MEP design in London

The energy rules that shape the services

Approved Document L sets the fabric standards that decide how big the heating system needs to be. For a new dwelling the limiting U-values are 0.26 W/m²K for walls, 0.16 for roofs and 0.18 for floors. Extensions are held to tighter values on some elements, with 0.15 for the roof.

Heat pumps have a design condition written into the guidance: the maximum flow temperature is 55 degrees Celsius. Radiators, underfloor loops and the cylinder are sized to work at that figure, not at the higher temperatures a gas boiler allows.

Newer dwellings also have a renewable electricity target. The Approved Document L (2026) calculation assumes panels covering 40 per cent of ground floor area. The next editions of Approved Documents L and F take effect on 2027-03-24 (year, month, day), so a scheme starting after that date may be judged under them.

Ventilation, overheating and water

Airtight homes need planned ventilation. Approved Document F sets a whole-dwelling rate that depends on bedrooms: 19 l/s for one bedroom, 31 l/s for three, and 6 l/s more for each bedroom after five. A minimum of 0.3 l/s per square metre of floor also applies. The design picks fans and ducts to achieve those flows quietly.

Overheating is a separate duty, covered by Approved Document O, and it applies narrowly: new residential buildings only (dwellings, institutional and other residential). Extensions are not in scope, though good design still limits solar gain.

Water efficiency is set by regulation. The standard is 125, and 110 where the optional requirement is imposed. Taps, showers and cisterns are chosen from that budget. For the drainage side, see our plumbing and drainage drawings page.

Electrical and charging provisions

Approved Document S requires a charge point for new dwellings with parking, and defines it: a nominal output of at least 7 kW. The consumer unit, cable route and load assessment need to allow for it from day one.

That connects to the wider electrical design, which our electrical design drawings page covers in detail, and to the sheets that show everything in one place: our M&E drawings service.

What we produce and what it costs

A typical MEP package has a heating strategy and heat-loss summary, a ventilation layout with flow rates, power and lighting layouts, a water and drainage schematic, plant and cylinder locations, and the notes the installer needs to certify the work. Everything is drawn into the model, so builders see one coordinated set.

We do not publish a starting price, because a one-room extension and a whole-house retrofit are far apart in scope. We run a free constraints check, ask what systems you want, and give a fixed quote. If the design needs a specialist calculation beyond our scope, we say so and agree it with you before any work starts.

How the design runs alongside the drawings

Early decisions carry the most weight. Whether the house heats by gas or by heat pump, whether it has a basement plant room, and how many bathrooms stack above one another all change the layout. We list those choices at the start and cost them in plain terms, so the decision is yours and made on paper.

Services design starts when the layout is nearly settled and finishes before construction drawings. We take the architectural model, add systems in rough, and test them against the structure. A short list of conflicts comes back, which we resolve with the architectural design.

An independent check follows: a second technologist reviews the services set against the regulations, and a senior review signs it off. Then it joins the construction set, and our construction drawings page shows what that final package looks like.

MEP design by borough

Boroughs differ in what they ask for, from air quality zones to local energy policies. Our council pages list the local designations and decision statistics that affect a home project. Start with Camden's planning facts, or see all places under architectural drawings by area.