Central heating systems

Central heating design, installation and repair in Surrey

Designed versus installed

A heating system that has been designed heats every room to the same temperature at the same time, quietly, without any radiator needing to be nudged. A system that has merely been installed has a hot room near the boiler, a cold room at the far end, and a towel rail that has never worked properly.

The difference is a heat loss calculation. Room by room, we account for floor area, ceiling height, external wall count, glazing type and area, insulation, and what the room is used for. From that we size each radiator individually, size the boiler to the total, and plan pipework that can actually deliver the flow required.

Balancing, and why one radiator is always cold

Water takes the path of least resistance. Left to itself it races through the radiators nearest the boiler and barely reaches the ones furthest away. Balancing corrects this by restricting the easy circuits at the lockshield valve so flow is distributed correctly.

It is done by measuring the temperature drop across each radiator and adjusting until every one shows a similar drop. It takes time and it is skipped constantly. If one radiator in your house has never got properly hot, balancing is far more likely to be the answer than a new boiler.

Microbore and what it means for you

A great deal of Surrey housing from the 1970s and 1980s was built with microbore pipework — 8mm or 10mm copper feeding each radiator from a manifold. It was quick to install and it works, but the narrow bore silts up with magnetite far sooner than 15mm pipe, and once restricted the far radiators starve.

Fitting a bigger boiler onto a silted microbore system achieves nothing. Clearing the pipework, or replacing the worst runs, is what restores performance. We check for it before quoting, because it changes the job entirely.

Zoning and controls

Building Regulations require most new systems to be zoned, and there is good reason beyond compliance. Heating an entire house to the temperature the coldest room needs, all day, wastes a great deal of energy.

Zoning splits the property so upstairs and downstairs, or living and sleeping areas, run independently. Thermostatic radiator valves give room-by-room control within a zone. A smart thermostat adds scheduling, remote control and occupancy awareness. Weather compensation, where fitted, adjusts flow temperature against outside conditions so the boiler spends more of its life condensing.

For most homes the return on controls is better than the return on a more expensive boiler. That is not the advice that sells the biggest job, but it is the advice we would give a friend.

Radiators: type, size and position

Output depends on surface area and the temperature difference between the radiator and the room. A double panel with double convector fins puts out far more than a single panel of the same dimensions, which matters when space is limited.

Position matters too. The traditional place under a window counteracts the cold downdraught, and with modern glazing it is less critical, but a radiator hidden behind a sofa or boxed into a cover loses a substantial proportion of its output. Vertical designer radiators solve awkward walls but must be sized on their actual output figure, not on how large they look.

Underfloor heating

Underfloor heating has an enormous emitting surface, which means it works beautifully at low flow temperatures — exactly the condition a condensing boiler or a heat pump prefers. It gives even heat with no cold corners and frees every wall.

It is best fitted during a renovation or in an extension, where floor build-up height is being decided anyway. Retrofitting into an existing floor is possible with low-profile systems but is a considerably bigger job. Mixing underfloor downstairs with radiators upstairs is common and works well, provided the two are properly zoned with their own controls.

Power flushing and system treatment

Any system that has run for years without treatment will contain magnetite. Cold spots at the bottom of radiators, black water from a drain-off, a noisy pump or a boiler that kettles are all symptoms.

A powerflush uses a high-flow pump and chemicals to scour that debris out. Done properly it takes most of a day. Afterwards, inhibitor protects against further corrosion and a magnetic filter catches anything that forms. A flush without inhibitor and a filter simply resets the clock.