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Insulation for underfloor heating

How important is having the right amount of insulation when installing warm water underfloor heating? Extremely!

A well-insulated property prevents heat escaping, enabling water (aka wet) underfloor heating to work efficiently at lower flow temperatures. This gives you an effective, economic heating system. Read on to learn more about underfloor heating insulation.

Why is insulation important for underfloor heating?

Insulation is a crucial consideration for UFH. Ideally there should be suitable insulation below the underfloor heating pipe to resist the heat going downwards. As you would expect, you need as much heat as possible to flow upwards and into the room.

The insulation level and fabric of the building should always be factored into an underfloor heating design as it will affect the system’s performance. If a property is well-insulated, the UFH can be designed to the lowest temperatures, which can be less than 40°C. This saves both energy and money.

Underfloor heating insulation: things to consider

  • Is the room you are looking to heat already well insulated, like a new extension?
  • Does it have several windows and high ceilings? This will require a higher output.
  • What is the floor construction? Concrete, timber joists, an upstairs floor?

Below are the best underfloor insulation solutions for new build properties, older house renovations, and suspended timber floors.

Underfloor heating insulation in new build properties

As a nation, we’re changing the way we think about heating our homes. Building regulations mean that new build homes – and even extensive refurbishments – are so well insulated there is no need for a high-temperature heating system, like radiators, to be fitted.

All new UK properties, and generally those built in the last 10 years, are likely to be suitable for underfloor heating due to strict guidelines on air tightness and insulation. They may also be suitable for an air source heat pump, a low-carbon renewable heat source that is compatible with UFH.

If you are embarking on a self-build project, it’s easy and cost-effective to include underfloor heating as part of the build process.

Find out more about underfloor heating for new builds

UFH insulation

Underfloor heating insulation in renovations

Older houses can benefit from retrofit underfloor heating providing that they are adequately insulated.

We would always recommend taking a fabric first approach. Start by taking a look at your Energy Performance Certificate to find out your property’s current insulation levels and how these can be improved. Do you have double glazing? Are the loft, walls and floors all insulated? A well-insulated home will lose less heat and require less energy to keep warm.

If the property has a solid concrete floor, it’s possible to install retrofit underfloor heating directly over this base without laying insulation. This is because there is minimal downward heat loss when UFH is installed over a concrete subfloor. If your renovation has suspended timber floors, it is important that there is insulation present. Read on to find out more.

Thinking of installing an air source heat pump too?

It’s possible to combine a retrofit underfloor heating system and air source heat pump in a renovated home. If you haven’t already done so, you should make some insulation upgrades such as loft, cavity wall and glazing improvements in line with Part L1B of the Building Regulations.

If you’re unsure whether it’s possible to upgrade your home to a greener heating system, contact us for advice.

Find out more about retrofit underfloor heating

What about laying insulation for suspended timber floors?

Underfloor heating can be installed in or over a suspended timber floor in a new build or renovation project providing that there is sufficient insulation to reduce downward heat loss. It’s particularly important to insulate in this scenario because of the free flow of air beneath the floor that would have a substantial impact on the efficiency of the underfloor heating.

A new build property will be adequately insulated but If retrofitting underfloor heating, check that there is insulation beneath your suspended timber floor. If there isn’t, mineral wool in a bag can easily be clipped to the sides of timber joists. Alternatively, solid insulation panels can be cut to fit and wedged/fixed in place between joists, or standard mineral wool can be laid on top of netting.

If you’re unsure about whether your floor construction will work with UFH, contact our team for advice.

Find out more about upstairs underfloor heating

Electric underfloor heating insulation

At Nu-Heat, we recommend electric underfloor heating in single, smaller rooms – like bathrooms and kitchens. Although it’s cheaper to install, electric systems use more energy than warm water systems and ultimately have higher running costs.

Just like water underfloor heating, insulation levels will affect how effective your electric underfloor heating system is.

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