Advice worth reading

Is it time to replace your boiler, or just repair it?

There is a point where repairing stops making sense, and it is not purely about age. Here is how to work out which side of the line yours sits on.

Four questions settle it most of the time.

How old is it? Under eight years, repair it — it has plenty of life left. Over fifteen, you are on borrowed time and parts get scarce. Between the two it depends on the rest of the answers.

What is the repair costing? A rough rule: if a single repair costs more than a third of what a replacement would, and the boiler is over ten, replacement usually wins.

Is this the second time this year? One fault is bad luck. Three in eighteen months is a boiler telling you something, and the next fault is rarely the cheap one.

Is it a condensing boiler? If it was fitted before around 2005 it probably is not, which means it is throwing a meaningful chunk of your gas out of the flue. A modern condensing replacement recovers some of that every single month.

The one thing we would ask you not to do is pour repeated repairs into a boiler that is clearly finished. We will tell you when we think that is what is happening, even though the honest answer earns us less that day.

Why your radiators are cold, and which fix you actually need

Cold at the top and cold at the bottom mean completely different things. One is free to fix and one is not.

Cold at the top, warm at the bottom. Air trapped in the radiator. Bleed it with a radiator key until water comes out, top the system pressure back up to around 1.5 bar, and you are done. This costs nothing and needs no engineer.

Cold at the bottom, warm at the top. Sludge. Iron oxide has settled in the base of the radiator and water is no longer flowing through it. Bleeding will not touch it. You need the system flushed and a magnetic filter fitted.

One radiator cold, the rest fine. Usually a stuck thermostatic valve. Take the head off and press the pin in the middle — if it does not spring back, it has seized. Often freed with gentle persuasion, sometimes needs a new valve.

Radiators furthest from the boiler are cold. The system needs balancing. Water takes the path of least resistance, so nearby radiators hog the flow. Adjusting the lockshield valves evens it out. It is fiddly but it is not expensive.

Everything cold. Boiler, pump, diverter valve or controls. That one is a call-out.

Hard water in Surrey and what it does to your boiler

Most of Surrey sits on chalk. That has a quiet, cumulative cost that shows up on your gas bill long before it shows up as a fault.

Hard water carries dissolved calcium. Heat it and the calcium comes out of solution as limescale, which coats every surface the hot water touches.

Inside a combi boiler that matters more than people expect. The plate heat exchanger that produces your hot water has very narrow passages, and scale builds up in exactly those. Symptoms arrive in order: hot water that fluctuates between scalding and lukewarm, then a kettling noise from the boiler, then reduced flow, then a failed heat exchanger.

There are three sensible responses. A scale reducer on the incoming main is the cheapest and takes the edge off. A water softener removes the hardness properly, protects every appliance in the house and makes a noticeable difference to how everything feels. An annual service catches scaling before it becomes a failure.

In a genuinely hard water area, protecting the boiler usually pays for itself over the life of the unit — and it is considerably cheaper than a heat exchanger.

Air conditioning is a heat pump, and that changes the maths

People buy it for August. The interesting part is what it does for you in January.

An air conditioning unit does not create cold. It moves heat from inside to outside. Run the same machine in reverse and it moves heat from outside to inside — which is precisely what an air source heat pump does, because it is the same technology.

Why that matters: an electric heater turns one unit of electricity into one unit of heat, and it cannot do better because that is the ceiling. An air conditioning unit in heating mode delivers around three units of heat for one unit of electricity, because it is transporting warmth rather than generating it.

So for a room your central heating has never handled well — a loft conversion, a garden office, a conservatory, an extension at the end of a long pipe run — a single air conditioning unit gives you a room that is usable in a heatwave and cheap to keep warm in winter. Compared with extending the central heating, it is frequently the cheaper install as well.

That is the reason we brought cooling into a heating business. It is not a different trade. It is the same physics pointed the other way.

What a proper boiler service should include

Services vary enormously between companies. Here is what to expect, so you can tell whether you got one.

A real service takes roughly an hour. If somebody was in and out in fifteen minutes, you did not have one.

It should cover gas pressure and gas rate measured against the manufacturer's figures; flue gas analysis with an electronic analyser; inspection of the flue inside and out; the heat exchanger checked and cleaned; the burner and injectors; all seals and joints tested for soundness; safety devices operated; the expansion vessel pressure checked and re-charged; the condensate trap cleared; and the controls and system pressure set correctly.

You should come away with a written record of the actual readings, not just a sticker with a date on it. Those readings are the useful part — they show whether anything is drifting year on year, which is how you catch a fault while it is still cheap.

And book it in late summer or early autumn if you possibly can. From the first cold snap every heating engineer in Surrey is fully booked, and a fault found in September is a problem you can plan around rather than an emergency.