Upgrading Heating and Plumbing in an Older London Home: Boilers, Water Pressure and Pipework
By the Golbik GBS team · Blog
Older London homes often have heating and plumbing that has been patched and extended over many decades: a mix of pipe sizes, old radiators, a tank in the loft and a boiler past its best. Upgrading the system can make the house warmer, cheaper to run and far more reliable. This guide explains the main choices when planning plumbing and heating work in an older property.
Key takeaways
- The right heating system depends on the number of bathrooms, your water pressure and the space available.
- Combi boilers suit smaller homes with good mains flow; system boilers with a cylinder suit larger households.
- London has hard water, so scale protection for boilers and hot water systems is worth planning in.
- Homes built before around 1970 may still have lead water pipes, which are best replaced.
- Gas work must be done by a Gas Safe registered engineer and notified under Building Regulations.
Choosing a Heating System
| System | Best for | Things to consider |
|---|---|---|
| Combi boiler | Flats and smaller homes with one bathroom | Needs good mains pressure and flow; no cylinder |
| System boiler and unvented cylinder | Homes with two or more bathrooms | Needs space for a cylinder; strong showers |
| Heat pump | Well-insulated homes with space outside | Larger radiators or underfloor heating; check grant eligibility |
| Regular boiler with tanks | Existing gravity-fed systems | Often replaced with a sealed system during refurbishment |
Heat pumps are increasingly common, and government grants such as the Boiler Upgrade Scheme may be available. They work best in homes with good insulation and properly sized radiators, so they are often considered as part of a wider renovation.
Water Pressure and Flow
Low pressure is one of the most common complaints in older London homes. Before choosing a boiler or shower, it is worth measuring both the static pressure and the flow rate at the kitchen tap. Typical solutions include:
- Replacing an old, narrow or lead supply pipe with a larger modern pipe.
- Converting a gravity-fed system to a mains-pressure unvented cylinder.
- Fitting a pump to a gravity-fed shower where mains pressure is not an option.
- Rebalancing or replacing undersized internal pipework.
Hard Water and Scale
London’s water is hard, which means limescale builds up in boilers, cylinders, showers and taps. In hard water areas, Building Regulations guidance calls for scale protection on new combi boilers, and a scale reducer or water softener can extend the life of the whole system. It also keeps bathroom fittings and kitchen taps looking better for longer.
Old Pipework and Lead Pipes
Homes built before around 1970 may still have lead supply pipes, and many older houses have a mix of galvanised steel, copper and plastic pipework. Replacing old pipework during a renovation improves water quality and pressure and reduces the risk of leaks. Your water company is responsible for the pipe up to the boundary, and can advise on replacing their section at the same time.
Radiators and Underfloor Heating
Radiators
Correctly sized radiators with thermostatic valves in each room give better comfort and control. A system flush or power flush before fitting a new boiler removes sludge from older pipework.
Underfloor heating
Wet underfloor heating is ideal in a new extension, where the floor is built from scratch, and works well with heat pumps. In upper floors and loft conversions, low-profile systems are available.
Doing It at the Right Time
The best moment to renew heating and plumbing is during a full refurbishment, when floors are up and walls are open, and it is usually coordinated with the electrical work. All gas work must be carried out by a Gas Safe registered engineer.
We work on homes throughout London, including Clapham, Fulham, Chelsea, Hammersmith, Dulwich and Mitcham.
Frequently Asked Questions
Should I choose a combi or a system boiler?
A combi heats water on demand and saves space, which suits flats and smaller homes with one bathroom and good mains flow. A system boiler with an unvented cylinder stores hot water and suits homes with two or more bathrooms used at the same time.
Why is my water pressure low?
Common causes include old narrow or corroded pipework, a long or shared supply pipe, gravity-fed systems relying on a loft tank, or simply being on an upper floor. A plumber can measure pressure and flow to find the cause before recommending a pump, a new supply pipe or an unvented system.
How do I know if I have lead pipes?
Lead pipes are dull grey, soft and do not make a ringing sound when tapped, and are most likely in homes built before around 1970. Check where the supply pipe enters the house, usually under the kitchen sink. Lead pipes are best replaced, and your water company can advise on their part of the supply.
Can I have underfloor heating in an older house?
Yes. Wet underfloor heating works particularly well in new extensions where the floor is being laid from scratch. In existing rooms, low-profile systems can be fitted over existing floors or between joists.
Planning Plumbing or Heating Work?
Golbik GBS carries out plumbing, heating and hot water upgrades across London, from boilers and radiators to full system replacements. See our domestic plumbing services or contact us to arrange a survey.
Related Guides
- Full House Refurbishment in London: Stages, Permissions and Timeline
- Loft Conversion Types for London Homes
- Side-Return, Rear or Wraparound Extension?
- Planning a Kitchen Renovation in a London Home
- Bathroom Renovation in London: Wet Rooms, Waterproofing and Safety Zones
- Does Your London Home Need Rewiring?
- Party Wall Agreements in London: A Homeowner’s Guide
- Do You Need Planning Permission? Rules by London Borough
- Extending a 1930s Semi in Sutton, Wallington and Mitcham
- Consumer Unit (Fuse Box) Upgrades Explained
- Renovating a Victorian Terrace in South West London
- How to Choose a Builder in London
