- August 29, 2025|
- Doors|
- sandymount_admin
Key points
- Composite doors installed by Sandymount & manufactured by Hallmark are 19% more thermally efficient than other doors, significantly reducing heat loss and energy costs
- Advanced materials including high-density foam cores and GRP skins provide superior insulation compared to traditional timber or uPVC doors
- Homeowners can expect lower heating bills year-round thanks to excellent thermal insulation properties that prevent air leakage
- Modern composite doors offer weather resistance, security and durability whilst maintaining an attractive appearance with minimal maintenance
- Sandymount’s Hallmark composite doors achieve incredibly low U-values and fantastic energy ratings, making them an excellent choice for energy-conscious homeowners
Rising energy costs have made home improvement projects focused on energy efficiency more important than ever. If you’re considering a new front door, composite doors offer exceptional thermal performance that can dramatically reduce your heating bills whilst improving your home’s comfort and looks.
Unlike traditional timber doors or uPVC doors, composite doors are engineered specifically to prevent heat loss through advanced insulation technology. With energy bills continuing to climb, investing in an energy-efficient front door is no longer just about comfort, it’s about long-term savings and reducing your carbon footprint.
What is a composite door made of?
Composite doors combine multiple materials to create a superior entry door that outperforms single-material alternatives. At Sandymount, our composite doors feature an innovative construction that includes:
- High-density CFC-free polyurethane foam core for exceptional thermal insulation
- Impact-resistant GRP (glass-reinforced plastic) skin for durability and weather resistance
- Rigid polymer subframe for structural integrity
- Steel-reinforced outer frame for added security
This multi-layer construction creates a door that’s significantly more energy-efficient than traditional options. The foam core acts as a thermal barrier, preventing heat transfer between your home’s interior and the outside environment. Meanwhile, the GRP skin provides a weatherproof seal that prevents air leakage, a common problem with older timber doors.
How can a composite door save me money on my energy bills?
The thermal efficiency of composite doors translates directly into cost savings on your energy bills. Independent testing shows that composite doors can reduce energy consumption substantially compared to other door types, as you’ll be less dependent on costly appliances.
Superior thermal performance
Our composite doors achieve incredibly low U-values, which measure how much heat passes through the door. The lower the U-value, the better the insulation. Sandymount’s composite doors are:
- 19% more thermally efficient than 48mm solid timber core composite doors
- 17% more thermally efficient than 44mm traditional timber panelled doors
This superior performance means less heat escapes during winter months, reducing the need for constant heating and lowering your energy costs.
Preventing air leakage
Air leakage around doors can account for significant heat loss in homes. Composite doors feature precision-engineered seals that create an airtight barrier when closed. This prevents cold draughts from entering your home and warm air from escaping, maintaining a comfortable temperature with less energy consumption.
Year-round energy savings
The thermal insulation properties of composite doors don’t just benefit you in winter. During summer months, they help prevent cool air from escaping, reducing the workload on air conditioning systems and keeping cooling costs down.
What are the other benefits of a composite door?
Beyond energy efficiency, composite doors offer numerous advantages that make them an excellent choice for homeowners seeking a comprehensive home improvement solution.
Weather resistance and durability
Composite materials are engineered to withstand Britain’s unpredictable weather conditions. The GRP skin resists warping, cracking and fading, whilst the foam core won’t deteriorate over time. This durability means your door will maintain its thermal performance and appearance for many years.
Security features
Security is paramount for any entry door. Our composite doors come equipped with:
- Multi-point locking systems
- High-quality hardware
- PAS24 certification capability
- Secured by Design accreditation potential
The rigid construction makes forced entry extremely difficult, providing peace of mind alongside energy savings.
Low maintenance requirements
Unlike timber doors that require regular painting or staining, composite doors need minimal upkeep. A simple clean with warm soapy water is sufficient to maintain their appearance, saving both time and money on maintenance costs.
Sound insulation
Composite doors provide weighted noise reduction of 31 decibels, creating a quieter, more peaceful home environment. This additional benefit makes them particularly valuable for properties on busy roads or in urban areas.
Composite doors from Sandymount
At Sandymount, we install premium composite doors from Hallmark, a leading UK manufacturer with over 30 years of British heritage. Our doors are fully customisable to match your property’s style and your personal preferences.
Design options
We offer extensive customisation options including:
- Over 135 door designs across traditional and modern styles
- Thousands of colour options including any RAL colour
- Dual-colour options for inside and outside finishes
- Various woodgrain effects for authentic timber appearance
- Decorative glazing options with numerous backing glass choices
Threshold and accessibility options
Understanding that every home is different, we provide various threshold options including low-threshold variants for mobility access. Additional features like sidelights, transom windows and flag options allow complete customisation of your entryway.
Frequently asked questions
How much can I save on energy bills with a composite door?
Savings depend on your current door and home insulation, but composite doors’ superior thermal efficiency can reduce heating costs by preventing heat loss and eliminating draughts, leading to noticeable reductions in energy consumption.
Are composite doors suitable for all property types?
Yes, our composite doors are perfect for both contemporary and traditional properties. With extensive design options and colour choices, we can create a door that complements any architectural style.
What warranty comes with Sandymount composite doors?
Our composite doors come with comprehensive material and manufacturing warranties. As a BSI 9001 registered company, Hallmark provides quality assurance, and we offer in-warranty repairs as part of our aftersales service.
Do composite doors require special maintenance?
No, composite doors are incredibly low maintenance. Unlike timber doors, they don’t require regular painting or treatment—just occasional cleaning with warm soapy water to maintain their appearance.
How long do composite doors last?
With proper installation and minimal maintenance, composite doors can last decades whilst maintaining their thermal performance, appearance and security features throughout their lifespan.
Who are Sandymount?
Sandymount Windows & Doors is a leading provider of quality home improvement products serving North Wiltshire, Oxfordshire, Gloucestershire and the Bristol area. With years of experience in the industry, we specialise in installing high-quality uPVC and aluminium windows, composite doors, French doors, bifold doors and other home improvement solutions.
Our commitment to excellence is backed by FENSA, BRFC and CHAS accreditations, ensuring all installations meet the highest standards. We complete all building and fitting work in-house, guaranteeing quality control and customer satisfaction throughout every project.
Visit our showroom at Unit 4, Sandpool Farm, Oaksey Rd, Cirencester, GL7 6EA, or contact us on 01793 230684 or windowsanddoors@sandymount.co.uk to discuss your composite door requirements and discover how we can help improve your home’s energy efficiency, security and appearance.
