A commercial refurbishment creates a window that most property owners and managers underuse.
When walls are open, systems are being replaced, and contractors are already on site — the cost of adding an energy upgrade is a fraction of what it would cost as a standalone project. The scaffolding is already there. The plant room is already accessible. The disruption has already been planned.
Doing it separately means paying twice: once for access and once for the work. Doing it during a refurbishment means paying once for both.
This guide explains exactly what to upgrade, in what order, and why — so your next commercial refurbishment delivers not just a better building, but a measurably more efficient one.
Why Right Now Matters: The MEES and EPC Picture in 2026
If you own or manage a commercial property in England or Wales, energy performance is no longer a nice-to-have. It is a legal and commercial obligation with tightening deadlines.
The current position:
For non-domestic (commercial) buildings, it is currently unlawful for landlords to grant or continue a lease on a property with an EPC rating of F or G unless a valid exemption is in place.
Where it is going:
The government has long signalled that these standards will tighten over time, moving towards much higher minimum EPC ratings for let commercial buildings. The EPC C (2028) and EPC B (2030) targets are widely expected to be confirmed. Retrofit projects for commercial buildings — particularly older offices — routinely take 12–18 months from assessment to completion.
In June 2026, the government confirmed an EPC B by 2031 deadline for large commercial buildings. Whether your building falls within scope depends on size and lease status — but the direction of travel is clear. Properties rated D or E today will not be legally lettable without significant investment.
The EPC framework itself is also changing:
From October 2026, new-style domestic EPCs will display four separate headline metrics: Fabric Performance, Heating System, Energy Cost, and Smart Readiness. The introduction of a standalone Fabric Performance metric is a significant policy shift — by decoupling fabric efficiency from heating costs, the new regime will expose properties that rely on low-carbon heating systems to mask poor insulation.
For commercial buildings, the single-metric system remains in place for now — but the fabric-first principle the new framework embeds is exactly the approach every commercial landlord should be taking in 2026, regardless.
The practical implication:
Landlords who delay until regulations are formally enacted risk being unable to let non-compliant space when the deadlines arrive.
A planned refurbishment removes that risk — if you plan the energy upgrades in from the start.
Step 1: Start with the Fabric — Always
The most important principle in commercial energy efficiency is fabric first.
Fabric first means improving the building’s envelope — its walls, roof, floors, and windows — before upgrading or replacing energy systems. The logic is straightforward: the best heating system in the world cannot compensate for a building that leaks heat through poorly insulated walls and a draughty roof.
Installing an efficient heat pump in a building with single-glazed windows and uninsulated walls is like running a bath with the plug out. The system works harder, uses more energy, and still delivers poor results. The building’s energy rating stays low. Your bills stay high.
A refurbishment is the moment to address this — because access to walls, ceilings, and structural elements that would be prohibitively disruptive to reach otherwise is already part of the project scope.
What Falls Under Building Fabric
Insulation:
- Wall insulation. For cavity walls, insulation can be injected relatively easily. For solid walls — common in older commercial stock — internal or external insulation can be installed during refurbishment without the disproportionate cost of a standalone project.
- Roof and loft insulation. One of the most impactful single measures. Heat rises. An uninsulated or poorly insulated commercial roof accounts for up to 25% of total heat loss in many older buildings.
- Floor insulation. Less commonly addressed but significant in buildings with suspended floors or ground-floor units.
Windows and glazing:
Replacing single-glazed or poor-quality double-glazed windows during a refurbishment — when scaffolding may already be in place and internal finishes have not yet been completed — is significantly cheaper than doing it later. Secondary glazing is an option for listed or heritage buildings where full replacement is constrained.
Air tightness:
Draughts are invisible energy waste. Improved air tightness through sealing around frames, penetrations, and junctions contributes meaningfully to energy performance and occupant comfort — and it costs very little when done during a fit-out.
Why the New EPC Framework Makes Fabric First Even More Important
For asset managers and landlords, the introduction of a standalone Fabric Performance metric reinforces the importance of a fabric-first retrofit strategy. Upgrades to insulation and glazing will now be directly visible on the certificate, rather than being buried within a composite score.
