Behind every plastered wall sits a network of cables, pipes and vents that most homeowners only think about when something fails. In 2026, that network still commands a serious slice of any renovation budget: an EICR costs £150–£350, a consumer unit upgrade runs £400–£900, and a full rewire on a typical semi is £3,500–£10,000 before a single socket goes back on the wall.
This guide brings our electrics, heating, plumbing, ventilation and smart home library together in one place, organised by the job you’re actually trying to do — whether that’s adding an outdoor socket, choosing a towel radiator, or working out if a security light needs a Part P-registered electrician. Every section links through to a dedicated guide with full 2026 UK pricing and the regulations that apply.
Electrics & Safety
A consumer unit upgrade costs £400–£900 and is worth pairing with an EICR — £150–£350, renewed every 10 years (5 for rentals). Check cable types and sizes match the circuit before trusting old wiring, and learn the signs you need a rewire: a full one runs £3,500–£10,000. Powering a detached space means wiring a garage’s electrics with its own consumer unit, typically £800–£2,500.
Sockets, Switches & Lighting
Adding a socket to a room costs £80–£200 depending on cable run; an outdoor socket needs armoured cable and RCD protection at £180–£400; and USB or smart sockets swap in for £60–£100. Match dimmer switches to your bulbs — leading- vs trailing-edge — or expect flicker. Choose ceiling lights with fire-rated downlights wherever insulation sits above them, ideally following a proper home lighting design rather than one central pendant. LED strip lighting runs £3–£30/m for stairs and cabinets, and smart lighting adds app control from around £200 for a room.
Heating & Hot Water Controls
Radiator sizing follows a BTU-per-m³ rule and spans £30–£800+ per unit; modern radiator valves — TRVs are required under Part L — can cut bills by up to 40%. Weighing radiators against underfloor heating? Budget £150–£400 per room versus £60–£120/m² for wet UFH, plus £300–£900 for underfloor heating manifolds and zone controls. In the bathroom, a towel radiator needs 1,000–2,500 BTU and costs £60–£400, tied together with a smart room thermostat that typically repays its £100–£300 cost within two years.
Plumbing, Drainage & Ventilation
Soil and waste pipes run 110mm for the main stack and 32–50mm for branches under Part H, while guttering and downpipes cost £400–£900 in uPVC or up to £2,500 in cast iron. Indoors, bathroom ventilation and extractor rules set a minimum 15 l/s extract rate, and choosing the right extractor fan — humidity-sensing or basic — changes the £80–£150 installed cost. For whole-house airtight retrofits, MVHR ventilation costs £2,500–£6,000 but recovers up to 95% of the heat you’d otherwise lose.
Security, Smart Home & Networking
Upgrade to BS 3621 window and door locks for £150–£350 — the best-value single security fix — or add keyless convenience with a smart lock from £80–£400. Outside, home CCTV spans a £150 DIY kit to a £2,000 installed system, a video doorbell is £80–£300 wired or battery, and PIR security lighting needs Part P wiring at £100–£200. A monitored home alarm system costs £600–£1,500 plus £15–£40 a month and can trim insurance premiums by 5–15%, while valuables belong in a home safe rated to EN 1143-1. A smart home hub tying Zigbee or Matter devices together starts around £30–£120, and home network data points cost £80–£200 each — cheaper to run while walls are open. Outdoors, an electric fence for a garden boundary costs £300–£900 installed.
Costs & Day Rates
Electricians in this cluster typically charge £40–£80 an hour, with day rates scaling from there depending on region and whether the job is notifiable. The table below pulls together headline 2026 figures from across this guide, so you can see where a modest job sits against a major one.
| Job | Typical 2026 Cost |
|---|---|
| EICR (electrical safety check) | £150–£350 |
| Consumer unit upgrade | £400–£900 |
| Full house rewire | £3,500–£10,000 |
| Adding a socket | £80–£200 |
| Bathroom extractor fan, installed | £80–£150 |
| MVHR system, 3-bed house | £2,500–£6,000 |
| Wet underfloor heating | £60–£120/m² |
| Monitored alarm system | £600–£1,500 + £15–£40/month |
Most of these prices assume straightforward access and an existing circuit or supply to extend from. Long cable runs, solid floors, or a consumer unit that also needs upgrading will push any of them toward the top of the range.
[!tip] Book the EICR Before First Fix, Not After An EICR before any work starts is the cheapest way to find out whether your consumer unit, cabling or earthing needs upgrading. Finding out once walls are replastered costs far more in disruption than sorting it up front.
When You Need a Certified Trade vs DIY
Most new circuits, consumer unit work, and anything in a bathroom, kitchen or outdoors falls under Part P of the Building Regulations — it must be carried out or certified by a registered electrician and notified to Building Control. Gas appliances follow the same logic under a different regulator: only a Gas Safe registered engineer can legally work on a boiler, gas fire or gas pipework, full stop. Plumbing and drainage connections sit under Part H and are usually self-certified through a competent person scheme.
Genuinely low-risk DIY territory is narrower than people assume: replacing a like-for-like light fitting or socket on an existing circuit, fitting a TRV or smart thermostat head, or swapping a shower head. Anything involving a new circuit, a consumer unit, or a gas or drainage connection is a job for a certified trade — the cost of getting it wrong, from invalidated insurance to an unsellable house, dwarfs the saving.
Where to Start
If you don’t know where your home’s systems currently stand, start with an EICR — a £150–£350 report that flags anything unsafe before you spend on anything else. If it flags the fuse board, consumer unit types and upgrade costs explains what a compliant replacement involves, and if it flags the wiring itself, the signs you need a rewire will tell you whether you’re looking at a partial fix or a full £3,500–£10,000 rewire.
