What is the best thermal insulation for ceilings?

An uninsulated ceiling makes it easier for the hot air in your home to escape through your roof on cold days, making your central heating system work extra hard to keep your home warm. The Energy Saving Trust estimates that poorly insulated homes in the UK lose about 25% of their heat through the roof.(1). While on hot days, an uninsulated ceiling will draw in the hot air from outside and make it impossible to keep your home cool.

Here are seven reasons to invest in ceiling insulation:

1. Prevent heat loss: when you insulate your ceiling you stop your home losing heat through its ceiling and roof.
2. Increase thermal performance: Time for a mini physics lesson. When you insulate your ceiling, you limit how much heat moves from the inside of your home to the outside. This means you keep the temperature in your home more stable and comfortable all year round, so your living spaces and bedrooms will feel cooler in summer and warmer in winter.
3. Slash your bills: as ceiling insulation is so effective, you won’t need to use your central heating so much on cold days and you won’t have electric fans whirring on hot days, reducing your gas and electricity bills.
4. Protect against humidity and condensation: an uninsulated ceiling can cause damp and mould in your home. Ceiling insulation helps prevent this and consequently makes the air in your home fresher and healthier.
5. Improve acoustic insulation: When you insulate your ceiling you also add a layer of soundproofing, so you won’t be able to hear the TV in the bedroom upstairs, and you can turn up your music up without disturbing anyone.
6. Increase your home's durability: As ceiling insulation helps you regulate the temperature in your home and prevents humidity and condensation, it extends the life of the structure of your property and its fixtures and fittings.
7. Help the environment: by reducing the energy you use for heating and cooling your home, ceiling insulation makes it more energy efficient and lowers your greenhouse gas emissions.

If your home is losing heat, it means that heat is escaping from its structure.

Heat will escape through your roof, walls, loft, windows, doors and ceilings.

To make your home more energy efficient, you must identify these heat-loss areas and address them.

There are several different products you can use to insulate your ceiling. This comparison chart guides you through the maze of ceiling insulation options, based on the materials they are made from, how they are installed and used and their pros and cons.

The cost of insulating a ceiling varies widely depending on the age, size and accessibility of your property, whether it has any existing insulation that is still usable and the type of insulation you decide to opt for. Get two or three quotes from highly qualified and recommended insulation installers to get a clear idea of the costs involved.

Insulating your home can significantly improve its energy efficiency and reduce your carbon footprint. If your home is in England, Scotland or Wales, financial support may be available for installing insulation through the Great British Insulation Scheme (2). This is a government initiative designed to help households cover the cost of insulation improvements that aims to lower energy bills and make homes more environmentally friendly. If your home is in Northern Ireland, you may qualify for a grant for insulation through the government Affordable Warmth Scheme.(2).

While insulating all the ceilings in your home can improve its comfort and energy efficiency, the following three areas should be prioritised:

Cellars, basements, and garages often lack adequate insulation. These spaces cool rapidly —particularly in winter— and will benefit from insulation to prevent condensation and damp.

For basement ceilings, moisture-resistant insulation boards — such as polyisocyanurate, polyurethane, extruded polystyrene or expanded polystyrene — are preferable to mineral wool products like glass wool or rock wool.

Before buying your insulation material, check that it conforms with the latest fire, safety and building regulations.

Up to 25% of heat in a home can escape through an uninsulated roof, so insulating your loft ceiling helps retain warmth in the rooms below. By insulating the ceiling of your loft, you help insulate the rooms below it. If your loft has been converted, your roof is also the ceiling for your loft space and should be insulated either from the inside or from the outside.

Read more on how to make your home more energy-efficient.

Tip: While you are carrying out insulation work in your loft, take the opportunity to also install modern roof windows or replace any old ones up there. The latest roof windows will help to insulate your home even more effectively.

Would you like to find out when and how to replace your old roof windows?

Learn more about how to replace your roof windows here.

If your loft and floor is insulated, you may not need to insulate the ceilings between your floors, but it can be worth it if a room is experiencing a lot of heat loss and if you want to improve the soundproofing of a room.

If you want your ceiling insulation to also block out noise, opt for acoustic insulation. For this, you often need to lower the existing ceiling by adding a self-supporting ceiling and you insert your insulating material into the space between the new false ceiling and the original ceiling.

The thicker the layer of insulation the more effective it will be at reducing impact noise.

There are two main types of ceilings: flat ceilings and sloping ceilings, which are typically under the roof. Depending on the design of your home and the space available, you have a choice of two main methods of insulating your ceiling.

One way of insulating a ceiling is to add a false or suspended ceiling made of plaster, wood or panelling. Insulation is then inserted between the two ceilings.

Although this reduces your ceiling height slightly, it means you can use thicker insulation materials and achieve optimal thermal performance.

When space is limited, a stretch ceiling is a practical option that doesn’t reduce your ceiling height too much.

Here, you apply insulation to the existing ceiling, ideally using several thin layers of different materials. You then decorate to conceal the insulation.

This should give you effective acoustic and thermal insulation, but thin layers may not perform quite as well as thicker materials when it comes to reducing noise and heat loss.

Whichever method you choose, the effectiveness of your ceiling insulation depends largely on how well it’s installed. For the best results use a professional insulation installer.