In practical terms: investing in fabric now means your building will score well not just under the current system, but under the reformed metrics arriving from October 2026 onwards.
Step 2: Upgrade the Heating System
After the fabric, the heating system is typically the largest contributor to a commercial building’s energy performance rating — and the largest single opportunity for improvement.
A refurbishment creates the ideal conditions for a heating upgrade because:
- Plant rooms are already being accessed for other works
- Pipework may already be exposed
- The building is already partially or fully vacated
- Installation can be sequenced without disrupting an occupied building
Options for Commercial Buildings in 2026
High-efficiency condensing boilers
If you are replacing a boiler, a modern high-efficiency condensing boiler is significantly better than systems installed ten or more years ago. Older boilers typically operate at 70–80% efficiency. Modern condensing boilers reach 92–95%. On a large commercial building with significant heating loads, that difference compounds quickly on energy bills.
As a Gas Safe registered contractor, Lime Construction Group installs, services, and replaces commercial boiler systems across Bristol and the South West. All gas work is completed by Gas Safe registered engineers — a legal requirement for any gas installation or repair in the UK.
Air source heat pumps (ASHP)
Heat pumps extract heat from outdoor air and deliver it to the building’s heating and hot water systems — running on electricity rather than gas. They are typically two to four times more energy efficient than a gas boiler on a unit-to-unit basis, depending on conditions.
Commercial heat pump installations are growing rapidly, driven by both energy savings and the direction of policy on fossil fuel heating. They work best when paired with good fabric performance — which is why fabric first is not just a principle but a practical prerequisite for heat pump efficiency.
Smart heating controls and thermostats
Even before a full system replacement, upgrading controls makes a measurable difference. Zone controls, programmable thermostats, and time scheduling ensure the system only heats the spaces that need heating, when they need it. In multi-room or multi-floor commercial buildings, poor zoning is one of the most common and most correctable sources of energy waste.
Step 3: Address Ventilation and Air Conditioning
Ventilation is frequently overlooked in commercial energy planning — but it is one of the bigger energy consumers in any occupied commercial building.
HVAC system age and efficiency
Many commercial buildings run on HVAC systems installed ten to twenty years ago. Efficiency ratings of older units can be significantly below current standards. A refurbishment is the right moment to assess whether the existing system is worth retaining, upgrading with controls, or replacing entirely.
Mechanical Ventilation with Heat Recovery (MVHR)
MVHR systems recover heat from extracted stale air and use it to pre-warm incoming fresh air — significantly reducing the heating load required to maintain comfortable temperatures. They are especially effective in well-insulated buildings, which is another reason fabric first matters.
Air conditioning efficiency
If air conditioning is part of the building’s system, ensure the units are correctly sized for the refurbished space. Oversized or undersized units both waste energy. A refurbishment that changes room layouts or removes partitions should trigger a reassessment of cooling loads.
Step 4: Switch to LED Lighting with Smart Controls
Lighting is one of the highest-return, lowest-risk energy upgrades a commercial building can make.
LED technology uses up to 80% less electricity than older fluorescent or incandescent fittings. The payback period on a well-planned LED upgrade in a commercial building is typically two to four years — after which the energy savings continue for the life of the installation.
During a refurbishment, the ceiling is likely already open or being worked on. New lighting circuits are being installed. This is the moment to specify LEDs, not fluorescents, as a standard decision — not an upgrade.
Smart Lighting Controls
Occupancy sensors, daylight-harvesting controls, and time-scheduling systems take the efficiency of LED lighting further. In office, retail, and hospitality settings, a significant proportion of lighting energy is used in areas that are unoccupied. Sensors that detect occupancy and dim or switch off automatically can reduce lighting energy consumption by 30–50% beyond the LED saving alone.
In social housing communal areas — corridors, stairwells, car parks — occupancy-controlled LED lighting is both an energy efficiency measure and a maintenance one, extending lamp life and reducing reactive call-out costs.
