Time to settle the argument – IT IS NOT more energy-efficient and cost-effective to leave heating on all the time. You should turn it on and off as needed.
There’s a commonly held opinion that it’s better and cheaper to leave the heating on all the time in cold weather because “it takes more energy to warm up a cold house than it does to keep it warm”. We can confirm, this is simply not true! It is better and cheaper to turn your heating on and off in a timely fashion when you need it, rather than paying to keep a house warm when there’s no one in it.
A house is not a car (obviously…)
We wonder if this myth stems from an analogy to driving, and how it is more efficient to maintain a steady speed in your car than to repeatedly speed up and slow down. While this is true for a car (accelerating consumes more fuel to overcome inertia and air resistance), it does not apply to heating a home because the physics are different. The biggest energy loss when driving is overcoming inertia during acceleration. A home does not need a massive burst of energy to overcome “thermal inertia”.
The science of heat loss
If you think of your heating system’s role as being to replace the heat constantly escaping to atmosphere through walls, windows, roof, and floor (rather than warming up the air) things make a bit more sense.
The speed at which your house loses heat is directly proportional to the difference between the inside temperature, the outside temperature, and how well insulated it is. This means the rate of heat loss drops when the temperature inside drops, so switching the heating off saves more energy overall than constantly running it to maintain a high temperature against the outside cold.
If you leave the heating on constantly, your system is constantly fighting to replace the extra heat lost due to a larger temperature difference between inside and out, (e.g., 15°C difference if it’s 5°C outside). The energy saved during the hours the house cools down far outweighs the brief, extra burst of energy required to reheat it later.
Insulation – the wisest energy efficiency investment
The most critical factor in managing your heating bill isn’t the latest boiler, internet-enabled smart thermostat, or even the latest heat pump; it’s the thermal envelope of your home. A well-insulated home will warm up quickly, and cost less to keep warm.
Investing in modern, high specification insulation for walls, roof, and floor, alongside high-quality double- or triple-glazing, is the most effective action you can take. This focus on minimising heat loss offers a superior return on investment (ROI) compared to any smart gadget or modulating boiler, guaranteeing a more comfortable, mildew-free home that simply requires less energy to heat.
The Charles Clarke & Son philosophy
When considering a new or upgraded heating system, we always recommend getting the fundamentals right first. Our goal is for warm, comfortable, energy-efficient buildings. For period properties and high-value homes, efficiency is achieved through intelligent construction and restoration, not quick fixes.
Get in touch today for a free consultation on how to permanently reduce your heat loss and make your home truly comfortable.
