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Don't Guess. Engineer Your Energy Future

Independent electrical design, specification, and consultancy for self-builders. We create the roadmap; our approved partners build it.

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Smart Hub

Solar PV

Generating 4.2kW
4.2kW

MVHR

Air Quality: Excellent
Active

EV Charger

Solar Divert Active
2.1kW

Heat Pump

COP 4.2 / 45°C
COP 4.2

Battery

Charging (98%)
98%

Grid

Export: 1.2kW
↑1.2kW
System Online
Net: -1.2kW (Exporting)

Real-Time Energy Orchestration

What you see above is not a static diagram. It represents the live automation logic we engineer into every Octopus Agile-optimised home — a 3-phase symphony of solar generation, battery storage, heat pump scheduling, and EV charging, all orchestrated to buy low, store smart, and export high. This is Active Engineering, not passive monitoring: every energy flow is visualised, every decision auditable, and every system commissioned to Flexitest Ltd commissioning standards.

Learn how we engineer this in our Technical Design Pack

The Design-First Model

Independent consultancy, not sales. Technical rigour, not guesswork.

01

The Design Pack

We conduct heat loss calculations, solar modelling, airflow rates and electrical specification to create a 'Construction-Ready' technical pack. Fixed fee. No upselling.

02

The Tender

We hand your detailed specification to our MCS-Certified Partner Network for a guaranteed fixed-price quote. You approve before any work starts.

03

The Build

Installation is carried out by MCS & Part P - certified specialists, with oversight from your design consultant. No variations. No surprises.

Impartial Advice Guaranteed

Design Services

Transparent Engineering. Fixed Fees. 0% Commission on Hardware.

Independent consultancy you can trust

Introductory Offer: Exclusive savings for new technical audits
LIMITED TIME LAUNCH OFFER

Feasibility Study

£495
£250

Desktop review & budget estimation

  • Desktop review from plans
  • Technology suitability (ASHP, PV, Battery)
  • Compliance feasibility (Part L & Future Homes)
  • 30-min video consultation with David Richards
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MOST POPULAR

Technical Design Pack

£1,495
£995

Complete specification for contractor tendering

  • Room-by-room heat loss calculations
  • PV array design & shading analysis
  • Single-line electrical schematic (3-Phase optimised)
  • DNO G99 application support
  • Part L compliance documentation
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FLEXITEST ENGINEERING STANDARD

Project Oversight

POA

Site visits & performance validation

  • On-site commissioning witness
  • System performance validation testing
  • Contractor technical queries & liaison
  • Full client handover training & documentation

Installation by our MCS-Certified Partner Network, including KeySpark Electrical (NAPIT, MCS, ECS & TrustMark Certified)

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Technical Capabilities

What's included in our design specifications

Solar & Storage Design

G99 compliant PV arrays with DC-coupled battery integration. DNO application management and export limitation design for 2026 mandatory compliance.

Heat Pump Electrical Spec

Electrical infrastructure design for ASHP/GSHP systems. Load profile analysis, COP optimisation, and buffer vessel control integration.

EV Charging Infrastructure

Load-balanced EVSE specification with dynamic current limiting. Integration with solar export and time-of-use tariff optimisation.

MVHR & Ventilation

Electrical specifications for mechanical ventilation systems. Silent operation validation and smart home integration for air quality control.

Smart Home Automation

Loxone and KNX system design specifications. Integrated control of lighting, heating, ventilation, and energy systems with predictive algorithms.

Integrated SAP & Part L Compliance

Full SAP calculation support and Building Regulations compliance documentation. Target emission rate achievement and evidence compilation.

Is Your Self-Build Ready for 2026?

Warm Homes Plan Compliance Verification

Mandatory Solar PV Installation

Minimum 1.5kWp per bedroom required for new builds from April 2026

Zero Carbon Heating System

Gas boiler ban in effect. Heat pump or equivalent low-carbon solution required

Smart Export Guarantee Registration

Export tariff integration for grid balancing and revenue generation

EV Ready Infrastructure

32A circuit provision for future EV charging capability

Building Regulations Part L Compliance

SAP calculation demonstrating target emission rate achievement

0% VAT Available

Eligible energy-saving installations qualify for zero-rated VAT

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Independent Consultancy
MCS Certified Designs & Partners
Integrated SAP & Part L Compliance Specialists
Impartial Advice Guaranteed
KNX Partner
Loxone Gold Partner
RECC Member
Independent Consultancy
MCS Certified Designs & Partners
Integrated SAP & Part L Compliance Specialists
Impartial Advice Guaranteed
KNX Partner
Loxone Gold Partner
RECC Member

The Self-Builder's Guide to the £15bn Warm Homes Plan

Independent analysis of the 2026 requirements. How to secure 0% VAT and avoid the £10,000 cost of mis-specification. We calculate loads precisely so you don't overpay for oversized hardware. Technical guide with heat loss methodology, schematic examples, and compliance checklists.

Instant PDF delivery. No spam. Technical content only.

About Integravolt

Integravolt is the energy consultancy division of Flexitest Ltd (Company No. 07344798), a UK-registered engineering firm founded by David Richards. With over 15 years of electrical engineering experience, Integravolt provides independent, fixed-fee energy design for self-builders and renovators across England and Wales.

All engineering work is carried out in accordance with BS 7671 (IET Wiring Regulations 18th Edition), BS EN 12831 (heat loss calculations), SAP 10.2 (Standard Assessment Procedure for energy rating), and Approved Document Part L (conservation of fuel and power). Integravolt is not an installer and does not earn commission on equipment sales, ensuring recommendations are based purely on technical merit.

Self-builders constructing a new dwelling can save up to 20% on qualifying energy technologies through 0% VAT under HMRC VAT Notice 708. Qualifying installations include solar PV, battery storage, air-source and ground-source heat pumps, EV charging infrastructure, and MVHR systems. On a typical energy package costing £50,000-£100,000, this represents a saving of £10,000-£20,000. Integravolt provides the engineering documentation to support your VAT reclaim.

The Part L solar requirement for 2026 mandates approximately 1.5 kWp of solar PV per bedroom for new dwellings under SAP 10.2. This means a 4-bedroom home typically requires a minimum 6 kWp system. Orientation penalties for non-south-facing arrays can increase this requirement by 15-25%. Integravolt calculates your precise requirement based on dwelling fabric performance, heating system COP, and roof orientation.