Cutting heating bills in a hard-to-heat East Kilbride home

A new boiler will reduce your bills. But a new boiler on a badly set-up system will reduce them by far less than it could, and most of the difference comes down to three things that cost little or nothing to fix. It is the single most common thing we find in East Kilbride homes.

1. Your flow temperature is probably too high

This is the big one, and it is free. A condensing boiler only condenses — only achieves its headline efficiency — when the water returning from your radiators is cool enough for the flue gases to give up their latent heat. In practice that means a return temperature below about 55°C.

Most boilers are commissioned at a flow temperature of 75°C or higher because it makes the house heat up quickly and generates fewer callbacks. The cost is that the boiler spends much of the winter not condensing at all.

Turning the flow temperature down to around 60°C typically recovers several percent of efficiency. The house takes a little longer to come up to temperature, so it suits a household that heats steadily rather than in short bursts. Ask us to set it when we commission, or we will show you the control.

2. Your system is probably not balanced

Balancing means adjusting the flow through each radiator so they all heat at a similar rate. Without it, the radiators nearest the boiler take most of the flow and the far end of the house lags — so people compensate by turning the thermostat up, which heats the whole house harder to fix one cold room.

In a typical East Kilbride semi, the back bedroom is the usual casualty. Balancing costs nothing on a new installation because it should simply be part of the job. We do it on every system we install, and it is the most commonly skipped step in the trade.

3. Weather compensation is worth more than a smart app

A smart thermostat that lets you turn the heating on from your phone is convenient. It is not, by itself, an efficiency measure.

Weather compensation is. It uses an external sensor to vary the flow temperature according to the outside temperature — running cooler water on a mild day and hotter only when it is genuinely cold. Because it keeps the boiler condensing for far more of the season, it does real work on your bills rather than simply making the controls nicer.

Most modern Worcester Bosch and Ideal units support it, and the sensor is inexpensive. If you are having a boiler installed, it is worth asking for.

What matters less than people think

Turning the heating off completely while you are out rarely saves what people expect in a poorly insulated house, because the fabric cools and has to be reheated from cold. A steady lower temperature usually beats short hot bursts in solid-wall and no-fines properties — which describes a good deal of the older East Kilbride stock.

Equally, a bigger boiler will not heat your house more cheaply. It will short-cycle, wear faster and spend less time condensing.

The order to do things in an East Kilbride home

• Turn the flow temperature down to around 60°C — free, do it today
• Get the system balanced — free with a new install, inexpensive otherwise
• Add weather compensation — modest cost, real ongoing saving
• Then, and only then, consider whether the boiler itself is the limiting factor

If your boiler is over twelve years old the unit may well be the constraint. But it is worth doing the first three regardless, because they apply to the new boiler too.