the underfloor heating pipework with water and perform a pressure test.  It is very important that the underfloor heating system is filled as the manufacturers recommendations, please see our underfloor heating instructions.

6.  The builder can now screed the floor and the electrican can connect all the room thermostats to the underfloor heating wiring centre when the screed is dry and safe to walk on.

7.  The Heatmiser PRT hard wired room thermostats are 3 core + earth.  The room thermostats are normally fitted beside the light switch in each room.

8. The underfloor heating pump and the underfloor heating actuators needs to be connected to the wiring centre.

9. Normally a two port valve by the boiler will be fitted on the flow pipework to the underfloor heating system after the boiler pump.

10.  The wiring centre has a boiler relay fitted inside.  The boiler relay will power up the two port valve and the two port valve will switch the boiler on.

11. There is no need for a separate timer for the underfloor heating system as our programmable digital room thermostats does the job.

Underfloor Heating Controls

Our wet underfloor heating system can also be operated with wireless control.  This will mean that the room thermostats do not require any wiring from the manifold to the rooms they are serving.  The underfloor heating wiring centre is fitted with a receiver. Please contact our sales office for more information about our wireless underfloor heating system.

We only supply water underfloor heating at Underfloor Heating Systems Ltd.  Electric underfloor heating is mainly used for existing floors and small areas such as a bathroom.

The installation cost is normally higher for a water underfloor heating system, but the running cost is lower than an electric underfloor heating system.

All of our standard underfloor heating system will come with an underfloor heating manifold. The manifold is the heart of the underfloor heating control system.

All ground floor insulation requirements must meet the current Building Regulations.  For the underfloor heating installer it is always important that there is mains water at the building site, as a pressure test will be performed of the wet underfloor heating system after the system has been installed.

All underfloor heating pipework must be protected from the sun and sharp objects.  If there is a risk of freezing, anti-freeze must be used when filling the underfloor heating pipework.

Check that a by-pass is fitted by the boiler as this is normally a requirement by the boiler manufacturer.  It is important to check that the boiler can cope with the underfloor heating water system.

Wet Underfloor Heating

Wet underfloor heating offers the best comfort levels possible.  The human feet is our own room thermostat, if our feet are warm, we will be warm.  This is why wet underfloor heating systems offer such good comfort levels.

It has been proven that wet underfloor heating systems can save at least 15 % – 20 % on the running cost compared to traditional heating methods.

A concrete floor solution is the best possible solution for a wet underfloor heating system.

Here at Underfloor Heating Systems Limited we only use very high quality underfloor heating products.  The underfloor heating pipe is from HENCO, one of the leading underfloor heating pipe manufacturers in the World.

Our wet underfloor heating manifolds are made in Germany by WATTS/DUMSER and are considered to be one of the best manifolds to use for wet underfloor heating systems.

Our electronic controls, such as our room thermostats and underfloor heating wiring centres are from HEATMISER, but we can also supply DANFOSS room thermostats.

The pump is made by GRUNDFOS and the underfloor heating mixing valve is made by RELIANCE WATER CONTROLS.  Please note that our underfloor heating mixer pack is a pre-made pack, ie the installer does not need to buy parts to connect the mixer and the pump to the underfloor heating manifolds.

Some underfloor heating companies will only sell a three port mixing valve and the underfloor heating installer will need to spend time and money to connect the mixer pack to the underfloor heating manifolds.

For any technical assistance please call the water underfloor heating technical department on 01905-616 928, we have over 30 years of underfloor heating experience in the UK and Europe. Underfloor Heating Systems Ltd have now been operating almost 10 years in the UK.

We offer a free quote service.  Please send us your floor plans for a free underfloor heating quote.  Plans can also be faxed to us to 01905-352 100, or sent by post to;

Estimating Department, Underfloor Heating Systems Ltd, Unit 1, 79 Friar Street, Worcester, WR1 2NT.