Step 5: Consider a Building Management System (BMS)
For larger commercial buildings — office blocks, hotels, multi-unit managed properties, educational buildings — a Building Management System brings heating, ventilation, lighting, and other building services under centralised control and monitoring.
A BMS allows facilities managers to:
- Monitor energy consumption in real time across the building
- Set automated schedules for heating and cooling zones
- Identify inefficiencies and faults before they escalate into costly breakdowns
- Demonstrate energy performance to tenants and compliance bodies
BMS installation is most cost-effective when building services are already being installed or upgraded — which is exactly what a refurbishment provides.
For smaller commercial properties, a smart thermostat system with data reporting capabilities delivers some of the same monitoring benefit at a lower cost threshold.
The M&E Opportunity: Why It Costs Less During a Refurbishment
The mechanical and electrical works already included in most commercial refurbishments — new wiring, upgraded distribution boards, pipework replacement, heating system works — overlap substantially with the infrastructure required for energy efficiency improvements.
If new electrical circuits are being installed, the incremental cost of specifying energy monitoring outputs is small. If pipework is being replaced, the cost of specifying it correctly for a heat pump system is far lower than retrofitting separately. If ceilings are being opened, the cost of installing LED fittings rather than fluorescents is minimal — sometimes less.
This overlap is the core financial argument for building energy efficiency into a refurbishment from the outset. Every measure added to a live project costs a fraction of what it would cost as a standalone project, because:
- Access is already arranged
- Disruption is already being managed
- The contractor and supply chain are already mobilised
- Scaffolding, hoardings, and protection are already in place
Waiting until after the refurbishment is complete means paying for all of that again.
What to Tell Your Contractor Before Work Starts
Most contractors will deliver what they are asked to deliver. If energy efficiency is not in the brief, it will not be in the project.
Here is what to raise before work starts.
1. Commission an EPC assessment before briefing the project. Find out your current rating, what is pulling it down, and what measures would move it. An EPC assessor will provide a recommendations report alongside the certificate — use it as your priority list.
2. Ask for a fabric-first review. Ask your contractor to identify opportunities to improve insulation, air tightness, and glazing as part of the scope. Wall cavities being opened for other works may present an insulation opportunity that would otherwise be missed.
3. Specify your heating intentions. If you are replacing or upgrading the heating system, clarify whether you want a like-for-like replacement or a more efficient alternative. A good contractor will give you options and costs — the decision should be yours, but the conversation needs to happen early.
4. Specify LED lighting as standard. Do not leave lighting specification to default. Confirm that all new lighting installations will use LED fittings with appropriate controls.
5. Ask about smart controls. Whether it is zone controls for heating, occupancy sensors for lighting, or a full BMS — ask what is available and what it costs within the project scope.
6. Request an energy performance outcome. Ask your contractor to advise on what the combined works are likely to do to your EPC rating. This should inform whether further measures are needed to reach your compliance target.
Are There Funding or Tax Relief Options?
There are some financial mechanisms worth investigating before committing your budget.
Enhanced Capital Allowances (ECAs)
The UK tax system allows businesses to claim capital allowances on energy-efficient plant and machinery. The Annual Investment Allowance (AIA) currently allows up to £1 million of qualifying expenditure to be deducted in full in the year of purchase. Energy-efficient heating systems, lighting, and building management systems may qualify. Always confirm with a qualified accountant.
The Warm Homes Plan and Business Energy schemes
While the Warm Homes Plan is primarily focused on domestic properties, some commercial energy support is available through local authority and energy supplier schemes. Bristol City Council, working through Bristol City Leap, has schemes supporting energy efficiency investment — worth investigating for Bristol-based properties.
Salix Finance
For public sector buildings — schools, local authority properties, NHS buildings — Salix Finance provides interest-free loans for energy efficiency improvements. Social housing providers working with Lime Construction Group on building fabric upgrades may be eligible.
Always verify eligibility with the relevant scheme before building it into a budget.
Practical Checklist: Energy Efficiency During Your Commercial Refurbishment
Use this before briefing your contractor.
- Current EPC rating is known — assessment commissioned if not
- EPC target identified (what rating do you need to reach for compliance?)
