Renovating your home? Here’s how to make sure your home improvements are energy efficient
Many UK homeowners invest in home improvements to boost comfort and value – but if done without energy efficiency in mind, these upgrades could lead to higher energy bills.
This article highlights risks to watch out for across five common renovation areas – loft conversions, extensions, window replacements, kitchen/bathroom refits, and flooring upgrades – where poor planning or execution can increase heat loss, damp, or inefficiency, outlining key UK building regulations you need to consider (Parts L, F, and P) as well as tips for engaging with professionals to ensure your upgrades save energy, rather than waste it.
Renovate smarter: why energy efficiency matters
As fluctuating energy prices become one of the core motivations for UK homeowners considering home energy upgrades, making the right choices during home renovations is more important than ever. While upgrades like loft conversions or new windows promise comfort and value, they can backfire if energy performance is overlooked.
Home improvement spending in the UK has been increasing year-on-year, with homeowners investing in everything from kitchen refits to loft conversions. While these upgrades can boost comfort, functionality, and property value, many are carried out without considering energy efficiency – resulting in missed opportunities for lower energy bills.
In this blog, we explore the top five home improvement trends where poor planning or bad execution could cost you more over time. We also cover relevant UK building regulations, planning considerations, and how to ensure the professionals you hire are working in your best interest.
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1. Loft Conversions
Loft conversions are one of the most popular ways to add space and value to a home. But if insulation and airtightness are not properly handled, the new space can either leak heat rapidly, or trap moisture and cause condensation.
Risks to watch out for:
- Insufficient insulation in roof slopes or dormers
- Poor ventilation leading to mould or damp
- Heat loss from downlights or poor air sealing
Building regulations to be aware of:
- Part L of Building Regulations requires minimum U-values (thermal transmittance) for roof insulation.
- Part F addresses ventilation – often missed during conversions.
Engaging with professionals:
Choose an eco-friendly builder with experience in energy-efficient retrofits. Or if you already have a builder you know who is open to getting involved and learning about energy-efficient building methods alongside you, that’s great too. Ask for SAP calculations and insulation specifications.
2. Extensions and Open-Plan Living
Creating larger, open-plan spaces is trendy, but knocking down internal walls or building new extensions without addressing heat loss or distribution can destabilise your home’s thermal performance.
Risks to watch out for:
- Increased surface area and glazing = higher heat loss
- Radiators or underfloor heating may be insufficient for the new space
- Poor zoning leads to overheating or cold spots
Building regulations to be aware of:
- Part L again applies – you must demonstrate the energy efficiency of the whole dwelling, not just the new part.
- Extensions may fall under Permitted Development, but exceeding size limits or altering a listed building needs planning permission.
Engaging with professionals:
Ensure your designer or architect works with a retrofit coordinator or energy consultant to model heat loss and system needs.
If you get an Ecofurb Plan for your home, you will be assigned a retrofit coordinator who can work with your designer/architect to identify the best course of action for your home – and make sure any measures installed by our trusted installer network are compliant with the appropriate regulations.
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3. Window Replacements
New windows are a common energy upgrade, but ones which are incorrectly specified or installed can increase condensation, reduce natural ventilation, or create draughts if poorly sealed.
Risks to watch out for:
- Choosing aesthetics over thermal performance (e.g. metal frames with poor insulation)
- Overlooking ventilation needs if replacing old, leaky frames with airtight ones
Building regulations to be aware of:
- FENSA certification ensures compliance with Part L and Part F.
- Trickle vents are often required to comply with ventilation rules.
Engaging with professionals:
Ask your installer for U-values, a ventilation strategy, and guarantees. Check their FENSA or CERTASS accreditation.
4. Kitchen and Bathroom Refits
Refitting a kitchen or bathroom often involves removing plasterboard, insulation, or making layout changes. And many homeowners miss the opportunity to upgrade insulation or ventilation during the process.
Risks to watch out for:
- Cold bridging from uninsulated external walls
- Damp or mould due to insufficient extractor fans
Building regulations to be aware of:
- Part L applies if more than 25% of a thermal element (like an external wall) is replaced – you must upgrade insulation.
- Part F governs extractor fan requirements.
Engaging with professionals:
Ensure your installer or builder is up to date on building regulations. Get a ventilation and insulation check as part of the quote.
5. Flooring Upgrades
Installing new flooring – especially solid floors or upgrading to underfloor heating – is increasingly popular. But replacing suspended floors or sealing old floors without insulation underneath can increase heat loss.
Risks to watch out for:
- New hard flooring reducing thermal insulation
- Underfloor heating installed without proper subfloor insulation, leading to higher energy use
Building regulations to be aware of:
- Part L requires floor U-values to meet minimum standards if more than 25% of the floor is replaced.
- Electrical underfloor heating must meet Part P (electrical safety).
Engaging with professionals:
Ask for insulation specifications before installation. Check installer competence and qualifications.
Take your next step: get the right advice
Whether you’re improving your home for comfort, resale, or aesthetics, energy performance should be a top priority at every stage. Many building professionals focus on the visible results – but it’s the invisible details like thermal performance, running costs, or air quality that will impact your comfort and bills for years to come.
To ensure your home renovations are as energy-efficient as they can be:
✅ Hire professionals accredited with TrustMark or compliant with PAS 2035
✅ Ask for heat loss or energy modelling, especially for major changes
✅ Ensure all upgrades comply with Building Regulations Parts L and F (or P if electrical)
✅ Get documentation, guarantees, and evidence-based performance predictions
Done right, your home improvements can lower your bills, improve your comfort, and boost property value. Done wrong, they can lock in energy inefficiency for decades.
Ecofurb is here to support homeowners to make the right choices when it comes to home energy efficiency. To make sure your next home upgrade is a smart one:
👉 Use the Ecofurb Options tool to explore which measures might work for you
👉 Get a tailored Ecofurb Plan for clarity on achieving our your energy-efficient dream home