Underfloor Heating News

Wet underfloor heating produces some of the best comfort levels of any heating system available on the market today. Properties in the UK are now better insulated than ever and with new technology such as heat pumps, water underfloor heating is growing in demand.

The running cost, when compared with radiators, is very similar but it has many advantages, such as higher comfort levels and no need for ugly radiators on the wall.

If installed in a property, the room temperature can be set lower than with radiators as the heat is at floor level with water underfloor heating systems.

Using a condensing boiler and heat pump in conjunction with underfloor heating provides a system that will save energy and money compared with conventional radiators.

With a ground source heat pump, the energy savings can be up to 30%.  This assumes that the heating system is fitted into a concrete ’screeded’ floor.

In a timber suspended floor, the water underfloor heating will act as a radiator system (i.e. fast response) and in a screeded floor, the underfloor heating system will be more of a slow response heating system.

Most underfloor heating systems now run 24/7 with set back options.  Always use a programmable digital room thermostat for the underfloor heating zones.  Analog room ’stats are very basic and will not provide full control of the water underfloor heating system.

When starting up an underfloor heating system for the first time it will take some time for the screed to get warm. Allow at least 48 hours of continuous operation before switching the underfloor heating system off.

Underfloor Heating Tips

Modern underfloor heating systems are very energy efficient.  A water underfloor heating system can also be referred to as a ‘hydronic system’.  In the States they call it ‘radiant heating’.

Our underfloor heating pipes are made by Henco to the highest possible standard.  The underfloor heating  pipes themselves are made by PEX/AL/PEX.

Using our staples to fix the water underfloor heating system to the underfloor insulation in a screeded concrete floor is one of the best solutions available on the market.

In the 80’s, water underfloor heating became very popular in Europe and the UK and ever since then underfloor heating has seen rapid growth all over the UK.

Commercial buildings can be heated during the low tariff time as they normally have a larger thermal mass.  The heat can then be distributed during peak times.

Make sure your wet underfloor heating system is designed and installed by approved underfloor heating installers. Check that the supplier has been in business for over 10 years.

Water underfloor heating does not circulate dust like most radiator systems.

Modern underfloor heating systems will work with any heat source,  a heat pump system will work very well with water underfloor heating, for example.

There are no hot surfaces to be aware of with water underfloor heating, therefore these systems are perfect for care homes, hospitals and families with young children.

Such a system should last as long as the building in which it’s installed and is virtually maintenance free.

Free Quote and Underfloor Heating Information

Here at Underfloor Heating Systems Limited we offer a free quote service.  Send us your floor plans by email, post or fax and, in most cases, we will produce a wet underfloor heating quote within two hours of receiving them.  We also offer free site visits across the UK.

It is worth telling us the floor construction for each floor, the heating manifold position and how many room thermostats are required  and also whether the heat source is boiler or heat pump.

Is the property built to current building regulations?

Water underfloor heating will perform best in a screeded floor construction.  Screed is one of the best conductors of heat. A standard 4:1 sand/cement mix screed is best used for underfloor heating systems. Anhydrite screed, or liquid screed is becoming more popular.  This type of screed can cost a little more but will dry out much faster than the 4:1 screed.

Install a perimeter insulation strip along all the walls of the property.

It’s worth bearing in mind that a vapour barrier is needed if the liquid screed is used for wet underfloor heating.

The maximum floor temperature for any underfloor heating system should be 29°c. Always install our underfloor heating mixer pack beside each underfloor heating manifold to control the flow temperature to the water underfloor heating system. An acceptable floor temperature for some bathrooms can be as high as 32°c.

Underfloor Heating Controls

Here at Underfloor Heating Systems Ltd we mainly supply Heatmiser PRT programmable digital room thermostats for our underfloor heating systems.  We can supply analog room thermostats if needed. We can also use the Heatmiser DS1 dial thermostats as a cheaper alternative room thermostat, though it is always recommended to use our Heatmiser PRT room thermostats as they out perform the Heatmiser DS1 in every aspect.

We can also offer wireless room thermostats for our water underfloor heating systems.  We use the Heatmiser PRT-W room thermostats with a the Heatmiser UH1-W wiring centre.

