Pre-heat versus CombiSmart

CombiSmart can be used with boilers with a pre-heat function (check comparability here) but in order to receive the maximum savings, you will need to turn off pre-heat or EcoMode.

What is Pre-heat?

If you’ve got a standard combi boiler, you’ll understand that when you turn on the tap, you need to wait patiently while the water heats up. The ‘pre-heat’ function does away with this wait, delivering hot water on demand and reducing water wastage. At first glance, pre-heat appears to be a good solution to reducing water wastage because it minimises the waiting time for hot water to reach the tap or shower, and therefore reduces wasting water and gas. However, there are significant disadvantages to pre-heat.

Pre-heat keeps a small reservoir of water within your boiler at a constant temperature at all times. It does this by firing up the combi boiler automatically (usually at hourly intervals) throughout the day and night. You may have wondered why your combi boiler is firing in the middle of the night when everyone is in bed. This is because the pre-heat function is keeping a reservoir of water within the boiler continuously hot.

Why choose CombiSmart over pre-heat?

While pre-heat saves water, it uses gas automatically when you don’t need it. With energy prices rising every year, this means that your boiler is burning gas when you’re at work, in bed or even on holiday, if you have the pre-heat function turned on.

Over the course of a year, we have made the following calculations:

Cost of pre-heat for one year (gas only) - £109.92

Cost of a pre-heat for one year (water only) - £8.93

Total cost to maintain pre-heat and provide hot water for one year- £117.52

With CombiSmart installed and pre-heat turned off this can save £33.74 in gas and £101.42 in water, which is £135.16 over a year.

Therefore the cost of CombiSmart will pay for itself and return additional savings in subsequent years, whereas pre-heat will continue to add costs to utility bills.

This means that buying and installing CombiSmart is a cheaper, more effective alternative to having the pre-heat function on your combi boiler turned on.

Alternatives to pre-heat

CombiSmart is the only solution to enjoying near instant hot water from a combi boiler that is friendly to both utility bills and the environment. CombiSmart is a thermostatic valve that heats the water almost instantly. It works by holding back the water and accelerating the heating process. You can save water and energy by only using gas to heat water when you actually need it.

With CombiSmart your boiler is saving energy on heating water as well as reducing water wastage. You no longer have to watch cold water disappearing down the drain, while your boiler heats it to the right temperature.

If you’re sold on the idea of CombiSmart then you’ll be pleased to learn that the installation is simple. Once CombiSmart is installed on your boiler, you’ll start to save water, energy and money, year after year. Even if you change boilers you can remove the CombiSmart thermostatic valve from your old boiler and simply re-install it to your new combination boiler and continue to save water.