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The Future Buildings Standard: what Part L 2026 changes for HVAC

Updated 23 October 2026 · SEO Dons Editorial

When do the new Part L rules apply in England?

From 24 March 2027, with a later date for higher-risk building work. The dates that matter for HVAC are:

DateWhat happens
15 June 2022The current 2021 edition of Approved Document L came into force; Volume 2 is the 2021 edition incorporating 2023 amendments
23 to 24 March 2026The Building Regulations etc. (Amendment) (England) Regulations 2026 (SI 2026/335) are made and laid before Parliament, and Approved Document L (2026) is published
8 September 2026Volumes 1 and 2 are revised to correct minor errors
24 March 2027The regulations and the 2026 Approved Documents take effect
24 September 2027The same changes take effect for higher-risk building work and work to existing higher-risk buildings
24 March 2028Last date to start work under the transitional rule below

Earlier versions of Approved Document L keep applying to buildings subject to previous standards. The transitional rule for ordinary non-higher-risk work has two tests:

  1. A building notice, initial notice or application for building control approval with full plans was given to the relevant authority for that building before 24 March 2027.
  2. The building work starts before 24 March 2028.

If both are true, the amendments do not apply to that building work. The regulations also revoke earlier transitional arrangements from 2013 and 2021, subject to some exceptions, and the guidance follows the same transitional arrangements as the law.

What changes in the law for HVAC?

Part L is reworded around two aims, saving energy and minimising greenhouse gas emissions. The new requirement L1(1) has two limbs that matter to HVAC:

LimbWhat it requires
L1(1)(a)(ii)Limiting heat gains and losses from pipes, ducts and vessels used for space heating, space cooling and hot water services
L1(1)(b)Fixed building services that are energy efficient to a reasonable standard, minimise greenhouse gas emissions, have effective controls, and are commissioned by testing and adjusting as necessary to ensure they use no more fuel and power than is reasonable in the circumstances

"Fixed building services" already covers any controls associated with fixed heating, air conditioning and mechanical ventilation systems, so controls are in scope. The regulations add fixed lifts, escalators and moving footways in new buildings to the definition, and amend the commissioning regulation, regulation 44, to follow the renumbered L1(1)(b). The new requirement L3, for on-site renewable electricity, applies when a building that is or contains dwellings is erected, so it does not reach a stand-alone office or warehouse. GOV.UK describes the aim as new buildings with low carbon heating and high energy efficiency.

What does the 2026 guidance add for HVAC?

The 24 March 2026 circular lists the areas of new or updated guidance across the 2026 Approved Documents. The 2023 consultation shows what was proposed for non-domestic buildings; its Table 6.2 is a proposal, so check the final Volume 2 text before relying on it.

TopicCircular 01/20262023 consultation proposal for non-domestic buildings
Efficiencies and controlsMinimum building services efficiencies and controls, heat pump controls, and insulation for building heat distribution systemsHeat pumps not covered by ecodesign: minimum COP of 2.5; heat pump controls made consistent with Volume 1; a lighting efficacy increase
Distribution heat lossLimiting heat loss from low carbon heating systemsFor buildings not covered by CIBSE CP1, pipework insulation to the BS 5422 thicknesses for secondary systems of district heating systems
Commissioning and installationFollowing manufacturers' instructions for heat pumps, and the role of competent persons schemes for heat pump or mechanical ventilation installationNot listed in Table 6.2
Certification and enforcementRoutes for certifying fixed building services installations, and enforcement options where work falls shortNot listed in Table 6.2
Other areasAppendix G now cites TM39 Building Metering and Monitoring [2026] and BG 49/2024 Commissioning Air Systems [2024]Circulators and pumps, and BACS systems, among areas of updated guidance

The numeric limits sit in the tables of the Volume 2 PDF on GOV.UK, which runs to 116 pages. This page does not restate them, so that no figure is out of step with the published text. The consultation's non-domestic table listed only heat pump efficiency, heat pump controls and lighting efficacy, so do not assume new specific fan power limits for air handling units: read the Volume 2 tables. The consultation response itself was published on 24 March 2026 as a 145-page PDF.

Which HVAC work does it reach?

New buildings and building work on existing ones. Under the Building Regulations 2010, building work must comply with the applicable Schedule 1 requirements, building work includes the provision or extension of a controlled service, and a controlled service is one for which Part L, among others, imposes a requirement. Replacing or extending heating, cooling or ventilation plant can therefore bring Part L into play, and the consultation proposed that the heat pump efficiency standard would apply to existing non-domestic buildings as well as new ones. What a commissioning pack contains is covered in the commissioning and handover guide.

What stays the same, and what differs elsewhere?

  • Ventilation. The 24 March 2026 circular lists Approved Document F Volume 1 (Dwellings) only, so non-domestic ventilation guidance is not part of that package. The commercial ventilation requirements guide covers it.
  • Wales. The Welsh Government has issued its own approval of the 2026 Approved Document L. It takes effect on 4 March 2027, with work that begins before 3 March 2028 protected if notices or plans were in before that date.
  • Scotland. The Scottish Government publishes technical handbooks under the Building (Scotland) Regulations 2004. The handbooks for use from 6 April 2026 revised Sections 0, 2, 3 and 4.
  • Northern Ireland. Technical Booklet F2 gives guidance on regulations 39 to 47 for buildings other than dwellings.

What should specifiers and owners do now?

SituationStep
Notice or full plans in before 24 March 2027, work starting before 24 March 2028Keep dated evidence of both, because the amendments do not apply to that work
Application later, or work starting after 24 March 2028Design to the 2026 edition of Volume 2 now, so tenders carry the right efficiency, controls and commissioning requirements
Higher-risk building workUse the 24 September 2027 date. The circular says the regulations do not apply where a valid building control approval application reached the regulator before that date

Ask each designer to state which edition a scheme assumes. Plant selection and seasonal ratings are covered under commercial air conditioning and in the SEER guide. Readers who want a design or replacement assessed can send an enquiry through the site's form.

Sources

Common questions

Does the Future Buildings Standard apply to an existing office?

The regulations amend the Building Regulations 2010 for building work in England. Part L bites when work is done, such as providing or extending a controlled service, rather than on a building simply because it exists. The consultation proposed that the heat pump efficiency standard would also apply to existing non-domestic buildings.

Is the 2021 Approved Document L still in force?

Yes, until the 2026 changes take effect. The 2021 edition came into force on 15 June 2022, and GOV.UK says earlier versions continue to apply to buildings subject to previous regulatory standards. Check the transitional rule for any project in progress.

Does the standard ban gas boilers in new offices?

The consultation stated that, under the Future Buildings Standard, all heating and hot water demand should be met through low-carbon sources. That was a proposal. The circular describes the final aim as new buildings with low carbon heating and high energy efficiency, so read the Volume 2 text for the exact requirement.

Where do the efficiency numbers appear?

In the tables of Approved Document L Volume 2 (2026), a 116-page PDF on GOV.UK. It was revised on 8 September 2026 to correct minor errors, so use the current file. This page deliberately gives no limits, to avoid repeating a number that may have changed.

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