Bathrooms can have the Heatmiser PRT-E fitted.  These come with an external sensor that can be located inside the bathroom.  The sensor is normally located on the wall or set into the floor.

For a water underfloor heating system to work correctly, you need a heat source, such as a boiler or a heat pump.  The underfloor heating water manifolds will distribute the heated water into each underfloor heating zone.  Programmable digital room thermostats will then control the heat output for each underfloor heating zone.

The boiler will pump the water into the underfloor heating manifold.  Our thermostatic mixing valve then reduces the temperature of the boiler flow to suit the wet underfloor heating system. An underfloor heating pump is fitted next to each underfloor heating manifold a.

The underfloor heating manifold will distribute the heated water to each zone.  Each zone will have its own room thermostat.  If the room temperature has reached its set level, the room thermostat will send a signal to the underfloor heating actuator via the underfloor heating wiring centre to shut the underfloor heating actuator off.  When more heat is needed, the room thermostat will open the underfloor heating actuator.

If the customer requires central control of the underfloor heating system we offer the TouchPad system from Heatmiser.  The TouchPad system can also work with internet access and phone access.

Manifolds ‘The Heart of Your Underfloor Heating System’

The underfloor heating manifold is the heart of the underfloor heating system.  From the water underfloor heating manifold, the heat is distributed to each room.  The underfloor heating manifold should always be centrally located within a property.

The underfloor heating pump and mixing valves should also be located by the wet underfloor heating manifolds. Normally the underfloor heating wiring centre is located above the underfloor heating manifolds. We use Heatmiser wiring centre and room thermostats for our underfloor heating systems.

One underfloor heating water manifold can do up to 180 – 200m² floor area or 1000m of 16 x 2 mm Henco underfloor heating pipe. It is normal to have one underfloor heating manifold per floor. It is standard practice to fit another underfloor heating manifold in those instances where the floor area is larger than 200m² per floor.

Each underfloor heating manifold needs to have a two port motorised valve to give independent control to each floor.

Our underfloor heating manifolds are made in Germany to the highest possible specification by Watts/Dumser.  The manifolds are pre-assembled for quick and easy installation of the underfloor heating system.

The flow meters on the underfloor heating manifolds can be isolated, as can the thermostatic heads on the return manifolds.  The flow meters can also be adjusted on the underfloor heating flow manifolds to allow maximum adjustability.

Water Underfloor Heating News – Floor Finish

It is important to choose the correct floor finish for water underfloor heating systems. Most floor finishes will work fine with wet underfloor heating, just follow the guidelines below.

If the floor finish has a high resistance it will restrict the heat output from the underfloor heating water system.  Using less resistant materials will give a greater output from the underfloor heating system.

Marble, stone and tiles are normally the best conductors of heat. Use flexible adhesive for the tiles.  Oak boards and Plywood provide more resistance for the underfloor heating system.

Carpet and underlay should not exceed a combined TOG rating of 2.5. Also, it is best to use 21 mm engineered boards. Never install wood on top of wood as this will provide too much resistance for the wet underfloor heating system to optimally perform. The maximum thickness for a wooden board system is recommended to be 25 mm.

Vinyl works very well with water underfloor heating systems.  Just make sure that the floor surface temperature doesn’t exceed 26°c.  Check that the glue will work with underfloor heating.

It is important to watch out for the moisture content when using wooden boards with underfloor heating water systems.  This should be between 8 – 10%. The moisture content of the screed must be very low before the wooden boards are fitted on top.

Finally always check with the manufacturer of any floor finish that it will work with wet underfloor heating.

Wet Underfloor Heating – Boiler Advice

Any boiler used for wet underfloor heating needs to be sized correctly.  There are many heat sources that can be used for water underfloor heating systems. See page three on our quote for the maximum heat output from a water underfloor heating system.

Normally 3 kW output should be added for the hot water demand. If radiators are fitted to the heating system the plumber would calculate the total output for the radiators.

Radiators need a high water temperature as their surface area is comparatively small. When using underfloor heating water systems, the heated surface is much larger, with the floor area effectively becoming a large, low temperature radiator.

