Just need the figures? The building regulations reference has the Part L U-values and dates, Part O tables, Part G factors, Part E limits, SAP carbon factors and the regs calendar on one page, dated and sourced.
- Asked for a water efficiency certificate? Here is what actually exists
What a Part G water efficiency certificate really is, what the document must show, and how to produce one free.
- 125 litres per person per day, explained
How the 125 l/p/d water calculation works, and which standard applies to your site.
- The 110 litres per person per day planning condition
The tighter optional water standard many councils require, and how to meet it.
- Asked for a condensation risk analysis? Here is what it has to show
What a condensation risk analysis for building control is, when it is asked for, what it must show, and how to check a build-up free.
- Asked for a soakaway test and design? Here is what building control needs
What building control needs for a soakaway: the Part H rules on where it goes, the percolation test, the BRE 365 sizing, the report, and how to do it free.
- Asked for heat loss calculations for your extension? Here is what they mean
What building control means by heat loss calculations for an over-glazed extension: the two routes, what the document shows, what it costs, and a free check.
- Planning application stuck on nutrient neutrality? Here is what the council needs
Why nutrient neutrality holds up planning permission, what the council needs from you and when, how credits are secured, and what the new levy changes.
- What is Thermal Bridging?
Why junctions leak heat, what Ψ-values are, and how calculated values improve your SAP result.
- New build compliance: what you need at each stage
Planning to completion certificate in order: every energy, water, overheating and testing requirement for a new home, and when each one is due.
- What is a psi value?
The Ψ-value in plain English: units, typical values per junction, SAP's default and notional figures, and how one is calculated.
- Why two U-value calculators give different answers for the same wall
The five real causes of a differing U-value, and how to check which calculator is right.
- Building Regulations Part L Explained
What Part L requires for new dwellings, extensions and conversions — which edition applies, and what changes in 2027.
- Part L photographic evidence: what to photograph, and when
The 13 details every new dwelling needs photographing under Part L 2021, when to catch each one on site, and a free printable plot checklist.
- Building Regulations Part O explained
What Part O requires of new homes: the simplified method's glazing and free-area limits, when TM59 modelling is needed, and the noise rule that decides it.
- What is PHPP (and when do you actually need it)?
What PHPP is, which planning policies require it for an energy statement, and how it differs from Passivhaus certification.
- SAP 10: What's New in Part L 2021?
The SAP 10 changes that matter: tighter notional dwelling, PV assumption, new carbon factors, thermal bridging.
- What is the Future Homes Standard?
The 2027 standard for new homes in full: mandatory solar PV, tighter U-values, heat pumps, SAP 10.3 vs HEM, costs and transitional dates.
- What is DER/TER?
The dwelling vs target CO₂ emission rates at the heart of every SAP pass or fail.
- What is Fabric Energy Efficiency (DFEE/TFEE)?
The kWh/m²/yr fabric target that ensures the building itself — not just its renewables — performs.
- What is a U-value?
The W/m²K measure of element heat loss, how it is calculated, and the Part L limits that apply to new builds, extensions and renovations.
- Accredited Construction Details (ACDs) and Recognised Construction Details (RCDs) explained
ACDs (retired), RCDs (current, masonry) and calculated psi values — what each is and which to use under SAP 10.
- What is the Energy Hierarchy?
The reduce-first principle behind Part L and most planning energy policies.
- Why is Fuel Choice Important in SAP?
How gas, electric, heat pump, LPG and oil choices change a SAP result.
- What is a Predicted Energy Assessment (PEA)?
The off-plan predecessor to the EPC, produced from design-stage SAP.
- Building regulations for an extension: the energy side, start to finish
The 25% opening allowance, the covered-openings credit, the Table 4.2 U-values every new element must meet, and the three routes when the glazing goes over.
- Building regulations when you renovate: the upgrades you may not expect
The 50% renovation trigger, the Table 4.3 thresholds and improved values, the 15-year payback escape, and how replacements, conversions and controlled fittings differ.
- Renewable Technologies: An Overview
The main low-carbon technologies compared, with their SAP impact.
- Solar PV (Photovoltaic Panels)
Electricity-generating panels: the workhorse of SAP passes and planning conditions.
- Heat Pumps: An Introduction
How heat pumps work and why they're the new-build heating default.
- ASHP — air source heat pumps explained
What ASHP means, how it works, real efficiency, grants, planning and noise rules, and how it scores in SAP.
- Ground Source Heat Pumps (GSHP)
The high-efficiency, high-cost heat pump: loops, boreholes and SAP performance.
- Solar Hot Water (Solar Thermal)
Solar thermal for hot water — and when PV + diverter beats it.
- MVHR (Mechanical Ventilation with Heat Recovery)
Whole-house ventilation that recovers heat — ideal for airtight new builds.
- WWHR (Waste Water Heat Recovery)
Shower drain heat recovery: small cost, easy SAP points, assumed in SAP 10's target.
- FGHR (Flue Gas Heat Recovery)
Recovering flue heat from gas boilers for extra hot-water efficiency.
- What is Weather Compensation?
Outdoor-sensing heating control that lowers flow temperatures and earns SAP credit.
- NHS Carbon Reduction Plans from April 2027: what suppliers need
The April 2027 NHS rules: which Carbon Reduction Plan your contract needs, what it must contain, how it's checked, and the dates.