- Fabric opportunities assessed — insulation, windows, air tightness
- Heating system age and efficiency reviewed — replacement or retention decision made
- Smart heating controls specified — zone controls, thermostats, scheduling
- Ventilation system assessed — HVAC efficiency rating checked
- All new lighting specified as LED with appropriate controls
- Occupancy sensors specified for applicable areas
- BMS or smart monitoring discussed for larger properties
- M&E contractor briefed on energy efficiency requirements at project outset
- Funding options investigated — ECAs, local authority schemes, Salix (public sector)
- Post-refurbishment EPC assessment planned — to document the improvement
Frequently Asked Questions
What EPC rating does a commercial building need in 2026? Currently, commercial buildings in England and Wales must have an EPC rating of E or above to be legally let. The government has confirmed an EPC B by 2031 target for large commercial buildings, with EPC C by 2028 widely expected as an interim milestone. Properties rated D or E should be prioritising improvement now, given that retrofit projects typically take 12–18 months from assessment to completion.
What is the fabric first approach? Fabric first means improving the building’s thermal envelope — walls, roof, floors, and windows — before investing in new energy systems like heat pumps or solar panels. The principle is that no heating or renewable technology can work efficiently in a building that loses heat through poor insulation. Fabric improvements also score better under the reformed EPC framework coming in October 2026.
Is it cheaper to make energy upgrades during a refurbishment? Yes — significantly. When walls are open, scaffolding is in place, and contractors are already on site, the additional cost of adding insulation, upgrading controls, or specifying LED lighting is a fraction of what it would cost as a standalone project. The access cost is the biggest variable, and during a refurbishment that cost is already committed.
Do I need a Gas Safe engineer to replace a commercial boiler? Yes. Any gas installation, repair, or replacement in the UK must be carried out by a Gas Safe registered engineer. Lime Construction Group is Gas Safe registered. Work carried out by unregistered individuals is illegal and invalidates insurance.
What is NAPIT accreditation and why does it matter? NAPIT (National Association of Professional Inspectors and Testers) is a government-approved certification body for electrical and other building services. NAPIT-registered contractors have been independently assessed for competence and compliance. It is a requirement for certain types of electrical work and a strong indicator of quality for M&E contracting generally. Lime Construction Group holds NAPIT accreditation.
Should I upgrade to a heat pump during a commercial refurbishment? It depends on the building’s fabric performance, size, heating load, and current system age. Heat pumps work best in well-insulated buildings. If the refurbishment is addressing fabric at the same time, a heat pump installation makes strong financial and environmental sense. If the fabric remains poor, a high-efficiency condensing boiler may be the more appropriate interim solution while fabric upgrades are completed.
How much can I save on energy bills through a refurbishment upgrade? It depends heavily on the current state of the building. A building moving from EPC E to EPC C through combined fabric, heating, and lighting improvements might see energy bill reductions of 30–50%. A building with particularly poor fabric and an old inefficient boiler could see savings beyond that. Your EPC assessor and contractor should be able to model indicative savings based on your specific building.
What areas does Lime Construction Group serve? Lime Construction Group is based in Hanham, Bristol, and delivers build, refurbishment, facilities management, M&E, plumbing, and heating services across the South West within approximately a two-hour radius. Their M&E team holds Gas Safe registration and NAPIT accreditation. Their trusted client base includes Bristol City Council, Julian House, Hilton Bristol, Oval Properties, and Pinnacle Property Management.
Final Thoughts
Energy efficiency is not a separate project. It is a layer of intelligence applied to a project you are already doing.
The fabric is already being touched. The systems are already being accessed. The contractor is already on site. The disruption has already been planned. All of that represents paid-for access to the elements of your building that determine its energy performance.
Using that window well — briefing energy requirements early, specifying correctly, and sequencing upgrades with the refurbishment — costs a fraction of what standalone projects cost. And it produces a building that is cheaper to run, better rated, and more attractive to tenants and occupiers for years to come.
That is the real value of getting energy efficiency right during a commercial refurbishment. Not just compliance. Not just lower bills. A better building, built to last.