As radiators need high water temperature to work correctly, they are not very suitable for use with heat pumps. Underfloor heating water systems are made to be used with heat pumps as they require only a very low water temperature.

The best boiler to use is a condensing boiler as they are very efficient. A condensing boiler works by using the latent heat created using another heat exchanger fitted within.

Part L of the Building Regulations now demands that all new boilers fitted need to be of the condensing type.

Some customers will use Combination boilers for their heating and hot water systems. The disadvantage with a combi boiler is that they don’t supply enough hot water. It is far better to use a separate cylinder for the hot water supply. Also, combi boilers can be quite noisy.

Solar heating systems should be used to only heat the hot water supply. Biomass systems are fine for wet underfloor heating, but are mainly used in the country side.

Underfloor Heating Systems Setup Tips

When using the programmable room thermostats with our wet underfloor heating system, always make sure that the time and the temperatures are set up correctly. Here at Underfloor Heating Systems Ltd we make sure that we supply programmable room thermostats for all of our standard underfloor heating systems.

Analog room thermostats can look cheap and should not be supplied for a high quality underfloor heating system. Programmable room thermostats give the end user much more control over their wet underfloor heating system.

Check that the underfloor heating thermostats are correctly fitted to the underfloor heating Heatmiser UH3 wiring centre.

It’s worth ensuring that the actuator is connected to the correct underfloor heating room thermostat because incorrect connection results in the underfloor heating system not working properly.

Make sure that all the air is gone from each underfloor heating water loop.  Check that the flow rate for each wet underfloor heating loop has been adjusted to the correct setting.

It is very important that both the flow and the return from the heat source are connected the correct way to the water underfloor heating mixing valve. The underfloor heating mixer pack is marked with H for flow and C for return.

If one room is getting too hot and another room is too cold then one room thermostat is controlling the wrong underfloor heating actuator.

If it takes a long time for the rooms to get warm, check that the boiler is running long enough and that the underfloor heating mixing valve is not set to minimum setting.

Underfloor Heating Installation and Care Information

After installing the wet underfloor heating system check that the pipe connections to the underfloor heating manifold are tight.

All the underfloor heating loops need to be marked on the manifold, i.e. which loop serves which room. It is key to check that the plumber connects both the flow and the return to the underfloor heating manifold the correct way.

One of the most common underfloor heating water issues is air in the system.  Check that all the air has been flushed out correctly as detailed in our underfloor heating instructions.

For a pressure test of the water underfloor heating system, we recommend a Rothenberger pressure testing kit.  These are available to hire from specialist shops or your heating engineer will have one.  Normally the pressure test is for 6 bar.

It is very important with any underfloor heating system to check that the correct room thermostat is operating the correct actuator on the underfloor heating manifold.

The underfloor heating pump should start when any of the room thermostats are calling for heat.  Also, check that the heat source is firing when a room thermostat is calling for heat.

Set the correct temperature for the underfloor heating mixing valves as it shows in our underfloor heating manual.

Underfloor Heating – Water Temperature and Efficiency

Here at Underfloor Heating Systems Limited we have made sure we use the highest specification European underfloor heating water products.

For the best performance, we recommend that the underfloor heating system is installed in a concrete screeded solution. Our underfloor heating system can also be installed in timber suspended floors and floating floors.

The COP (Coefficient of Performance) for a heat pump will be much higher if water underfloor heating is used in a screeded concrete floor instead of a radiator system.

The efficiency of the heat pump will increase dramatically if the flow temperature is reduced for the heating system. This is why water underfloor heating systems are the best accompanying heating system for heat pumps.

The main benefit of water underfloor heating systems is that they can achieve the same comfort levels as radiators with a lower room temperature, as the heat is at floor level.

Weather compensation control systems don’t work very well in the UK when combined with water underfloor heating as the weather changes too quickly for them to react.

In a timber suspended floor the water underfloor heating system will respond as quickly as a conventional radiator heating system.

The floor surface temperature should never exceed 29 degree C for a water underfloor heating system, unless the underfloor heating loop is fitted in a bathroom.

Maximum flow temperature to a screeded floor is normally 55 degree C.  The water underfloor heating pipework must be pressure tested to 6 bar.