When it comes to keeping your home warm and your bills low, insulation is key. But not every property has the same type of walls – and if your home was built before the 1920s, it’s likely to have solid walls rather than cavity walls. Solid walls can lose up to twice as much heat as cavity walls, making insulation especially important.
So how do you know if your home could benefit from solid wall insulation? Here are four clear signs to look out for.
1. Your home feels cold and draughty, even with the heating on
One of the first clues is comfort – or rather, the lack of it. If you often feel chilly indoors, even with the heating running, poor wall insulation could be to blame.
Why this happens:
Solid walls don’t have the gap that cavity walls do. Without added insulation, heat escapes directly through the brick or stone. This makes rooms feel cooler and forces your boiler to work harder.
What you’ll notice:
- Rooms that never seem to warm up
- Uneven temperatures between different areas of the house
- Higher thermostat settings needed just to feel comfortable
If your home fits this description, solid wall insulation could make a dramatic difference to comfort levels.
2. Your energy bills are higher than they should be
Heating accounts for the majority of household energy use. If your bills are consistently high despite having an efficient boiler, your walls could be the weak spot.
The numbers:
According to the Energy Saving Trust, insulating solid walls could save homeowners £300–£500 a year depending on property size and energy use. That’s because less heat escapes, so your heating system doesn’t have to work overtime.
Clues to look for:
- Bills that seem out of proportion compared to similar homes
- A boiler that runs frequently or struggles to maintain temperature
- High winter costs even after bleeding radiators and checking boiler pressure
Solid wall insulation doesn’t just reduce bills – it also helps protect your boiler from unnecessary wear and tear.
3. You see condensation, damp, or mould on walls
Poorly insulated walls can create cold surfaces where moisture condenses. Over time, this can lead to damp patches, peeling paint, or mould growth – all of which are not just unsightly but also bad for your health.
Why insulation helps:
Adding internal or external insulation creates a barrier that keeps walls warmer. Warmer walls mean less condensation, which in turn helps prevent damp and mould.
Warning signs:
- Black mould around external-facing walls
- Damp smells or flaking wallpaper
- Condensation forming quickly in certain rooms
If you’ve ruled out leaks and ventilation issues, solid wall insulation could be the long-term solution.
4. Your property is older and built with solid walls
The clearest indicator is the construction of your home itself. Properties built before the 1920s were typically made with solid brick or stone walls rather than cavity walls.
How to check:
- Measure the thickness of your external walls. Solid walls are usually around 220mm thick, while cavity walls are at least 260mm.
- Look at the brick pattern. Solid walls often have an alternating brick pattern (headers and stretchers), while cavity walls show only stretchers.
If your home is a period property or built before World War II, it’s very likely to benefit from solid wall insulation.
How is solid wall insulation installed?
There are two main methods:
- Internal wall insulation – Insulation boards or stud walls are fitted inside the property. This reduces room size slightly but keeps the exterior unchanged.
- External wall insulation – Insulation is added to the outside of the house, then covered with render or cladding. This improves weatherproofing as well as efficiency.
Both methods can significantly reduce heat loss. The right option depends on your property type, budget, and preferences.
Grants and funding support
Solid wall insulation can be more expensive than cavity wall insulation, but help is available. Schemes such as ECO4 and the Boiler Upgrade Scheme can contribute towards insulation and efficiency upgrades. At NCS Plumbing & Heating, we can advise on what funding options may apply to your property.
The bottom line
If your home feels cold, your energy bills are high, damp is creeping in, or you own an older property with solid walls, insulation could be the answer. By investing in solid wall insulation, you’ll save money, reduce your carbon footprint, and enjoy a more comfortable home.
At NCS Plumbing & Heating, we don’t just install boilers – we help homeowners across Hertfordshire make their properties more energy efficient from the ground up. From grant support and heating system upgrades and insulation, our team is here to help.
Think your home could benefit from solid wall insulation?
Contact us today for a free, no-obligation quote and expert advice tailored to your home.
