AC System Design & Consultation London

Bespoke Air Conditioning System Design and Consultation

London AC Pro offers professional air conditioning system design and consultation services for residential and commercial projects across all 32 London boroughs. Whether you are a homeowner planning a whole-house AC system, an architect designing a new development, a developer fitting out a commercial building, or a facilities manager upgrading an existing installation, our F-Gas certified and REFCOM Elite registered team (company reg 15526897) provides expert system design that ensures you get the right solution from the very start.

Proper AC system design is the foundation of a successful installation. An incorrectly designed system — whether undersized, oversized, poorly laid out or using the wrong equipment type — will underperform, consume excessive energy, create comfort issues and cost more to run and maintain throughout its lifespan. Our design service eliminates these risks by applying rigorous engineering principles, detailed calculations and extensive practical experience to every project. We work with all leading manufacturers including Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu and Toshiba, selecting the optimal equipment for each application without bias toward any single brand.

Our AC System Design Process

We follow a structured design process that has been refined over thousands of residential and commercial projects. Each stage builds on the last to produce a system specification that delivers optimal comfort, efficiency and reliability:

Stage 1: Initial Consultation and Brief

Every design project begins with a thorough understanding of your requirements. During the initial consultation, we discuss what rooms or areas need climate control, how the spaces are used and by whom, your priorities (comfort, efficiency, aesthetics, budget), any specific constraints (listed building, conservation area, lease restrictions), your timeline and budget expectations, and whether you have a preference for visible or concealed equipment. For commercial projects, we also discuss operational hours, occupancy patterns, internal heat gains from equipment and lighting, and any regulatory requirements specific to your sector.

Stage 2: Site Survey and Data Collection

Our engineer visits the property to carry out a detailed site survey, measuring room dimensions, ceiling heights, window sizes and orientations, wall constructions, insulation levels, and identifying potential equipment locations and pipework routes. For commercial buildings, we also assess existing building services, ceiling voids, electrical capacity, and access for installation and future maintenance. The quality of this data directly affects the accuracy of our design — which is why we invest significant time in getting it right.

Stage 3: Heat Load Calculations

The heat load calculation is the most critical technical element of AC system design. It determines exactly how much cooling (and heating) capacity each room or zone requires. Our calculations are carried out room-by-room and factor in:

• Solar gain — heat entering through windows, which varies dramatically based on orientation, window size, glazing type and any external shading
• Building fabric — heat transmission through walls, roof, floor and windows, which depends on insulation levels and construction type
• Internal gains — heat generated by occupants, lighting, computers, kitchen equipment and other internal sources
• Ventilation and infiltration — heat entering with fresh air and through air leakage around doors and windows
• Design conditions — the target indoor temperature and the external design temperature for your location (London design conditions are typically 32°C summer, -4°C winter)

We use professional heat load calculation software compliant with CIBSE guidelines to produce accurate results. Getting this right is essential — an undersized system will struggle to maintain comfort during peak conditions, while an oversized system will short-cycle (turning on and off too frequently), reducing efficiency, increasing wear and creating temperature fluctuations.

Stage 4: System Selection and Specification

With accurate heat load data, we select the appropriate system type and equipment for each zone. This involves choosing between system types (split, multi-split, VRF, ducted, cassette) based on the building characteristics and your requirements, selecting the right brand and model range from Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu or Toshiba, specifying indoor and outdoor unit models with the correct capacity, planning pipework routes and sizing, determining electrical requirements and distribution board capacity, and selecting controls (wired controllers, wireless remotes, Wi-Fi, BMS integration). We present our recommendations with clear reasoning, explaining why we have selected each component and how it meets your requirements.

Stage 5: Energy Modelling and Running Cost Estimates

We provide detailed energy modelling that estimates the annual running cost of the proposed system. This includes seasonal energy calculations based on typical London weather data, comparison of running costs between different system options where relevant, heat pump heating efficiency compared to existing heating methods, and projected energy savings for upgrade projects. For commercial projects, energy modelling is particularly important for demonstrating compliance with Part L of the Building Regulations and for building a business case for the investment.

Stage 6: Design Documentation

We produce comprehensive design documentation including equipment schedules with model numbers, capacities and specifications, layout drawings showing equipment positions, pipework routes and electrical requirements, a full heat load report, an energy model and running cost estimates, a compliance summary (Part L, F-Gas, TM44 where applicable), and a detailed quotation with itemised costs. This documentation gives you everything you need to make an informed decision and, if required, to obtain Building Control approval or landlord consent.

Residential AC System Design

Designing air conditioning for London homes requires a sensitive approach that balances performance with aesthetics and practicality. Our residential design expertise covers:

• Single-room cooling — selecting the right wall-mounted unit for a bedroom, living room or home office, positioned for optimal air distribution without draughts
• Multi-room systems — designing multi-split systems that serve several rooms from a single outdoor unit, minimising external equipment and maximising convenience
• Whole-house ducted systems — designing concealed ducted installations that deliver climate control throughout the home without any visible wall units, including ductwork routing through loft spaces, bulkheads or ceiling voids
• Period and listed properties — designing discrete installations that respect architectural heritage, with careful attention to pipework concealment and external unit positioning
• Loft conversions and extensions — integrating AC into building projects at the design stage, when it is easiest and most cost-effective to install
• New-build homes — working with architects and developers to incorporate AC into new-build designs, including provision for pipework routes and equipment positions

For homeowners, our design consultation is provided free of charge as part of the quotation process for a residential installation.

