If you are planning a fit-out, an extension or a plant replacement in the next couple of years, the rules you will be building to have already changed. In March 2026 the Government published the amendments that bring in the Future Homes and Buildings Standards, including a new edition of Approved Document L Volume 2 covering non-domestic buildings. Most of it comes into force on 24 March 2027, with some provisions for higher-risk buildings following in September 2027 and transitional arrangements in between.
That sounds comfortably far away. It is not. Commercial projects are specified twelve to eighteen months before anyone turns a spanner, which means the design decisions being signed off this autumn are the ones that will be judged against the new standard. At AKS Air Conditioning we have spent over 34 years working through successive revisions of Part L, and the pattern is always the same: the businesses that plan early spend less than the ones that react late.
What Actually Changed in March 2026
Two Approved Documents matter most for anyone responsible for heating, cooling or ventilation in a commercial building:
- Approved Document L (Conservation of fuel and power), Volume 2 — the 2026 edition replaces the 2021 edition for buildings other than dwellings. It tightens fabric performance, pushes hard towards low-carbon heating, and sets stricter limits on the energy used by building services.
- Approved Document F (Ventilation) — amended alongside Part L, because you cannot make a building more airtight without dealing with how fresh air gets into it.
The two are deliberately linked. Part L was historically treated as an energy exercise and Part F as a box ticked afterwards. That approach no longer survives contact with building control.
Part L Volume 2: What It Means for Your Plant
Low-carbon heating becomes the default
The direction of travel is unambiguous. New non-domestic buildings are expected to be served by low-carbon heating, which in practice means heat pumps for the overwhelming majority of offices, retail units, warehouses and hospitality venues. Gas-fired heating in a new commercial building is now the option that has to be justified, rather than the assumption.
For most businesses this is less painful than it sounds. Modern VRF and air source heat pump systems already do both jobs, heating in winter and cooling in summer from the same equipment — which is why we increasingly specify Daikin and Mitsubishi Electric systems for clients who had budgeted for separate heating and cooling plant.
Building services efficiency is under the microscope
The new edition sets tighter limits on specific fan power, minimum heat recovery efficiency, lighting efficacy and control strategy. Practically, that means the cheap approach — oversized fans, no heat recovery, timeclock-only controls — is heading towards non-compliance.
| Area | What to look at now |
|---|---|
| Heating source | Can the scheme be served by a heat pump, or is a gas boiler being specified out of habit? |
| Specific fan power | Are AHUs and fan coils sized properly, or oversized to cover a lazy design? |
| Heat recovery | Is recovery included on ventilation systems, and at what efficiency? |
| Controls | Zoning, occupancy sensing and setback — or a single timeclock for the whole floor? |
| Commissioning records | Are performance figures actually being evidenced, not just designed? |
Part F: Ventilation Is Now a Design Decision
As buildings get tighter, ventilation stops being something you can leave to opening windows. Part F sets out the fresh air rates a commercial space needs, and in an airtight, heavily insulated building the only reliable way to hit them is mechanical ventilation — ideally with heat recovery so you are not throwing away the heat you have just paid for.
This is where a lot of projects come unstuck. A contractor who only sells cooling will size the air conditioning correctly and leave fresh air provision to somebody else. The result is a compliant cooling system in a building that fails on ventilation. Cooling and fresh air need to be designed together — you can read more about our approach on our ventilation page.
The Deadline Sitting Behind All of This
If you rent out commercial space, there is a second timeline to plan around. In June 2026 the Government issued an interim response on minimum energy efficiency standards for the non-domestic private rented sector in England and Wales. The stated intention is that from 2031, privately rented commercial buildings over 1,000 square metres will need to reach EPC B where cost effective, with smaller properties required to hold at least an E. The previously proposed interim EPC C milestone for 2027 has been dropped, and a full government response is still to come.
Softer than the original plan — but the destination has not changed. For most landlords, heating and cooling plant is the single largest lever on an EPC rating. Replacing ageing equipment at the end of its natural life, rather than in a panic before a lease renewal, is considerably cheaper.
What to Do This Autumn
- Check where your projects sit against the transitional provisions. Schemes still on the drawing board in 2027 are the ones at risk.
- Get an honest condition report on existing plant. Anything over twelve years old is a replacement conversation, not a repair one.
- Ask your contractor to price a heat pump option alongside any gas proposal. If they cannot, that tells you something.
- Keep your compliance records straight. F-Gas logs, commissioning data and inspection reports all get asked for at exactly the wrong moment. Our compliance page sets out what you are responsible for as a system owner.
- Protect the systems you already have. A well-maintained system holds its efficiency; a neglected one quietly loses it. See our commercial maintenance options.
None of this requires panic. It requires the next specification you sign off to have been written with 2027 in mind rather than 2021.
Talk to Us Before You Specify
AKS Air Conditioning has been designing, installing and maintaining commercial heating, cooling and ventilation systems for over 34 years, from single offices to nationwide retail estates. As Daikin and Mitsubishi Electric partners we can specify equipment that meets the new standards and back it with extended manufacturer warranty cover.
Call us on 01704 833 755 or get in touch for a straight conversation about your building — whether that is a new scheme, a plant replacement, or a review of how your existing systems will stand up to what is coming.
This article is a general overview and is not legal or regulatory advice. Building regulations guidance and MEES policy are subject to change — check the current position with your building control body or professional adviser before making decisions.