Commercial AC System Design

Commercial AC system design is a more complex discipline involving larger equipment, multiple zones, regulatory compliance and integration with other building services. Our commercial design capabilities include:

• VRF system design — designing multi-zone VRF/VRV systems from Daikin and Mitsubishi Electric for offices, hotels and mixed-use buildings, including heat recovery configurations that simultaneously heat and cool different zones
• Office fit-out design — specifying cassette, ducted or wall-mounted systems for office spaces of all sizes, from serviced offices to corporate headquarters
• Hospitality design — designing hotel bedroom fan coil systems, restaurant cooling, kitchen ventilation and conference room climate control
• Retail design — specifying high-capacity systems for retail environments with high foot traffic and large glazed frontages
• Server room design — designing precision cooling systems with redundancy and monitoring for IT environments, including N+1 configurations
• Healthcare design — specifying systems that meet healthcare air quality and temperature requirements

For larger commercial projects, we provide a formal design consultation service that can be engaged independently of the installation. This is particularly useful for architects, M&E consultants and developers who need AC design input at planning or tender stage. Contact us to discuss your commercial project requirements.

Building Regulations and Compliance

Our system designs are fully compliant with all relevant regulations:

• Part L (Conservation of Fuel and Power) — all commercial AC installations must meet Part L minimum efficiency standards. Our designs meet or exceed these requirements, and we provide the necessary documentation for Building Control notification.
• Part F (Ventilation) — where AC design interacts with building ventilation requirements, we ensure both systems work together effectively.
• F-Gas Regulations — our designs consider refrigerant charge limits, leak detection requirements and the ongoing shift toward lower-GWP refrigerants such as R32.
• TM44 — for commercial systems over 12 kW, we ensure the design facilitates future TM44 energy assessments and provides optimal energy performance.
• Planning and conservation — for properties in conservation areas or listed buildings, we design installations that minimise visual impact and can support planning applications where required.

Why Professional AC Design Matters

You might wonder why a formal design process is necessary when many companies simply visit, measure the room and recommend a unit. The difference lies in accuracy and long-term performance. A properly designed system delivers precise comfort without hot or cold spots, runs at optimal efficiency with the lowest possible energy costs, operates quietly because the correct capacity avoids the noise problems caused by undersized systems working at maximum output, lasts longer because it runs within its designed parameters rather than being constantly overloaded, and complies fully with all regulatory requirements. The cost of professional design is negligible compared to the long-term cost of a poorly designed installation — yet the difference in performance, efficiency and comfort is substantial.

Frequently Asked Questions About AC System Design

Do I need a professional design for a single-room AC installation?

For a straightforward single-room installation, a full formal design is not usually necessary — our engineer will carry out a heat load assessment as part of the free home survey. However, for multi-room systems, ducted installations or any commercial project, professional design is essential to ensure the system performs correctly and efficiently.

How much does AC system design cost?

For residential projects, our design service is included free of charge as part of the quotation process. For commercial projects, design fees depend on the scale and complexity of the project. Where we carry out both design and installation, design fees are typically absorbed into the project cost. For standalone design commissions (where we provide design only, without installation), fees are quoted based on the project scope. Contact us for a quote.

What information do you need to start the design process?

Ideally, we need floor plans (even rough sketches help), an understanding of how each room or zone is used, any constraints or preferences for equipment positioning, and your budget range. For commercial projects, additional information such as occupancy numbers, equipment heat gains and operational hours is helpful. If you do not have this information readily available, our site survey will capture everything we need.

Can you design a system for a building that is still under construction?

Absolutely. Working from architectural drawings and specifications, we can design and specify the AC system before construction is complete. This is the ideal scenario because it allows pipework routes, power supplies and equipment positions to be incorporated into the build, avoiding costly retrospective modifications. We regularly work with architects and developers on new-build residential and commercial projects.

How long does the design process take?

For a residential project, the design is typically completed within three to five working days of the site survey. Commercial projects vary depending on scale — a small office design might take a week, while a large multi-zone VRF design for a commercial building could take two to four weeks. We always agree timelines upfront and keep you informed of progress.

Do you work with architects and M&E consultants?

Yes. We regularly collaborate with architects, M&E consultants, interior designers, project managers and main contractors on both residential and commercial projects. We can provide design input from RIBA Stage 2 onwards and are happy to work within established project teams and design processes.

What brands do you specify in your designs?

We are brand-agnostic in our design approach, selecting the optimal equipment for each project from Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu and Toshiba. We do not receive preferential commissions from any manufacturer, so our recommendations are always based on technical merit, reliability, value and suitability for the specific application. Visit our brands page for detailed information on each manufacturer.

Can you redesign or upgrade an existing AC system?

Yes. If your current system is underperforming, inefficient or no longer meeting your needs, we can carry out a full design review and recommend upgrades, modifications or replacement. This might involve replacing ageing units with modern, more efficient models, adding zones to serve new areas, upgrading from split systems to VRF for a growing business, or re-routing ductwork to improve air distribution. Call us on 07301 010244 to discuss your project.